How many Batteries??

brbpab94brbpab94 Registered Users Posts: 14
Hello everyone

I just recieved a 45 watt solar kit from Harbor Frieght as a gift. I would like to know how many batteries should I buy and whats the highest watt inverter I should buy? I won't be useing it all the time and it will be used in the gaurage. I was hoping to use some power tools from time to time ,some christmas lights , and maybe a small freezer if the power goes out.
Any help please
Brian

Comments

  • brbpab94brbpab94 Registered Users Posts: 14
    Re: How many Batteries??

    am I asking too much? I saw a tread that someone used 1- 15 watt pannel to light there back yard ...That was awsome. Is that all you can do with that system? if so I should be able to do 3 times as much. do I need three times as much batteries,Three times as much wattage controller, three times wattage inverter?

    Please help
    Brian

    P.S.
    I have read some where that the controler that comes with the kit is junk so I'll have to buy a controller...Programable sounds Great!
  • BB.BB. Super Moderators, Administrators Posts: 29,702 admin
    Re: How many Batteries??

    We can help... But I am not at a computer for awhile today.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: How many Batteries??

    Hi Brian. Welcome to the form.
    BB will give a far better and more detailed answer, but until that answer comes - - a heads up. Don't expect to run a freezer. Fridges and freezers are actually heavy consumers of electricity and would require a substantially bigger system. You might expect to harvest less than 10 amp hours per day, and given inverter losses, you could probably run a 100 watt light bulb for somewhat less than one hour per sunny day. Or a 10 watt LED light for 10 hours, assuming the inverter inefficiencies don't drain the battery too low first. A 12 volt DC LED would eliminate the inverter. And don't talk batteries as in more than one. The battery must be recharged ASAP after use, and too big a battery, or too many for the panel wattage will take too long, sometimes days or weeks to recharge, assuming no loads, and by them sulfation will have set in, ruining the batteries. Also be aware that "deep discharge" lead-acid batteries should never be discharged below the 50% level, otherwise their life will be greatly shortened.
    That said, a small battery used with your panel, and some small lights will give you a small system that can be a great and wonderfully interesting learning tool. Something that may open up a whole new world in energy production and conservation. But I must caution you - this can become very addictive, and can lead to far bigger and very useful systems. I know. i got addicted a number of years ago! :D:D:D
  • brbpab94brbpab94 Registered Users Posts: 14
    Re: How many Batteries??
    Hi Brian. Welcome to the form.
    BB will give a far better and more detailed answer, but until that answer comes - - a heads up. Don't expect to run a freezer. Fridges and freezers are actually heavy consumers of electricity and would require a substantially bigger system. You might expect to harvest less than 10 amp hours per day, and given inverter losses, you could probably run a 100 watt light bulb for somewhat less than one hour per sunny day. Or a 10 watt LED light for 10 hours, assuming the inverter inefficiencies don't drain the battery too low first. A 12 volt DC LED would eliminate the inverter. And don't talk batteries as in more than one. The battery must be recharged ASAP after use, and too big a battery, or too many for the panel wattage will take too long, sometimes days or weeks to recharge, assuming no loads, and by them sulfation will have set in, ruining the batteries. Also be aware that "deep discharge" lead-acid batteries should never be discharged below the 50% level, otherwise their life will be greatly shortened.
    That said, a small battery used with your panel, and some small lights will give you a small system that can be a great and wonderfully interesting learning tool. Something that may open up a whole new world in energy production and conservation. But I must caution you - this can become very addictive, and can lead to far bigger and very useful systems. I know. i got addicted a number of years ago! :D:D:D

    If I can only run a couple of lights for a few hours a day with a system that big then how come when I buy solar garden lights with one or two little batteries and a tiny solar cell I can do the same? I thought bigger more powerfull pannel bigger more powerfull batteries = more stuff I can run???

    I'm confused.
    Brian
  • Eric LEric L Solar Expert Posts: 262 ✭✭
    Re: How many Batteries??

