Need help with a small heater setup

[Davious]

Hi all,

First post here, seems to be a good place for help

Years ago I converted a van into a camper van (RV) and fitted it with a small solar panel to charge the leisure batterys that ran the internal electrics, water pump, gas heater system (fan) etc.

I have scrapped the van a few years ago but still have the following equipment from the van :

An Astropower Solar Panel Model ap 50 50 Watts, 16.7 volts rated, 3 amps

2 Elecsol 90 Leisure Batterys (carbon fibre) which I think are 110 amp/hour

and a Fox 40 regulator.


What I would like to do is get some free heating by using this equipment to power a small room heater to help cut down on fuel bills.

As far as I remember I connected the feed from the panel to the fox, then to the batterys. (the fox has a simple diagram showing what to connect and where )

Questions:

The batterys are quite old now, but I have kept them topped up while in storage with distilled water. However they have not been kept charged.
Should I use a car charger on them to get them to full power before connecting the panel? how can I tell if they are beyond use? I have a tester, but dont know what to look for.


What , assuming the batterys are ok , would be a good system to use for the heater? I want to use the heater just to boost house heat, helping to save money. But the panel and heater would be seperate from the house system.

Can I get a 12v caravan/RV heater and run right off the batterys, or do I need to get an inverter to power a conventional 220v heater.

Any help you can give me is very appriciated. I need recommedations for the heater and help with the wiring.

Thanks in advance.

Dave

(Ireland)

Questions:

[denisl]

Not familiar with RV heaters but you are not going to get much heat from 50 watts

[Sunking]

Well I assume you are talking electric heat right? Forget about it unless you want to pay 30 times more for electricity than you do now.

For one your battery was toast years ago, but that is the least of the problems.

If this for electric heat let me run some numbers for you. Let's say you want to run one of those little 1500 watt heater. You know those little things people might buy to heat an extremely small room or maybe take to the office and put under their desk to keep their feet warm. And let's say you want to run it just 8 hours per day, and you live somewhere like Kansas City.

1500 watts x 8 hours = 12,000 watt hours or about $1.50 worth of electricity per day.

It would take a 6000 watt solar panel array at a cost of $18,000. You already have 100 watts.

With a 48 volt battery bank for this monster of a system would require 1900 AH battery stack at 48 volts the size of a very large kitchen table, weigh around 6000 pounds, and cost about around $12,000 plus a whole room to house them. Keep in mind they have to be replaced every 5 years on average at even higher cost.

You would need at least 2 top of the line 80 amp MPPT charge controllers that would cost about $500 per unit so $1000

Then an 2000 watt inverter at around $1000 or slightly more for a good one that can take that kind of abuse.

Then around $3000 for misc material, and around $5000 for permits, labor, inspection, and test equipment to maintain it all.

Total bill around $40,000 for what amounts to a foot warmer. If you used it for say just 3 months per year, the first 5 years per kwh cost when the batteries need replaced comes out to 12 Kwh per day x 90 days per year x 5 years = 5400 kwh, so $40,000 / 5400 Kwh = $7.40 per kwh to replace what you can buy from the power company at around $0.12 per Kwh. Ok I messed up with this example you would pay 61 times more for power.

Can I sign you up?

[Mike90250]

testing your batteries: Get a meter, test your car's starter battery, engine off, should be about 12.5 - 13V This makes sure your meter is good. Now test your stored batteries, if they are under 11.5-12V, they are likely toast. a year stored, no charge, they should be about 50% charged, which has sulphated the cells. sorry


Solar electric for heat, is not very efficient. Look into some of the Solar Air heaters, DIY versions are all over the place, even here!

[Davious]

Thanks for the messages, I will test my batterys but dont hold out much hope

Maybe I'll get my propex out of storage and use that, it's a gas one so would have the cost of buying the canisters. The batterys and panel would then just power the fan not create heat.

Thanks for the breakdown on the figures, I'm a noobie at this and just wondered what I could do to save cash. Any other applications for this kit>?

I appriciate the replys and explanations, thanks!

[Sunking]

Thanks for the messages, I will test my batterys but dont hold out much hope

Maybe I'll get my propex out of storage and use that, it's a gas one so would have the cost of buying the canisters. The batterys and panel would then just power the fan not create heat.

Thanks for the breakdown on the figures, I'm a noobie at this and just wondered what I could do to save cash. Any other applications for this kit>?

I appriciate the replys and explanations, thanks!

The panels should be fine and usable, although the amount of power than can generate is very limited they could be used to say charge a laptop, cell phone, and a few small battery powered devices but not practical to to do much with. Your battery is likely ready to be used for a boat anchor.

Do you have natural gas at your home?