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Newbie -no idea about electric/solar-with fast-draining batteries

L

lflock

New Member
Joined
Oct 3, 2023
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49
Location
Mexico
Bought the DIY-4 package from Rich Solar at shopsolarkits. https://shopsolarkits.com/products/complete-solar-panel-kit-4 (except mine came only with 3 200w panels) and I bought the extra lithium battery, so 2 100 ah batteries. Was told this was enough to run my RV plus extras.
Hooked everything up, controller shows charging (most of the time), charged batteries to 100%, but when I go to plug my RV shorepower into the invertor, it directly starts dying, running only for approx. 15-20 mins before invertor starts beeping.
I am ignorant about electrical/solar, so please explain it to me like I am a child. I have approx. 1 month to fix this problem.
 
So you plug the shore power into the inverter, and the RV just drains the battery dry in 20 minutes? Are there any other loads on the inverter besides the RV? What all in the RV do you have running? Is your RV trying to charge the batteries?
 
Do you have any circuit diagrams of how you have it wired?

Just to be clear, you're plugging the inverter 120v output into the shore power input connector on the RV? 30a or 50a?

What, exactly, are you running in the RV to consume power?
 
Rednecktek said:
So you plug the shore power into the inverter, and the RV just drains the battery dry in 20 minutes? Are there any other loads on the inverter besides the RV? What all in the RV do you have running? Is your RV trying to charge the batteries?
Click to expand...
Nothing other than the RV is plugged into it. Running inside is a fridge, a laptop, fan, and clock. That's it.
 
russc25 said:
Do you have any circuit diagrams of how you have it wired?

Just to be clear, you're plugging the inverter 120v output into the shore power input connector on the RV? 30a or 50a?

What, exactly, are you running in the RV to consume power?
Click to expand...
Capture.PNG
 
Just an idea, but is it possible the convertor, 60a also, inside the RV is draining it?
 
russc25 said:
Do you have any circuit diagrams of how you have it wired?

Just to be clear, you're plugging the inverter 120v output into the shore power input connector on the RV? 30a or 50a?

What, exactly, are you running in the RV to consume power?
Click to expand...
The plug is 50a with an adapter
 
2000W inverter, 200 Ah x 12V = 2400 Wh batteries.

RV propane/electric refrigerators are notorious electricity hogs, but I'd think you should get some hours.
Turn off fridge or switch to propane.
Turn off all breakers, do transfer, let solar kit run a while with nothing on.
Turn on circuits one at a time, see what you can run without draining it too fast.

Either your batteries aren't fully charged, or load exceeds inverter capacity, or there is just a big load.
Is there a house battery and battery charger which might be drawing power?
Any heating devices?
 
Hedges said:
2000W inverter, 200 Ah x 12V = 2400 Wh batteries.

RV propane/electric refrigerators are notorious electricity hogs, but I'd think you should get some hours.
Turn off fridge or switch to propane.
Turn off all breakers, do transfer, let solar kit run a while with nothing on.
Turn on circuits one at a time, see what you can run without draining it too fast.

Either your batteries aren't fully charged, or load exceeds inverter capacity, or there is just a big load.
Is there a house battery and battery charger which might be drawing power?
Any heating devices?
Click to expand...
The original house batteries and driving battery are all disconnected.
Thanks, I'll try that once the load is fully charged again.
 
I was going to try Hedges suggestion after the batteries showed fully charged. This morning the controller showed charging, but about 4 hours later, it went to sleep, showing the moon, and hasn't started charging since. I disconnected the PV panels and batteries and then reattached. Same response. Any ideas?
 
Check voltages. Battery terminals of SCC, PV terminals of SCC, terminals of battery.
Maybe there is a bad connection, maybe it thinks battery is charged.
What does manual says the moon means? ("night", or maybe "sleep mode"? Would think it meant zero voltage from PV array.)
 
lflock said:
went to sleep, showing the moon, and hasn't started charging since.
Click to expand...
Your SCC isn't seeing anything from the panels, that's a problem. Hit the PV terminals at the SCC with a meter when it's showing Moon Mode and see what kind of voltage you're getting.

