# battery banks &quot;Thinking out loud&quot;

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Registered Users Posts: 11
Ok I have no use for this "as of yet" But I'm just thinking out loud and looking for input, thoughts, ideas.

Ok a battery bank of 12volt batteries to make 48volt Obviously is charged with
a little more than 48 volt.

Now same setup If I used a pair of high current diodes per bat would I be able to
get a 12 volt rail that would be balanced across all four bats?

P.S. just thought of something If I used the diodes in between the bats on
the 48volt side could I yield 12volt high amp paralleled output and still charge at 48volt?

Like I said thinking out loud looking for opinions.
«1

• Banned Posts: 17,615 ✭✭✭
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Re: battery banks "Thinking out loud"

If I understand what you propose right the answer is NO!

Same source feeding a bunch of batteries connected in series equals (+) and (-) going to the (-) and (+) on every battery, diodes or not. This would be the formula for a nasty situation involving smoke, sparks, flames, death ...

Maybe I just don't understand you right.

But there is no way to charge multiple batteries from one fractional DC Voltage source if those batteries are connected in series.
• Registered Users Posts: 11
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Re: battery banks "Thinking out loud"

Yeah after thinking about it reality smacked me - and realized it would not work.

So last question is I could still tap one of the four batt to run maybe 12 volt lighting?
• Solar Expert Posts: 10,300 ✭✭✭✭
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Re: battery banks "Thinking out loud"

again the answer is no. if you need 12v from a larger battery bank you have 2 options.
1 get a converter.
2 use an inverter and then plug a power supply or wall adapters into it.
the reason you can't tap one of them is that it throws the battery bank out of equalization and it will lead to real problems for all of your batteries.
ok a 3rd option might be to have another system with another 12v battery separate from the larger one.
• Registered Users Posts: 11
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Re: battery banks "Thinking out loud"

Ok thanks. makes sense about making them unequal that why
I wanted to charge them as a series and use them as a parallel to
avoid killing one batt and subsequently killing the other 3.

Thanks for the help.
• Solar Expert Posts: 272 ✭✭
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Re: battery banks "Thinking out loud"

Another way of looking at this, realize that the whole bank is a battery. You would never think about taking a 12 v battery and just tapping two cells to power a 4 v load! When you take a 12 v "battery" and combine it with another, you are really combining modules. The modules are "sized" for weight, size and convince. These modules are then combined to make a "battery" which then must be treated as a whole.

A DC to DC converter is your best bet.
• Solar Expert Posts: 5,436 ✭✭✭✭
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Re: battery banks "Thinking out loud"

While I don't disagree with any of the previous posts in essence, the fact is that you could pull off 12 vdc off a 48 vdc battery bank,, it is just not a good idea.

That said, if the load were small enough (like a single led light, or a small vent fan for the battery box) one could make a calc that the shorter life of the battery bank was worth the trade off.

Now, once again, thinking out loud, let's assume that you have 4 12 volt batteries (or 8 6 volts), why couldn't one take a tap off of each 12v to feed the 12 volt load, such that each battery was contributing equally to the load might that not solve the problem?

Fuse all the conductors, tie them together to make a common positive and negative, it seems like it might work. (It's early and I may not be thinking clearly) but I suspect that there is something I am not thinking about.

T
• Solar Expert Posts: 386 ✭✭✭
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Re: battery banks "Thinking out loud"
Fuse all the conductors, tie them together to make a common positive and negative, it seems like it might work. (It's early and I may not be thinking clearly) but I suspect that there is something I am not thinking about.
Wouldn't that just blow all the fuses, you would be shorting the battery out. I suspect you could run a floating 12 volt LED off each 12 volt battery if balanced.
They would have to float and not have any common leads with other batteries.
• Solar Expert Posts: 5,436 ✭✭✭✭
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Re: battery banks "Thinking out loud"

Like I said, it was early and I wasn't thinking (or writing) clearly!

Tony
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Re: battery banks "Thinking out loud"

Wouldn't it be nice if there was a fast, easy way to draw a schematic and post it here? A lot of this stuff is hard to explain with words, but as they say "one schematic is worth a thousand blown fuses" (or something like that).

No matter how many diodes you put in where, whether you're talking about charging or drawing, you end up with the batteries connected in both series and parallel at the same time. That's called a short. Potentially a 'dead short'.
• Solar Expert Posts: 10,300 ✭✭✭✭
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Re: battery banks "Thinking out loud"
icarus wrote: »
Like I said, it was early and I wasn't thinking (or writing) clearly!