    Brian,

    Like a lot of people, I have three of those same panels. They're a good 'starter' to experiment with. When mine were new (they're now several years old), they would give a max of about 3 amps total at around 14.4 volts (charging voltage of a 12 volt battery), but usually less. So I would say they can work with a 12 volt battery of around 30-40 amp hour capacity. I don't know the charge controller in the HF kits, but I assume it's designed for a 12 volt battery. An AGM battery like this one might work:

    http://www.solar-electric.com/unba35amseag.html

    A system this small can't realistically handle an inverter, IMO, but it can power small DC items like DC lights. I have no idea how someone lit their whole backyard with one of those panels. He probably trickle-charged an oversized battery, but as Wayne said that's not the way to go to keep your battery going long-term.
  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: How many Batteries??
    brbpab94 wrote: »
    how come when I buy solar garden lights with one or two little batteries and a tiny solar cell ???

    I'm confused.
    Brian

    Well Brian, those solar lights use Ni-Cad batteries that thrive on being drained nearly dead, AND the little LED may use 1/10 of one watt. AND they usually run out of power before morning. A huge difference between that and running a freezer that sucks back 1000 watt hours per 24 hour day.
    Unfortunately (and I'm not suggesting you think this way) there is the notion among many not familiar with solar electric installations, that promotes the idea that all one has to do is buy a $350.00 solar panel, mount it on the roof and all their energy problems are over.
    Many inverters, even little ones available at hardware/automotive outlets, suck back 5 to 10 watts just to keep it running in case it might be needed. That's 120 to 240 watts hours, OR MORE per day, just to run the inverter. There goes any idea of running a 100 watt light bulb for one hour per day, or of even turning it on for one second.
    We're not trying to scare you off from solar by any means, we just don't want you to jump in with unrealistic expectations, only to wrongly come to the conclusion that it's useless and turn your back on it. Start with very small expectations, and let them build as you learn.
  • plongsonplongson Solar Expert Posts: 113 ✭✭
    Re: How many Batteries??

    I started off with one little panel years ago from Camping World expecting to power my energy needs in my travel trailer. I was woefully unprepared for how inadequate it was, and I ended up with the entire roof covered with panels, but it did start me down the path to building a full off grid home. Dang, I've come along way now I think of it...LOL

    There is lots to learn and lots of math involved to understand what a system is capable or (incapable) of. If you're really interested and have lots of time, start reading here on NAWS forum and you won't be disappointed.

    The bottom line is it takes a lot of solar infrastructure to do way less than one imagines, AND it ain't cheap!

    Paul
    3500w solar, 800AH with Rolls Surrette, Magnum inverter, Midnite charge controller, Kubota 21kW diesel genset...private well...and just recently connected to city power for additional options...nice to have options 
  • brbpab94brbpab94 Registered Users Posts: 14
    Re: How many Batteries??

    I'm going to keep going but I don't think I have enough land to put the pannels to be off grid ever.I do have two roofs though...my yard space is for hanging out and gardening.

    The charge controller from Harbor Freight that came with it I here is junk. I would like one that runs automatic and it would be nice to have a timer with it. I can build some led light strips to accent the garage roof with it,that would be cool.
  • RandomJoeRandomJoe Solar Expert Posts: 472 ✭✭✭
    Re: How many Batteries??

    I also started with the HF kit. I knew it was going to be a relatively small amount of power, but was also greatly surprised by just how *little* it was!

    One of my primary motivations when I first started down the solar path was to have backup power in extended outages. I'd sat in the cold and dark for two days after an ice storm and wanted no more of it! So my initial target for sizing my system was to keep the fridge going. That was an eye-opening experience!

    The quick back-of-envelope calculations for that, which leave out system losses (batteries take a bit more power to charge than you took out, inverters have losses, so forth) were thus:

    My fridge is a reasonably efficient one, and not large. Draws 100W while running, and a Kill-A-Watt meter said it averages 1.6kWh per day. I wanted to be able to keep it going three days with no input in case the weather was particularly bad and no sun was available, so 1.6kWh x 3 days = 4.8kWh. Lead-acid batteries don't like being drawn below 50% else you really reduce their life, so double it again. 9.6 kWh minimum battery bank size.

