Maintaining batteries

[kweinert]

OK, so I have had the issue with the inline 30A fuse blowing. Batteries weren't getting charged and they're now out an on a charger. Hopefully I caught it soon enough that they'll recover.

I do have some follow on questions:

I have two 12V deep cycle batteries connected in series. I attempted to use one of the 1.5A Harbor Freight solar chargers to keep the batteries charged up while it was in storage. At this point I can't tell you when the fuse blew.

Questions:

1. Is the 1.5A charger sufficient to keep both batteries charged up? It's just plugging in to the solar on the frame plug right now.

2. I was reading the reviews on those solar chargers on HF and one person said the he had 1 per battery and the negative was disconnected. If this is what's needed my guess is that I need a negative disconnect for each battery - the one closest to the TT and the one between batteries. Is this correct?

3. If one is sufficient then I still need a negative disconnect between the battery closest to the TT and the TT, correct?

Anything I do here is meant to be short term as we have plans to add 200W of solar to the roof and put in a proper charge controller before we go camping next spring. It's almost time to winterize here and so leaving the batteries disconnected and on a maintenance charger is certainly a viable way to go this winter. I'd just like to have a better understanding in case the occasion comes up where those small solar chargers would work.

Thanks.

[MichaelO]

First of all are your 12v’s actually in series or parallel? In series you would be putting out 24v’s to your trailer. In parallel you are putting 12v’s to your trailer.

I personally would skip the habor freight solar charger and put the money towards the solar setup you plan to put on. Does it snow where you live? If it does the snow will cover the solar panel and you will get nothing. In that situation you would be better off putting them on charger hooked up to a/c. Something like a battery tender would be a good choice. When you do the 200 watt solar kit for your trailer I recommend the Renogy brand. You can get two 100 watt panels and a controller that can handle more panels if you decide to upgrade in the future. Do you normally camp where there are trees that can shade part of one of the panels? If you do you’ll want to wire your panels in parallel and not in series.

[kweinert]

You are correct, they are in parallel.

It definitely snows here, but it doesn't usually stick for long periods of time.

Im pretty sure that I'll be putting the collectors in parallel when they go on.

[Nathan S.]

There are wiring diagrams and calculators on the renogy website which are very helpful.

A couple comments on your future install. If you are just going to use the panels to maintain your batteries then 200w is more than enough, you could even get by with a single 100w panel. But if you plan on installing an inverter so you can run some AC plugs or your entertainment system while boondocking, then max out your capabilities. You have 30 amp wiring in your TT already. Once you decided on the panels you want look at their output and that will determine how many panels you can put on your roof. The panels I picked, put out about 9.4 amps each. I put 2 up for a total of 340w. I’m going to add one more panel to get to a total of 510w and an optimum output of 28.8 amps. Also keep in mind your roof space and moving around up there. (Not my favorite place to be) That’s why I picked a slightly larger and more expensive panel in addition to the increased performance.

You have all winter to figure this out. It’s a bit mind boggling if your not an electrician, which I am not.