New Renogy 170ah bottoming out

solarstuff

Solar Enthusiast
I hooked up 2x new renogy 170ah 12v batts up to my renogy rover li 30a controller fed by 300w of 12v panels.

This morning the bank was sitting at 80+% until I turned the air fryer on. After 4 or 5 minutes of 1500w the battery read 11% ?!

I turned the load off and the battery immediately started jumping up. Ten minutes later I'm at 42%... and battery Error Code E1 (over-discharging).

What the heck happened????
 

Attachments

  • 20210821_134652.jpg
    20210821_134652.jpg
    939.1 KB · Views: 29
  • 20210821_133643.jpg
    20210821_133643.jpg
    677.2 KB · Views: 26
  • 20210821_133617.jpg
    20210821_133617.jpg
    657.4 KB · Views: 25

Short_Shot

Photon Sorcerer
Excessive voltage drop?

Not sure how the percentage is figured but I'm guessing it's measuring voltage for it to suddenly climb back up rather than measuring incoming and outgoing power in amp-hours.
 

solarstuff

Solar Enthusiast
Excessive voltage drop?

Not sure how the percentage is figured but I'm guessing it's measuring voltage for it to suddenly climb back up rather than measuring incoming and outgoing power in amp-hours.
I think you're right. I disconnected the batt bank and when I slid the fuse back in place (after a minute with my good ol' resistor in place) now I get E3 (low battery voltage).
 

740GLE

Solar Addict
Whatd you do about that fuse that was over heating with the washer between the fuse and the lug?

Also remember 1500w is prob 2-2300 watts drawn from the batter with losses.

Also what’s with the massive oversized leads off the SCC breaker? Def don’t need 2/0 for 30A protected SCC
 

solarstuff

Solar Enthusiast
Whatd you do about that fuse that was over heating with the washer between the fuse and the lug?

Also remember 1500w is prob 2-2300 watts drawn from the batter with losses.
I did as suggested by the forum and was testing when this happened.

I sand-papered the tarnished cable end, put the washer on top of lug (not between lug and fuse) then tightened it all up.

Tested with a small voltage and it seemed good. Today I tried the high voltage and got the e1.

Am waiting for the battery to recharge now and when/if E3 goes away (then will test).
 

740GLE

Solar Addict
I have heard bad things about those bimetallic breakers, lots of resistance and heating, I def wouldn’t be using it as a bus bar type connections like you are.

It almost looks like you should be using some sort of bus bars all those massive lugs double triple stacked with tight bend radius maybe placing strain on the connections. Just a thought.
 

Texas-Mark

Solar Addict
I sand-papered the tarnished cable end, put the washer on top of lug (not between lug and fuse) then tightened it all up.
Is that an after picture, because it still looks like the washer is between the cable terminal and fuse.

Also, even though you said you only have 300W of panel, that wiring from the charge controller to battery looks thin. I always use the largest gauge wire that I can fit into the connectors.

Oh, and one last thing, I would have the charge controller's battery cables tied as close to the battery as possible rather than to the inverter inputs. When pulling serious amps, there can be a voltage drop across the cables and the charge controller may not see the actual battery voltage and give false readings. Granted, your cables are not that long, but that is still how I would do it.
 
Last edited:

solarstuff

Solar Enthusiast
Is that an after picture, because it still looks like the washer is between the cable terminal and fuse.

Also, even though you said you only have 300W of panel, that wiring from the charge controller to battery looks thin. I always use the largest gauge wire that I can fit into the connectors.

Oh, and one last thing, I would have the charge controller's battery cables tied as close to the battery as possible rather than to the inverter inputs. When pulling serious amps, there can be a voltage drop across the cables and the charge controller may not see the actual battery voltage and give false readings. Granted, your cables are not that long, but that is still how I would do it.
Sorry yes I sent a before pic. Work was done after :)

I wondered about the wiring, but my research said to keep a circuit breaker between the batter and the MPPT, which is why I branched off the inverter tona circuit breaker then smaller wires to the rover MPPT.

How would you handle it?
 

solarstuff

Solar Enthusiast
Whatd you do about that fuse that was over heating with the washer between the fuse and the lug?

Also remember 1500w is prob 2-2300 watts drawn from the batter with losses.

Also what’s with the massive oversized leads off the SCC breaker? Def don’t need 2/0 for 30A protected SCC
Texas asked me the same....my understanding was that the wires on the inverter side of the 30a breaker could carry a lot more load from the inverter. Could you tell me how you would rewire?
 

740GLE

Solar Addict
Bus bar of some sort, I see what 8 or so connections, if you had bus bars you’d reduce that by about half.

Also measure the voltage from the high side of that circuit breaker to the positive battery terminal when the SCC is generating, you may find that breaker is causing a loss of voltage.
 

Texas-Mark

Solar Addict
How would you handle it?

I would have slightly larger wires (if possible) from the charge controller going to the battery. I always try to use the largest gauge that will fit in the charge controller connectors. Then I would have them (both positive and negative) run directly to the battery terminals instead of the inverter terminals. That way the charge controller does not see the any voltage drop across the inverter battery cables when the inverter is pulling a lot of amps. And as someone else mentioned, you don't "need" those huge cables on the one side of the breaker that you have between the charge controller and battery. The cable going from the battery to the inverter will be carrying lots of amps, not that one. You only need the same size wire that you used on the charge controller side. It's not going to hurt anything, just not needed.
 

solarstuff

Solar Enthusiast
Wisdom seems to agree here:

1. Bigger wires from charge controller direct to battery (after circuit breaker) instead of to inverter.

2. Replace those wires from charge controller to battery sith smaller ones on both sides of breaker.

3. Replace the ANL fuse given I've switched to lifep04 batts?

I can't source a t fuse for a while...would this circuit breaker be better than the current ANL fuse?

As always, I'm learning lots and appreciate all your suggestions!
 

Attachments

  • 20210822_092409.jpg
    20210822_092409.jpg
    3 MB · Views: 4

740GLE

Solar Addict
I’d keep the fuse over that circuit breaker while you wait for a T fuse.


Again I’ve seen bad things of those breakers, may have been a bad batch of them but the construction of everything about them doesn’t seem solid.
 
Top