Off Grid Power Troubleshooting. Input appreciated. Thanks!

[Rhiannon]

Hi Skoolie Fam,

Our power sometimes works and sometimes does not. I'm hoping one of you might be able to point out where common issues are. We are seriously scratching our heads.

We have 2 345 watt solar panels running through a 60A Renogy Charge Controller with a AIMS Lithium Battery (12V 200Ah LiFePO4). We have DC (right now only running lights and fridge). AC – keeping it off while we try to figure this out.

We've tried unhooking the battery and charging that with a special lithium battery charger.

What tends to happen before power turns itself off is a flickering between __% battery and battery overdischarged (flashing 0% on our charge controller).

Recently the issues seem to be happening with the setting of the sun. There didn't seem to be a correlation with this before.

I've also noticed that the charge controller does not come on display panel wise with just the battery—once the solar is plugged in the display then comes on. Shouldn't the battery be enough for this to come on? Charge controller issue?

In the beginning, the charge controller was not set to “lithium” as battery type. We fixed this recently. Could we have messed up the battery or the charge controller?

We have warranties/policies on most things but definitely want things stable before winter.

I've attached the original wiring diagram. We haven't hooked up the alternator (as a backup generator) and aren't using shore power.
https://drive.google.com/file/d/16kt...ew?usp=sharing

Thanks so much for taking the time to read this!

Juniper



Inverter: AIMS 180 Watt, 360 Watt Peak, Pure Sine DC to AC Power Inverter

Fridge: Unique 3.8 cu/ft Solar Powered DC Fridge
only drawing 445 Wh/24hrs
Operation: DC power, 12V / 24V
Total Watt. Hr. Draw (24V DC): 445 Wh/ 24 hrs (set to -14˚C freezer/+4˚C fridge performance in a +25˚C ambient)
Total Amp. Hr. Draw (24V DC): 14.5 Ah/ 24 hrs (set to -14˚C freezer/+4˚C fridge performance in a +25˚C ambient)
Power Consumption: 49 W on 12V/24V
Average Run Current: 4.1A on 12V – 2.1A on 24V

PS My partner may be more aware of specifics that I don't understand so I can ask him any clarifying questions.

[JDOnTheGo]

Very little info to work with but given your statement "the charge controller does not come on display panel wise with just the battery", my first guess is that your battery is dead. Could also be wired wrong - I'm not going to open an unknown file from a shared drive to take a look - too dangerous.

[Texan]

I'm with JD. Check the battery. Also check the charge controller. Its kind of like troubleshooting your car battery. Always check the alternator when you replace a dead battery.

I know it's probably obvious, but check polarity of everything. I worked on some power equipment at a nuke plant a few years ago. They wouldn't let me touch the equipment. Their "highly qualified " electricians would do my work. I found that they didn't know how DC voltage worked and wired the external battery cabinets reverse polarity.

[Booyah45828]

Do you have a multimeter?

Do you have voltage available at your battery terminal?

If yes, then I'd say your charge controller has a fault. The way you describe that the charge controller will only come on connected to solar, I'd say either your controller has a fault, or you have it wired incorrectly.

[ACamper]

My first thought would be battery. How old is it ?

[Rhiannon]

Originally Posted by JDOnTheGo

Very little info to work with but given your statement "the charge controller does not come on display panel wise with just the battery", my first guess is that your battery is dead. Could also be wired wrong - I'm not going to open an unknown file from a shared drive to take a look - too dangerous.

Thanks. We think our next step is to take the battery in to have it looked it.

The link is just to a jpg in my google drive. I'm not sure how to attach photos to posts here. Totally get the link danger vibes...

[Rhiannon]

Originally Posted by ACamper

My first thought would be battery. How old is it ?

It's not old. Bought it a year ago. But only had it working March-May then it's been on the fritz.

Could be junked from received the wrong charge through the controller? Also my honey said at one point when we was using ratchets to unplug the terminals he crossed it accidentally and shocked himself... Enough to destroy the battery?

[Booyah45828]

Originally Posted by Rhiannon

Also my honey said at one point when we was using ratchets to unplug the terminals he crossed it accidentally and shocked himself... Enough to destroy the battery?

Possibly. Check for voltage at the terminals with it unplugged from the controller. Shorting it like that might have burned up a fuse or something internal. I'm not that familiar with lithium batteries to be certain if something like that could happen.