    My initial setup was 12V. 9.6kWh / 12V = 800AH bank size - which meant eight Trojan T-105 "golf cart" batteries!

    You need to have a minimum charge current else the batteries won't be happy. Bare minimum is 5% of bank size, 800AH x 5% = 40A charge current.

    40A x 12V = 480W minimum solar panel array size! (480W also happens to be about bare minimum to replace 1.6kWh + losses in winter in my location.)

    Just to run the refrigerator!

    Also, the inverter. My fridge only draws 100W once running but requires a whopping 1200W for several seconds to get going! That's pretty common with compressors and any motor will have a fair startup current. So while I had several smaller inverters - 300W, 600W - that could have handled the run load fine, they were unable to supply the surge required to get the motor running. It took a larger, more expensive inverter just to start it - and larger inverters also have a higher idle current of their own, wasting more battery power.


    If you can do without running the fridge, and are willing to investigate very low power lighting (LEDs primarily) you can have a capable backup power system even with the HF panels. You just have to be very careful to watch how much power you use and that it gets replaced properly. I have a collection of 12V lighting, I found some LED "drop lights" at Ace Hardware that draw only 150mA (2W) on low but well-light my desk and adequately light the room. Worst case (or if I happen to go camping or such) I could run one of those for many hours on one of my 7AH AGM batteries - which can be nicely recharged with the HF panels. I also first used the HF panels to run my ham radio bench. Took a bit of a change in operating habits - I used to leave the radios on all the time, so I could hear activity any time I was near, but that used too much power to be replaced by the HF panels. But with turning the rigs off when not in use, the HF panels were usually adequate - only occasionally requiring use of an AC charger.
  • RandomJoeRandomJoe Solar Expert Posts: 472 ✭✭✭
    Re: How many Batteries??
    brbpab94 wrote: »
    The charge controller from Harbor Freight that came with it I here is junk. I would like one that runs automatic and it would be nice to have a timer with it. I can build some led light strips to accent the garage roof with it,that would be cool.

    They have had several models of "controller" over time and I understand they have made improvements. The one I had was lousy, I couldn't leave it connected at night as it would allow power to trickle out through the panels - wasting power and draining the battery overnight.

    I got a Morningstar SunKeeper 6, which is a tiny credit-card size controller, mostly because I intended to use it portable (it's a little more expensive). Morningstar makes a wide variety of controllers, some of them have special outputs just for turning on lights at night and also include a low-voltage disconnect so the battery doesn't get drained too far.
  • brbpab94brbpab94 Registered Users Posts: 14
    Re: How many Batteries??

    Lil' 12V solar lighting system post number 16 in the beginner solar.This is where I saw the 15 watt panel lighting the back yard. I'd like his controller
  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: How many Batteries??
    brbpab94 wrote: »
    Lil' 12V solar lighting system post number 16 in the beginner solar.This is where I saw the 15 watt panel lighting the back yard. I'd like his controller

    Didn't find the post, but seriously, a 15 watt panel connected to a standard deep cycle, automotive (physically) sized battery, it will do little more than keep an already charged battery topped up, replacing it's normal internal electrical leakage and losses.
  • brbpab94brbpab94 Registered Users Posts: 14
    Re: How many Batteries??
    Eric L wrote: »
    Brian,

    Like a lot of people, I have three of those same panels. They're a good 'starter' to experiment with. When mine were new (they're now several years old), they would give a max of about 3 amps total at around 14.4 volts (charging voltage of a 12 volt battery), but usually less. So I would say they can work with a 12 volt battery of around 30-40 amp hour capacity. I don't know the charge controller in the HF kits, but I assume it's designed for a 12 volt battery. An AGM battery like this one might work:

    http://www.solar-electric.com/unba35amseag.html

    A system this small can't realistically handle an inverter, IMO, but it can power small DC items like DC lights. I have no idea how someone lit their whole backyard with one of those panels. He probably trickle-charged an oversized battery, but as Wayne said that's not the way to go to keep your battery going long-term.

