Epever Controller/solar/battery question (4 Viewers)

[Tennessee Jed]

I have what I thought was a pretty dependable system in the back of my cruiser. 2x 100 watt panels on the roof > Epever MPPT 20 amp charge controller > 100ah LiFePO4 battery. It has been set up for several months without a hitch, keeps the fridge cold all the time. I don't have a lot of loads, mainly just the fridge.

The other day I noticed the state of charge was 35%, which is the lowest it's ever been. I started trouble shooting - both panels check out good (about 18 watts coming from each panel, wired in parallel). Since they're in parallel I get 18 watts from both panels linked up - (I didn't measure the amps out at the panels themselves).

I get 18 watts at the breaker (where the panel wires come in) and I get a solid 10 amps incoming current there as well.

I get 10 amps coming in from the breaker to the charge controller (so the breaker is good). BUT: I get 0 amps coming out of the controller, going to the battery. The charge controller display panel shows 18 watts coming from the panels, then 0 amps. There used to be an amp reading there in the 8 - 10 range depending on sun/clouds.

So do I have a burnt out charge controller? The battery is also good - I charged with my AC charger and it went right up to 100% - 14.7 volts - in about 7 hours. And it was fine today, 12 hours later.

This is a pretty new controller, about 6 months old I guess. We had a recent hot snap into the mid 90's every day, and it got over 100 - 110 in the back of the troopy. Could that have cooked the controller?

Thanks for any input.

 

[Tennessee Jed]

Just a little more info. The smart shunt read out shows daily battery charge up and down with day/night cycles, as well as incoming solar charge likewise alternating. At the thin red arrow you see something happened, not sure what, and the power stops coming in, and the battery voltage starts steadily dropping. The fridge was on this whole time and as it drew all night it pulled the batter down. The next day I hooked it to my AC charger which caused the two flat topped spikes to the right (had to take it off the charger for a few hours to do some stuff.)

Also the charge controller showing 17 v coming in, and 0.0 amps out.

 

[e9999]

Your numbers seem inconsistent as in 18W (low) with 10A (quite a bit), but you describe the situation as there is nothing coming out of the controller. So I would check it and the downstream wiring / connections first, of course. Easy to check the controller if you have it all connected already and a load handy, and have a good multimeter (or just use the smartshunt). But to get the painfully obvious out first -sorry-, have you checked to see if there is a fuse in the controller that could be blown? On some of mine there is an exterior ATO type fuse that is easy to see and change.

 

[Tennessee Jed]

Have not opened the controller to check for a fuse, but I'm at that point. Good idea, thanks.

Sorry I mean 18 volts, not watts, from the panels. Duh. I'll edit the original post.

The wire to the battery is fused and heavy gauge (10ga), but it's a 25 amp fuse and it's not blown. All the connections are tight and clean. I'll take the controller down and see if it's openable/serviceable. This is their basic unit so it may not be.

 

[e9999]

Some of the less-than-greatly-designed models out there have soldered in fuses, which is pretty bad, IMO. Being in the desert with a full fridge and a fuse on the motherboard blown does not sound great. Of course, they will tell you to put a separate external fuse to protect their unit, which is indeed a good idea. (Note to self: make sure I have spare fuses for my controllers when going out there...)

Anyway, if the fuse is blown, you may want to figure out what happened before replacing it. If it blew, it did its job to protect from something bad.
If the controller is rated at 20A, it is possible that the inner fuse would blow before your external 25A one. Personally, I would use an external fuse at 20A or -likely better- even a bit less for safety.

 

[Tennessee Jed]

OK - opened the controller and there is a 35 amp fuse there, soldered in place, but it's not blown. I didn't see any burned areas on the circuit board, to the naked eye.

 

[Tennessee Jed]

It's weird - I get a normal volt reading, and a KWH reading, but no amp reading on the controller screen.

 

[e9999]

The voltage readings mean just that, there is voltage, and kWh is likely history, all that is not inconsistent with there being no current out currently. But you'll want to make sure there is indeed no current coming out, notwithstanding what the controller says, it is conceivable the current reading of the controller is off. But sounds like no power out based on your description.

So, if the inner fuse is good , then your problem is either outside or someplace else in the controller (cap'n obvious here). It would be better if outside, that may be cheaper/easier to fix. But if it is the controller, if you have better things to do than try to fix a blown controller, and since you already have a Victron smartshunt, upgrading to a Victron controller may not be a bad idea anyway (it will talk to other victron units, from memory some of mine if not all have an external fuse, and they are high quality). (Here again, I would still try to find out what happened before risking a new controller.)

Rereading your OP, with 18V instead, there is something off. If you were to have 18V 10A coming in and 14V 0A out, that would mean there is 180W dissipated in the controller, that would get noticeably hot pretty fast. So something is not making sense there.

 

[Tennessee Jed]

I'm with you, what happened in the first place? - important thing to figure out. If possible. Looking back at the original screen cap of the smart shunt graph, there is that blue spike after which things fail.

I feel like it's inside the controller because I put the points of the multimeter on the cables going IN to the controller, and I get 10 amps, give or take. And I move them over to the cables coming OUT, and I get nothing.

Maybe I should get a Victron controller. I put an Epever on the sailboat and it was great (the Renogy literally melted in place.) I'm gonna go back over everything again and if I don't come up with something I guess I'll order one. I'm sort of up against a trip in 2 weeks and I want to get things up and running.

