MPP Solar PIP-1012LV-MS Charging amps

[trose9999]

I just purchase a PIP - 1012LV-MS and was expecting to get around 20 amps of charging power while connected to shore power. The 280 a/h lithium battery is only charged 35%. The charger starts charging at about 17-18 amps (which is fine), but then cuts down to around 8 amps after and hour and a half ( the battery is still only 45% charged. Any ideas? Is it going into a premature float? Settings are as follows:
1. UEI
2. 60A
3. APL
4. SDS
5. USE
6. LFD
7. LFD
8. 120
9. 60
11. 20
12. 14.5
13. 14.4
16. SNU
18. 6ON
19. ESP
20. LON
22. AON
23 BYD
25. FDS
26. 14.6
27. 14.6
29. 10.5
31. N/A
33. EDS
34. 14.6
35. 60
36. 120
37. 30D

 

[sunshine_eggo]

gauge of wire?
length of wire?
Confirmation that you've quadruple checked that all connections including cell interconnects, etc. are 100% properly torqued?

When inverter indicates <20A:

Voltage @ battery terminals:
Voltage @ inverter terminals:

 

[trose9999]

Guage of wire - 8 AWG (this matches the rv battery wiring which has accommodated a 55 amp charger just fine).
Length of wire - 24 inches
All connections are properly torqued

Voltage at inverter terminals 13.48
Voltage at battery. 13.36

Interestingly, when both utility and solar are connected, the system charges consistently at around 16 amps (when the sun is shining). As soon as I disconnect the solar (but leave utility connected) the charging amps drops down to 8-9 amps.

This morning I tested the system again (utility only connected). When I connected utility, the system charged at 17.9 amps and the green light was blinking indicating “Charging.” Within about a minute the light turned solid green indicating “charged” and the amps dropped to 9.5.

 

[sunshine_eggo]

What was the current when you observed 13.48/13.36V readings?

 

[trose9999]

8.59 amps

 

[sunshine_eggo]

It's behaving like you have high resistance; however, .12V on 9A is only about 13mΩ of resistance, which isn't enough to make it choke.

Settings:

#26 and #27 are wrong. Change to:

26: 14.4
27: 13.6

This likely isn't going to solve your problem, but it will reduce the likelihood of damaging your batteries due to over-charge. Additionally, MPP Solar and Growatt units can behave erratically when bulk and float are the same.

Why are 12 and 13 set that way? That's not typical, but it shouldn't really matter since you have Ut1 set. I would restore them to the defaults. Is it your intention to only use the solar or battery in the event the grid goes down?

 

[trose9999]

The setting changes were suggested by the vendor who sold me the unit in attempting to solve the problem. Since the changes did not solve the problem I’m going to change 26 and 27 to your suggestions and 12 and 13 back to default. I am using the system in an RV. I want to use the solar panels to sustain the batteries when I am boondocking and wish to use shore power to recharge the batteries when I have access to shore power (about one day a week).

 

[sunshine_eggo]

Okay. I can see the Ut1 approach working.

With 16:SNU, I don't think Ut1, SOL or SbU matter - utility will always charge battery, but I don't know that for sure.

Might try 16:CUt just to see if the behavior changes.