How to improve system?

krharley
krharley Solar Expert Posts: 34
newbie- pretty sure i'm in wrong section, sorry. i'm so confused. i'm off grid. i have bp solar panels at 180 watts, one 240 watts from a water heater replaced that i salvaged, and a 180 watt i got for cheap. i strung them all together in parallel . i have a Xantrex 1000 watt inverter, and a pro-star 30 charge controller - 12 volt battery bank of the fork lift heavy/big ones all wired in parallel as well. 1st battery plus tp inverter, then plus to plus all the way, and the minus from the last one to inverter. i have 6 of these batteries.

i also have 6 automotive type marine batteries on stand by with a morning star controller 10L and was wanting to take one panel the bigger one run a small mini frig. what is the best way to do that, can it be done. i'm super poor, live in Louisiana, very hot. currently in winter i do not need to run generator. i have plenty power, very happy with that. but summer, i'm hurting- no a/c. i have a freezer on a timer, and fans, run gen for 4 hrs for a/c after work, then switch to ceiling fans/and other fans to sleep thru night, i'm in yellow zone by morning and have to wait to 10-12 to put freezer back on with blinking green light while i'm at work- can u give me a diagram visual as to what is best for this situation.

Should i get more panels or more batteries? help
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Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: How to improve system?

    Welcome to the forum.

    I'm putting this in its own thread to avoid confusion with the other.

    There's some vital numbers you need to get in order to figure out what to do. The first of these would be Watt hours consumption of your loads. The second would be the Amp hour capacity of the six batteries. Then we compare this to the total panel capacity. I'm a bit unclear on how many of those you have too. Seems like two 180's and one 240. It is unlikely any of these are "12 Volt" panels, so you may be wasting half of their power potential (the 180's are probably Vmp 35 and the 240 is most likely around 30).

    What you're trying to achieve is: enough battery capacity in Watt hours to meet the load demands and enough solar panel to recharge said battery.

    It sounds as though you have lots of battery, albeit probably not in the best configuration. Six in parallel @ 12 Volts is asking for trouble. The "diagonal wiring" really doesn't work well past two. After that you're at the bus bar stage.

    If your panels total 600 Watts and you could make good use of all of it you would need more than a 30 Amp charge controller to handle the power. What you are likely getting is 5 Amps from each of the 180's and 8 from the 240: 18 Amps total. That is not going to charge much battery.

    In short you have more than one problem here. The main one seems to be a lack of charging capacity, but the wiring problems should not be overlooked either. At first glance I'd say the biggest improvement you could make is probably changing the inverter for a 24 Volt model and increasing the system Voltage. That may sound odd, but it would be more efficient. The charge controller can handle 30 Amps on either system Voltage, and that works out like this:

    30 * 12 = 360 Watts of usable panel, 300 Amp hours of battery @ 12 Volts = 1800 Watt hours capacity

    30 * 24 = 720 Watts of usable panel, 300 Amp hours of battery @ 24 Volts = 3600 Watt hours capacity

    Since the panels are likely "24 Volt" and you have enough batteries to get 24 Volts changing would only require rewiring, new inverter, and possibly more panels.

    In any case you should check each and every one of those batteries (disconnect from everything, measure resting Voltage and specific gravity if possible) and see which ones can be charged up to "good" and which should be scrapped.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: How to improve system?

    In general, the first place to start is to measure your loads and battery performance.

    A Kill-a-Watt type meter (should be able to find one at your local big box hardware store) and a hydrometer to measure your specific gravity. I would also suggest a DC Current Clamp DMM too--Good for debugging your system.

    A Battery Monitor would also be nice, but if you use your volt meter and understand what it is telling you -- the Battery Monitor is something to get when you have more money.

    You are probably pretty lucky if your Freezer starts off a 1,000 watt AC inverter--Especially if there are some other loads too (is this a chest freezer, no defrost?). Usually a 1,200 to 1,500+ watt inverter is needed.

    The battery wiring should be double checked to make sure your batteries are connected in a way so that they share current better. Also wiring (length and wire gauge is going to be important too... Batteries are very sensitive to voltage and too much voltage drop (say between charge controller and battery bank) will reduce the performance (slower to charge, wasted energy, etc.).

    Next, can you let us know more about your solar panels? For a PWM charge controller, the solar panels should be around Vmp~17.5 to 18.6 volts or so. It would not be unusual for the larger wattage solar panels to have Vmp~30 volts or higher. Unfortunately, the way everything works, with a PWM controller a large percentage of the solar panel's output wattage of a "higher" voltage panel is wasted with a PMW type charge controller (what you have).

