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Inverter/Charger/ DC to DC charger Confusion

crccrkc1995

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New Mobile Solar guy here. We are converting a 2002 Ford E450 Shuttle Bus into an RV and are adding solar for off grid camping. So far we have done an energy audit and have concluded that we will need an 800 watt solar array, a 2000 watt inverter and at least 400 Amp hrs of batteries. However, we decided to up our panels to 1000 watts and our inverter to a 3000 watt Epever 40 Amp MPPT Solar Charge Controller. We want as many charging options as possible because we are people who always want options. So we'd like to utilize shore power, if needed, and also charge off our alternator as we travel. We have 2 alternators in our shuttle bus so this seems like a good option, possibly? So when doing my research, I can't seem to grasp what components I need to make all of this work, I get lost and overwhelmed when it comes to electricity, but I've never been one to shy away from a challenge. I am thinking what we need is 3000 watt inverter and a Dc to DC charger, but I'm also thinking we need an Inverter / Charger instead of an inverter, along with the DC to DC charger. Can anyone advise me on the system components I would need to make this whole idea work? Thank you so much for the help/advice!
 
You need the following components.
dc2dc charger(charges from alternator)
mppt solar charge controller(charges from photovoltaic panels)
inverter/charger(includes an inverter, ac2dc charger and automatic transfer switch)
Alternatively you could use and all_in_one which adds an mppt solar charge controller to an inverter/charger.

Which system voltage are you thinking of?
 
A 3000 watt inverter is big for a 12 volt system.
3000 ac watts / .85 conversion factor / 12 volts low cutoff = 294.12 service amps
294.12 service amps / .8 fuse headroom = 367.65 fault amps
That means 4/0 awg pure copper wire with 105C insulation and a 400 fuse.

~300 serivce amps is a lot.
 
Either that or move up to 24 volts.
Are you thinking about store bought or diy batteries?
I think I misunderstood your system voltage question. We have already bought 2 12v 206ah SOK batteries that we plan to connect in series to create a 412ah 24 volt system. I hope I explained that correctly.
 
I think I misunderstood your system voltage question. We have already bought 2 12v 206ah SOK batteries that we plan to connect in series to create a 412ah 24 volt system. I hope I explained that correctly.
in series, that will be a 24v 206ah system. series connection: voltage increases AH stays the same, parallel connection: AH increases, voltage stays the same. This means you are planning to use a 24v battery bank, which is recommended for your described plan.
 
I think I misunderstood your system voltage question. We have already bought 2 12v 206ah SOK batteries that we plan to connect in series to create a 412ah 24 volt system. I hope I explained that correctly.
Ok then the math look like this...
3000 ac watts / .85 conversion factor / 24 volts low cutoff = 147.06 service amps
294.12 service amps / .8 fuse headroom = 183.82 fault amps
That means 2 awg pure copper wire with 105C insulation and a 200 fuse.

Can your batteries deliver 150 amps continuous?
 
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I believe so but don't know for sure. How can I figure that knowing what batteries I have?
 
Arent LFP rated for 1C? or is that not true of all LFP? If so, the short answer is yes.
2 wrinkles.
1. the BMS continuous rate, which we need to determine.
2. Even though the cells themselves are rated at 1c discharge rate, the reality is they get noticeably hotter internally just above .5c when ion starvation starts to occur.

I'm assuming these cells are optomized for storage capacity as opposed to high current.
 
Im really sorry, im having a hard time finding that. Here's the SOK link.
 
2 wrinkles.
1. the BMS continuous rate, which we need to determine.
2. Even though the cells themselves are rated at 1c discharge rate, the reality is they get noticeably hotter internally just above .5c when ion starvation starts to occur.

I'm assuming these cells are optomized for storage capacity as opposed to high current.
Gotcha, they use prismatic cells (we know from Will's teardown) but I do not recall what their BMS was or what he discharged them at. If my memory serves correct, I think 1C is good for 5 minutes. I would have to go back to datasheets to verify though. I'll poke through Will's vids to find the SOK reviews.
 
"Max Discharge Current:100 A"

Max Discharge Current:100 A

Two of the sok 206ah batteries in series is 206ah @ 25.6 volts nominal and can deliver 100 amps continuous.
 
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