 

[e9999]

What do you mean by "put the points of the multimeter on"? If it it's a regular multimeter you have to disconnect the wires and put it in series to measure current. If it's a clamp DC meter, well then it's a clamp, not points. Or I'm behind the times, as usual...

And, yes, sounds like a controller issue. If you have a trip coming, getting a better controller now is a good move. Even if yours proves OK, one never has too many controllers anyway...

You did check all the settings of the controller, correct?

 

[Tennessee Jed]

If you insert the needle points of the multimeter in next to the cable terminals you can get a reading without having to remove the cables. Plenty of room in there. I also figured out that you can touch the contacts to the screws themselves - they're a direct connection to the cables beneath them. That also explains why they're so deeply inset into the face of the controller. Same result.

I went through the settings screen by screen and nothing was changed from when it worked. I didn't see anything that seemed like it would fix the issue.

Thanks for your help - ordered a Victron. I'll carefully hook it up and if it doesn't work I'll just return it and go back to square one.

 

[e9999]

If you mean that you set a regular multimeter on current mode and touch the test leads to the still-connected ends of either the panel or the battery cable at the junction block, and then read the current value like that, well, that's a new one for me...

 

[spressomon]

@Tennessee Jed, just in case you are not aware, Victron MPPT solar charge controllers require a 5v differential from static battery charge and incoming voltage from the charge controller...to initiate current flow. Other brands might be like this, or not...most of my experience is with Victron.

 

[e9999]

^ Spresso, that is true, and I was concerned about that at first, but in practice I found that it is not an issue, even with only one panel, because all nominal "12V" panels I know of will easily get to about 20V under open circuit -even with very minimal insolation-, they're designed that way (with 36 cells usually). The ones I measured myself were all about 20-22V open circuit IIRC. So you end up always having the +5V anyway and I don't think it's anything to worry about. Obviously, if you use a "24V" panel or put 12V panels in series or use a "house-type" panel, you'll have way more voltage than needed for 12V batteries in any case.

 

[Tennessee Jed]

Thanks for the ideas. These are regular 100 watt solar panels, bog standard. I get about 18 volts from each one of them.

The saga continues, if you're interested. I went out this morning and looked at everything once again. Still 0 amps coming out from the controller - the panels showed 7-9 amps at the cables coming down from the panels.

So the cable from the charge controller (CC) goes into a Blue Sea fuse block - the standard 12 circuit one - and that feeds the battery. That wire has a 25 amp fuse on the block. Now yesterday, I checked it and it was not blown, but this morning I checked it and it was blown. I can't explain that. The panels were off all night. Maybe me futzing around with the multi meter did something. So thinking Aha! I replaced the fuse, and bingo - it started immediately dumping amps into the battery. As the sun came up the amperage increased. I thought I had fixed it. So I turned on the fridge, which didn't change anything except pull the expected 5 amps while the compressor ran. I buttoned it all up and went inside. About 3 hours later I went back out to check the history on the Victron app, and there had been several on/off cycles of the compressor, then the same thing - it cut off to 0 amps. And I was getting 0 amps showing on the CC panel.

I pulled it apart and the 25 amp fuse was NOT blown. I replaced it with another new 25 amp fuse, and it didn't start working. So I'm confused.

In addition to the fuse block (for fused loads) I have a regular positive distribution block/bus bar that I use for a couple of loads that are fused at the switches themselves and don't need to be double fused. So I moved the cable (coming from the CC) off of the fuse block over to the secondary unfused positive bus bar, and BINGO - it immediately started pumping in 7 - 8 amps. And climbing slowly as the clouds cleared. The battery charge slowly and correctly increased. All was right with the world. I guess it was the fuse block maybe?

So I head off down the road to run an errand and I'm watching the app and I literally watch it stop working. It went back to 0 amps. When I got home I opened things up and it was all cool, nothing burnt, nothing out of the ordinary.

I'm honestly stumped. Could it be the heat? The battery has a 150 degree temp cutoff, but it comes back on at 130 degrees. It did get up to 105 in the back of the truck on the battery temp gauge. I don't know if the Epever CC has a high temp cut off but I can't believe a measley 105 ambient would do that. It did not feel hot in any way and all the other readings were normal.

I give up. I thought I understood this stuff. I'm sure a true 12v expert could look at it and diagnose it but I can't. I have a Victron CC coming tomorrow to try - it's a higher quality unit. We'll see. If you don't live in a big city you're out of luck getting a 12v system diagnosed or even installed.

Sorry to blather on.

 

[Tennessee Jed]

Also - all circuits ground to the battery negative. I don't have a body/frame ground. I guess it's what is referred to as a floating system. I've read several things about this and it seems to not be an issue, lots of people run larger and more complex RV installations like this. But FWIW.

 

[spressomon]

Sheesh! It seems to be acting like a loose wire connection. Have you tried bypassing the BlueSea fuse block entirely...as a test?

Dunno, just a wild guess...and it doesn't really hold water even as a guess: I wonder if the battery's BMS might be the problem. Throwing more mud on the wall: Bad crimp somewhere in the runs?

 

[96bruizer]

I Have the same setup. These batteries hate 2 things, extreme cold and extreme heat. It may be as simple as the fact that it had too much heat and now the performance isn’t as good?