    Ideally, panels should match Vmp and use a MPPT charge controller for higher wattage panels. Big panels are usually cheaper on a $$$/Watt basis, but MPPT charge controllers are 3-5x more expensive. It is a tough problem to build an inexpensive system with random parts.

    So--Can you tell us exactly:
    • Batteries: Amp*Hour Capacity and type (i.e., 100 AH @ 12 volts marine; 300 AH @ 12 volt fork lift, etc.)
    • Solar panels (#1 is a 240 Watt Vmp=30.1 volts and 8.0 amps; #2 is...).

    Without knowing the details, we don't know that everything is working OK or not. And what you should do next.

    Adding panels can be a help, but if the batteries are not sharing current properly (bad connection, bad cell, etc.), the extra panels are not going to help.

    And if you have a bad cell (shorted or open) it can damage the other connected batteries.

    With batteries, measuring their voltage and specific gravity and logging the data is a help (you are looking for differences, bad electrical connections, etc.). But parallel 12 volt batteries are difficult--You may need to disconnect the cables from them and measure the resting voltage of each one.

    Also helpful is understanding how much distilled water you have to add to the batteries. Normally, typical deep cycle batteries will require some water every 1-2 months. If you hardly ever add water, they may be under charged. If you have to add a lot of water every month (or more often), they probably are over charging.

    If you can get a DC Current Clamp Meter, you can measure the current flow through each parallel connected battery during heavy charging and discharging (DC Current Clamp meter is simply, zeroed, then clipped over one wire/cable and you read the value--Very safe and nothing needs to be disconnected). This will make managing your 12 volt battery bank with lots of paralleled batteries much, much, much, easier.

    This is going to be pretty frustrating for you. A mix of different solar panels and batteries makes for a difficult system to design and manage--And not much money to get better matched hardware.

    I would suggest you start reading about batteries:

    http://www.windsun.com/Batteries/Battery_FAQ.htm
    http://www.batteryfaq.org/
    http://batteryuniversity.com/

    More or less, you need to define your needs/loads, then design the battery bank. Then finally design the charging system to properly support your battery bank.

    Batteries are the "heart" of your system--If they are "happy", everything else will be fine. If the batteries are not properly managed, they will die an early (and expensive) death.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: How to improve system?

    Observation: battery monitors are only good if you are starting out with new batteries. Wiring one into a system full of old, unknown quantities will not provide you with much useful information. It would tell you about how many Amp hours are being used (if you can get the programming in the right ball park) but on the whole not worth the expense in my opinion. A hydrometer is a better investment.
  • krharley
    krharley Solar Expert Posts: 34
    Re: How to improve system?

    ok, let me give some back ground, i'm a 52 year old female who crashed when the market crashed. painter by trade, but dis-abled, but not enough for big brothers in any way, right. so i work about 4 hrs a day and struggle to do that. but i had enough money to purchase 1/2 acre of land, build a small shelter, and some solar gear because i had no funds for permints, did it in 2 weekends, so i'll never be able to receive electric as u can imagine. so i took some photos of my system and hope i can figure out how to attach them to this so as you can see what i'm dealing with. i have 2 sets of harbor freight panels which does take care of all my lighting with ease, LED lighting, outside i have mr. beans motion activation set of 3.
    panels on roof are BP brand 1st one the string is from the water heater i salvaged for cheap- its PMAX 225 watt, max fuse 20 amp, volts @PMAX is 29.1 current @ PMAX 7.7 amps, open circuit 36.6 volt ,short circuit current 8.3 amps. next is 3 BP's @ 130 watts, 17.4 volts. 8.09 amps, the last in line is BP 180 watts, 35.6 volts
    so i have 795 watts total right?
    my freezer is 5.0 cu. ft, 115 volt 1.69 amps/ start up amps 12 Amp, i have it set on a timmer from 10:00 am- 4:00, which is fine, usually don't have any problems till the clouds/rain comes into play, so i check weather every a.m. before leaving home.. i have ran out of juice in the beginning of this project and the inverter shut down, so the system works in relation to fire/trouble while away, which i'm grateful for. i don't watch tv much, i'm mostly on computer for all my needs. a small laptop and i have extra battery for it, so thats not an issue either.in the winter, hardly ever run out of juice, really only the freezer and computer running. i have a woodstove for heat, gas oven, and the ceiling fan i do use all the time. now in summer where i run into trouble. i have a 10,000 BTU a/c that i run on generator at night, then i need the fans after 9:00 pm to get me thru the night, so i'm on yellow in a.m but it takes 11/2- 2 hours to fill up so timer comes on at 10:00. i also have a sm a/c unit in window and would like to be able to run that for 2-3 hrs per day say from 12-3:00 which would help so much and i really wanted to purchase a mini fridge they have on sale for 139.00 at home depot with 2 doors, energy star. i collect rainwater for water supply, so the bildge pumps run on a float charger to a common auto battery for 4 years now- not a problem their. i have a camping propane water heater, tankless 104.00 that works great, so thats taken care of.
    i don't know if my batteries are connected up right, i don't know if my panels are connected up right either- i'm on my own now, so was delighted to find you guys the other day, because nobody knows what the hell i'm talking about when it comes to off grid- seems people know only about grid-tie. all of your help will be so welcomed, it is a different language and i do need to study all the info you have available, but it takes me a while to get it, got to read 3x and all.i'm gonna try to send photos now- i don't see h
  • krharley
    krharley Solar Expert Posts: 34
    Re: How to improve system?

