I've got a small sealed lead-acid 12V 1.3Ah battery I need to frequently keep charged (wireless tow lights), and I have some problems to solve around that.
1. The charge cord for the battery is "dumb" and just a simple lighter socket plug-in. If you follow the manufacturer's advice of "you can leave it plugged in all the time" you will kill the battery by over-charging it. Seen it happen many times, you'll leave it plugged in because you forget to unplug it.. boom, seriously shortened battery life.
2. I'd like to source an automatic charger that actually does what it claims. It seems the Battery Tender type stuff still just boils people's batteries to death. The charge cord plugs into a small socket on the bottom of the tow light housing. Whatever suitable charger I might find, I'd just hardwire the output to that charge cord end, and hardwire the input side of the charger to a 12V supply in my truck.
There's all kinds of 120V->12V stuff that claims to do this (Battery Tender, Noco Genius, etc.) but I need a 12V->12V solution so it can live in my truck.
The batteries:
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Any ideas? Thanks!
Richard
You might want to look into marine equipment and post the question on sailing forums.
Battery charging is a real major issue on sailboats.
These days solar seems to be the cheap easy option.
Back before cheap solar was available I just used a battery isolator switch and a dedicated volt meter for each battery.
The battery switch has
Off
Bank 1
Bank 2
Both.
Bank 1 is the start battery
Bank 2 is the "house battery"
Both is both charging.
So you can switch too bank 1 charging or bank two or both etc...
You then wire a dedicated volt meter to each battery but not to " both"
The volt meters are on a switch were you can check battery voltage without putting it online to charge and these days you can buy a voltmeter that will light up when that battery has low charge or full charge or overcharge.
You still need to moniter what is going on but the led volt meter will tell you about it.
If you have an obd2 vehicle and you dont want to loose power if you switch it to off you can just wire all of your start systems as bank 1 and not wire the off side at all.
That still keeps bank 2 isolated but monitered.
But you cant switch banks or add banks while it is running unless you have a way to isolate the sudden load and the potential backfeed if your low voltage is from a shorted battery cell.
That is a whole different problem and would require some type of a diode setup that is way beyond me.
I know you can buy them, I just am not qualified to tell you how they do whatever it is that they do.