new system

SystemSystem Posts: 2,511 admin
hi there.... i want to have a solar system

i will have two light bulbs @ 7 watts each

i will have a laptop @ 40watts

i estimate on average maximum i will use them for 4 hours a day simultaniously.

so that's 57watts running for 4 hours each day.

I have an inverter that i got out of an old ambulance that i want to use.

what i want to know is how many car batteries i will need and how many watts of solar panels if i recive average light.

just an estimate will do.... i can add more solar panels and batteries if my needs change. I don't have very much money to spend on this but i need some power... at least for lights as i'm scared of the dark lol.

thanks,

andre

Comments

  • BB.BB. Super Moderators, Administrators Posts: 31,330 admin
    Re: new system

    Andre,

    You are off to a good start--you have an idea of how much power you will need. And, conservation (laptop set to low power, or a new/smaller system), using LED or CPFL for your lighting, etc. will all help keep your system cheap and small...

    57 Watt * 4 hours = 228 Watt*Hours...

    From this link, we can estimate how much power you will get from your system:

    Assuming you are near Sydney Australia, you will use a fixed array (not tracking), a Derating Factor of .50 (reasonable for a small off-grid system using lead acid wet cell batteries). Note, the link I just gave you will only go down to 1kW of solar panels... So we will use 1kW and work backwards to figure out your actual need base on the load.

    The month with the lowest production for you is June and is 46kWhr per month or 46kWpermonth/30days=1.5kWhrs/day or 1,500 watts per day (usable average power with an Inverter).

    Assume that your minimum power need is about 500 WattHours (rounding the 228 Watts up to allow for some cloudy weather), and your system would be about 1/3 the size or 1/3kW of panels or ~333 watts of solar panels.

    Battery size, assuming three days of bad weather, and don't discharge the battery below 50% capacity (for long life),

    228watt*hours per day * 3 days of storage / 50% discharge = 1,368 WattHours of battery storage.

    Assuming 12 volt battery bank:

    1,368 Watt*Hours / 12 volts = 114 amp*hour battery bank (at 12 volts DC).

    Don't use car batteries--get a true storage storage battery (in the US, for a beginning system, 6 volt golf cart batteries are a good choice).

    The above numbers are a guess--they can certainly adjusted by 2x or 1/2 and you will still have a workable system. And, if this is an off grid setup (no mains power), then you will probably need a back up generator.

    If, you are doing this for emergency backup power--Solar + Battery is not a great place to spend the money unless you have a lot of power blackouts...

    Questions?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • hillbillyhillbilly Solar Expert Posts: 334 ✭✭
    Re: new system

    You mention not having a lot of $$$ to throw into this system, but you also mention the idea of possibly adding panels and batteries later as funds become available. If this is a system that might grow later on down the road, you might want to really look at the whole thing from another angle. One of the biggest is the fact that you cannot just keep adding batteries every few years, they will not play nicely together; you may want to consider how big your needs might grow to over the next 5-10 years, and if possible ($$$) try to size your battery bank accordingly and get a good generator to make sure that you keep your batteries fully topped up.
    In the short run this will cost you more cash for sure, as you could probably get by MOST of the time with a pretty small solar array and smaller batteries. But if your needs/wants grow in a few years and you end up having to buy a whole new set of batteries (and probably a whole new charge controller, maybe a bigger inverter....etc...) you may end up saving yourself some money in the long run.
    Your needs sound fairly similar to those that my wife and I started out with a couple of years ago, and in our case we very quickly outgrew our initial system set up and ended up switching our sytem around quite a lot (had to buy a new charger and inverter, and rewire our batteries to 24V instead of 12V). Lucky for us we started with a large battery bank (of good quality batteries), and we used a generator to make up for our comparitively small solar array in the winter months. Don't know if this applies to you specifically or not, but sure seems like it might be worth looking a bit deeper before you start building your system. Think of the batteries as the "foundation" of the system, if you "over-do" it a bit on the foundation you can add on to the system as a whole later on. Just be aware that the larger the battery bank is the more power you will need to have to keep them charged up; that will NOT be cheap to do with PV panels alone, therefore I would recomend adding a backup generator.
    Definately consider getting a generator if:
    -You think that you may have larger power demands at some point in the next few years
    -Can't stand another dark night, don't want to be without power when the clouds hang around for a few days
    -Don't have a ton of money to buy a totally self sufficient solar array