    i also have the 10L morning star controler- but i thinkn thats only 10 amp, not sure. the marine batteries- 6 of them are sitting on float till i figure out what to do. the pro star /well batteries kick off freezer with no problem, it can be blinking green and not skip a beat, i'v also tried the 10,000 btu a/c and it runs it as well , just didn't test long enough to see. i was wanting to see if i could hook the morning star mppt to those batteries from either the big panel i got or from the same panels, can i do that? that's what i want to do real bad, but scared to. i'm off grid all the way. would like to run a sm a/c for 3 hrs a day - again i don't know if i can hook up from same solar panels cause that would be awsome for me. this weekend i will do some more reading from this site, i just found it and think its great. i'm just not that smart. i can't afford to make any more mistakes, i need to gather info and prices to see how long it will take me to save the money necessary to fix this if it needs fixing. want to eliminate generator. i can put everything on timmers as well. all my panels are wired with stranded 10 ga wire, and batteries with automotive cables. i have them all stringed together plus to plus- to minus. tried to up load photos, bt i'll have to work on that , spent hours trying today. i'll do that this weekend
    thanks alot you guys
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: How to improve system?

    Regarding how to add attachments/photos... When you reply to a post, click on "Go Advanced" button lower right of post (on rare occasions, a "reply" will sometimes load the advanced interface for me--so you will not have to do it again).

    Next, look below the edit window for "Manage Attachments:"

    You open that window and "upload" the documents you wish to add to your post. Then, drag from the "upper window" to the lower window and click "add-inline"--and they should appear in your post.

    There are other ways of doing this too (for some file types). Above the edit window there is something that looks like a box with four black corners and a "tree" (I think) in the middle. You click on that and you can upload from your computer.

    Note--Does not appear to work for all file types (should work for pictures--Just keep them "small"--forum software will now allow to upload HD Photos (you can "hot link" to photos from Flicker and Youtube videos). Also, I find I have to have a couple sentences typed in the post first... If I try to upload photos with a "blank post" it seems to balk at that.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: How to improve system?

    I am truly sorry for your present condition. It is a tough world out there right now.
    krharley wrote: »
    i have 2 sets of harbor freight panels which does take care of all my lighting with ease, LED lighting, outside i have mr. beans motion activation set of 3.

    Just keep an eye on those systems... 45 watts is an "optimistic" output for those panels--And it is unclear how long they will last (5+ years may be pretty good for panels and controller).
    panels on roof are BP brand 1st one the string is from the water heater i salvaged for cheap- its PMAX 225 watt, max fuse 20 amp, volts @PMAX is 29.1 current @ PMAX 7.7 amps, open circuit 36.6 volt ,short circuit current 8.3 amps. next is 3 BP's @ 130 watts, 17.4 volts. 8.09 amps, the last in line is BP 180 watts, 35.6 volts

    so i have 795 watts total right?

    This is tough... For PWM charge controllers, they have narrow input requirements for "efficient" charging of battery banks... For example:
    • 12 volt battery bank--Vmp ~17.5 to 18.6 volts STC rating
    • 24 volt battery bank--Vmp ~35 volts to 38 volts
    • 48 volt battery bank--Vmp ~70-76 volts

    The problem is that STC ratings, in the real world, panels run much hotter than "standard test conditions". In hot climates, the Vmp can derate by 80% (hot sun, high air temperatures, poor air circulation). So, the Vmp rated voltage should be as least the range above. If the Vmp is >> Vbatt-charging, then you have don't get all of the wattage from the panel. For example, if you put a Vmp~35 volts on a 12 volt battery bank, about 1/2 the wattage is "lost" do to miss-match between Vmp and Vbatt charging (PWM controllers are simply "on/off" switches--nothing "special" inside to down convert the solar array to battery charging voltage).

    So, if all of these panels are in parallel--Then the higher Vmp panels (~35 volts) are, effectively, only supplying ~1/2 of their available power to the 12 volt battery bank.

