Yeh I have noticed its a bit of a sore subject. I wouldn't even necessarily plan to have the solar take the entire load of the AC, moreso just that it would prevent the batteries from draining in a very short period of time.
"Overkill" Solar Setup and Battery Bank for Camper
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Yeh I have noticed its a bit of a sore subject. I wouldn't even necessarily plan to have the solar take the entire load of the AC, moreso just that it would prevent the batteries from draining in a very short period of time.
Seems like the thread got a bit off base. Lets forget the idea of using the AC off battery power.
Assuming I had 4 clusters of the Renogy 400w solar "kits", so 4 separate charge controllers, a large battery bank, and the 3000w renogy inverter. What do you guys suggest as far as wiring. I just want to make sure that the solar setups charge the batteries evenly, and that the inverter drains the batteries evenly.
Assuming I had 4 clusters of the Renogy 400w solar "kits", so 4 separate charge controllers, a large battery bank, and the 3000w renogy inverter. What do you guys suggest as far as wiring. I just want to make sure that the solar setups charge the batteries evenly, and that the inverter drains the batteries evenly.
John Frum
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@ghostwriter66 had some good ideas that apply here.
The post was about shipping containers but should apply to an RV as well.
The trick is to insulate outside the metal envelope.
It makes me think of this
Just looking for suggestions for fuse placements, etc. I've never used a battery isolator and i dont know if it applies here, just looking for suggestions
John Frum
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assuming this one https://www.renogy.com/3000w-12v-pure-sine-wave-inverter/
3000 ac watts / .85 conversion factor / 12 volts = 294.117647059 dc amps
294.117647059 dc amps * 1.25 fuse factor = 367.647058824 fuse amps
that means a 350 amp anl or class t fuse and 4/0 awg wire.
Assuming 105 Celsius rated wire and less than 20 feet round trip.
3000 ac watts / .85 conversion factor / 12 volts = 294.117647059 dc amps
294.117647059 dc amps * 1.25 fuse factor = 367.647058824 fuse amps
that means a 350 amp anl or class t fuse and 4/0 awg wire.
Assuming 105 Celsius rated wire and less than 20 feet round trip.
Thats just between the battery bank and the inverter correct? Should I do fuses anywhere else, and do I need any other hardware to ensure that multiple batteries charge evenly from multiple charge controllers?
The challenge of AC on solar becomes considerably less daunting if you forget about the low-effciency roof mounted unit that came on your RV and look into a small 20+ SEER mini split system. There are a number of examples of people running these systems successfully while boondocking.
I could be totally wrong but it doesnt seem like the SEER systems are all that much more efficient. The RV unit is 13500 BTU and pulls 1200w or so while running. A 12,000BTU SEER unit pulls about 1000w.
boondox
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it isn't that it is a sore subject, at least not with me. It is just a significant engineering challenge and many don't understand just how difficult it is. Sounds like you are wrapping your head around that and figuring out where you want/need to go.
John Frum
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Yes I am only referring to the master fuse and the master wires.
Yes you should do fuses elesewhere.
Time for a drawing.
No additional hardware is required to ensure multiple batteries are charged evenly by charge controllers.
You should look at wiring unlimited though.
section 3.3
Thats exactly what I'm doing. you guys have already helped me, and saved me a couple bucks regarding the 4kw inverter haha. Now I just need to figure out battery capacity and wiring.
beat you to the drawing
. Yes I know its a bit primitive but I'm at work right now so I just scribbled it really quick. So if I had 4 charge controllers the number of batteries doesnt affect their ability to charge evenly. If I wire everything in parallel to keep it 12v, the 4 solar chargers will charge any quantity of batteries evenly?I am just starting to dig into the complexities of this, but as I understand it, the mini-split systems use variable speed compressors and fans to match the AC output to the load. The unit may draw a lot of power when 1st cooling down a hot camper, but quickly drop to a fraction of that power draw as they continue to run.
shavermcspud
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As the OP stated in his first post, he is aiming to run 4x SCC @12v each, so he could in effect run one controller to each battery from each bank of panels, combine 4x 12v batteries in series to a 48v bank, draw the small internal 12v loads from a single battery and span the 4x batteries for the 48v inverter. Providing the internal 12v loads aren't high the batteries wont go out of Ballance plus he will have an SCC per battery to keep each one charged.
John Frum
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yesbeat you to the drawing
John Frum
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absolutely
busbars for both legs make things sane.
boondox
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Can't say I have ever tried such a system but it seems too complicated for me, especially for a boondocking system. Just because it can work doesn't make it robust or a good idea. Too many points of failure for me and no real benefit.
Sorry I may not have be clear. I'd like to run 4 clusters of 4 panels. So a total of 16 panels.
I noticed that 400w (4 panels) was the most that renogy offered tied into one charge controller.
I wouldn't do anything at 48v. The power coming out of those charge controllers is 12v at up to 400w. I would wire those parallel to get charging of 12v at up to 1600watts. They would be charging multiple 12v lithium batteries which would also be wired in parallel to be approximately 400ah of 12v capacity. Then those batteries would be wired to a 12v 3000w inverter.
mapguy525
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Again -the inverter you infer will need much larger cabling than 0 or 1 awg to avoid massive voltage drop.
There is no cutting corners on equipment installation -if the desired outcome is to use the 4k / 12v inverter and running AC. It will require more battery, very large cabling, and appropriate over current protection(OCP)(Fusing). That is -if you want a safe and reliable system.
Yes, I'm aware. That is exactly what my question is lol
mapguy525
Solar Enthusiast
Seems we are going around in a circle......
Unfortunately it does. Thats why I removed the AC from the equation. I got one question answered regarding the equal charging of multiple batteries. Now I'm just wondering where people would put fuses, and possibly isolators in the "circuit" that I drew above, and whether or not I should wire everything to a center Distribution Block or just keep wire runs separate.
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