    If you have a generator you could definately start a bit smaller on your solar array, go a bit bigger on your battery bank, and eventually add more and more panels as you can... in the long run could have a pretty sweet set up. Check out this link from NAWS on batteries http://www.windsun.com/Batteries/Battery_FAQ.htm . Also there's a nice article here on sizing and maintinence http://www.wholesalesolar.com/Information-SolarFolder/battery.maintenance.html .
    Good luck...
  • System2System2 Posts: 6,290 admin
    Re: new system

    awesome help! thanks.

    I'm off grid.

    333 watts of solar panels is HEAPS!!! and costs HEAPS for me. It cost me under $2000 to build my house and I don't really want to spend more than the cost of my house just to power it. I was really hoping I could run my system on 80watts or less. I can probabally afford 20watts ha ha.

    One 80watt panel will cost me $769, more than I want to spend on my whole system realistically.

    http://www.jaycar.com.au/productView.asp?ID=ZM9069&CATID=7&keywords=&SPECIAL=&form=CAT&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID=624

    320watts I would need 4 of them, $3076. This is totally out of my reach.

    Any other bright ideas??? lol

    I have a 750watt generator and was going to get a battery charger to plug into it so I can charge my batteries when the sun doesn't favour me or I want to use extra electricity.

    If I ever have to use a power tool, vacumm, watch tv or something I will just use the generator and forget the solar.

    The advantage of car batteries for me is I can collect second hand batteries from hard rubbish and other sources that are free. Perhaps they won't be the best batteries at holding charge, but they cost nothing. That's why I was going to go down this track.

    Hum.. have to have a think about this.
  • System2System2 Posts: 6,290 admin
    Re: new system

    maybe i need to look at this the other way around.

    my money can dictate my needs :roll:

    if i saved up for this

    http://www.energymatters.com.au/folding-portable-140watt-12volt-solar-power-with-regulator-kits-p-819.html?cPath=158_222

    what could i power?
  • BB.BB. Super Moderators, Administrators Posts: 31,330 admin
    Re: new system

    Yea, solar electric is not cheap... In the US, we pay about $0.10 to $0.35 per kWhr. Solar Off Grid power (with our cheaper component prices) still costs $1.00 per kWhr or more.

    First, conservation. Get the most power efficient PC you can. And the most power efficient lights you can.

    Panels, you are about 2-3x our costs, and if cannot find a better source down there--you are probably out of luck.

    Car batteries--probably not worth the effort. A car battery if it is cycled below 85% state of charge (100%=full charge), will start to die withing a few weeks to a few months. A true storage battery you can take down 50% and it will last 3-10 years (rough guess).

    For now, your best bet would probably be to make a "hybrid" system... Build a good battery bank that can run your home for 1-3 days by itself. Then use a generator to recharge the battery bank (4-6 hours of running) every 1-3 days. Helps keep the noise down and the generator running near full power--usually much more fuel efficient than simply using a generator to supply all of your loads.

    You could always add an alternate charging source (solar PV, wind, etc.) later as your finances and needs dictate.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2System2 Posts: 6,290 admin
    Re: new system

    That probabally sounds like the best idea so far.

    So the new idea is:

    to spend my money on proper batteries to power my house for 3 days.

    buy a good battery charger for the generator.

    when i go to work, turn on the generator and let it run until it's out of petrol.... about 6 hours.

    come home from work and enjoy silent power.

    not the most renuable energy or good for the environment, but solar can be added later when i can afford it.
  • BB.BB. Super Moderators, Administrators Posts: 31,330 admin
    Re: new system

    Just to be clear, for normal wet / flooded cell lead acid batteries, you don't want to discharge them below 50% (and really don't want to store them below 75%) for long life.

