Critique my solar charger/battery monitor setup?

Buddha.

Lurker
I'm not sure which needs more work, my microsoft paint or my wiring skills.
We're traveling to Alaska in the spring as workcampers and I want to run the generator as little as possible. Biggest electrical load is the furnace blower which is tempature dependant, it draws something like 10 amps when it's running. I've been researching and buying stuff online for months and this is what I came up with. It's still a bit jumbled in my head so I'm explaining my system best I can.
Alright, this is mounted in the front storage compartment of my 2005 30' travel trailer. The batteries are 2 6 volt golf cart batteries mounted on the tongue about 3' away. I drilled a hole in the floor to bring the wires inside to this panel I came up with. There are positive and negative wires going to the 60amp converter approximately 20' back at the electrical panel. The factory used 6 awg cables for this which I assume is pretty underized. I have 4 100w renogy panels that will go on the roof. I plan to run them at 24 volts. I'm not sure I've got the wires on the correct side of the 200amp breaker on the bottom left. My reasoning for the breaker was to be able to disconnect the batteries easily. Should the charge wires from the converter be on their own breaker? Also with the shunt, I'm not sure I've got the cables on the correct side. Solar controller is good for 30 amps the the breaker there is rated for 30 amps. Is 30 amps a good size for my 215ah battery bank?
The small positive wire mark with black goes to the back of the rig somewhere maybe the brakes? It's too wet and muddy for me to want to investigate that.
 

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john61ct

Adventurer
You'll want a bigger bank, IMO 600+ Ah @12V

As much solar as will fit on the roof.

A genset and mains charger that will close to max out the genset when the bank is thirsty.

Best of course is a powered site for long-term stays. And a woodstove if any forests around.

For wiring gauges, check out Blue Sea "Circuit Wizard" come back with questions.
 

larryqp

Full-time RVer
I know this is about your electric system, but the next best investment you might consider is a catalytic heater, such as a Wave 3. Rather than try to supply enough energy to the furnace, a catalytic heater will maintain the temperature with a window and vent open slightly to supply O2 and vent moisture. You will need heat on rainy cloudy days when you won't get much solar. Or even a Buddy Heater if you don't want to plumb the propane.

Another benefit is quiet, if your furnace is like most, the noise will make you crazy, almost as bad as the generator
 

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luthj

Engineer In Residence
Aside from being a ”disconnect the batteries easily” device. The 200A OCPD (grossly oversize for 6AWG conductor) is rendered pointless.
If that's a random breaker from amazon (brandless) it will probably trigger around 60A anyways! Ha!

10A is a significant load, but some of those furnaces make 15k BTU, so they don't run very long. Whats the furnace rated at? The amps per BTU may be reasonable. Otherwise there are often lower power blower motors if needed/.

We need to know the specs for the other equipment, and the minimum wire sizing for each circuit. The fuse must not be larger than the continuous current of the wire/cable being used. This will vary with wire size and insulation temperature rating.
 

RJ Howell

Active member
I do suggest doing a power/solar audit. Dual 6v's and 400w's of panel don't match up well.. Under-powered batt's for over-powered solar, in my mind. Then I'd look very closely at reducing power consumption as much as possible.

Here's a sample of my audit. Dual 6v's (going lithium in spring) and 130w solar.

 

Buddha.

Lurker
Lets hope there is 55-60A (max. ) OCPD adjacent to your battery.
With that it correctly protects 6AWG (copper) conductor.
Extra credit too !
Aside from being a handy ”disconnect the batteries easily” device. That 200A OCPD (grossly oversize for 6AWG conductor) is rendered pointless.
I forgot to mention that the cables going back to the 60 amp converter have a 30 amp self resetting circuit breaker in-line. The factory installed it down on the frame behind the batteries and just under the panel I’m working on.
I'm not sure how I arrived at 200 amps for the breaker.
 
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Buddha.

Lurker
Thank you all for the replies.
I'm curious what you all think of the image above and my description of it. Did I wire the shunt right? It's disconnected from shore power and the batteries right now. I don't want to fry something when I connect it.
I have the Victron battery monitor and want to get the system running (I'll let the furnace run for ~24 hours)and see what actual power consumption is. If the current batteries don't have enough capacity I'll add a couple more.

I switched all the lights over to LED, the TV and stereo/dvd player were changed from 120v to 12v and according to my amp clamp only use 2.5amps while watching a dvd. There's the water pump but that only runs while doing dishes and showering, we'll be trying to conserve water anyway so I don't think the pump will run much. There's only a small converter for charging a laptop and a couple phones to charge.
 