    Is this the biggest battery I should get?
  • BB.BB. Super Moderators, Administrators Posts: 29,702 admin
    Re: How many Batteries??

    For sizing of a battery bank, we generally recommend 5% to 13% rate of charge based on the battery's 20 Hour discharge rate (and a 1% rate of charge for float service)...

    So:
    • 45 watts * 0.77 charger+panel derating * 1/14.5 volts charging * 1/0.13 rate of charge = 18 AH @ 12 volts (usually about the maximum recommended rate of charge for flooded cell battery)
    • 45 watts * 0.77 charger+panel derating * 1/14.5 volts charging * 1/0.10 rate of charge = 24 AH @ 12 volts (healthy array to battery charging ratio)
    • 45 watts * 0.77 charger+panel derating * 1/14.5 volts charging * 1/0.05 rate of charge = 48 AH @ 12 volts (maximum battery size)
    • 45 watts * 0.77 charger+panel derating * 1/14.5 volts charging * 1/0.05 rate of charge = 239 AH @ 12 volts (largest battery for float only charging)

    For a 45 solar array in Rhode Island mounted tilting at latitude of 42 degrees (PV Watts defaults):
    Month    Solar Radiation (kWh/m 2/day)
    1      3.37     
    2      4.31     
    3      4.87     
    4      5.26     
    5      5.35     
    6      5.57     
    7      5.85     
    8      5.76     
    9      4.68     
    10      4.54     
    11      3.27     
    12      2.82     
    Year      4.64      
    

    Toss out the "bottom" producing 3 months of winter, you will average a minimum (20 year average) of 4.31 hours of sun per day (February). The amount of power you can generate per day:
    • 45 watts * 0.52 AC system derating * 4.31 hours of sun = 101 WH per day (120 VAC through small inverter using power at night)
    • 45 watts * 0.62 DC system derating * 4.31 hours of sun = 120 WH per day (12 VDC--charge daytime, use power at night)

    A relatively efficient laptop computer will use ~30 watts:
    • 120 WH (DC) / 30 watts = ~4 hours minimum of use for 9+ months a year

    If you want to run a typically efficient full size fridge for ~9 months a year--A good number is 1.5 kWH (or 1,500 WH) per day. Working backwards:
    • 1,500 WH per day * 1/0.52 AC system eff * 1/4.31 hours of sun per day = 669 Watt minimum solar array in Rhode Island

    The size battery bank needed to run 1.5kWH per day would be (based on 1-3 days of no sun, 50% maximum discharge):
    • 1,500 WH * 1/0.85 inverter eff * 1/12 volt battery bank * 2 days no sun * 1/0.50 max discharge = 588 AH @ 12 volt battery bank

    Although, for a 1,500 watt minimum inverter to run a standard full sized fridge--I would suggest going with a 294 AH @ 24 volt battery bank (keep DC currents lower).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • brbpab94brbpab94 Registered Users Posts: 14
    Re: How many Batteries??
    BB. wrote: »
    For sizing of a battery bank, we generally recommend 5% to 13% rate of charge based on the battery's 20 Hour discharge rate (and a 1% rate of charge for float service)...