    So, 1 days of use would be 3x for three days storage x 2 for not going below 50% State of Charge (my first reply to your original question).

    Also, if you have a chance to see what others in your area of done... Older battery chargers have some pretty nasty wave forms and many generators may not be able to properly run such a charger at 50% of the generator's rating.

    Newer chargers can be "power factor" corrected so that they will operate on a generator at 80% or so of the generator's rating.

    And for your generator, typically, they are more efficient at 50% load and above, and below 50%, they use almost the same about of fuel generating 25% load as they do at 50%...

    So--before you lay out good money for a genset/charge controller pair.

    The little Honda and equivalent inverter/generators are pretty nice because at lower power levels, they can throttle back the engine and still be pretty fuel efficient at 25% power.

    Depending on your best fuel source (petrol, diesel, propane, etc.), you may find different solutions that we would use here.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2System2 Posts: 6,290 admin
    Re: new system

    Thanks for your help. So running the genrerator as often as possible is the key? Never let my batteries run too flat.

    The generator I have currently is

    http://www.gmcompany.com.au/index.cfm?module=products&pid=598

    it cost $98 so it is a fairly cheap pice of crap. Will that do for now or do i need something better. I was just going to buy a battery charger for that if possible. Do you have a recomendation on a battery charger I could get.

    Maybe I could get a 20watt solar panel to keep the batteries toped up if they are being stored for a while. Just a thought.

    I'm yet to talk to the neighbours, but it looks like they have a mean solar set up. I'm interested where they went shopping.

    It's certainly more tricky and costly than i thought getting power. I didn't really budget for this.
  • mike95490mike95490 Solar Expert Posts: 9,190 ✭✭✭✭✭
    Re: new system
    narky wrote: »
    Thanks for your help. So running the genrerator as often as possible is the key? Never let my batteries run too flat.

    The generator I have currently is

    http://www.gmcompany.com.au/index.cfm?module=products&pid=598

    it cost $98 so it is a fairly cheap pice of crap. Will that do for now or do i need something better. I was just going to buy a battery charger for that if possible. Do you have a recomendation on a battery charger I could get.

    Maybe I could get a 20watt solar panel to keep the batteries toped up if they are being stored for a while. Just a thought.

    I'm yet to talk to the neighbours, but it looks like they have a mean solar set up. I'm interested where they went shopping.

    It's certainly more tricky and costly than i thought getting power. I didn't really budget for this.

    Letting a generator starve itself of fuel, is a bad auto-off idea. If a load is connected to alternator, and it spins down loaded, it can de-magnetize the rotor enough that it may stop generating power.
    Other problems are that the alternator coils are hot from a full load, and when cooling air stops, they overheat. (like a car at a gas station after a long drive)
    In your case, that may be OK, because the max power happens at the begin of charge, and it tapers off toward the end.
    Does the generator have a "govener" to stabilize the output frequency, I see it's ad says unloaded RPM = 3000 & This product is suited for lighting, camping and car battery recharging applications. It is not recommended to be used with any electronic devices.

    So is your charger an electronic device ? The good 4 stage ones are.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • BB.BB. Super Moderators, Administrators Posts: 31,330 admin
    Re: new system

    Iota Engineering and Xantrex make some very good chargers--but probably would cost you an arm and a leg to get in your part of the world.

    Ideally, you want to find a multi stage charger with an external battery temperature sensor (battery's voltage change with temperature). And they should have PFC (Power Factor Correction) for the AC input (although, that is not always clear in the documentation).

    For used storage batteries (and perhaps used chargers), you might look for companies that service forklifts or boats--they have some pretty good sized batteries and equipment to charge them.