[Texan]

Lithium batteries are very new to the market and there is no industry standard. Many batteries have built in monitoring systems. Some have internal fuses. I'm just starting to see them in my industry and don't know much about them yet.

I work on Uninterruptible Power Supplies and deal mostly with VRLA and wet cell lead acid batteries. I'll see the occasional gel cell or nicad battery system.

[bubb, the real one]

The several charge controllers I have used all powered themselves with electricity from the battery, not the panels.
When I read the manual they all said hook up the charge controller to the battery for a few minutes so it can power itself and sense the battery voltage and only then do you hook up the panels.



This then points to either a wiring issue or a battery issue, test both ends of the wires with a multimeter and then check the battery post with the meter.

[kazetsukai]

Originally Posted by bubb, the real one

The several charge controllers I have used all powered themselves with electricity from the battery, not the panels.

This is may be true with controllers you have encountered, it is not true for mine. I've both a Victron MPPT and a Renogy MPPT that will power the output or load terminals "sun only", die at night and resume in the morning when the sun comes back up.

I have a feeling that the OP may have a defective BMS in that lithium battery, or if a short did indeed occur in the past, that might have blown some internal fuse like suggested by another poster. Many of these "drop in replacement" lithium batteries have very low current limits due to the BMS.

[dzl_]

So as everyone else has said, check the voltage using a multimeter at the battery terminals. Report back your findings


Also has others have said, the short (dropped ratchet) could have:
1. Blown an internal fuse
2. Tripped the internal BMS (overcurrent situation) and need some user intervention to reset
3. Done something else less than ideal


Also, you stated the charge profile was not set to LiFePO4 for a while. That is not great at all, but I suspect the BMS would protect itself against too much damage from overcharging. I suspect this would not be the cause of the charge controller not working.


You really don't want to be running a lithium battery (or any battery) down to dead zero (if whatever battery monitor you are using to get that info is accurate) or to the point where things start flickering. That doesn't sound ideal. But again, I would expect the builtin BMS to protect the battery in these situations.




If I were in your shoes I would:
1. Check the battery with a multimeter
2. Check if your battery will power loads/devices other than the charge controller
3. Make sure the wiring between SCC and Battery is in good shape, make sure no fuse or breaker has tripped, make sure connections on both ends are snug and secure and correct.
4. Read your manuals (renogy and aims) there should be troubleshooting advice, one or the other device might be trying to communicate to you what is wrong, you just need to know what to look for.
5. Reset/restart/clear BMS or SCC if possible
6. Hopefully one of the above will give you more to work with, reassess at this point.


Based on what you have said so far, I think beyond this immediate problem you would benefit from educating yourself a bit on how to take care of and prolong the life of a lithium battery. This article is a good place to start.

[Rock-N-Ruth]

I've also noticed that the charge controller does not come on display panel wise with just the battery—once the solar is plugged in the display then comes on. Shouldn't the battery be enough for this to come on? Charge .

Sounds like you may have the battery input to the solar controller in the wrong place. Normally the solar controller will light up with battery input and not light of you have solar input without battery input, and light with battery input but no solar input. Your inverter should be on the load side of the battery and not on the load output of your solar controller

[rffffffff]

I have renogy 40A MPPT controllers and I think everyone here is spot on.

Looking at your wiring diagram I would disconnect the wire from the charge controller after the 60A fuse and wire that directly to the battery instead of the bus bar and additional fuses and switch.

Disconnect the solar panels from the charge controller and make sure that the charge controller comes on with the batteries and nothing else connected. If that doesn't happen you have a bad 60A fuse (unlikely if it works during the day) or you have a bad charge controller. (or the battery wires to the charge controller aren't seated properly, etc.

You can download the manual for the charge controller but it should stay on in battery only mode one way or another unless it's drastically different from mine.

[rffffffff]

I responded prior but I just wanted to chime in again after looking at your wiring diagram that you really need a transfer switch added from what I gather. It looks like when you plug in to shore power you are going to create AC from shore and AC from your inverter and those things can't mix unless you have a grid tie inverter, which wouldn't make a lot of sense.

I have a big switch that makes the charger work and sends power to the AC panel from the generator or shore power but when I turn it to the other position the inverter generates the AC which is isolated from the charger so I'm not converting dc to ac to turn the charger on to charge dc again.

I don't think this is your issue that you've described but it could cause havoc if it's wired as it looks in the diagram.