Also check the SCC's settings. By default most SCC's come programmed for lead acid batteries which doesn't charge high enough to fully fill a LFP and leaves a lot of power on the table. Just because it's set for LiFE doesn't mean it's actually doing it, many times I've changed SCC's from FLA to LiFE and it just kept the same settings until I went into USR mode, changed the voltages, then put it to LiFE.
 
Okay, update, as I stated before the controller went to sleep and didn't wake up again. This morning, I checked each individual panel by disconnecting each and measuring with the volt meter and they have power, so I hooked them up to the controller and voila, they worked....Once reaching 100% battery, I plugged in the power cable for the RV with everything off, so far so good, then I flipped the fuses on inside the RV and it started draining, not as fast but still draining and the solar panels continued supplying power for about 30 mins. and then the controller went to sleep again. Tested the pv cables at the controller(after disconnecting) with the meter and nothing, no power. So, checked the batteries with the volt meter and they seem fine. Approx. 11.8 V at 50% charged. I rechecked the panels individually again and they have power. SO, is it possible that the 15a inline fuse is bad?
 
Rednecktek said:
Your SCC isn't seeing anything from the panels, that's a problem. Hit the PV terminals at the SCC with a meter when it's showing Moon Mode and see what kind of voltage you're getting.

Also check the SCC's settings. By default most SCC's come programmed for lead acid batteries which doesn't charge high enough to fully fill a LFP and leaves a lot of power on the table. Just because it's set for LiFE doesn't mean it's actually doing it, many times I've changed SCC's from FLA to LiFE and it just kept the same settings until I went into USR mode, changed the voltages, then put it to LiFE.
Click to expand...
Thank you, I will check that too.
 
You can leave the panels connected at the SCC when you test, that way you can compare the meter to the SCC. It could be a dead fuse, the inline ones are notoriously flakey. The fact that it keeps coming back is the weird part. It could be something as simple as a flakey connection wiggling in the breeze.
 
lflock said:
Tested the pv cables at the controller(after disconnecting) with the meter and nothing, no power. So, checked the batteries with the volt meter and they seem fine. Approx. 11.8 V at 50% charged. I rechecked the panels individually again and they have power. SO, is it possible that the 15a inline fuse is bad?
Click to expand...
Voltage at the PV panels, but not at SCC after the fuse? Sure, it could be bad.

"in line fuse" (is that MC4?) not touch-safe, so best to disconnect fuse hold both ends before opening.
Just disconnecting at panel, you can check continuity from cable to SCC.
 
Hedges said:
Voltage at the PV panels, but not at SCC after the fuse? Sure, it could be bad.

"in line fuse" (is that MC4?) not touch-safe, so best to disconnect fuse hold both ends before opening.
Just disconnecting at panel, you can check continuity from cable to SCC.
Click to expand...
Don't know, just says 15a inline fuse with holder. By Rich Solar
 
Do I even need a 15a inline fuse? I mean, I want to keep the system safe, but I'm in Mexico and parts are difficult to get. Can I plug the pv panels into the controller without the fuse?
How do I even tell if the fuse is bad?
 
You only have 1 string there, pull the fuse out of the loop.
lflock said:
Approx. 11.8 V at 50% charged.
Click to expand...
11.8 on a LFP is pretty much dead. 12v is about 10% charged, a little less.

.
msf4vpdl-1_14.jpg
LiFePO4-Battery-Voltage-Charts-Image-19.jpeg


If your batteries are at 12v, they'll run dry in a few minutes at best. You gotta get those batteries charged up!
 
Last edited:
Rednecktek said:
You can leave the panels connected at the SCC when you test, that way you can compare the meter to the SCC. It could be a dead fuse, the inline ones are notoriously flakey. The fact that it keeps coming back is the weird part. It could be something as simple as a flakey connection wiggling in the breeze.
Click to expand...
Not clear about what you mean:
leave the panels connected at the SCC when you test, that way you can compare the meter to the SCC
Click to expand...
I understand leaving them connected, but when I test, don't I have to unplug at the panel?
 
Are your 3x 200W panels in series, or in parallel?
What are the ratings on the label?

I'm wondering why fuse blew. Series panels it shouldn't, parallel it would.
 
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