    So:
    • 45 watts * 0.77 charger+panel derating * 1/14.5 volts charging * 1/0.13 rate of charge = 18 AH @ 12 volts (usually about the maximum recommended rate of charge for flooded cell battery)
    • 45 watts * 0.77 charger+panel derating * 1/14.5 volts charging * 1/0.10 rate of charge = 24 AH @ 12 volts (healthy array to battery charging ratio)
    • 45 watts * 0.77 charger+panel derating * 1/14.5 volts charging * 1/0.05 rate of charge = 48 AH @ 12 volts (maximum battery size)
    • 45 watts * 0.77 charger+panel derating * 1/14.5 volts charging * 1/0.05 rate of charge = 239 AH @ 12 volts (largest battery for float only charging)

    For a 45 solar array in Rhode Island mounted tilting at latitude of 42 degrees (PV Watts defaults):
    Month    Solar Radiation (kWh/m 2/day)
    1      3.37     
    2      4.31     
    3      4.87     
    4      5.26     
    5      5.35     
    6      5.57     
    7      5.85     
    8      5.76     
    9      4.68     
    10      4.54     
    11      3.27     
    12      2.82     
    Year      4.64      
    

    Toss out the "bottom" producing 3 months of winter, you will average a minimum (20 year average) of 4.31 hours of sun per day (February). The amount of power you can generate per day:
    • 45 watts * 0.52 AC system derating * 4.31 hours of sun = 101 WH per day (120 VAC through small inverter using power at night)
    • 45 watts * 0.62 DC system derating * 4.31 hours of sun = 120 WH per day (12 VDC--charge daytime, use power at night)

    A relatively efficient laptop computer will use ~30 watts:
    • 120 WH (DC) / 30 watts = ~4 hours minimum of use for 9+ months a year

    If you want to run a typically efficient full size fridge for ~9 months a year--A good number is 1.5 kWH (or 1,500 WH) per day. Working backwards:
    • 1,500 WH per day * 1/0.52 AC system eff * 1/4.31 hours of sun per day = 669 Watt minimum solar array in Rhode Island

    The size battery bank needed to run 1.5kWH per day would be (based on 1-3 days of no sun, 50% maximum discharge):
    • 1,500 WH * 1/0.85 inverter eff * 1/12 volt battery bank * 2 days no sun * 1/0.50 max discharge = 588 AH @ 12 volt battery bank

    Although, for a 1,500 watt minimum inverter to run a standard full sized fridge--I would suggest going with a 294 AH @ 24 volt battery bank (keep DC currents lower).

    -Bill

    Where do I go to learn all the formulas you use. I was only thinking of running the freezer during a power outage. We had a huricane last year and lost power for a week.
  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: How many Batteries??
    brbpab94 wrote: »
    I was only thinking of running the freezer during a power outage. We had a hurricane last year and lost power for a week.

    Unfortunately, when talking very small scale solar, the words "only" and "freezer" don't belong in the same sentence. :cry:
  • BB.BB. Super Moderators, Administrators Posts: 29,702 admin
    Re: How many Batteries??

    Where to learn the formulas? Right here. In most cases, I try to link back to the source of my data (such as PV Watts), what values I use (like 1 kW / 1,000 W--the rest PV Watts Default) so that you can see my assumptions and understand why I choose them (I tend to be conservative in my choices).

    And I tend to carry 3+ digits so you can reproduce my math (and find my errors:blush:). Most of the equations/results are doing pretty well if you are within 10-20% of the numbers calculated.

    Pretty much all my formulas are written in Math-glish... I try to make them readable with the Numbers/Units/English Description of each value.

    I also try try to use (* (1/xx) *) instead of a whole bunch of proper math of (a bunch of stuff on top)/(a bunch of stuff on the bottom) so you can see each factor/conversion as you read through. Note I am a big stickler for carrying through the units (not that I did this as a kid in math :roll:). Many times I find my mistakes by seeing that Watts/Volts does not equal Hours but "I" current instead (as an example where P=V*I).

    None of it is written in stone--You are more than welcome to change the assumptions to better fit your needs and even plug them into a spread sheet so you can quickly play with the values.

    Most of these equations are written based on the questions asked... If somebody said I need XX KWH per day, I write them one way. If another person Says I have X,XXX watts of solar panels, how big of battery can I put on the system--I tweak them around to answer the different question.

    After a few years of practice here--I can pretty quickly setup an equation and some values which will give a pretty good SWAG (scientific wild a$$ guess) at the answer.

