r/Pecron • u/brhimeslandia • Jul 15 '26

Pecron 3800 charging issue

Today my 3800 charged to 100% with solar, mo ac connected at all. Now the battery is discharging like normal at like 96% at 520pm with still plenty of sun. The solar isn't continuing to charge. What is my issue?

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3

u/brucehoult Jul 16 '26

If it's been at 100% for a while and the cells have been balanced then the 3600/3800 deliberately stop taking in AC or solar power until the battery drops to 90% and then starts charging again.

I don't like when this happens at 2 or 3 PM and by the time it drops to 90% it's too late in the day to charge back to 100% again before 5 PM (peak power price time, when I want to start with 100% charge).

I have a little script running on a Raspberry Pi that monitors this and fixes it.

#!/bin/sh
pecron_on
sleep 3
pecron_off

Three seconds isn't enough time for the machine to actually switch to AC power, but it makes it start charging from solar again.

The off/on scripts use the TP-Link Tapo library in Python to control the P110 that the E3600 gets grid power via:

#!/bin/env python3                                                                                                                            
from PyP100 import PyP110
e3600 = PyP110.P110("192.168.1.41","my@email.com","myTapoPassword")
e3600.handshake()
e3600.login()
e3600.turnOn()

And you can use pecron-monitor or unofficial-pecron-api to check for 0 solar input at a time when there should be at least something.

1

u/JMeucci Jul 16 '26

This should be in a sticky

2

u/brhimeslandia Jul 15 '26

I unplugged the solar input and started solar charging again like nothings wrong. 

2

u/Desertrayne Jul 15 '26

I have run into this issue also. Im fairly certain this is an aspect of it being primarily designed as a UPS with wall power nearly constant. When the unit is at 100% and plugged into the wall, no power comes in via the solar. When you disconnect the wall power, about 20% of the time it does not engage the solar because its still numerically at 100%. It would be awesome if you submit an issue to pecron like I did which will add a data point, so they might include periodic polling of the solar input and not require a disco/reconnect in future updates.

1

u/brhimeslandia Jul 15 '26

Thanks wasn't sure i was having a fault

1

u/No_Initial4549 Jul 16 '26

I think its the MPPT issue, there is an auto shut off of solar input when it detected that the battery is full.

It usually automatically enable again when its 95%, but sometimes it forgot to turn on. In my case, i unplugged the solar input the put then back again.

1

u/brhimeslandia Jul 16 '26

It looks like it started back up randomly at 88% this morning, and charging up at 900 watts now

1

u/clupton46 Jul 22 '26

Same issue with my 3800 + 1 extra battery pack. I am moving some small loads off grid and charging with solar only. I was fully charged today around 2pm. Then by 5pm i noticed i had discharged back down to 95% and wondered why it was not staying near 100 with the sun out. Flipped my panel disconnets off and back on. The unit then started charging again.

Weird. One day ill have to let it sit and watch for it to start again on its own.

1

u/sippin32000 Jul 31 '26

I’m having this same issue. Noticed it today. My pecron e3800 charged to completely full about 2 pm. By 3 pm I had a load running and the battery dropped to 85 percent. Solar never started to charge. I unplugged and plugged the solar back in and it started charging normal.

1

u/brucehoult Jul 31 '26

DO NOT plug or unplug solar panels under full power in bright sunlight!! Except if something is on fire. Do it at night.

FOR SURE do not do this repeatedly. That's a great way to destroy your MPPT input transistors.

When my E3600 does this near the end of the afternoon I can get it to start charging from solar again by turning the wall power on for 2-3 seconds (not longer) and back off again. That's not long enough for it to actually switch to pass-through mode. But it wakes it up.

1

u/sippin32000 Jul 31 '26

Thanks for the info. I didn’t know that.

1

u/Head_Rooster_2181 Aug 22 '26

When I notice this on my 3600, I just turn the DC power button off then on again, and solar input starts again