Tony

i'll say as i was going to ask you to post a diagram of how you would do series and parallel at the same time as tapping each 12v battery would create.:roll:
• Solar Expert Posts: 5,436 ✭✭✭✭
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Re: battery banks "Thinking out loud"

I did draw it out,, but it caught fire!

I have no idea what I was thinking,,, or not thinking! Duh!
• Banned Posts: 17,615 ✭✭✭
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Re: battery banks "Thinking out loud"
icarus wrote: »
I did draw it out,, but it caught fire!

I have no idea what I was thinking,,, or not thinking! Duh!

Everyone's entitled to a "dumb day" now and then.
I claim 364 per year (Tax Form T76-RU1)
• Solar Expert Posts: 10,300 ✭✭✭✭
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Re: battery banks "Thinking out loud"
Everyone's entitled to a "dumb day" now and then.
I claim 364 per year (Tax Form T76-RU1)

in the u s it's iq0 form f.:p
• Registered Users Posts: 8
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Re: battery banks "Thinking out loud"

Why not just connect your load leads from the first end last batteries to ensure an even drew on the batteries; also why not use the opposit post on the same batteris to connect the chardge controller to ensure an even charge? Just foog for thought, and wondering why it could not be done! Or if you have more than one charger, why not hook one up on each battery?
• Banned Posts: 17,615 ✭✭✭
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Re: battery banks "Thinking out loud"

1965 GMC - great truck!

You missed the info in the original post: he has a 48V system (four 12's in series) and was wondering about charging all the batteries from a single 12V source. Can't be done without a lot of re-wiring which would shut down the system.
• Registered Users Posts: 8
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Re: battery banks "Thinking out loud"

8) OK just asking, I did not know it was a 48V system, that changes every thing!
So let me ask, How much power would I need if I had a (3-12V batteries- 12V sysatem) to run a (12V) 2500w inverter? How many panles would I need and how big or small of a chage controller would I need to run the inverter as long as I can?:-)
• Banned Posts: 17,615 ✭✭✭
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Re: battery banks "Thinking out loud"
1965GMC wrote: »
8) OK just asking, I did not know it was a 48V system, that changes every thing!
So let me ask, How much power would I need if I had a (3-12V batteries- 12V sysatem) to run a (12V) 2500w inverter? How many panles would I need and how big or small of a chage controller would I need to run the inverter as long as I can?:-)

Don't mean to be rude but ... if that's a real question I don't understand what you're asking.
Not for the first time nor, regrettably, the last either.
• Registered Users Posts: 8
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Re: battery banks "Thinking out loud"

OK, I have a 2000watt inverter. I would like to know now much power my solar panles would have to produce to charge 3-12V bateries and how long would the batteries run the inverter? Also would I need a big charge controller or a smaller one to affectively charge the batteries?
I think this is a real question to ask as being a newbe to this forum, don't you? I would like to do my part in helping save the planet and help clean-up our air and such.
• Super Moderators, Administrators Posts: 33,478 admin
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Re: battery banks "Thinking out loud"
1965GMC wrote: »
So let me ask, How much power would I need if I had a (3-12V batteries- 12V system) to run a (12V) 2500w inverter? How many panels would I need and how big or small of a charge controller would I need to run the inverter as long as I can?:-)

It is not a question we can really answer in any way that will be useful to you...

Basically, it is like asking how much gas will this car use every week. It has a 2,500 CC engine and a 10 gallon fuel tank.

We do not know--If you drive the car for 5 miles a day x 5 days a week... You will get one answer. If you drive the car 100 miles a day x 7 days a week and pull a trailer up hills both ways in the snow--you will get another answer.

Take for example your 2,500 watt inverter--that one inverter will power my entire suburban home very nicely (if I don't run the microwave, toaster oven, sump pump, all at the same time).

If I ran that 2,500 watt inverter at full power for 24 hours per day * 7 days a week:
• 2.5 KW * 24 hours * 30 days = 1,800 kWhrs per month
But if I ran that same inverter with an average of 250 watt load for 1 month:
• 0.25 kW * 24 hours * 30 days = 180 kWhrs per month
The first number is what somebody may use with A/C in the central valley or in the desert southwest. The second number is around the lowest I ever used for my home (4 people near San Francisco) if I try really hard to conserve energy...

