Will this work? Inverter to battery hooked to charger...

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Will this work? Inverter to battery hooked to charger...

Postby Poorlytiedfly » Mon Apr 04, 2016 2:01 pm

I am to the point in my build where I need to layout my electrical system. From the start I have wanted to have a relatively simple electrical system and did not want to worry with 15/30amp fuse boxes, separate A/C and D/C power systems, etc. What I am planning is to primarily power my TD with D/C power from our deep cycle marine battery so here is my question… assuming I have the DC items in my trailer wired directly to the battery and the A/C items plugged into a 1000w inverter coming off of the battery – can I also have a charger hooked up to the battery ready to plug in to shore power or our generator when I need to charge up the battery? Below is a pretty pathetic picture of what I am thinking about doing. I have searched online for an answer but keep getting folks looking to power a battery charger off of an inverter hooked to the same battery... :thinking: that isn't what I am looking to do.


My teardrop will have the following inside:
Cabin – A/C powered:
28” LED TV consumption 50watts
2 x 120v AC power outlets

Cabin – DC powered:
3 x LED ceiling lights
Car Stereo/CD/DVD player with speakers
2 x outside LED porch lights
2 x 12v DC accessory outlets (cigarette lighter sockets)

Galley – A/C powered:
2 x 120v AC power outlets

Galley – D/C powered:
2 x LED ceiling lights
2 x 12v DC accessory outlets (cigarette lighter sockets)
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Re: Will this work? Inverter to battery hooked to charger..

Postby capnTelescope » Mon Apr 04, 2016 2:37 pm

This will work, but with a big but. If the DC + inverter load is greater than the charger's rated amperage, the battery will continue to discharge, only more slowly. And the charger may become unhappy because it would be running at full capacity = heat. You probably won't run everything all at once, in which case you're probably OK. Just turn off the inverter when not in use.

What you might want is something more like this:
Don't let this scare you. This will allow you to charge while towing, and by adding an inverter hooked directly to the battery, run your 120V stuff even in the boonies. Adding another relay to switch your 120V system from shore to inverter power, and you have complete automatic convenience without remembering to throw switches, etc.

I hope I didn't completely lose you. :oops: It isn't really that complicated. I'll redo that diagram to show everything.

good luck! :beer:
I'll burn that bridge when I come to it.


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Re: Will this work? Inverter to battery hooked to charger..

Postby daveesl77 » Mon Apr 04, 2016 4:59 pm

I assume when you said directly to the battery you did mean through a fuse block. It is cheap, easy to install and will help keeping things from burning up the camper if a circuit gets shorted.

Next, if the TV draws 50 watts on 120v AC, then that is essentially .5 amp at 120 or 5 amp at 12 plus inverter. Inverter runs at about 90% at best efficiency, so figure 6 amp draw on 12 volt side. I find that number awful low for an operating TV, but maybe so. While the inverter is rated for 1,000 watts, that normally doesn't work so well with a "resistive" load, like a toaster oven. You are going to run wires to the 120v receptacles, so you might as well put in an actual 120v circuit(s). Not hard to do or expensive. If using a compressor on anything you must take into account the initial surge load, which can be 8-10 times higher than the running amp draw.

Dave and Regina - Enjoying old age, a LOT!

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Re: Will this work? Inverter to battery hooked to charger..

Postby MtnDon » Mon Apr 04, 2016 5:29 pm

Why a 1000 watt inverter? Just curious; it's not necessarily a bad thing. What 120 VAC devices do you plan on using? Some 120 VAC devices, like microwaves, operate much better on pure sine wave power. Other devices like plain old toasters don't care. In general electronics like PSW best; and last longer. Inverters that are bigger than necessary have higher losses when running small AC loads.
Our 6x12 deep vee nose cargo trailer camper conversion... viewtopic.php?f=42&t=58336

We have a small off grid cabin we built ourselves in the NM mountains; small PV solar system; 624 watts PV, Outback CC & inverter/charger ... http://countryplans.com/smf/index.php?topic=2335.0
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