    Please feel free to ask more questions and I or somebody else will be more than happy to help. And if something does not look right--it probably is not right and I made a mistake somewhere.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BB.BB. Super Moderators, Administrators Posts: 29,702 admin
    Re: How many Batteries??

    By the way, you will see some things that may not make sense... For example I will use 12 volts in one equation and 14.5 volts in another...

    The reason is that, typically a battery will output ~12 volts when under load and be at ~14.5 volts under charging. I could use 13.25 volts as an "average" but I do want to take into account the losses when planning a Solar PV system. For example, the losses between 12 volt load and 14.5 volts charging:
    • 12 volts / 14.5 volts = 0.83 = 83% charging efficiency

    In real life, it is more complicated... The battery is closer to 13 volts when first discharging... And if you discharge a battery fairly deeply, it may start charging at 12.5 volts and not reach 14.5 volt until late in the charging cycle. And remember older batteries are less efficient--Older solar panels may be 10-20% less efficient, etc...

    Remember when I said if you got to within 10-20%--It is those details that make it difficult to model a quick and accurate answer. Will you deep cycle a smaller battery bank or shallow cycle a large battery bank? I don't know... And it does not really matter. The answers I take a SWAG at--You should meet or even beat those values when new, and, hopefully, not fall much below the estimates as your system ages.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • brbpab94brbpab94 Registered Users Posts: 14
    Re: How many Batteries??
    BB. wrote: »
    Where to learn the formulas? Right here. In most cases, I try to link back to the source of my data (such as PV Watts), what values I use (like 1 kW / 1,000 W--the rest PV Watts Default) so that you can see my assumptions and understand why I choose them (I tend to be conservative in my choices).

    And I tend to carry 3+ digits so you can reproduce my math (and find my errors:blush:). Most of the equations/results are doing pretty well if you are within 10-20% of the numbers calculated.

    Pretty much all my formulas are written in Math-glish... I try to make them readable with the Numbers/Units/English Description of each value.

    I also try try to use (* (1/xx) *) instead of a whole bunch of proper math of (a bunch of stuff on top)/(a bunch of stuff on the bottom) so you can see each factor/conversion as you read through. Note I am a big stickler for carrying through the units (not that I did this as a kid in math :roll:). Many times I find my mistakes by seeing that Watts/Volts does not equal Hours but "I" current instead (as an example where P=V*I).

    None of it is written in stone--You are more than welcome to change the assumptions to better fit your needs and even plug them into a spread sheet so you can quickly play with the values.

    Most of these equations are written based on the questions asked... If somebody said I need XX KWH per day, I write them one way. If another person Says I have X,XXX watts of solar panels, how big of battery can I put on the system--I tweak them around to answer the different question.

    After a few years of practice here--I can pretty quickly setup and equation and some values with will give a pretty good SWAG (scientific wild a$$ guess) at the answer.

    Please feel free to ask more questions and I or somebody else will be more than happy to help. And if something does not look right--it probably is not right and I made a mistake somewhere.

    -Bill


    LOL! Thanks Bill

    When I get going I'll be asking more,Much more. I work out of state so my time is short that I have to play.




    l
  • brbpab94brbpab94 Registered Users Posts: 14
    Re: How many Batteries??

    I just received 6 used trojan 105 batteries. I'd like to to use 2 of them seeing that there 6 volt batteries. How long would it take to fill up using my 45 watt pannel? And how long would it take to charge them with a 10 amp car battery charger?

    thanks
    Brian
  • westbranchwestbranch Solar Expert Posts: 5,163 ✭✭✭✭
    Re: How many Batteries??

    I would start by putting them on a regular charger seeing as you travel a bit and you don't want to leave them sitting for a period and not be fully charged.
     