Assuming that such an off-grid system was 52% efficient and your area averages around 4 hours of sun per day over the year--The first system would need:
• 1,800 kWhrs * 1/30 days * 1/4 hours of sun per day =15kW (15,000 watts) of solar panels
The second home would require:
• 180 kWhrs * 1/30 days * 1/4 hours of sun per day =1.5kW (1,500 watts) of solar panels
That is the difference in off-grid system costs of \$225,000 vs \$22,500 worth of off-grid solar system (assuming \$15 per watt installed for an off grid system--you could probably cut 1/2 the cost if you did it yourself and worked to keep costs low).

For the most part, people underestimate their loads and over estimate how much power a Solar System can actually supply.

More than happy to help you size out your system--but we have two ways of doing it--1) based on your actual needs (and where the system will be installed) we can estimate how large a system you will need; or 2) give us a cost/system size, and we can estimate how much power you can get out of it.

If you are looking to power an off-grid home/cabin, you probably should estimate around 1-3 kWhrs per day worth of power use (~30-100 kWHrs per month)---Basically, powering everything from propane except maybe an energy star fridge (assuming lights, computer, small fan, radio, etc.).

In the end, conservation will be your friend here for off-grid solar power. Very roughly, off-grid solar will cost you around \$1-\$2+ per kWhr, vs the \$0.10-\$0.20 per kWhr that most people are used to paying (hardware, replacement battery banks, fuel for backup genset, etc.).

-Bill
Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
• Banned Posts: 17,615 ✭✭✭
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Re: battery banks "Thinking out loud"

Ah, well, you see batteries come in many different capacities; Voltage alone is not the issue.

So we go back to the basic issue of how much power you need to supply. A 2 kW inverter doesn't need to supply 2 kW all the time, but rather can supply up to 2000 Watts. Over the time loads are applied this becomes Watt hours - or as we're used to seeing on our electric bills kiloWatt Hours.

One Watt hour on a 12 Volt system is roughly 0.09 Amp/hrs. Another way to look at is: every 100 Amp/hrs of battery on a 12 Volt system is approximately 1.2 kW/hrs (except for the loss factors and DOD limits).

To recharge those Amp/hrs you need not only to 'replace' them, which involves putting Amps into the battery over time, but also to do it at a suitable rate to keep battery life up - without 'cooking' it - and supplying the energy lost to inefficiencies in charging.

There's lots of FAQ's available here, beginning with the battery FAQ http://www.windsun.com/Batteries/Battery_FAQ.htm#Battery%20Charging - batteries being the 'center' of an off-grid system.

To supply 2000 Watts on a 12V system you need approximately 167 Amps. To supply this continuously for 20 hours (24 hours minus 4 hours 'good' sun re-charge time) would require about 3340 Amps. To recharge you'd need 434 Amps @ 14.2 Volts = 6156 Watts of panel - plus 2 kiloWatts more for the constant power consumption and a loss correction factor means about a 10,000 Watt array. And good sun.

I've probably made at least six mistakes in that last paragraph, so don't count on it.
• Registered Users Posts: 8
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Re: battery banks "Thinking out loud"

First off, I wont to thank you for taking the time to explain that to me.

I can do most of the work my self, I'm just having a problem with the numbers. I know how to biuld solar panels, but I don't know how big to build it or how many I would need. I am in an area where there is 3-3.5HR of good sunlight.
I want to power a very small fedge,desk top, low power lighting, small fan, and maybe a hot plate; I only use in bad wheather for I solar cook most all my meals. I will be powering a 20foot camper.
Lets say I build 3 solar panels with 36-3x6 solar cells, which put out 3.5V each cell which should give me 18watts. Will this be enough to power my needs and how long could I have power once the sun goes down?
When I fist got the inverter, I tested it on a 12V care battery, turned on every thing on and the power lasted about 45min before the battery voltage dropped from 12V to 10V which should be about 75 to 80% of power left in the batery.
With this lay-out, how well the system perform, and what kind of charge controller would I need?
I hope this is enough information for real help, thank you for your time and knowledge
• Banned Posts: 17,615 ✭✭✭
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Re: battery banks "Thinking out loud"

Okay, some load warnings.
Hot plate = very bad. In fact, for off-grid power anything that heats with electric is a no-no. Electricity is a dreadfully inefficient heater. Have you considered propane? Much better heat source.
Then there's the small 'frige. Refrigerators are hard on solar too, because their start-up currents are substantial. This applies to anything with an AC induction motor. On a per-cubic-foot basis, the small ones aren't as efficient as the big ones. You might be better off with the 3-way type that are common to RV's.

