please critique my setup before i commit to putting it all together

[bikeymikey]

note: I already have all the components, just need to buy wires and fuses. And that's what I need advice on: wire gauges and fuse ratings. The CC will be maybe 4 feet worth of wire away from the batteries. The inverter about the same. The DC fuse box like 5 or 6 feet away and the panels probably 8 ft of wire away...

Thanks in advance!

 

[goodtimes]

There are plenty of wiring size charts on the internet - just be sure to remember that for length you are looking at the distance from the source, to your load, and back to the source. With your common negative between the shunt & battery - that section is going to see a cumulative load. Look at the cross section of the wire sizes (also listed on most wiring size carts) needed for each individual load, add those together, and that'll tell you what size that last stretch needs to be.

You may want to consider circuit breakers instead of fuses for the larger circuits - and I would also recommend a positive buss - it will be much cleaner & easier to troubleshoot.

Remember that you size the wire for the load, and size the fuse or breaker for the wire.

One last note - your diagram shows the batteries in series - which is correct if you are running 6v batteries. If they are 12v, then you want them in parallel (+ to +, and - to -).

 

[bboyle]

Where's that Like button? Nice thorough answer, goodtimes. Very helpful as I am about to install my own solar setup.

There are plenty of wiring size charts on the internet - just be sure to remember that for length you are looking at the distance from the source, to your load, and back to the source. With your common negative between the shunt & battery - that section is going to see a cumulative load. Look at the cross section of the wire sizes (also listed on most wiring size carts) needed for each individual load, add those together, and that'll tell you what size that last stretch needs to be.

You may want to consider circuit breakers instead of fuses for the larger circuits - and I would also recommend a positive buss - it will be much cleaner & easier to troubleshoot.

Remember that you size the wire for the load, and size the fuse or breaker for the wire.

One last note - your diagram shows the batteries in series - which is correct if you are running 6v batteries. If they are 12v, then you want them in parallel (+ to +, and - to -).

 

[G35Vortec454]

When deciding on wire size, also think of the possibility of upgrading your mobile power in the future, so you don't have to rewire later. For example, Is it possible that you might want to power a fan, a small HDTV, or a bigger fridge later?

Things I don't see addressed in your wiring diagram:
1. How are you going to fully charge those batteries? your 300W panels will not properly do the job.
2. Are you going to let your alternator charge the batteries?
3. Are you going to use the solar panels to float charge your starting battery?
4.

 

[bikeymikey]

There are plenty of wiring size charts on the internet - just be sure to remember that for length you are looking at the distance from the source, to your load, and back to the source. With your common negative between the shunt & battery - that section is going to see a cumulative load. Look at the cross section of the wire sizes (also listed on most wiring size carts) needed for each individual load, add those together, and that'll tell you what size that last stretch needs to be.

You may want to consider circuit breakers instead of fuses for the larger circuits - and I would also recommend a positive buss - it will be much cleaner & easier to troubleshoot.

Remember that you size the wire for the load, and size the fuse or breaker for the wire.

One last note - your diagram shows the batteries in series - which is correct if you are running 6v batteries. If they are 12v, then you want them in parallel (+ to +, and - to -).

Thanks for the reply. Yes, those are two 6V batteries, 225 amp/hr. I think I'll use the largest size wire each component will accept, keep the wire runs as short as possible and fuse for the wire size like you suggested.

When deciding on wire size, also think of the possibility of upgrading your mobile power in the future, so you don't have to rewire later. For example, Is it possible that you might want to power a fan, a small HDTV, or a bigger fridge later?

Things I don't see addressed in your wiring diagram:
1. How are you going to fully charge those batteries? your 300W panels will not properly do the job.
2. Are you going to let your alternator charge the batteries?
3. Are you going to use the solar panels to float charge your starting battery?
4.

Thanks for that. I sure hope I didn't get it wrong; I understood that a system cannot have batteries with fewer amp/hrs than the wattage of the panels. But the t-105s are 225 amp/hr so I was under the impression that I had more than enough. How many panels would you say is needed?

Regarding upgrading appliances, we're going to go with what we got. We want to be on the road by the 1st of October, and hope to cross the border into Mexico a couple of weeks later. So we're in all likelihood not going to be making any changes. I do want to get a little tv and a fan.

Just for simplicity's sake I'm keeping the two batteries' charging systems separate. Probably a mistake so our "farewell California" trip will allow us to see what we really use and if we need it I'll get that isolator and install it.

 

[G35Vortec454]

. I understood that a system cannot have batteries with fewer amp/hrs than the wattage of the panels. But the t-105s are 225 amp/hr so I was under the impression that I had more than enough. How many panels would you say is needed?

It depends very much on the dod (depth of discharge) in the morning before the sun shines. Remember that your 300W panels won't be always putting out its rated 15A or whatever. You'd be lucky if you get an average of 10A in the 6-hour period. That's why more panel watts is better for any battery, as many as you can fit / afford. In cases where the battery has completely pulled what it needs, the charge controller will regulate the charge. Most often than not, the battery will need a primary source of charge (other than panels) to FULLY charge the battery. Keeping a battery in less that 80% SOC for more than a few days is not good for the battery.

 

[graynomad]

I understood that a system cannot have batteries with fewer amp/hrs than the wattage of the panels.

You can have as much solar as you like regardless of the battery size, it's just that it may be wasted a lot of the time but it won't do any harm as long as you have a regulator.

I know you want to use what you have but I prefer 2x 12v in parallel rather than 6v in series, the reason being that if a battery fails you still have a usable system just at half the capacity. If one of your 6v batteries fails you are up ******** creek. That said my new system will have 8x lithiums in series, so don't pay me no mind


_____
Rob

 

[bikeymikey]

Look at the cross section of the wire sizes (also listed on most wiring size carts) needed for each individual load, add those together, and that'll tell you what size that last stretch needs to be.

S@#t! Does that mean that if I'm using 6AWG for the three circuits at 13mm2 each, then the last stretch has to be 1AWG??? Does the cable connecting the batts have to be the same size too?

 

[G35Vortec454]

S@#t! Does that mean that if I'm using 6AWG for the three circuits at 13mm2 each, then the last stretch has to be 1AWG??? Does the cable connecting the batts have to be the same size too?

Yes, add the loads of the 3 6ga ckts, not the crosssection or dia. That is if you'll be using the full capacity of the 3 6ga wire simultaneously, which is far from practice. In practice, max simultaneous loads dictate the wire size; actual loads dictate the fuse used. Therefore, I'm in disagreement with goodtimes that you use the amp capacity of the cable for the fuse rating. I personally would rather use a LOWER fuse rating that is appropriate for the ACTUAL load(s). When you increase the load later, that's also the time to upgrade the fuse, up to but not exceeding the wire current capacity.

Btw, 3 6ga loads is a LOT of load for your circuit with only 210AH battery capacity. I can see only one 6ga load in your ckt. Are you upgrading already?