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Discussion Starter #1
Would any kind souls want to review my electrical diagram?

Disclaimers: I am a complete beginner. I reviewed several threads on this forum, read many websites and watched many Youtube videos. I understand that my system is probably going above and beyond my needs (and my head) but I already own the main components listed below and am looking for feedback to ensure safety with the overall set up. I have not purchased the fuse box, fuses, circuit breakers or wires.

Here is a brief breakdown of the system:
Battery bank: 2 x 100Ah Lithium batteries wired in parallel
Charge Source: Sterling B2B 60A
Charge Source: 2 x 175 watt solar panels wired in series
Load: 12V DC via fuse box (lights, fridge, USB outlets, etc)
Load: 120V AC via 1000W pure sine inverter (plan to plug power strip into inverter for laptop charging)
System Monitoring: Victron BM 712 with added battery temperature sensor

Thanks in advance for your time and feedback!
 

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You don't have to run two lengths of 4 gauge 9 feet, you can run one to the bus bar and from there to the sterling b2b charger.

Depending on the battery you need a way to prevent them from being charged when below freezing. Some built in BMS systems do this, and some don't. It is important.
 

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Thanks for the feedback jracca!

You don't have to run two lengths of 4 gauge 9 feet, you can run one to the bus bar and from there to the sterling b2b charger.
This Sterling B2B charger was a challenge for me. I initially wired the B2B as you suggested which would have saved me lots of wire. I emailed Sterling to confirm that this would be okay to do but never heard back from them so ultimately changed it to follow the Sterling installation guide exactly as suggested sinceI have limited experience and knowledge. Your comment makes me think I could switch it back safely.

Depending on the battery you need a way to prevent them from being charged when below freezing. Some built in BMS systems do this, and some don't. It is important.
Fortunately my batteries have a "Smart" BMS built-in that includes temperature charging protection.
 

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It's not clear from the diagram if you did this or not, but the when you have batteries wired in parallel the positive and negative terminals are typically taken from the first and the last batteries in the chain to ensure that all the batteries are drawn from equally.
 

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It's not clear from the diagram if you did this or not, but the when you have batteries wired in parallel the positive and negative terminals are typically taken from the first and the last batteries in the chain to ensure that all the batteries are drawn from equally.
Great catch, ferall! Thank you so much! It does appear I did it wrong in the diagram. I have updated it and moved the shunt connection to the other battery so now the positive connection is from the first battery and the negative is from the last battery. I attached the updated diagram. Does this look accurate now for wiring the batteries in parallel?
 

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I don't know that I would buy a pure sine inverter for a kettle and a laptop. You can get 12V laptop adapters, then plug into 12V and skip the inverter for the laptop. That would be more efficient than 12v -> 120v -> ~20v. Then, the kettle won't need a pure sine wave. Get a modified sine, but test the kettle. Many are 1000 or 1200 watts.
 

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Thanks for the review 83Grumman!

How long is the circuit to the dometiec? 16 awg might be too small if it really draws 12 amps.
The circuit is 16 ft return with dometic max current 8 amps. I used the Blue Sea calculator and it stated 18awg but decided to go with 16awg.
 

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I don't know that I would buy a pure sine inverter for a kettle and a laptop. You can get 12V laptop adapters, then plug into 12V and skip the inverter for the laptop. That would be more efficient than 12v -> 120v -> ~20v. Then, the kettle won't need a pure sine wave. Get a modified sine, but test the kettle. Many are 1000 or 1200 watts.
Thanks WanderingWakes! Totally agree. My plans changed along the way for the 120v but already had the pure sine inverter. Thanks for the suggestion it will definitely save some money.
 

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I used 3% on mine. I want to make sure that the fridge does not fail to start for low voltage. A 10% drop with a low battery (SOC 50%), would put you at 10.8 volts. I don't know that all fridges would start at that low of a voltage. Certainly lights, chargers, other things would be ok at 10%. Although honestly, I used 3% max drop for all of my 12 volt wire calculations. It was not that much more expensive to be size a bit larger. To each his own though... Just my $0.02.
 

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I used 3% on mine. I want to make sure that the fridge does not fail to start for low voltage. A 10% drop with a low battery (SOC 50%), would put you at 10.8 volts. I don't know that all fridges would start at that low of a voltage. Certainly lights, chargers, other things would be ok at 10%. Although honestly, I used 3% max drop for all of my 12 volt wire calculations. It was not that much more expensive to be size a bit larger. To each his own though... Just my $0.02.
Thank you for the insights. I am definitely going to consider re-calculating my 12v with 3%. You make good points. I really appreciate it. Any and all feedback is very helpful.
 

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You don't have to run two lengths of 4 gauge 9 feet, you can run one to the bus bar and from there to the sterling b2b charger.
Excuse me if I'm asking a dumb question, but I thought the B2B charger was wired between the van's starter battery and the bus bar... in between the two, and from the bus bar, the house battery would get the charge. No?

On the side, since I'm going to have to ask the same question very soon, how do people make up these nice charts/graphs? Seems I'll have to hand draw one myself.
 

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Excuse me if I'm asking a dumb question, but I thought the B2B charger was wired between the van's starter battery and the bus bar... in between the two, and from the bus bar, the house battery would get the charge. No?

On the side, since I'm going to have to ask the same question very soon, how do people make up these nice charts/graphs? Seems I'll have to hand draw one myself.
The sterling is a non isolated charger, so it shares the ground. There must be a connection between the ground for both batteries and the sterling can connect at a convenient place that can carry the current. It does go in between for the positive connection.
 

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The positive cable from the start battery goes to the B2B +tve input terminal, not the positive bus bar. The output of the B2B goes to the positive bus bar which is connected to the house positve.
 
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