    If you get flooded cell batteries (the standard type), you can use a good temperature compensated hydrometer to monitor the charge level (and check the water levels too at the same time).

    If you can swing it, a battery monitor is the best tool for monitoring the state of your battery... It monitors the current flow into and out of a battery--So it is about as close as you can get to a "gas gauge" for your battery.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • hillbillyhillbilly Solar Expert Posts: 334 ✭✭
    Re: new system

    Narky,
    You're right that solar power IS expensive, but on the other hand so is gas and maintinence on the generator... in the long run it's a sweet deal, but it's not very cost effective in the short (here and now) term. Couple of points from reading your posts...

    First of all did you really mean your generator is only 750watts? Thats VERY small for a generator, and will not be enough to run a lot of power tools and such, should be ok for charging a small set of batteries, but many tools will draw far more than 750watts...

    Secondly, you mention just running the generator while off at work until it dies. I would say this is a very wastefull (and EXPENSIVE) way to use power; I think if you start doing the math, it would turn out to cost a lot more money than a small solar set up if you are running the generator "redundantly" for a couple of hours every couple of days if the batteries are already charged. Probably the best would be to use the generator just enough to charge your batteries, even better if you can just do the bulk charging and then let some solar panels kick in to provide a finish charge. Perhaps there is some way that you could work this into your weekly routine so that you can moniter and shut things down when the batteries are all done.
    Also Bill's kind suggestion about getting a battery moniter of some sort was offered far too politely imo... I would consider it an essential item; if you spend any money on quality batteries the extra $100-$300 (?) for a good battery moniter to care for them is far cheaper than having to replace them prematurely. I am not familiar with all moniters out there, and you may have access to some that I don't, but I do know that there are some that can be very helpfull in learning. I have a Trimetric for example, which has been very helpfull to me in terms of seeing how much power I am using at any given moment, seeing how charged or discharged the batteries are, reminding me of how many days it's been since they were fully charged or equalized, etc... VERY educational little device.

    I also wonder how much is gas in your part of the world? Might be worth sitting down and working out all the expenses over a longer term to figure out what would be most cost effective. A very rough guess on my part would be that with a smaller PV array, and using your generator in a well planned and conservative manner you would probably come out cheaper in the long run than just using the generatoer for all charging. Having enough PV to do some charging could be a real gas $ saver: such as durring ideal sunny weather, or when you have low power demand for a couple of days, and the ability to "finish the charge" on your batteries. Remember that good maintinence on your batteries will require about 2 hours in "absorb" stage to finish charging; since the batteries in this stage should be recieving a much smaller amount of charging current this is not a very efficient job for a generator. On the other side of the coin trying to do it all with PV is VERY expensive as you discovered, so trying to work out a balance is key. Just some stuff to think about.

    If you just have no way of spending any money on good batteries, chargers, moniters, solar panels, etc... then you may want to look into just buying a cheap set of "marine" or "RV" batteries to use for now. Not my first recomendation, but I did use that route early on in the learning process. The only real advantage to them is that they are much cheaper in the SHORT term, I think here in the states they run about $100 a pop or so; you could probably do ok with one or two of these for a year or three depending...

    Like most things in life you do tend to get what you pay for: cheap batteries will need frequent replacing, good batteries will cost a small fortune but should last much longer and cost far less over the course of 10-15-20-30 years. Pretty much the longer you stay there and keep using batteries for power, the more sense it makes to buy the best you can afford. PV panels also tend to be much more expensive ($/per watt) for the smaller panels, and far more cost effective for the larger panels... so your mention of using a 20watt panel would probably be somewhat of a waste of $ (I'd say save that money and wait a year or so until you can afford a bit bigger panal). Being off grid, there is no real quick and cheap way that I've found to provide power, in addition to being very carefull to conserve power at every opportunity I think that you also really need to look LONG term... and think big picture every time you think about opening up the wallet...
    Best of luck...
  • mike95490mike95490 Solar Expert Posts: 9,190 ✭✭✭✭✭
    Re: new system

    1) the generator is a little 2 cycle screamer, got to mix oil and gas. Short lifetime.

