question

timo-san avatar image
timo-san asked

Could this ve temperature compensation gone wrong or firmware / settings related?

EasySolar 1600/24/40, victron agm deep cycle batteries 4 pcs 12v 220Ah each, connected as two 24V packs to get 440Ah capacity.

Two generator aided loading scenarios. Both started after slowly discahrged to arpund 23,9V

First one was 5th of december, temperature went -27 celcius degrees and 2000w generator ran for few hours, i started it several times cause every time voltage hopped up, and charging power went rapidly down. Strange voltage, almost immediately absorption mode because voltage so high.

After I got home, i upgraded latest firmware to easysolar and double checked everything. Believe that only setting I altered was UPS functionality on. Checked charger voltage and max charging amps…

Second try. Temperature around 0 degrees celsius. Same setting, now it workef just like it should. Amps went up to >33A and voltage hopped 24->27 and SLOWLY reached absorption voltage a litte under 30 (default voltage settings for victron AGM from vconfig software) After hitting absorption mode, voltage flatlined and current dropped more rapidly.


question, did I have something terribly wrong on first run or was there some known firmware bug causing this or could the temperature be the reason, I read that victron VRLA battery such as AGM should have -4mV/c temp compensation per cell, so would that mean -48mV for 24VDC pack? I remember that default compensation in EasySolars vconf is not -48mV but rather somewhere around -30mV? Thats default when I choose AGM deep cycle victron battery preset. Could that affect this much?




aed70b64-356d-423b-8539-508619a6b8fd.jpegYellow is current blue voltage. Started and stopped generator several times wondering why it jumped immediately over 30V



a6b049ec-0331-410c-9169-85d90aac7b14.jpeg

Also, the charger mode seemed a little restless



44d271ad-4b0c-4878-a49b-10cda92d8f8e.jpeg

And the better run shown here. Few stress tests for genset with coffee machine and microwave oven shown here. ;-)



9871c429-50c0-47e9-aa8e-837901d5e6dc.jpeg

More peacefull mode changing here

EasySolar All-in-One
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

1 Answer
snoobler avatar image
snoobler answered ·

Cold lead is SLUGGISH. It's part of why compensation exists. An immediate jump to 30V isn't alarming. I would expect to see about 31.3V with .048V/°C @ -27°C if your normal absorption is 28.8V.


-27°C is a pretty extreme environment for charging.


At 0°C, I would expected to see 30.0V.


At 0°C you've lost about 30% of your battery capacity. At -27°C, it's even worse, so the charge current is a higher C rate than it would be at higher temperatures.


I don't really see a problem here.



2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.