Charging wire resetting Circuit Breaker

[Ktn1966]

When the generator is running the circuit breaker that the charging wire goes to keeps resetting. Victron shows 45 ah going in to the batteries then the circuit cuts off charging until it resets and starts back over again. Can I replace the 30 ah to a 50 ah circuit? Will the larger circuit breaker interfere with the other circuit brakes it feeds through a metal shunt.

2021 Momentum 395MS-R

[howson]

Ktn1966

If I'm interpreting the issue correctly, the 30A self-resetting circuit breaker for the converter is opening due to the 45A current as seen by your Victron battery monitor.



So the system works OK when on shore power? Why? Is there a different converter or charger connected to the batteries when powered by the generator vs shore power? What is the amperage going to the batteries when on shore power?

In direct response to your question, I don't know why the 395MS series has a 30A mini-breaker on a 6 AWG wire in a system with a 55A converter ( see https://legacy.granddesignrv.com/ifr...ts-detail/2502 or https://legacy.granddesignrv.com/ifr...s-detail/78411 for the converter in your rig). According to the documentation GD has made available to the moderators, all M Class and Big Mos have the configuration shown above except for the 376THS. The 376THS has a 50A breaker and uses the same converter/charger. The G Class also has a 50A breaker between the converter and battery. All the systems show a #6 AWG wire.

Please do not assume what is shown in the drawing above is installed in your rig--there can be a difference. Please verify.

If the charging system works fine off of shore power but faults with the generator, that issue must be explored to understand why there's a difference. Assuming an OEM electrical configuration, it's the same converter providing charging power to the battery regardless of where the 120vAC originates. I wouldn't mess with the breaker until it's understood why there's only a problem when the generator is running.

Howard

[Ktn1966]

We are boondocking so have not tested it yet on shore power. This just started happening after I removed the Battery cut off switch. It was getting damaged from being bumped in the pass through and started to heat up. Taking it out should not of interfered making it reset

[howson]

We are boondocking so have not tested it yet on shore power. This just started happening after I removed the Battery cut off switch. It was getting damaged from being bumped in the pass through and started to heat up. Taking it out should not of interfered making it reset

What else is electrically modified in your rig besides adding the Victron battery monitor and removing the battery cut off switch?

[Ktn1966]

The converter was changed to A lithium converter 3 years ago. Installed 4 100 AH batteries lithium 3 years ago. Zero issues until I removed the disconnect switch.

[Jkwilson]

I’ll offer a guess that your cutoff switch was getting hot because of the higher current rather than from physical damage. It may have been running near its rating and dropping enough voltage to limit battery charge current.

I’ll also guess that the current in the circuit was originally limited to less than 30A by the charging characteristics of lead-acid batteries.

Seems like with 4 lithium-ion batteries you should see the full output of the converter, which should be just over 50A at charging voltage.

I’d check converter output voltage and voltage at the battery terminals to see if you need a wiring upgrade to avoid voltage drop and then upgrade the breaker to at least 50A depending on your wiring.

[Jlawles2]

Since the converter change and the battery upgrade, have you been boondocking where you may have needed the 50A charging from the converter? If not, then it's possible that you have not over loaded the breaker until now.