    2) Can somebody explain why a computerised battery monitor is so much better than a GOOD DVM. Would a "Current Totalizer" be a better name for a battery monitor ?
    With a preprinted voltage chart, and a good DVM, why can that not measure the actual State Of Charge (SOC) of any lead acid battery ? They have a very well defined charge/voltage curve, 12.24V @70f always means a particular charge level.

    3) use the generator, with 2 hours of fuel in it, leave home in the AM, and it will bulk charge batteries for 2 hours, then the solar will top it off at the slower adsorbation rate. Best bang for your buck ($$) smaller solar array, and a small genset. If you know it's going to be a cloudy day, put 3 hours of fuel in the tank.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • BB.BB. Super Moderators, Administrators Posts: 31,330 admin
    Re: new system

    Andre,

    Make sure you keep track of how much money you have spent and will be spending on a generator, fuel, etc.

    And monitor the amount of power you are consuming (kill-a-watt equivalent for Australia--or, I and others have done, is just get an old utility power meter and wire that up--Nothing fancy, you just write down the numbers and a week or a month later, write down the new numbers and subtract).

    The math equation would be along the lines of:

    ($fuel + $gen cost / %used for period + etc)/kWhrs used...

    I am going to guess that you are "north" of (or would that be "south of" in Australia) $2.00 per kWhr for your power costs (if everything purchased new, expensive fuel, etc.)...

    To reduce those prices, search for used stuff, and trying to find out what happens to old solar panels when equipment is upgraded, etc. it going to be your best way...

    Here in the US, we can get new panels for USD$4-$5 per watt (sometimes less)--you are paying almost $10 per watt (AUD$?)... Used panels here, either you find a deal or on Ebay they try to sell them near new costs.

    Looking to conserve--lowest power computer, lights, etc., can save you a bunch of cash too... My 8 year old laptop runs about 20 watts with the screen off and about 30 watts screen on (120 VAC power, not charging battery pack).

    If you can find a few of the new Cree and other high power/high efficiency LEDs out there now--1 watt size are now used in pretty bright flashlights--a few of those would provide more than enough light for a workspace/living space.

    As Solar Guppy says, solar is not cheap...

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • hillbillyhillbilly Solar Expert Posts: 334 ✭✭
    Re: new system

    Quoting Mike:
    "2) Can somebody explain why a computerised battery monitor is so much better than a GOOD DVM. Would a "Current Totalizer" be a better name for a battery monitor ?
    With a preprinted voltage chart, and a good DVM, why can that not measure the actual State Of Charge (SOC) of any lead acid battery ? They have a very well defined charge/voltage curve, 12.24V @70f always means a particular charge level."

    Mike please forgive my ignorance in this matter... and please enlighten... I have always been lead to believe that voltage levels (regardless of how accurate) could not take into account the effects of load or charge currents. Is there such a device that can automatically factor all this in? How much cheaper would it be then say a Trimetric?
    I do still find some of the other features on the trimetric quite handy from an educational angle. Personally when I first started out, I was always somewhat frustrated at not knowing exactly how much energy I was pulling out of the batteries (in other words how efficient or innefficient things were running off the batt's), and guessing a lot as to how low the batteries were really getting if the voltmeter read say 12.25V...
    I've also managed to catch a few small errors with the Trimetric, where I had charging current showing on the charge controller, but none on the Trimetric (whoops, minor wiring error... quickly fixed). Plus, to make things further "idiot proof" (a very important feature to me for most expensive things), I like having a reminder to tell me exactly how many days it's been since the batt's recieved the FULL charge, or since the last EQ... etc.