    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
  • brbpab94brbpab94 Registered Users Posts: 14
    Re: How many Batteries??

    how many hours is it safe to be on the 10 amp charger? They've been sitting for a couple of monthsand I'd like to top them off. Is a 10 amp battery charger strong enough for the dual deep cycle batteries. There 6 volt so I charge them in series to get 12 volts.
  • westbranchwestbranch Solar Expert Posts: 5,163 ✭✭✭✭
    Re: How many Batteries??

    Yes, in series. What brand/model of charger? It may be a multi stage charger and if it is, it will step down to a trickle charge, but best to check.

    You should do a voltage test to see where they are at before starting, since they have been sitting without a charge for a while, a fully charged battery should be in the range of 13.2 V, but ti is doubtful they will be at that voltage. If you can access a tester to check the SG ( specific gravity) that is the best, as you can test for weak cells. Do you have a regular garage fro your car, they should have one. NAWS sells them too. http://www.solar-electric.com/brtecoprhy.html

    HTH

    Do NOT charge if the fluid is not covering the tops of the plates, top them up if needed
     
    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
  • BB.BB. Super Moderators, Administrators Posts: 29,702 admin
    Re: How many Batteries??

    My cheap and dirty way to use a car charger for floating a battery bank... Use a lamp timer and set it to run (example) 1 hour per day... That is the rough equivalent of plugging a battery charger 1 day out of the month. Keeps the batteries topped off and does not "boil them dry". And I don't have to remember to hook up the charger 1 day out of the month and unplug it when done.

    If you need more charging, bump it to two hours per day... If less, 30 minutes per day.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • brbpab94brbpab94 Registered Users Posts: 14
    Re: How many Batteries??

    When I was charging them It started to bubble a little , I read that it's called boiling. The charger I have is a sears 10 amp 2 amp charger That I have to manualy change from 10 amps to 2 amps. It's about 20 years old.I tested them with a hydrometer and it read recharge.


    westbranch wrote: »
    Yes, in series. What brand/model of charger? It may be a multi stage charger and if it is, it will step down to a trickle charge, but best to check.

    You should do a voltage test to see where they are at before starting, since they have been sitting without a charge for a while, a fully charged battery should be in the range of 13.2 V, but ti is doubtful they will be at that voltage. If you can access a tester to check the SG ( specific gravity) that is the best, as you can test for weak cells. Do you have a regular garage fro your car, they should have one. NAWS sells them too. http://www.solar-electric.com/brtecoprhy.html

    HTH

    Do NOT charge if the fluid is not covering the tops of the plates, top them up if needed
  • westbranchwestbranch Solar Expert Posts: 5,163 ✭✭✭✭
    Re: How many Batteries??

    Were there any numbers or just a good/recharge scale?
     
    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
  • brbpab94brbpab94 Registered Users Posts: 14
    Re: How many Batteries??

    good ,fair/ recharge
  • westbranchwestbranch Solar Expert Posts: 5,163 ✭✭✭✭
    Re: How many Batteries??

    too bad now you are shooting in the dark as to their current state. Judging by the 'bubbling' comment they may be pretty low. don't leave them unattended.

    you will want to read this http://www.windsun.com/Batteries/Battery_FAQ.htm
     
    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
  • brbpab94brbpab94 Registered Users Posts: 14
    Re: How many Batteries??

    What do you mean by "don't leave them unatended"? If there low I could be charging them for hours.
    westbranch wrote: »
    too bad now you are shooting in the dark as to their current state. Judging by the 'bubbling' comment they may be pretty low. don't leave them unattended.

    you will want to read this http://www.windsun.com/Batteries/Battery_FAQ.htm
  • westbranchwestbranch Solar Expert Posts: 5,163 ✭✭✭✭
    Re: How many Batteries??

    what I meant was don't just hook it up and leave it alone for long periods...There is a thing called thermal runaway, not totally familiar with the mechanics/chemistry, but your battery temp rises and the charger will keep pumping in Amps and the temp keeps rising and the battery can potentially explode... It is a thing that depleted batteries will do if not treated gently. If you want to let it run, do it at the lowest amperage you can (2?)
     
    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
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