The best way of designing an off-grid system is to get a firm handle on the loads. If you can come up with a daily average Watt hour need and a maximum draw you can figure out what you need for an inverter, battery bank, and panels to charge it with.

Most of us here are reluctant to recommend the use of home-made panels. They can be a good learning experience and interesting for experimentation, but there are two issues with them. The first is that you really can't build a panel as well as a manufacturer can - the efficiency will be lower for one thing. The other, related issue is safety. There are problems with home-made panels burning up. It's impossible to duplicate the factory quality, including the use of non-combustible materials and good weather-tight sealing.

You state that in your testing the battery dropped from 12 to 10 Volts. Voltage isn't a reliable indicator of a battery's power, but 10 Volts is dead for a 12 Volt battery. 12V inverters shut off when the battery Voltage reaches 10.5.

For the applications you mention, 18 Watts isn't much. Consider a standard CFL light: 13 Watts. Your one panel would just about manage to run one of those for the equivalent of however many hours of daylight you get.
• Super Moderators, Administrators Posts: 33,478 admin
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Re: battery banks "Thinking out loud"
1965GMC wrote: »
I can do most of the work my self, I'm just having a problem with the numbers. I know how to build solar panels, but I don't know how big to build it or how many I would need. I am in an area where there is 3-3.5HR of good sunlight.
I will warn you--I am not a big fan of building your own solar panels--but that is for another thread.

Regarding your 3-3.5 hour of sun light--is that from 11am to 2pm type sun light, or is that from a solar irradiation table for where you live?

Normally, we recommend that a solar panel be free of shade from ~9am to 3pm every day... If you have any shading during the middle of the day, it becomes very difficult to collect very much useful power from PV panels.

When we talk about "4 hours of sun per day"--we are talking about solar panels that are in full sun from morning to night, and it is the equivalent of 4 hours of noon time sun (1,000 Watts per Square Meter)... In winter, many areas get 2-3 hours of sun per day. And in summer it may range from 5 to 7+ hours of sun per day--All very dependent on the local weather conditions and where on the earth your system is.
• I want to power a very small fridge,desk top, low power lighting, small fan, and maybe a hot plate; I only use in bad weather for I solar cook most all my meals. I will be powering a 20foot camper.
Believe it or not--a "small bar refrigerator" uses only a bit less power than a full sized Energy Star refrigerator (maybe 250-300 kWH per year for a 1-4 cuft bar/dorm fridge vs 350-400 kWH per year for a full sized 15-20 cuft fridge).

A desktop computer may use 100-200 watts whereas a low power notebook computer may use 20 watts--Or upwards of 1/10th the amount of power.

Small loads that run 10-24 hours per day vs large loads that run 10 minutes per day (say microwave for 10 minutes or 1/6th of an hour per day) can be much more energy intensive:
• desk top computer: 200 watts * 10 hours = 2,000 WH per day
• note book comp: 20 watts * 109 hours = 200 WH per day
• Microwave: 1,200 watts * 1/6 hours per day = 200 WH per day
• Refrigerator = ~ 1,000 to 1,500 Watt*Hours per day
You really need to measure your true loads to know how to design the rest of the system around your needs.
Lets say I build 3 solar panels with 36-3x6 solar cells, which put out 3.5V each cell which should give me 18watts. Will this be enough to power my needs and how long could I have power once the sun goes down?

Generally, a solar cell outputs maybe 0.5 volts and 3.5 amps for a large cell. Put 36 of those in series:
• 0.5 volts * 36 series cells = 18.0 volts
• 3.5 amps * 18 volts = 63 watt panel (just guessing)
Using a notebook computer, a little for lighting and water pumping, and such--you probably need around 500-1,000 watts of solar panels for your needs. Add a refrigerator, and you would need another 1,000+ watts of solar panels.
When I fist got the inverter, I tested it on a 12V care battery, turned on every thing on and the power lasted about 45min before the battery voltage dropped from 12V to 10V which should be about 75 to 80% of power left in the battery.
It really does not tell us much--No idea of how full the battery was. How good the battery is. Or what the Amp*Hour capacity of the battery was.