    Just my $150 worth :)
  • mike95490mike95490 Solar Expert Posts: 9,190 ✭✭✭✭✭
    Re: new system
    mike90045 wrote: »
    2) Can somebody explain why a computerized battery monitor is so much better than a GOOD DVM. Would a "Current Totalizer" be a better name for a battery monitor ?
    With a preprinted voltage chart, and a good DVM, why can that not measure the actual State Of Charge (SOC) of any lead acid battery ? They have a very well defined charge/voltage curve, 12.24V @70f always means a particular charge level.

    Ok, I guess I meant, an idle battery. When being charged, or drained, then the voltage reading is skewed. To be really accurate, I guess the battery needs to be idle for an hour or longer. I guess that's the strong point of the battery monitor. I guess it uses a shunt to sense how much charge vs load is going or coming from the battery, and it factors in the efficiency for the style of chemistry.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • BB.BB. Super Moderators, Administrators Posts: 31,330 admin
    Re: new system

    You got it Mike!

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2System2 Posts: 6,290 admin
    Re: new system

    Well I spent some money.

    I ended up getting 2 T-105 Trojan batteries and a 85watt solar panel. Too dark to see the brand right now. I set it up just to test and got a multimeter instead of a battery monitor to start with.

    I'm planning on getting a car alternator and pulling apart my generator so it runs the car alternator directly. Not sure how much of a mission this will be but hopefully it means i get close to optimal charging out of my shitty gen without having to fork out another $300 for a battery charger.

    Until I get my generator up and running I'll just run one compact fluro and check my voltage before i turn it on each time night comes so i can get an accurate voltage reading. As long as I never let my battery fall below 12.10 volts I should be okay.... right?

    I guess it will just take time before I get used to how much appliances discharge my batteries, but at least I will have some light in the mean time.

    Thanks everyone for your help. The cost of the system so far is just over $1000. I really didn't want to spend that much, but my alternative lifestyle should save me money in other ways.

    I'll let you know how the generator/car alternator project goes.

    :D:DThanks everyone for your help.:D:D

    Andre.
  • BB.BB. Super Moderators, Administrators Posts: 31,330 admin
    Re: new system

    The 12.10 volts is at 77-80F and after, ideally, several hours of resting. If you measure the voltage just after the sun sets, you may still read too high (surface charge on battery).

    Also, at least, get a good hydrometer. And use it once in a while to confirm your charge levels. And only used distilled water to refill the cells.

    Regarding your generator--I would not pull it apart--instead I would get an old Brigs and Stratton or equivalent engine and convert it.

    The generator conversion may not be really a good idea... May be several issues... 1) some use the generator as a flywheel and won't start/run without it. 2) some special purpose engines are not designed for side loads if they were designed to run axial loads. 3) generator may have fan to pull cooling air through the motor.

    And, you can probably get a cheap car charger and just crank it up to high current charging and just monitor it with your volt meter.

    Lastly, unless your car alternator is manually adjustable, it probably does not output a high enough voltage to properly charge your battery bank.

    You would need somewhere around 14.8 to 15.5 volts for daily charging and equalizing your cells. A car alternator does not allow you to (easily) set/change its output voltage. A truck or marine alternator may allow adjustments...

    To a degree, your 85 watt panel may help here... Use the lower voltage charger/alternator first thing in the morning, and the 85 watt panel to finish up charging (at higher voltage) and your 1-2 per month equalization charge.

    Read Wind-Sun's battery FAQ for a good understanding on how to keep your batteries healthy.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mike95490mike95490 Solar Expert Posts: 9,190 ✭✭✭✭✭
    Re: new system
    narky wrote: »

    I'm planning on getting a car alternator and pulling apart my generator so it runs the car alternator directly. Not sure how much of a mission this will be but hopefully it means i get close to optimal charging out of my shitty gen without having to fork out another $300 for a battery charger.

    http://theepicenter.com/tow02077.html for info about converting a small engine to a generator with a car alternator.

    Alternators need pretty high RPM's (6 - 8,000) in the right direction for the cooling fan to work. They overheat quickly and output falls to half of name plate raeted power.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

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