MPP LV2424 hybrid charging issues

[dbutler31]

I have a small system installed in my square drop camper. It's a 200w solar panel with 24v 230Ah LiFePO4 battery and the MPP all in one inverter. The last time I used the camper back before winter, I ran into a charging problem. With little sun available for solar, I used my little 2200w generator to charge my batteries. Trying to charge at 40 or 50 amps, the inverter immediately shuts it off. Charging at 30 amps, it will charge for about 30 seconds, then shuts off. At 20 amps, no problem will charge all night until 100%. I replaced the bms and no change. My cells were all within 3 Ah of capacity and wire resistance is .04 to .05 ohms. I also have the same issue if I plug into a house receptacle. When I first got the system up and running 2 years ago, I was able to charge at 50 amps with no issues. Any ideas?

 

[sunshine_eggo]

Voltronics units are notorious for being intolerant of non-inverter generator/non-grid power. Since it's also an issue on grid, I can only guess that it's possibly a degradation of the charger itself. Have you tried charging in standby mode?

I assume since you're reporting resistances, you have a JK with active balancing. Are you seeing any of the cells go over-voltage or exceed any other limits?

 

[dbutler31]

Yes I have the JK bms, all the cells stay pretty tight while charging, .005 volts from highest to lowest. I'm not familiar with charging in standby mode.

 

[sunshine_eggo]

Yes I have the JK bms, all the cells stay pretty tight while charging, .005 volts from highest to lowest. I'm not familiar with charging in standby mode.

I believe the unit will charge from PV or AC when the switch is in the off/standby position.

https://watts247.com/manuals/mpp/LV2424%20hybrid%20manual-20190717.pdf

page 24

 

[meetyg]

I have a small system installed in my square drop camper. It's a 200w solar panel with 24v 230Ah LiFePO4 battery and the MPP all in one inverter. The last time I used the camper back before winter, I ran into a charging problem. With little sun available for solar, I used my little 2200w generator to charge my batteries. Trying to charge at 40 or 50 amps, the inverter immediately shuts it off. Charging at 30 amps, it will charge for about 30 seconds, then shuts off. At 20 amps, no problem will charge all night until 100%. I replaced the bms and no change. My cells were all within 3 Ah of capacity and wire resistance is .04 to .05 ohms. I also have the same issue if I plug into a house receptacle. When I first got the system up and running 2 years ago, I was able to charge at 50 amps with no issues. Any ideas?

What is your setting #2 set to ?

If it's set to UPS, it might be intolerant of noisy/unstable AC voltage. Make sure it's on APL.

 

[dbutler31]

What is your setting #2 set to ?
View attachment 213768
If it's set to UPS, it might be intolerant of noisy/unstable AC voltage. Make sure it's on APL.

It's on APL

 

[dbutler31]

I believe the unit will charge from PV or AC when the switch is in the off/standby position.

https://watts247.com/manuals/mpp/LV2424%20hybrid%20manual-20190717.pdf

page 24

I'll try that, might be a couple days. Right now it's 30°, 50 mph wind plus snow

 

[sunshine_eggo]

We're going to be in the 90s today...