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Separating battery from charging

elewis33

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Feb 13, 2020
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I've built a small solar power pack (20ah battery) and included the solar charge controller on-board with the battery and power outlets. However I want to add an AC power charger and there's not enough room in my current box to fit it all in. In the spirit of being as modular as possible I've been considering putting the SCC and AC charger in a box of their own and only having the battery, inverter and power in/out options in the battery box.

I'm thinking that the battery box could potentially have one 12v power input/output and the 110 outlets. The charging box could have the inputs separated (solar vs AC) with the output to the battery combined, because presumably the SCC and the AC charger are going to be putting out roughly the same charging voltage (the amperage of course would differ).

The logic behind this is that it's a little more portable than an all-in-one box and I can just grab the charging box and plug in the charging when/as needed. This is really more of an experiment than anything, since it's a pretty small system to begin with.

What do you guys think? Is it worth separating these things out into separate boxes? Or should I just bite the bullet on a bigger box and "start over"?
 
When I see a 20 ah battery pack, that is 240 watt hours total, 110 watt hours which is usable, so that does not have a lot of power. If those are your power requirements, that is fine. I also think that for those power requirements, you could get DC devices and not worry about an inverter.

For me, whether or not its one box or two boxes, would just depend on how professional the product would be. Not sloppy looking in other words.

To me, I think the Power point I designed for my bunk looks OK. However, the first place I tried to put it is not good. You can see the hole. A little bit of sparkling compound fixed that hole.BCF0E949-2FAE-48C3-A742-244AC15CC4F3.jpeg
 
You're right, right now those are pretty modest power requirements. I use the inverter to run an electric fan on the wood stove in our yurt. Right now the inverter just plugs into the cigarette outlet in the power box if we need it. That fan is the only thing I have, besides power tool battery chargers, that I absolutely have to have the 110-120 volts for (no 12 volt blower motor that I've found yet). And we typically charge the batteries for the tools at home or a nearby family home if we need to.

I've made some 12 volt lighting for the yurt (photo) and that and charging phones is the main requirement right now. I plan on finding a 12 volt RV ceiling fan to help exhaust hot air in the hotter months. Hopefully that will work out and I won't have to add to the 110-120 volt requirements.

Of course power requirements will evolve and I do have a 100ah SOK battery on order, so everything evolves i suppose.
 

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I found to move a bit of air, 12 volts may not be enough.

My propane blower motor at 12 volts and 6 amps does move air, but for me to be comfortable using using it overnight I’d want 100 ah, especially the long winter. Nights where I’d have no useable solar for 18 hours.

Even the 12 volt bathroom fan uses around 2 amps so that adds up.

I’m not sure what type of batteries you have, but my lead acid can only take 1/8 their rating in PV amps. Lithium’s may be 1/2. So I can’t push more than 13 amps per 100ah of battery for my lead acid or 50 amps per 100 ah of battery if I had lithium.

So with just a 100 ah battery and constant loads, your panels have a limit it can push into the system.
 
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