Sorry...
With this lay-out, how well the system perform, and what kind of charge controller would I need?

Once you know how much power you need and such--then you pick what solar charger you need. They run from a few amps to 60-80 amps and the battery bank voltage runs from 12 volts to 48 volts. In general, if you have less than 400 watts of solar panels, you probably can get away with \$100-\$200 charge controllers. If you have > 400 watts--you are probably looking at \$300-\$500+ solar charge controllers.
I hope this is enough information for real help, thank you for your time and knowledge

I am sorry--but not really... You can measure your AC loads with a Kill-a-Watt meter and your DC loads with an Amp*Hour/Watt*Hour meter.

Sizing your system is important--If not well thought out--you will have just wasted a lot of money.

-Bill
Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
• Registered Users Posts: 8
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Re: battery banks "Thinking out loud"

Thank you gentalmen, it looks like I am back to the drawing board with this thing. It seems I need to produce too much power for what I have to spend, disite my inverter ability to surges up to 4000W
Well for the future, well it be better to use welding wire to connect my batteries or should I stick with oldfashioned battery cables. The reason I am asking, I heard it said that DC flows batter through welding wire, thought I'd ask.

I know those three-way fredge your talking about and two-way also, they are very costly. I will study the information you guys gave my and keep working on an off grid system that will not kill my or brake my. I do have a laptop on the way, so that will help a lot. I don't use propain because it heats up the place too much in the summer. Whats why I solar cook, but it seems this is something I will have to do to cut my load. I have no room for 15 to 16 panels to 63w each. I have no chioce put to puy.
Here is a thought, would it work if use more efficient cells combined with a mettal fram, rese, and glass? Which is the way I would have made it any way without the rese.
• Banned Posts: 17,615 ✭✭✭
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Re: battery banks "Thinking out loud"

Wire is wire, except when it's aluminium.
The reason why 'welding cable' is better than automotive battery cables is because it's bigger. Typically battery cables are 4 AWG, and welding cable will typically be 2/0 or larger.

See the wire gauge explanation here: http://en.wikipedia.org/wiki/American_wire_gauge

In some ways welding cable is worse, but that's in the realm of technical stuff that you shouldn't worry about really.

You've just discovered the worst part of solar electric: it's bloody expensive! As a rule of thumb, off-grid power is produced at a cost of about \$1 per kiloWatt hour over the lifespan of the equipment. The reality is, commercial solar panels are only about 18% efficient, there's loss in wiring, loss in charge controllers (about 90% efficient), loss in batteries (takes about 25% more power to put back what's been used), loss in inverters (about 90% efficient). That's why it's reasonable to predict that by the time you get to AC Watts you've only got about 50% of the 'nameplate' rating of the solar panels.

Rather discouraging, isn't it? But you'll find this is a 'realist' forum, not a "solar panels are the answer to all mankind's woes" forum.
• Super Moderators, Administrators Posts: 33,478 admin
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Re: battery banks "Thinking out loud"
1965GMC wrote: »
It seems I need to produce too much power for what I have to spend, despite my inverter ability to surges up to 4000W
For the most part, the expensive side of solar power is "generating the power" (solar panels) and storing the power (battery bank)...

Solar panels are about as cheap as they are going to get (my 2 cents guess)--but batteries are expensive and getting more so. The rest of the hardware (inverters, charge controllers, etc... are probably not getting cheaper anytime soon).

It is sort of like having an old V8 van--they don't cost much to run until you start driving. Then you dump a lot of money on gasoline.
Well for the future, well it be better to use welding wire to connect my batteries or should I stick with old fashioned battery cables. The reason I am asking, I heard it said that DC flows batter through welding wire, thought I'd ask.
Copper cable is copper cable... Welding cables tend to be finer strands and therefore more flexible. However, the finer strands are actually more difficult to swag/bolt up than heavier stranded copper wire (more "air space" in fine strands). At higher frequencies and/or larger gauge cables (not DC), finer strands do have a lower impedance (skin effect).
I know those three-way fridge your talking about and two-way also, they are very costly. I will study the information you guys gave my and keep working on an off grid system that will not kill my or brake my.
Look for used RV appliances (wrecking yard?). You may find some good deals.

