Solar Maintainer?

[Riwright]

I was wondering if anyone was using a solar battery maintainer that they are happy with. I bought the Deltran Battery Tender 15 Watt model but after only a few months in service it shorted out nearly causing a fire (I was at the trailer when it started smoking and was able to use by new battery shutoff switch).*

So I am looking at getting something different.*

I usually take frequent, short trips. I tend to favor shaded campsites. I am working towards doing a lot of dry camping. The storage lot where I park my TM has no electricity. *I have a Honda 2000 generator and a Progressive Dynamics converter. I am in Southern California so there is a lot of sunshine.*

I don't know if the kind of full-bore 180 watt solar setups that are discussed here would be worth the money for me. They would certainly keep the batteries topped off between trips but if I camp at shaded sites I will rely on the generator.*

I am thinking that something in the 45-80 watt range might be good for me. If I come back from a trip with my batteries 100AH lower than they need to be then a panel of this size could top them off in a week or two. The most important thing that I need the panel to do for me is to take a partially discharged set of batteries and top them off while the trailer is parked.*

I'd also need a good charge controller. Since it will spend a lot of time attached to this rig I don't want a "battery boiler" that will kill off my batteries in a year.*

My price point is around $200. I was looking at getting an 80 or 100 watt panel and a separate charge controller. This would be nice and I would have the capability to upgrade if I do get the "solar bug" but I don't know if I can hit that price point.*

If you read the rvdoctor (http://www.rvdoctor.com/2010/05/rv-b...rcharging.html) he will tell you to NOT keep your battery charging all the time, top it off and then disconnect it for storage. By the way, if you never heard of this guy his web page is one of the best for solving problems in your RV, from each appliance to Thetford toilets, to tires, axles, bearings, etc.

[Bill]

As Clown and the RVDoctor point out, the best thing is to fully charge your battery(ies), then completely disconnect them and leave them alone. They will hold a charge quite nicely over a period of a month or two - no need to get overly fiddly with them, as my Brit friends would say.

Note that they must be completely disconnected. Any trailer or RV has a few parasitic loads that will quietly drain a battery in storage if allowed to do so. This is best accomplished by removing a wire from one of the battery posts (doesn't matter which one) or pull the fuse out of the fuse holder (near the positive basttery post), or put in and use a battery cutoff switch, which it sounds like you have.

You should start your storage period with the batteries fully charged. Your generator can do this while you are at your campsite. Alternatively, you probably swing by your house after a trip, so you can de-stock the refrigerator, bed linens, etc. This would be a good time to plug your camper into house power for two or three hours, and let the on-board charger bring your battery back. Or, if you are lucky (not all of us are), your tow vehicle will charge the battery as you drive home. Anyway, when the batteries are charged, take the trailer to the storage yard and disconnect the batteries.

Do you park your TM in covered storage? As you know, solar panels won't do you any good if they are in the shade.

Finally, you need to distinguish between a battery maintainer (which assumes you already have a fully charged battery) and a battery charger (which assumes you want to recharge a discharged battery, or keep up with the load in real time). A maintainer, solar or not, won't do you any good when you are dry camping. In the ideal case, you want to have enough charge capacity (solar, generator, whatever) to keep your batteries from discharging deeply while you are camping. Conventional batteries (motor start batteries or Marine/RV batteries) don't tolerate deep discharge well at all. True deep cycle batteries are better, but deep discharge will still shorten their lives.

Bill