Mpp solar shows low pv wattage

[OffgridinFL]

Hello all,

new to solar and have finally taken the step to getting setup. Having an issue with low watts from panels to inverter. Wonder if I’m reading this wrong or have low amps from panels.

Equipment
Mpp solar lv 5k 48v
2 24v wolf big battery in series
3 270 watt panels in series ( have more but haven’t added them yet)

panels are about 100 feet away. 8 gauge wire

I’ll attach pic of inverter readings from panel and panel specs. Feel like the watt output is low. Voltage looks right though

any insight would be appreciated

 

[snoobler]

Apply a 1000W load and see if it increases.

When battery is near full at peak voltage, only the power that is needed is pulled from the array. By adding a load larger than the solar, solar power should increase as the battery's voltage drops in response to the load.

 

[OffgridinFL]

Apply a 1000W load and see if it increases.

When battery is near full at peak voltage, only the power that is needed is pulled from the array. By adding a load larger than the solar, solar power should increase as the battery's voltage drops in response to the load.

Thanks. Just tried it and it pulled over 500.
Hmm. Then I wonder if I have a different problem with the batteries not charging efficiently because they are not near full charge and I’m not running much off of them. Only a few 100 watt load for a few hours each night

 

[snoobler]

500W out of 810W isn't great, but that may just be other factors like panel orientation/tilt, shading, clouds, haze, solar irradiance, etc. You only get peak power in perfect conditions at high noon.

Is your MPP properly configured for your batteries?

P.S. Welcome to the forum.

 

[OffgridinFL]

I worked through those based on some threads I read on the forum. Not sure they are optimal. They were really similar to default.

Battery type - User defined
Bulk charging - 56.4
Floating- 53.6
Low dc cutoff- 45.4

certainly open to better settings

 

[snoobler]

I don't see where you indicated LFP or lead-acid.

Are the bulk and float consistent with your battery specification?

 

[OffgridinFL]

Oh sorry it’s a LiFePO4. In the mpp solar inverter the only options are agn, lead acid or user defined. Based on some other threads it seemed like user was the recommended approach.

specs say suggested charge is 28.8. So I’m assuming that would be 57.6 running two in series for a 49v system

of course I’m new and could be off base

 

[snoobler]

Oh sorry it’s a LiFePO4. In the mpp solar inverter the only options are agn, lead acid or user defined. Based on some other threads it seemed like user was the recommended approach.

Yep.

specs say suggested charge is 28.8. So I’m assuming that would be 57.6 running two in series for a 49v system

of course I’m new and could be off base

3.65V/cell max
16* 3.65 = 58.4V

HOWEVER, you don't need to go that high.

I don't believe you can change your absorption time, so I'd stick with your bulk and change float to 3.4V/cell @ 54.4V. They will still slowly charge at 3.4V, but they will stop at about 95% SoC, and charging to a lower peak voltage may improve cycle life.

 

[OffgridinFL]

Thanks for your help. I adjusted the settings earlier. Batteries seemed to charge close to full by end of day 56.6v in stand by mode. When I turn on inverter for ac it immediately drops to 47.7v gives fault 4 for low battery voltage. No loads other than inverter itself

 

[snoobler]

You either have a loose connection, too small a battery, a massive load, or failing batteries.

 

[GSXR1000]

what makes you say your battery's are not close to fully charged?
could be they are and your system is great.

 

[OffgridinFL]

what makes you say your battery's are not close to fully charged?
could be they are and your system is great.

Based off what mpp inverter is saying. The pic in the middle only was showing 1 bar which is supposed to indicate 25% or less.

 

[OffgridinFL]

You either have a loose connection, too small a battery, a massive load, or failing batteries.

The two wolf batteries a 3kw each. so total 6k

The load was just the inverter, which is about 50watts I think.

I’ll check connections but the are Anderson quick connect. No much I can do with them. I’ll just go through and reconnect.

I guess if none of that works I’ll talk with bigbattery.

thanks again

 

[GSXR1000]

Based off what mpp inverter is saying. The pic in the middle only was showing 1 bar which is supposed to indicate 25% or less.

based on the inverter your battery is 100%.

 

[OffgridinFL]

based on the inverter your battery is 100%.View attachment 46467View attachment 46469

 

[OffgridinFL]

Here is a better shot. Bars move up and down when “charging”. If I disconnect pv it shows 1 bar. Fault 4 comes on when I go from standby to on/ac mode

 

[GSXR1000]

what is your battery voltage at the battery input when solar is on and off?

 

[OffgridinFL]

what is your battery voltage at the battery input when solar is on and off?

46 with no solar

57.4 with everything connect but no ac on

46 everything connect with ac on

 

[GSXR1000]

i think per the other thread you need to tighten up your bulk and float. I set my bulk at 13.80 and float at 13.73 so that it can stop charging but not discharge much before it tops it off again

 

[OffgridinFL]

i think per the other thread you need to tighten up your bulk and float. I set my bulk at 13.80 and float at 13.73 so that it can stop charging but not discharge much before it tops it off again

Ok I just noticed something I didn’t before. Testing the individual batteries one is bouncing up to 34v when ac is on. the other is stable at 23v. I guess this leaves me with 2 questions. Is the bouncing to 57 triggering the inverter to think is fully charged? Leaving the other battery drained. Then the second question is with that battery running that high on voltage is it defective and potentially dangerous? I shut it all down for now to be on the safe side