Buddha.

Lurker
If that's a random breaker from amazon (brandless) it will probably trigger around 60A anyways! Ha!

10A is a significant load, but some of those furnaces make 15k BTU, so they don't run very long. Whats the furnace rated at? The amps per BTU may be reasonable. Otherwise there are often lower power blower motors if needed/.

We need to know the specs for the other equipment, and the minimum wire sizing for each circuit. The fuse must not be larger than the continuous current of the wire/cable being used. This will vary with wire size and insulation temperature rating.
I'm seeing 15k all the way up to 35k were options, I'll have to check myself when I get home. It's a big travel trailer but two 1500w heaters keep it plenty warm at 30f.
 
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john61ct

Adventurer
Wut? Nothing "underpowered" about the Duracell/Deka GCs at 200+ Ah per pair. Plenty of 800Ah banks out there lasting 7-10 years,

Lots of people do just fine with one pair and 200W of panels, but yes as stated OP needs at least another pair with those loads.

Unless overnight mains is frequent and / or lots of driving daily.
 

Buddha.

Lurker
I should have mentioned we'll be on mains/shorepower once we get to Alaska. This is just for the 2-3 weeks we'll spend getting to Alaska and for any bumming around we do after. There will be a fair bit of driving everyday.
 

Bayou Boy

Adventurer
I should have mentioned we'll be on mains/shorepower once we get to Alaska. This is just for the 2-3 weeks we'll spend getting to Alaska and for any bumming around we do after. There will be a fair bit of driving everyday.
Your driving will do nothing to recharge those batteries unless you run a dedicated charge line of AT LEAST 8AWG.

I have a set of 4 Duracell GC2s in my 5th wheel and only get about 3 amps charging through the 7 way. I have a length of 6AWG duplex that will be installed before the next boondocking trip. Testing with that cable uninstalled gets me almost 40 amps of charge. A serious difference.

Also, I'd find a place for two more batteries. I can do 3 days with nights getting to about freezing with a family of 4 not really conserving all that much before I'm down to 60% with zero recharge. With that much trailer to heat, you'll eat watts like crazy. 400 watts of panel will give you 25 amps in perfect conditions like we get down here on the gulf coast. Alaska isn't perfect. Plan on half that.
 

Buddha.

Lurker
Your driving will do nothing to recharge those batteries unless you run a dedicated charge line of AT LEAST 8AWG.

I have a set of 4 Duracell GC2s in my 5th wheel and only get about 3 amps charging through the 7 way. I have a length of 6AWG duplex that will be installed before the next boondocking trip. Testing with that cable uninstalled gets me almost 40 amps of charge. A serious difference.

Also, I'd find a place for two more batteries. I can do 3 days with nights getting to about freezing with a family of 4 not really conserving all that much before I'm down to 60% with zero recharge. With that much trailer to heat, you'll eat watts like crazy. 400 watts of panel will give you 25 amps in perfect conditions like we get down here on the gulf coast. Alaska isn't perfect. Plan on half that.
I've got a dedicated charging wire from the truck. I have a 12 to 36 volt booster(~500w) that I've run to the back of the truck. Planning to feed it into the MPPT solar charger. If I did the math right with 36 volts I can get by with 10 awg. It's going through the solar charger so I should get a good charging profile same as if it was just powered by the panels.

I was planning on 2 days without driving so I thought the 2 batteries would be good. Maybe I'm wrong.
 

Bayou Boy

Adventurer
I've got a dedicated charging wire from the truck. I have a 12 to 36 volt booster(~500w) that I've run to the back of the truck. Planning to feed it into the MPPT solar charger. If I did the math right with 36 volts I can get by with 10 awg.
Can you even do that? I can honestly say that I’ve never heard of someone boosting 12v to 36v and then using a charge controller to drop it back down to 12v. Sounds like a ton of complexity and loss from conversion and heat out of those boxes.

I’ll sit back and let someone that has done that before comment...




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luthj

Engineer In Residence
The mppt route will work fine with correct components.

400w and 200AH will run a fridge all summer without trouble. In the winter there are capacity loss issues and low sun angle.
 

Buddha.

Lurker
Can you even do that? I can honestly say that I’ve never heard of someone boosting 12v to 36v and then using a charge controller to drop it back down to 12v. Sounds like a ton of complexity and loss from conversion and heat out of those boxes.

I’ll sit back and let someone that has done that before comment...




Sent from my iPhone using Tapatalk
Someone stated they had done it, I don't remember who.
 
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