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Hickey

Hickey

Burn-barrel enthusiast
Supporting Member
Location
Grantsville, Utah
J-mobzz said:
So I have a question for those of you running solar. Does anyone else use any other form of charging? I currently have a 60 amp DC DC charger hooked up to 200 amp hours of lifepo 4 lithium batteries. Currently thinking of adding a couple hundred Watts of solar panels on top. But I have room to run up to 450 Watts of panels if I decide it’s worth it.

My lithium set up can handle 50 A of charging per battery So in theory, I should be able to add a solar controller on top of my DC to DC charger without having to worry about sending too much amperage to the batteries. But I would rather error on the side of caution.

I’m thinking about just running like a 60 amp relay and wiring the solar panels in on a normal closed circuit and then when I turn the ignition switch on, it would disconnect the solar panels from the solar controller allowing just the DC to DC charger to do the charging.

Does anyone see a reason why this wouldn’t work? it seems like some of the solar controllers are a bit picky about how you wire them up, but it looks like as long as I disconnect the panels from the controller not the batteries it shouldn’t matter.

At 450 W divided by 12 V that’s 37 A plus the 60 from the charger would put me right at the 100amp limit. I realize the panels will never see full efficiency and that’s probably not a realistic number. But I do think I would be more comfortable, disconnecting the solar while the vehicles running just to prevent any potential problems.
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We run our generator sometimes when we need AC or watch tv during a rainstorm. Anytime that’s running, the batteries are also charging. My solar controller is wired straight to the batteries, and I’m totally unaware of how much is coming from the generator to the barriers while it’s running. I haven’t had a single issue doing that, though.
 
anderson750

anderson750

I'm working on it Rose
Location
Price, Utah
Hickey said:
It’s my experience that all batteries won’t last more than 5-7 years. You will need to replace them no matter what. I bought my last pair at Autozone in Ephraim last year and I’ve been kicking myself for waiting as long as I did (they started boiling). The old batteries were not always maintenance with solar, as I added that halfway thru their life span. The old batteries wouldn’t hold the charge through winter with snow on the solar panels. New batts made it all the way thru winter and stayed at full charge.

I just never worry about the batteries now, and that’s exactly what’s great about the solar on an RV.
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When I bought my coach it had 4 big AGM batteries that were about 7 years old. I do not recall what the amp hours they were. Essentially about the end of life. When it came time to replace them in 2021 I could not stomach how much the price had gone up during Covid and went a different route. The Interstate 6 volts I put in my coach have lasted about 3 years. At that time I also added 500w of solar and a Victron controller to mange the solar. My uneducated belief is that AGM and Lithium hold up better to solar than lead acid. I have not been diligent on checking fluid levels and know I have gotten low a couple times on some cells

A friend of mine that has built a few of these super C’s from the ground up is a distributor for VoltGo LiFePo4 batteries. He is selling them to me at cost, so I ordered 2 of the 400ah batteries. If they last the 10 years of the warranty then they will be worth it for me. I am plugged into shore power about 10% of the time so the lack of prolonged battery bank is a total PIA even with the 500w of solar I have.

Going this route is definitely not I would look at for average RV user. We use our coach an average of 20 times a year and only a couple of those times are in a place where we plug into shore power. The more you use it, I would recommend you g with the best battery set up you can. There is nothing worse than being in a situation where you cannot run a heater all night when you need to.
 
Corban_White

Corban_White

Well-Known Member
Location
Payson, AZ
J-mobzz said:
So I have a question for those of you running solar. Does anyone else use any other form of charging? I currently have a 60 amp DC DC charger hooked up to 200 amp hours of lifepo 4 lithium batteries. Currently thinking of adding a couple hundred Watts of solar panels on top. But I have room to run up to 450 Watts of panels if I decide it’s worth it.

My lithium set up can handle 50 A of charging per battery So in theory, I should be able to add a solar controller on top of my DC to DC charger without having to worry about sending too much amperage to the batteries. But I would rather error on the side of caution.

I’m thinking about just running like a 60 amp relay and wiring the solar panels in on a normal closed circuit and then when I turn the ignition switch on, it would disconnect the solar panels from the solar controller allowing just the DC to DC charger to do the charging.

Does anyone see a reason why this wouldn’t work? it seems like some of the solar controllers are a bit picky about how you wire them up, but it looks like as long as I disconnect the panels from the controller not the batteries it shouldn’t matter.

At 450 W divided by 12 V that’s 37 A plus the 60 from the charger would put me right at the 100amp limit. I realize the panels will never see full efficiency and that’s probably not a realistic number. But I do think I would be more comfortable, disconnecting the solar while the vehicles running just to prevent any potential problems.
Click to expand...

If the engine is running and charging the batteries, the solar will back off because the charge controller senses the higher battery voltage and thinks that the batteries are charged. I wouldn't worry about a relay on the ignition, the chargers are smart enough that they will work together (which really means that one or the other will take the lead).
 
Kevin B.

Kevin B.

