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diy solar

Noob building very small system for van conversion

gac1222

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Mar 27, 2022
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Hey guys, new to the forum and very green when it comes to solar. I've watched many of Will Prowse / explorist.life videos and am trying to build a small camper van system (2 12v 100W panels run in series and 1 SOK Lithium 100AH battery). It will run very small modest loads (~60a / day) with most everything being DC (led lights, fan, water pump, diesel heater), and the only AC being used to charge phones occasionally. Most videos and tutorials I see seem catered to building larger 3-400AH systems, and that is more power than I'll need.

Anyways, here is a small sketch of a system I am planning to build, was wondering if I had this set up correctly with fuses/wires. System will operate entirely offgrid and will be used as a weekend warrior setup, so only needs to maintain power for a few days of light use . Any advice is welcome, again I am very new to all of this..wiringchevypaint.jpg
 

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Seems like a lot of equipment for a small system. It will be ready for expansion as needed.

Fuse on the solar panel feed is not needed.

One foot SOK to LYNX I would skip the fuse or reduce the wire size to #2

#8 is fine for the ground as the inverter has a return feeder.

I would go 150a and #2 to the inverter.

The 40 amp #12 that I think is fed by the solar I would drop to 30 amp or better to increase the wire to #10 or #8

Battery switch is nice but since there is solar I would skip it and just remove a cable if set in long term storage.

I might save the money and skip the shunt. Get the bluetooth SOK and virtually the same info might be available.

Sorry that is a lot of changes. Nothing is especially terrible or dangerous.
 
Why are there two pairs of wires from the inverter to the Lynx? Oh, I think the pair going to the 40A fuse is meant for the charge controller.

1100W inverter on a 12V battery is about 105A. That requires at least 4AWG. 2AWG would be better. Then use a 125A to the inverter.

The 30A charge controller needs 10 gauge to the Lynx, not 12AWG.

With the 105A for the inverter and 40A for the DC fuse box you could be pulling 145A from the battery. That only needs 1AWG wire, not 2/0AWG. Nothing wrong with larger wire but I wouldn't bother with anything larger than 1/0AWG.

Raise your main battery fuse to 175A.

Agree you do not need the 25A PV fuse. You can use a breaker for the on/off switch. Use a proper PV DC rated breaker that can handle the full Voc of the panel array. Since you have a 100V SCC, a breaker that can handle 120V would future proof your wiring if you add more panels.
 
Yeah sorry my paint skills are horrendous. Thank you all for the insight, I will be making the changes as needed.

Unfortunately its a low budget system with plans to upgrade in the future. Is it worth it saving up and attempting to use all victron components for the future so everything speaks to itself?
 
Yeah sorry my paint skills are horrendous. Thank you all for the insight, I will be making the changes as needed.

Unfortunately its a low budget system with plans to upgrade in the future. Is it worth it saving up and attempting to use all victron components for the future so everything speaks to itself?
The Victron fanboys would tell you it's absolutely vital. Those of us with bills to pay will tell you that a set of mid-range components will be MUCH cheaper than Victron and still do the job of turning solar panel DC into battery DC. EPEver, HQST, etc are all perfectly suitable for what you need and plenty reliable unless you absolutely NEED things like the WiFi and BT and online system monitoring and showing off to your friends.

Now I gotta go outrun all the Victron people with their blue pitchforks and torches. :)

On other thoughts:
and the only AC being used to charge phones occasionally.
12v USB ports are available at any auto parts store. No need to DC -> AC -> DC for a phone.

Are you sold on 100w panels? You can gain a lot out of larger panels as the price per watt goes down as you go larger. If you can find them used for a good price even better! Those panels are only going to produce about 700-800wh a day and your battery is 1200Wh so you can't charge the battery in 1 day, much less charge it AND run any loads. Pretty undersized.
 
The Victron fanboys would tell you it's absolutely vital. Those of us with bills to pay will tell you that a set of mid-range components will be MUCH cheaper than Victron and still do the job of turning solar panel DC into battery DC. EPEver, HQST, etc are all perfectly suitable for what you need and plenty reliable unless you absolutely NEED things like the WiFi and BT and online system monitoring and showing off to your friends.

Now I gotta go outrun all the Victron people with their blue pitchforks and torches. :)

On other thoughts:

12v USB ports are available at any auto parts store. No need to DC -> AC -> DC for a phone.

Are you sold on 100w panels? You can gain a lot out of larger panels as the price per watt goes down as you go larger. If you can find them used for a good price even better! Those panels are only going to produce about 700-800wh a day and your battery is 1200Wh so you can't charge the battery in 1 day, much less charge it AND run any loads. Pretty undersized.
Yeah totally. I understand its quality but man, all that cash for all that blue would cost me as much as the conversion itself.

Regarding the 100W panels, no preference. Was loosely following Will's modest solar plans for a van and he linked a deal through Rich solar that had 2 100W panels. Open to suggestions.
 
It really depends on how much space you can allocate for panels and how big a SCC you want to get. You could go for a 60a SCC and 2x 400w Trinas that everyone here likes and that would get you 720w max power for your 12v system. I wouldn't recommend going less than 400w of panel for what you have now but you'll run into under-paneling issues when you add another battery potentially.
 
Ill look into the trinas. Is there any downside to buying as big a SCC as you can afford?
 
Ill look into the trinas. Is there any downside to buying as big a SCC as you can afford?
OK to be realistic on what panels can fit on the roof. If the space cannot get past 400 watts there is no reason to buy 1200 watt controller.
 
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