question

prb avatar image
prb asked

100/50 mppt charging lithiums, flashing between 13.6 and 15.5v - problem???

Precharging lith batts with 100/50 mppt. Checked with app and saw rapid cycling between 13.5 and 15.5v. I don't know what this means? We properly set the mppt to lithium profile, absorption 14.2v, float 13.5v, voffset to 0.1v, absorption duration to fixed, time 2 hr, tail current off? I've included Chins requirements below. No error messages.

Charging Limit Voltage: 14.6V

Over Voltage Disconnect Voltage: 15V

Over Voltage Reconnect Voltage: 14.2V

Float Charging Voltage: 13.8V

Discharging

Low Voltage Disconnect Voltage: 10.8V

Low Voltage Reconnect Voltage: 11.6V

Under Voltage Warning Voltage: 12.4V


I don't understand why it is cycling. I have another batt charging from another different mppt which does not cycle at all.


MPPT SmartSolar
4 comments
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

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

Alexandra avatar image Alexandra ♦ commented ·
@Prb

Not sure if this is the issue in your case but have seen this on a battery whose bms was unhappy.

Is your battery able to take the 50amp charge current? Some of them aren't able to.

0 Likes 0 ·
Show more comments
1 Answer
Paul B avatar image
Paul B answered ·

Without more information my guess is that your batteries BMS is turning off then back on then off again etc etc

This maybe caused by having a unbalanced cell thus the batteries BMS is turning the battery off or you maybe sending to much current to the battery. so to answer in more detail, please supply a wiring diagram and maybe some photos of the installation, the more info the better. even some screen shots of the smartsolars settings and some historical details (presuming that you have a smart solar and a Bluetooth connection

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

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