    You can get an MPPT (maximum power point tracking) charge controller which has a buck mode switching power supply inside--These can "efficiently" take high voltage/low current from the array and down convert to low voltage/high current needed for charging the battery bank.

    However--MPPT controller are not cheap, and they also require panel Vmp/Imp and their series/parallel connections to be properly matched and wired too. An eclectic mix of solar panels can be impossible to (efficiently mix/match) to properly supply even an MPPT charge controller...

    Sometimes it is better to sell the odd ball panels on Craig's list and use the money to get the "right ones". Not fun in either case.
    my freezer is 5.0 cu. ft, 115 volt 1.69 amps/ start up amps 12 Amp, i have it set on a timer from 10:00 am- 4:00, which is fine, usually don't have any problems till the clouds/rain comes into play, so i check weather every a.m. before leaving home..

    Knowing the kWH per day of your major AC loads would be helpful. I have heard that some libraries will check out Kill-a-Watt type meters if you cannot swing it right now.

    Only running the freezer when the sun is up does give you ~20% more power (no battery storage losses). But if you don't have enough solar panels, then you are pulling extra power from the batteries.
    i have ran out of juice in the beginning of this project and the inverter shut down, so the system works in relation to fire/trouble while away, which i'm grateful for. i don't watch tv much, i'm mostly on computer for all my needs. a small laptop and i have extra battery for it, so thats not an issue either.in the winter, hardly ever run out of juice, really only the freezer and computer running.

    Possible issue is that when an inverters "under-volts", the batteries have been taken to "near dead" (anything below ~11.5 volts). This can easily permanently damage the battery(ies).

    Deep cycling "all the time" or not getting the batteries back over 90% SOC a couple times a week can dramatically shorten battery life too...

    Read about batteries here:

    http://www.windsun.com/Batteries/Battery_FAQ.htm
    http://www.batteryfaq.org/
    http://batteryuniversity.com/
    i have a woodstove for heat, gas oven, and the ceiling fan i do use all the time. now in summer where i run into trouble. i have a 10,000 BTU a/c that i run on generator at night, then i need the fans after 9:00 pm to get me thru the night, so i'm on yellow in a.m but it takes 1 1/2- 2 hours to fill up so timer comes on at 10:00. i also have a sm a/c unit in window and would like to be able to run that for 2-3 hrs per day say from 12-3:00 which would help so much and i really wanted to purchase a mini fridge they have on sale for 139.00 at home depot with 2 doors, energy star. i collect rainwater for water supply, so the bilge pumps run on a float charger to a common auto battery for 4 years now- not a problem their. i have a camping propane water heater, tankless 104.00 that works great, so thats taken care of.

    Really need to get a Kill-a-Watt meter. And a hydrometer to measure your battery bank temperature corrected specific gravity. The charge controller LEDs are not very accurate for our needs.

    The Mini-Fridges can take almost as much kWH/day as a full sized Energy Star refrigerator. A converted Chest Freezer to refrigerator can be a more efficient solution (if you can live with top food access).

    If you are running short on solar panel power--You might be able to get an AC battery charger and help recharge the battery bank some when you are running the genset.
    i don't know if my batteries are connected up right, i don't know if my panels are connected up right either- i'm on my own now, so was delighted to find you guys the other day, because nobody knows what the hell i'm talking about when it comes to off grid- seems people know only about grid-tie. all of your help will be so welcomed, it is a different language and i do need to study all the info you have available, but it takes me a while to get it, got to read 3x and all.i'm gonna try to send photos now- i don't see h

    Poster "2manytoyz" has a personal website with lots of documentation on his small(er) off grid/emergency backup solar power system:

    http://2manytoyz.com/

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • krharley
    krharley Solar Expert Posts: 34
    Re: How to improve system?

    i can't get it to drag, its telling me its to big i think, so i'll work on that this weekend, but if i had an e-mail address, i could do it,
    anyway the batteries are 8D. the only info on them is date purchase, COM-8DP,D8,K10, 813jo61 052, 00155xow 9A3. that;s it so i'm clueless of amp hours and would like to know.
    i'll be studing your site, an c how much the amp clamp is today. this is what i got, all ideas welcome, should i take the big panel out, but another cc, another panel- i just don't know proper steps. i know i need freezer to keep food to survive, so that's most important, i have a canapy that's screened that was given to me because come august, i'm sleeping outside in it. the box i built to live in just stores hot air in louisiana, so its not that bad, usually tired and sleep till i hear the helicopters flying around which turn out to be mosquitos during the night, so lots of off come august, really want to send photos, but i got to go get my hours in at work, more like i'm paying to go to work, seems crazy i know but what are you going to do. i do need help in the right direction so bare with me.
    also i fear the 24 volts system just because i'm scared to cross those wires plus to minus- my mind has been brain washed for not ever doing that and am having trouble wrapping my mind around it. plus i would have to buy more parts i'm sure. i need to get you the photos and perhaps we could go from their. thanks so much- awsome site guys!! thumbs up!!
  • gww1
    gww1 Solar Expert Posts: 963 ✭✭
    Re: How to improve system?

