Balmar regulator charging issue with LFP

[skippeer]

Installed new Balmar alternator XT 170 and regulator MC 618.
Working fine with LFP at SOC 70-80%.

Leaving the harbour with SOC 100% charging starts and stops over and over again triggering engine charging lamp / buzzer. Gives up disabling the buzzer over and over again. (Currrent charging ramps up over and over again).

After motoring some time does the MC 618 regulator reach FLOAT phase, battery voltage higher than calculated voltage. Disable buzzer one time.

Considering to install a switch disconnecting ignition (brown) signal or
dessigning a circuit sending ”charging working” when battery voltage is over 13,5 voltage.

Anyone recognizing the pattern?

 

[geem]

Installed new Balmar alternator XT 170 and regulator MC 618.
Working fine with LFP at SOC 70-80%.

Leaving the harbour with SOC 100% charging starts and stops over and over again triggering engine charging lamp / buzzer. Gives up disabling the buzzer over and over again. (Currrent charging ramps up over and over again).

After motoring some time does the MC 618 regulator reach FLOAT phase, battery voltage higher than calculated voltage. Disable buzzer one time.

Considering to install a switch disconnecting ignition (brown) signal or
dessigning a circuit sending ”charging working” when battery voltage is over 13,5 voltage.

Anyone recognizing the pattern?

Most likely the battery BMS is shutting down due to high voltage. Your alternator voltage may be too high. If that is the case, you may have damaged the alternator diodes

 

[skippeer]

Have a battery system designed by Batterybalance.
All chargers are connected to a charge bus always connected to the AGM starter battery.
BMS controls a charger relay (500 amp capacity), have a pre-disconnect AFD (Alternator Field Disconnect) relay (Victron Solidswitch 104). BMS sends a signal till AFD relay breaking brown ignition signal 2 seconds before charge relay is open/stop charging LFP.

I have verified the Balmar MC 618 pattern several times.

SOC 100% => Balmar system initially ramps up current, stops, ramps up (guess Bulk/Abs), over and over again.
Have video recording of phase Float, battery voltage higher than calculated voltage = no charging. Easy to confirm Penta buzzer one time.

SOC 70-80% charging as expected, have started with low usage of XT 170 by setting F-8 / field max 60%.

Verified several times so XT 170 and MC 618 is working but not as I would it like to do.

For example when battey bank(s) are full and the Balmar stop charging I don’t expect that MC 618 Dash Lamp to go neutral triggering a charging alarm on the engine panel.

Anyone here at YBW experienced similar issues when leaving harbour with SOC 100% ?

# # #
Here is an old discussing thread on similar issue, full bat banks when leaving dock
Balmar MC-614 Regulator Settings

post #31 by CMS (Rod Collins) explains a lot of Balmars internal design and a possible workaround on my issue by a switch (CMS note #4).

#4 You can also install a dash switch and interrupt the brown/ignition wire for the first 30 minutes or so from the dock (or depending upon planned motoring duration) then flip it back on and you're now well within your not exceeding your desired duration back to full from a high SOC.
#

As I have a pre-disconnect AFD relay I could break high signal from the BMS to the relay with a switch
or
maybe use the BMV-712 using SOC and/or starter battery voltage value as trigger to cut the ignition signal with another relay.

Regardless manual switch or BMV interrupting the ignition/brown signal the Penta engine alarm needs to be considered.
Don't like to disable the engine buzzer in case of oil pressure or engine temperature warning can be missed.

 

[skippeer]

This might be the classic Volvo Penta ”false” alternator alarm since yachties started to install hydro, wind and/or solar charging.

The sad thing is my bad memory, for 10-15 years ago did I invest similar issues on a Hanse 371 with a Penta.
Suspected solar charging in conflict with alternator.

Spent the night in marina charging battery banks with Victron IP43. Switched of the fuse for the solar charging as preparation for today sailing.

If no alternator alarms with full batteries I might have evidence for the suspected root cause.

Future improvement could be to buy a Victron MPPT RX-cable and stop solar charging via a signal from Balmar regulator.

There are many discussion threads on this subject, Balmar even have FAQ item.

 

[Trollman]

The MC wants to ramp down, after bulk.
Lithium batteries, if there isnt heavy load on them, are not following but keep the cell-voltage up (and maybe your solar is still charging and keeps the voltage up too).
Each digital regulator will shut down when the voltage stands higher then the calculated voltage is, just to avoid overcharging..
The MC will do that when the difference is about pluss 0.2V above the calculated voltage.
And it must do so.
The regulator just can neither know why your battery isn´t following while he needs to ramp down, or can do something about it.
That thing just see a higher voltage, and needs to stop his own charging to avoid overcharging, as "he see it".
Thats it, nothing more to understand.

To avoid that:
Stop the MC; or have a load on the batteries;
MC-618 can be forced to float earlier, so you avoid to charge to calculated bulk at all.

And dont think that other regulators are doing better: None does, just caused by the Lithium batteries which are not following.

Hope that does help to understand.