Not often wrong. Never quite right.
Moderator
Location
Stinkwater
str8axleguy said:
So possibly silly question, do the lithium batteries charge well when cold? I know lithium tool batteries don’t like extreme temperatures
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No, they don't like that at all. In fact, if you're planning on winter use you should have a heating pad or some other method of keeping them warm.
 
anderson750

anderson750

I'm working on it Rose
Location
Price, Utah
str8axleguy said:
So possibly silly question, do the lithium batteries charge well when cold? I know lithium tool batteries don’t like extreme temperatures
Click to expand...
Kevin B. said:
No, they don't like that at all. In fact, if you're planning on winter use you should have a heating pad or some other method of keeping them warm.
Click to expand...
Lithium have a cutoff point where they will not charge. Some of the lithium batteries come with built in Bluetooth so that you can monitor them as well as heating pads built into them for cold weather charging. The ideal situation is to have them in an insulated battery compartment.
 
nnnnnate

nnnnnate

Well-Known Member
Supporting Member
Location
WVC, UT
I don’t love these electrical connections. To be fair, they were taped up, but I still don’t love them. Can I solder them instead of using the wire nuts? I also think I should upsize the wire gauge size on the fuse and red wire that will connect to the battery post. The black power wires are 3 @ 8 gauge. I forgot to check what size fuse it had.

I also need to make a connect cable for the 6v batteries. The internet told me I should use 4 gauge wire for that. Any issues there?
20240810_102041_Original.jpeg

I also bought this Noco Genius 2x2 battery charger and maintainer. Its got two banks so you can connect both batteries at the same time. I figure this would be a good option for them to be connected to while at the house and I've had a Noco jump pack for a while and have been really happy with it. It only charges at 2 amps per bank so its not ideal for in camp use off a generator but should be perfect (I think) for off season maintenance.
 
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N-Smooth

N-Smooth

Smooth Gang Founding Member
Location
UT
Pretty much any option is better than wire nuts, yeah.

I pull my trailer batteries in the winter and put them on a shelf in the garage. I will throw a charger on them once or twice to make sure they stay fresh. Is it necessary? I dunno... it could easily be another overkill process my dad taught me- FWIW
 
ID Bronco

ID Bronco

Registered User
Location
Idaho Falls, ID
I plug my trailer in during the winter and leave the batteries in it. They still get cold but are topped off, they would be just as cold in my garage. I have no idea if this makes any scientific sense, but they last so I keep up the practice.
 
nnnnnate

nnnnnate

Well-Known Member
Supporting Member
Location
WVC, UT
I spent $40 buying some wire and battery lugs and glue 3-1 heat shrink. Pretty sure I could have bought the finished cable I needed for $10. That's kind of how we roll though, isn't it.
 
jeeper

jeeper

I live my life 1 dumpster at a time
Location
So Jo, Ut
I've got 4 bottles of the ?8lb propane tanks that I have decided I don't want. 1 is nearly full, the others empty. They are all due for certification and could use new valves. I was going to go exchange them for some 5lb tanks.. but thought I'd check here to see if any one wants to swap them first. In previous years I would have died to get these over the 5lb size.

IMG_7559.jpeg
 
J

J-mobzz

Well-Known Member
J-mobzz said:
So I have a question for those of you running solar. Does anyone else use any other form of charging? I currently have a 60 amp DC DC charger hooked up to 200 amp hours of lifepo 4 lithium batteries. Currently thinking of adding a couple hundred Watts of solar panels on top. But I have room to run up to 450 Watts of panels if I decide it’s worth it.

My lithium set up can handle 50 A of charging per battery So in theory, I should be able to add a solar controller on top of my DC to DC charger without having to worry about sending too much amperage to the batteries. But I would rather error on the side of caution.

I’m thinking about just running like a 60 amp relay and wiring the solar panels in on a normal closed circuit and then when I turn the ignition switch on, it would disconnect the solar panels from the solar controller allowing just the DC to DC charger to do the charging.

Does anyone see a reason why this wouldn’t work? it seems like some of the solar controllers are a bit picky about how you wire them up, but it looks like as long as I disconnect the panels from the controller not the batteries it shouldn’t matter.

At 450 W divided by 12 V that’s 37 A plus the 60 from the charger would put me right at the 100amp limit. I realize the panels will never see full efficiency and that’s probably not a realistic number. But I do think I would be more comfortable, disconnecting the solar while the vehicles running just to prevent any potential problems.
Click to expand...
I added 3ea 100 watt panels to the roof of the van. While I was at it, I completely rewired pretty much everything with better connectors and thicker gauge cable to distribution blocks. I also install a few 65 W USB-C plugs so I can run my Starlink and charge my laptop without having to use the inverter. I still only have 200 amp/h of lifepo4 batteries mainly because I’m hesitant to take up any more storage space and aside from running the air conditioner I haven’t really been close to needing more.

My question is for those running solar how efficient are your panels? With my 300 W I typically seem to get anywhere from 5 to 10 Amps. I have seen as high as 15 Amps but I was for a very short amount of time. I don’t think it’ll be an issue for me, I’ve left the fridge turned on all week and it doesn’t really seem to get much below 90% even first thing in the morning but obviously it’s pretty cool at nighttime right now so the fridge probably isn’t running much. And with the 60 amp DC to DC charger, I can always just idle the van to charge them up really quick. But I guess I am a little disappointed in the performance.

IMG_1011.png
 
J

J-mobzz

Well-Known Member
I Lean said:
I see 4-5 amps with a 100 watt panel.
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So that’s aligns with what I saw peak. I probably just don’t have the most efficient panels. Kinda a bummer to drop that much into it to only see mid results but it’s better than nothing I guess.
 
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