    Krharley
    The picture thing. I have never been able to get any program on my computer to resize a picture. what I do is make it an attachment to an email, then I drag it from the email to my desktop, then I use this forums add picture and find the picture on my desktop, click on it to get it to the add picture spot and then it will add it to your post.
    Hope this helps
    gww
  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    Re: How to improve system?
    gww1 wrote: »
    Krharley
    The picture thing. I have never been able to get any program on my computer to resize a picture. what I do is make it an attachment to an email, then I drag it from the email to my desktop, then I use this forums add picture and find the picture on my desktop, click on it to get it to the add picture spot and then it will add it to your post.
    Hope this helps
    gww

    Paintbrush works good for that if I remember my Windows days correctly. On MAC iPhoto does just about anything you want.
  • gww1
    gww1 Solar Expert Posts: 963 ✭✭
    Re: How to improve system?

    Solar dave

    I have tried paint and I am not smart enough to make it work.
    Cheers
    gww
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: How to improve system?
    krharley wrote: »
    panels on roof are BP brand 1st one the string is from the water heater i salvaged for cheap- its PMAX 225 watt, max fuse 20 amp, volts @PMAX is 29.1 current @ PMAX 7.7 amps, open circuit 36.6 volt ,short circuit current 8.3 amps. next is 3 BP's @ 130 watts, 17.4 volts. 8.09 amps, the last in line is BP 180 watts, 35.6 volts
    so i have 795 watts total right?

    As I suspected your panels are not compatible with a 12 Volt system an PWM type controller. As such you do not have 795 Watts of panel.
    The 225 Watt is 29.1 Volts, meaning it will act like a (7.7 Imp * 17.5 typical Vmp) 135 Watt panel (current stays the same, Voltage is reduced to system level, power is lost).
    The three BP 130's are "12 Volt" panels and should supply 390 Watts.
    The BP 180 is a "true 24 Volt" panel and will suffer the same fate as the 225 Watts: (5 Imp * 17.5 Vmp) 88 Watts.

    So the panel Wattage adds up to 795, but functionally it will perform like 613 Watts. In total you should see about 35 Amps out of that, which a 30 Amp charge controller can't handle so the 'additional' 5 Amps will be lost.

    And 30 Amps of charge current would be fine for 300 Amp hours of battery. From your original description you have far more battery capacity than that. This means your system is in a state of chronic deficit charging, which will manifest itself as less and less capacity over time as the batteries sulphate.

    What to do:
    1). Test each battery separately for Voltage and specific gravity. Charge them individually either from the solar or a generator powered AC charger if you've got it. Retest. You're trying to find the best ones: those that charge up the best in terms of SG and holding Voltage at rest.

    2). Reduce the battery bank to something resembling 300 Amp hours. This will only supply about 1.5 kW hours, which may not be enough to handle your loads as a freezer alone may use up that much power in a day.

    3). Win the lottery. You aren't going to be able to make this system any better without spending some money, which like most of us you haven't got.

    4). Do not add batteries back to the bank. It will only make things worse again. Your only other option is to use that generator to recharge when it is running.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: How to improve system?
    krharley wrote: »
    i can't get it to drag, its telling me its to big i think, so i'll work on that this weekend, but if i had an e-mail address, i could do it,
    anyway the batteries are 8D. the only info on them is date purchase, COM-8DP,D8,K10, 813jo61 052, 00155xow 9A3. that;s it so i'm clueless of amp hours and would like to know.

    I am guessing it is an "Exide COM-8D-P" truck/large equipment starting battery.

    http://www.ecovantageenergy.com/catalog/items/item2577.htm

    Probably around 225-255 Amp hours at 12 volt. Roughly 2x larger than a typical 6 volt ~225 AH golf cart battery. Check prices next time with golf cart batteries.

    Starting Batteries are not (usually) deep cycle type batteries and will not last as long as a "cheap" deep cycle golf cart batteries (GG batteries should last 3-5+ years with reasonable maintenance).

