fridge draw

[Ryan Kennelly]

Im with Steves', The optima is not the way to go, Go with the Exide or delco Group 31. they have a 5 year warranty, and don't mind being cycled a few times! But if you drop a cell, the warranty will fix that! Also, beware of the solar, I've heard of people overcharging there batteries, and boiling them. Batteries like to be topped off, they last to there full potential.

Good luck, Ryan

[Brian B-P]

...Also, beware of the solar, I've heard of people overcharging there batteries, and boiling them...

Any battery charging source requires control, and a solar panel is no exception. My 30W panel came with a warning to use a [b]charge controller, but the units up to 15W are claimed to be safe just connected directly - they can't push enough current through a typical battery to hurt it.

The most basic approach is to unplug it when the battery is appropriately charged, but this doesn't seem like a good idea to me.

The next step up is the same scheme as a basic automatic charger, which shuts off at a set voltage: the solar version is the same cutoff relay, set up to turn back on at some lower voltage. I have one of these, but it took weeks to get one since the store (Canadian Tire) never had them in stock. Mine can only handle 7 amps, but it was about $20, and all the other brands I could find were substantially more expensive.

More sophisticated controllers act like the nice three-stage chargers, but with a solar panel as a source instead of being plugged into AC power. One of those would be as much as a 15W panel, but I'm sure it would be worthwhile in a major solar installation.

The best solar panel power contollers are maximum power point tracking units, which step the panel output voltage up or down for the battery so both panel and battery are at optimum voltage. Very cool, very pricey, maybe worthwhile as an alternative to buying more panel.

It would be interesting to compare the total cost and weight of a 12VDC Norcold refrigerator plus enough solar panel, controller, and battery to keep up with it, to a 3-way fridge of the same capacity. The same comparison could be made with the Norcold, a battery, and a small generator verus the 3-way. Those 3-ways are expensive, heavy, and bulky (counting the venting space).

[colin k]

Good stuff Brian. Where would one find a panel for my application? Is there a canadian website that sells panels and controllers? I would like to start sourcing things out and any guidance would be much appreciated.

Also. I would like to just get a group 31 battery but i have to mount the battery inside so i would have to vent it. Can you get a group 31 in a sealed battery so i dont have to vent?

[Brian B-P]

...Where would one find a panel for my application? Is there a canadian website that sells panels and controllers?...

Also. I would like to just get a group 31 battery but i have to mount the battery inside so i would have to vent it. Can you get a group 31 in a sealed battery so i dont have to vent?

There's now another topic for just this question: [b]Canadian Solar Panel, Where to buy. I'm no expert in this area - I bought my panel and cheap charge controller at Canadian Tire, and generally don't buy major items online (I like to see stuff in person). They're online, and so are many of the RV dealers who carry solar stuff.

While gell and AGM batteries do not vent except as an emergency pressure relief, the Safety and Handling page on the Optima website still says

Install battery in a ventilated area for operation and during charging.

I doubt much vent is really needed, but I don't really know. A compartment with some outside ventilation and effectively closed off from the rest of the interior seems like a prudent idea to me.

[colin k]

Thanks Brian. I have the battery problem figured out. Finally.... Im going with a group 31 and building a battery enclosure under the dinette. While sitting at the dinette i found that there is a good chunk of space by your knee/foot that could be used. So its built and ready for a battery install. Just have to put a vent on the outside .