High battery voltage on mt-50

[Pixturethis]

I have a epever BN 30 amp SCC w/ mt-50 12v SOK 100ah lifePo4 and 2 100 watts of solar. What I’m seeing is that my mt-50 shows 24.6 volts after it finishes charging. Why is this. Here are my settings.
many idea of what it is doing ?

 

[MisterSandals]

my mt-50 shows 24.6 volts after it finishes charging.

That is alarming. What does a volt meter reading on the battery show in volts?

Did you connect the battery before the array? I've seen a charger get set to 24V charging (matching the panel voltage) when the battery momentarily lost contact. Just a wild guess.

Do you have the battery voltage actually set to 12V (recommended)? or is it on Auto-Detect (or automatic)?

 

[Pixturethis]

I have it at set to 12v. I have circuit breakers on the PV input. 7.5 amp. The voltage when I got home was 14.1. Was not charging at the time. My victron shunt showed 16.96 volts as max. I have ever had the PV connected without the battery. I do not have a fuse on the positive from the battery.

 

[Pixturethis]

Could it be when the battery BMS shuts off at full charge that it is seeing a spike in voltage ?
I don’t know enough about this SCC. I’m still new to the solar world.

 

[Pixturethis]

I’m going to try and lower the charge voltage to 14.4 and see what it does tomorrow.

 

[740GLE]

My guess is that the SCC shows Voc when charged. I think there was another thread like this with another SOK disconnecting once charged.

 

[Pixturethis]

Thanks for the info, I hope lowering the max charge to 14.4 fixes it. Will see tomorrow, and will post my results. Maybe on Monday , I’ll put a video camera on it while it’s charging to see what is happening.

 

[MisterSandals]

I’ll put a video camera on it while it’s charging to see what is happening.

More importantly, monitor the voltage with your own meter. If you can quickly disconnect things to get a battery only voltage, that is best but not always possible.

I think there was another thread like this with another SOK disconnecting once charged.

Linky?

 

[Pixturethis]

Not possible, I work 7 days a week, so I’ll have to use the camera idea, I think lowering the max charge voltage will help it, will see today.

 

[Pixturethis]

Ok, camera is set and max charge volts set to 14.4.

 

[fratermus]

Could it be when the battery BMS shuts off at full charge that it is seeing a spike in voltage ?

That max value is a transient, and I'm guessing it's associated with BMS shutoff. If so, I'd config the setpoints to something lower than what trips the BMS.

The max value shown on my FLA setup is the same as Vabs, unless EQ occurred.

 

[Pixturethis]

I have set to 14.4 today, will see how it goes.

 

[Pixturethis]

Up to 15 + volts at 32.2C temp. Wonder if that has anything to do with it ?

 

[Pixturethis]

Ok just watched to go from 16v to 23.3. Instant just. Like right when the SCC stops charging. Tomorrow I’ll see about putting the video on a volt meter on the battery.

 

[DerpsyDoodler]

Do you have "equalization time" set to 0? That's the only way to disable it. Also set equalization voltage to a safe voltage (say make it equal to your charge limit). Maybe its going into equalization? that's bad for lifepo4. It can damage them.

 

[Pixturethis]

Yep it is at zero.

 

[Pixturethis]

Tomorrow I’ll see what my victron shunt shows.

 

[Pixturethis]

Nice, victron shunt lost connection, can’t get it to reconnect, even when 5ft away. I think I’m not going worry about.