    Since these are 12 volt batteries and you have (I think) a 12 volt system+AC inverter, etc... Then your system capacity would simply be the number of batteries times ~225 AH.
    i'll be studing your site, an c how much the amp clamp is today. this is what i got, all ideas welcome, should i take the big panel out, but another cc, another panel- i just don't know proper steps.

    You are going to be in for a quick education in electrical 101--If you don't have the experience, see if you can find somebody to work with you for an hour or two for some quick instruction. From another website, I saw this Boatowner's Illustrated Electrical Handbook recommended. If you can find a boat wiring book at the library--That would be a good start (solar on the DC side and boat wiring is virtually identical).

    The high Vmp panels--If you can sell it to somebody who needs that panel and you can buy a larger "12 volt" (i.e., vmp ~18 volt) solar panel with funds--probably do it. If you cannot buy a higher power lower voltage panel (funds, and large format 18 volt panels are getting rare)... Maybe stay with what you have for the moment (assuming everything is working).
    i know i need freezer to keep food to survive, so that's most important, i have a canopy that's screened that was given to me because come august, i'm sleeping outside in it. the box i built to live in just stores hot air in Louisiana, so its not that bad, usually tired and sleep till i hear the helicopters flying around which turn out to be mosquitos during the night, so lots of off come august, really want to send photos, but i got to go get my hours in at work, more like i'm paying to go to work, seems crazy i know but what are you going to do. i do need help in the right direction so bare with me.

    Food, work, and money--Understand the priorities. Again, if you can find somebody with boat or even car wiring experience--They can probably get you started.
    also i fear the 24 volts system just because i'm scared to cross those wires plus to minus- my mind has been brain washed for not ever doing that and am having trouble wrapping my mind around it. plus i would have to buy more parts i'm sure. i need to get you the photos and perhaps we could go from their. thanks so much- awsome site guys!! thumbs up!!

    If your loads remain low--You can probably stay with 12 volts for the time being... But realistically, when you get much over 1,200 watts (that is over a 100 amps at 12 vdc)--You are a good candidate to go higher voltage.

    24 volts is still pretty "touch safe" (you may get a small "bite" if your hands are wet. But all lead acid battery systems should be treated with great respect.

    An average sized battery bank (12, 24, or 48 volt) can easily output hundreds or even thousands of amps into a dead short. Rings and jewelery should be removed. Wrenches used to bolt up cables should be wrapped with electrical tape to prevent accidental short circuits.

    Lead Acid batteries create hydrogen gas when charging... Covering the top of a battery bank with an old towel to prevent sparks from causing an explosion (and spraying acid in your eyes/face/etc.) can make things safer.

    24 volts is not gong to be much different than 12 volt system (other than 1/2 the current to your AC inverter). And, yes, you would be forced into buying a new AC inverter and possible some charge controllers.

    This stuff is not cheap--And doing "paper designs" first to work out what you need and any issues first before you buy more parts can help save you money.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • krharley
    krharley Solar Expert Posts: 34
    Re: How to improve system?

    ok then, i'll take those 2 panels out of system and reduce battery size.
    after that with those 2 panels can i buy a cc and hook them up to the batteries i took out of the big bank? you see what i'm saying? can i make another array of those 2, if so what one should i get, charge controller if i wanted to stay at 12v, if not could i do it at 24 volts and what type of cc if that would work?
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: How to improve system?
    krharley wrote: »
    ok then, i'll take those 2 panels out of system and reduce battery size.

    If the system is working and you have no replacements at this time--Might as well as leave them in. You are getting 50% "power" from them and not hurting anything.
    after that with those 2 panels can i buy a cc and hook them up to the batteries i took out of the big bank? you see what i'm saying? can i make another array of those 2, if so what one should i get, charge controller if i wanted to stay at 12v,

    Yes, but you would (ideally) have to purchase a MPPT type charge controller. And you are looking at $250-$400+ for such a controller. If you get a large enough capacity MPPT charge controller, you could always add more "compatible" panels (there are rules/guidelines for how to series/parallel connect the panels together and have everything work well).
    if not could i do it at 24 volts and what type of cc if that would work?

    Yes, you can do this--And use a "cheaper" 24 volt PWM controller. The possible problem is that Vmp~36 volt panels (and large format/cheaper priced smaller Vmp~18 volt) panels are getting hard to find new.

    So--if you go with a new array and charge controller--You might hunt around on Craig's List and find somebody selling a group of compatible solar panels.

    This is a real issue with trying add/repair solar power systems. Panels "go away" in 18 months (next series of bigger/cheaper/better panels come out) and trying to work with the existing array becomes an issue.

    There are times when the choice comes down to ripping out the existing array and putting it on EBay/Craig's List or simply buying an array of new panels and a new PWM/MPPT charge controller and simply adding it to the existing battery bank (paralleling charge controllers can be done quite nicely--again, just have to understand "the rules" for doing this).