A cooler that is used for weekends/seasonal use--propane may be a better choice. If you are using a fridge 24x365, an energy star fridge + more solar panels and batteries may be a better choice. Check out the "chest freezer as a fridge" conversion thread--may use 1/4 as much power.
I do have a laptop on the way, so that will help a lot.
If you have a satellite internet service/etc.... Turn your power off--many electronic devices use almost as much power when "off" as when on (such as DVRs/satellite receivers, etc.).
I don't use propane because it heats up the place too much in the summer.
Cooking outside/external structure?
Whats why I solar cook, but it seems this is something I will have to do to cut my load. I have no room for 15 to 16 panels to 63w each. I have no choice put to buy.
I am guessing on your panels and what you typed--I am not saying how much your design/parts will produce. However, if you can swing factory made panels--you would be better off.
Here is a thought, would it work if use more efficient cells combined with a metal frame, rese, and glass? Which is the way I would have made it any way without the rese.
Crystalline Silicon cells are the most cost effective for use by us earth bound mortals (space rated cells are a different animal).

There are cheaper panels that are called Amorphous (and other names like "thin film") that cost much less to purchase, but they are also about 1/2 as efficient--so you need twice the square feet for the same energy collection...

-Bill
Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
• Super Moderators, Administrators Posts: 33,478 admin
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Re: battery banks "Thinking out loud"

Sorry, I forgot to add a link for the Kill-a-Watt meter... And here is an example of a DC Amp*Hour/Watt*Hour meter.

-Bill
Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
• Solar Expert Posts: 5,436 ✭✭✭✭
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Re: battery banks "Thinking out loud"

As for "propane" heating up too much??? If you are cooking, with the proper amount of heat for the pot/oven etc one could argue that propane heats up less. The fact is that a propane burner gets hot right away, not wasting heat into the room as it heats up, and when you turn it off, it is off right away, without having to cool down into the room.

As for a propane fridge heating up a space more than a conventional. There is probably some merit in that argument. That said, a properly designed fridge enclosure (for propane) that draws combustion and vent air into the enclosure from outside the building, vents the combustion gases out of the building, passes ventilation air over the coils, and then vents that air out the building is essential for efficient use of a propane fridge. Net/net with a properly designed installation, the amount of heat introduced into the room is probably less than with a conventional fridge. (I also add insulation to the boiler of my fridges to allow the to run a touch more efficiently, but mostly to keep the excess heat off the condenser coils)

The following is probably the best LP fridge site I know of. There is extensive discussion on the hows and whys of venting fridges: http://rvmobile.com/Tech/Trouble/vent.htm

There is also a very learned forum to trouble shoot problems with various fridges, much like this one. (follow the links from the above link)

Finally, the inverter should be nearly the last part of a system to look at as you design it. Start with the loads, and work to the solutions on how to power those loads within the size/budget range you have. Because you have 4000 watt inverter, doesn't mean you can power 4000 watts worth of stuff from it!
• Registered Users Posts: 8
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Re: battery banks "Thinking out loud"

icarus, I understand your point, I do not have a 4000w inverter. I have a 2000w inverter that can peek to 4000w. Your right I cannot pull 4000W's of power from it any longer than it takes a motor to start-up. From the information gathered here, my new goal is to cut my load as much as I can, even if I have to turn something off to use something else. As I see it the biggest draw is the fridge and I have a laptop coming so that will cut down the draw as well. I will get the metters Moterater was telling me about to see if I can duild my system around my draw once I find out exactly what it is.
I have a panel I built to see what it can do, and to test my design against the weather. So, I have found out from this forum, that is a bad idea. I have to rethink evey thing to do this thing right and cut my cost where I can, and it seems the only way to cut cost is to think and try things to test my thoughts. Thank you for your input and knowledge, all is welcomed as I am learning the art of solar power.
I will check-out your links and get back to you on what I find there, for they are very costly and push come to shuve I will run the fridge off the gride and every thing else from solar power to start with. A 2000W inverter should handle every thing well with room to spare, which I will not use all the time. Maybe run a power tool here and there.
• Solar Expert Posts: 5,436 ✭✭✭✭
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Re: battery banks "Thinking out loud"

I confess that I haven't this thread from the beginning, but if you have the grid available, I would suggest that if you are going to experiment with solar that's fine, but if you are doing it so save money, the grid is way cheaper than solar. If you wish to experiment the fridge may not be the place to start.

Like I said, I haven't read to the beginning so I am not clear as to what it is that you are trying to achieve.

Good luck,

Tony