MPP LV2424 (white) won't charge battery from generator unless the unit is turned off.

[samuelprsns]

I have seen some discussion on this elsewhere, but I still am not clear on exactly what may be going wrong with my particular set up. I bought the [HBK-2 White] kit from shopsolarkits.com with the bigbattery Hawk Max 24v battery. I'm a newbie, and I've been learning the system and working out kinks, but there is one issue I can't seem to wrap my head around.

My setup is at an off-grid cabin, with only the battery and solar, no utility. But since it's winter in Southern Vermont, I get very little daylight, many days none. So I have a propane generator there so I can charge the battery during the day to use at night.

Here's the issue: When I have the lv2424 switched on, it seems to recognize that there is AC power attached to it, but does nothing with it. The little icon is there to let me know that it recognizes that there is power, and it will tell me on screen that there is 120v AC power coming in, but then it doesn't charge the battery. The solar panels are indicating that they're working but in heavy cloud cover sometimes they're only bring in like 20w, so the battery is still only draining, not using the generator at all. The only load is a little 35w fan I have on my composting toilet to keep the place from stinking up. But when I turn the lv2424 off, it begins to show me that the battery is now working with the solar to charge the battery.

Sometimes if the lv2424 has been off and then I turn it on while the generator is plugged in, or if the lv2424 is on and I plug in the generator, for a while it will show that the generator is charging the battery and bypassing that to power the load at the same time, but after a few minutes, that disappears and it goes back to simply not using the generator for anything. This happens even when my battery is at 25v and clearly needs to be charging.

I know I've been confused about their "power save" vs "battery" modes, so I'm hoping there's just some setting to change that their terrible manual isn't making clear to my inexperienced eyes.

Here are the specs of my setup:

Solar panels:
(4) Rich Solar Mega200 Panels - wired in series
Vmp 20.4v, Imp 9.80A, Voc 24.3v

Battery:
BigBattery Hawk Max 24v 5.2kWh LFP

MPP lv2424 settings:
01 - Sbu
02 - 40A
03 - APL
04 - SdS
05 - USE
06- Lrd
07 - trd
08 - 120v
09 - 60hz
11 - 30a
12 - 23v
13 - 27.0v
16 - snu
18 - bon
19 - ESP
20 - Lon
22 - Aon
23 - byd
25 - FdS
26 - 28.7v
27 - 28.6v
28 - SiG
29 - 21.6v
30 - one
31 - SbE

Attached are photos of the unit turned on and turned off so you can see what I'm talking about.

Any advice at all would be so helpful to me. I'm desperate to keep the power going while I charge the battery. Thank you! Also, if any of my other settings don't make sense, feel free to absolutely drag me. I have no shame. This is how I learn. I'm new not just solar but to electricity in general. I've already made leaps and bounds thanks to forums like these. Thank you!

 

[sunshine_eggo]

In SBU or SOL mode, setting 12 must be ABOVE battery voltage. Recommend you set 12 to 0.2V below your bulk/absorption voltage (#26) and 13 to your absorption voltage.

Bigbattery is notoriously moronic for the way the spec their batteries. LFP batteries should be floated at 3.375V/cell, not held at max. Recommend you set #27 to 27.0V.

 

[samuelprsns]

In SBU or SOL mode, setting 12 must be ABOVE battery voltage. Recommend you set 12 to 0.2V below your bulk/absorption voltage (#26) and 13 to your absorption voltage.

Bigbattery is notoriously moronic for the way the spec their batteries. LFP batteries should be floated at 3.375V/cell, not held at max. Recommend you set #27 to 27.0V.

Thanks! That helped me a lot, but unfortunately setting #12 can only be set as high as 25.5v, so this doesn't help me top the battery up. Should I switch to SUB mode? Would that preference the "utility" over the battery, thus allowing utility to power load and charge battery?

 

[sunshine_eggo]

Thanks! That helped me a lot, but unfortunately setting #12 can only be set as high as 25.5v, so this doesn't help me top the battery up. Should I switch to SUB mode? Would that preference the "utility" over the battery, thus allowing utility to power load and charge battery?

12 should be when charging STARTS.

13 should be the charge end voltage.

SUB would help if the above doesn't resolve it.

 

[jl123]

Hey Samuel, I have the exact same system and battery from SSK. And I am having the same issue. They are telling me that my generator is at fault even though I have tried 2 generators a westinghouse 3400 watt as well as a honda 2000 watt inverter type and still it is not charging the battery. Did you ever get this figured out?

 

[sunshine_eggo]

Hey Samuel, I have the exact same system and battery from SSK. And I am having the same issue. They are telling me that my generator is at fault even though I have tried 2 generators a westinghouse 3400 watt as well as a honda 2000 watt inverter type and still it is not charging the battery. Did you ever get this figured out?

Setting 12 is higher than battery voltage? Will not charge from generator is voltage is > setting 12.