    It is like going into the fridge/shelves and trying to figure out what to make for dinner and will you have to go to the store for some ingredients, or make something else.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: How to improve system?

    I believe the controller the OP has can handle 24 Volts as well as 12. Hence my original suggestion of rewiring for 24 Volts.

    To do that you'd lose one of the BP 130 panels, but the 225 and 180 would come to "full power". Two of the 130's would be wired in series to work for 24 Volts. As such you'd have 260 Watts from them, plus the 180 Watt panel and the 225 Watt panel (which would contribute to Bulk but not Absorb as its Voltage is too low for that @ 29.1). Essentially a 665 Watt array: 50 Watts larger than what you have now, but with one less 130 Watt panel. If you could get another with similar specs to that they could be included as well.

    You'd get about 22 Amps from that array, but on a 24 Volt system. As such the battery bank would be reconfigured and you'd have 2.6 kW hours capacity maximum, a big improvement over what you can actually support now.

    It seems to me that this is the cheapest way to get the system efficiency up, as it involves mainly buying a new 24 Volt inverter and some rewiring (along with charging and evaluating batteries so you get a viable bank).

    Two tools you really must own would be a decent digital multimeter and a hydrometer.
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: How to improve system?

    krharley could you please add the specifics on each piece of equipment (number, make model , watts) you have to your signature line so we can refer to it , it will show at the bottom of each posting. Go to the top of your NAWS screen, on the right click, Settings, then from the choices on the left, Edit Signature...

    hth
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • krharley
    krharley Solar Expert Posts: 34
    Re: How to improve system?

    ok, that sounds great, and that's what i'm going to do, i own the multimeter, and a hydrometer , so what 24 volt inverter , do ya'll sell what i need? if so i would like to order. also is their any way i could get a wiring schmatic from you as to how to wire it all up, or is that asking too much?
    thank you for all your help.
    very tired, but i'll start studing all the info you have sent my way and i'll get started on it
  • krharley
    krharley Solar Expert Posts: 34
    Re: How to improve system?

    i certainly will starting saturday, have to go write it all down , my bag, was wondering why everybody was doing that, makes sense
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: How to improve system?

    Oh gee, another schematic request. (I'm gonna die of guilt here for all these drawings I haven't done.)

    Can't get too specific on the wiring without sorting out the batteries first. How they are connected is a big part of it (the heart of the system as Bill says) and we need to determine what ones will be kept and how much capacity they're supposed to have.

    As for inverters ... you're trying to run a freezer there, yes? Invariably that is a pretty big start load. It also would "prefer" pure sine rather than the so-called modified version. I don't know what you've got for AC wiring either: some inverters have built-in plug sockets, others are "hard wired" to a standard distribution system. Starting that freezer will probably take the power of a good 1kW inverter at least. Even though most of the time you won't need that much power. Something like this Samlex is probably the minimum you can get away with: http://www.solar-electric.com/sa1wa24vosiw.html

    If possible, go for a 2kW unit.
  • krharley
    krharley Solar Expert Posts: 34
    Re: How to improve system?

    ok, trying to absorb all the info i read this weekend, i'm getting a much clearer understanding now, have lots of work to do
  • krharley
    krharley Solar Expert Posts: 34
    Re: How to improve system?

    wiring question with the mixed panels- I'v been able to add a MPPT Morningstar 45A, and a powerbright 2300 24v to the system and stepped up to the 24volts. i wired the 2 BP's 12v minus to plus in middle, plus and minus on ends i put with the 2 24's parallel i think. i went plus to plus, minus to minus then connected to minus from 12v and plus to 12v, then to cc, would that be right?
  • krharley
    krharley Solar Expert Posts: 34
    Re: How to improve system?

    also have 2 HF kits wired together and ditched the cc that came with it. i placed a Morningstar 10L as it is used for 12v lighting only and a D8 battery. never comes off green light, just goes from blinking green to green, blinking/green. once i left the outside light on all day and even then was on green. real happy with that, now if i could get the rest of the system to do that i'll be in good shape.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: How to improve system?
    krharley wrote: »
    wiring question with the mixed panels- I'v been able to add a MPPT Morningstar 45A, and a powerbright 2300 24v to the system and stepped up to the 24volts. i wired the 2 BP's 12v minus to plus in middle, plus and minus on ends i put with the 2 24's parallel i think. i went plus to plus, minus to minus then connected to minus from 12v and plus to 12v, then to cc, would that be right?

    If it works out to something like this:

    (-)---12V---(+)(-)---12V---(+)
    (-)
    24V
    (+)
    (-)
    24V
    (+)

    Yes; you put the two 12 Volt panels in series to make a 24 Volt 'string' which will parallel to the 24 Volt panels.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: How to improve system?
    krharley wrote: »
    also have 2 HF kits wired together and ditched the cc that came with it. i placed a Morningstar 10L as it is used for 12v lighting only and a D8 battery. never comes off green light, just goes from blinking green to green, blinking/green. once i left the outside light on all day and even then was on green. real happy with that, now if i could get the rest of the system to do that i'll be in good shape.


    That is mainly due to the capacity of the 8D battery and the low power demand of the load. Basically you are keeping an automotive battery floating against a very small draw. It should last a long time if not asked to provide more.
  • krharley
    krharley Solar Expert Posts: 34
    Re: How to improve system?

    yes just like that. i'm good then. i was scared to go 24, but i see i have a little more with one less 130w panel. i wouldn't think so, but it is. not scarry at all, you were right. so now i can add panels as i go along. i really miss a refridgerator and if i could get up to their, i'll be real happy. i took for-ever to charge those batteries i had. again you were right, they were never charging up right, under charge all the time, i'm lucky was able to salvage the them at all. i got the 2 best sets. i can dump some if i need too, i'v just been switching between the 2 sets. now that i have a full charge on both sets, their doing much better.
    i know for me in the winter time, i hardly run the gen set, get good power, the colder it gets- but i'm in Louisiana, so cold is in the 30's for me, we rarely get in 20"s, so its like the panels really love that cold spot, i have to use genny for 2-3 days cloudy/rain stuff. a really surprising to me, was thinking my best power intake for summer with longer days.
    thanks for all the help, i needed direction.
  • krharley
    krharley Solar Expert Posts: 34
    Re: How to improve system?

    yes, i would like to achieve the same with the other system but with a fridgerator.
    on another note, now i got 24v comming in at some outlets that i had wired 2 12v truck fans, now at 24v those things sure spin nice now. i know their going too fast, but i sure like it. how short of a life span can i get out of these fans, or should i fix them in some way to go back to 12v?
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: How to improve system?
    krharley wrote: »
    yes, i would like to achieve the same with the other system but with a fridgerator.
    on another note, now i got 24v comming in at some outlets that i had wired 2 12v truck fans, now at 24v those things sure spin nice now. i know their going too fast, but i sure like it. how short of a life span can i get out of these fans, or should i fix them in some way to go back to 12v?

    Can you clarify that please?

    You have two 12 Volt fans but now you only have 24 Volts available to run them?

    If that is so you have some options:

    1). Replace the fans. Although 24 Volt ones may be hard to come by.
    2). Use DC to DC converter to reduce Voltage for the 12 Volt loads. Can be expensive. http://www.solar-electric.com/12to24or24to.html
    3). Add some resistance or regulation to the 12 Volt fan wiring to reduce Voltage. Wastes power.
    4). Construct separate 12 Volt system to run those loads. Expensive.
    5). Take your chances with battery imbalance by drawing off half the bank. One fan on each half would be best, providing they run consistently.
  • krharley
    krharley Solar Expert Posts: 34
    Re: How to improve system?

    i had a whole wall pre-wired for 120v at the 2' level, and 12v at 3' level. so i had like 6 outlets at 12v from old system, but i replaced the 12 volt inverter to 24 volts, so everything i had wired/plugged into the outlets that was 12v went 24 volts i guess. i know my fans are spinning real real fast, and my floursent lighting was blinking, un plugged the lights, liked the fans going that fast.checked voltage and i have 24, so their at least 4 years old, thinking i could run em till they quit. it puts out like it should have from the beginning to me, but thats me. how long do you think they would work if i keep them at 24v, a wild guess?
    i probably should change that back to 12 like you suggested, i wouldn't have thought to use one half of bank, good idea. i did like that lighting i had as well, its only stuff that is used after hours, the fans blows the sqitters away from ya when sleeping-their very loud here, and the little lite for when i wake up in middle of night, so it shouldn't draw them off much, they use 10 watts 0.08amps is what the sticker says. i'm gonna run the kill-o-watt tonight while still at 24v, then switch it back.those 2 wires we one the old load for the pro-star 30 for the 12v
    thanks
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: How to improve system?

    How long will a 12 Volt device last if run off a 24 Volt system? That will depend on its Voltage tolerance. The thing is that when charging the "24 Volts" is more like 30. Few 12 Volt items are going to take that for very long.

    I'm confused about you statement "i'm gonna run the kill-o-watt tonight while still at 24v". Going to run the K-A-W on what? Nothing that's 24 VDC as the meter is only for 120 VAC.