Circuit breaker for dc-dc charger

[chris-s]

We have a Renogy onboard combined mppt/dc-dc charger that manages the charging of both house and engine batteries from solar and alternator where it will charge the lithium house from alternator when it detects 13.2v in the engine battery feed and engine from solar once house batteries full.

We have a generic 20 amp circuit breaker like this….




…. on the engine battery connection to the unit and noticed that there is an intermittent voltage drop across the breaker which prevents the charger from seeing a high enough alternator voltage and so doesn’t charge the house from the alternator.

Firstly, I think the breaker has developed a fault, but since its terminals are marked ‘battery’ and ‘load’, it got us to thinking that in this situation the charge could be going in either direction, so which way would you consider it should be connected?

A simple blade fuse would avoid any issue but I hate them.

Chris

 

[PaulRainbow]

We have a Renogy onboard combined mppt/dc-dc charger that manages the charging of both house and engine batteries from solar and alternator where it will charge the lithium house from alternator when it detects 13.2v in the engine battery feed and engine from solar once house batteries full.

We have a generic 20 amp circuit breaker like this….

View attachment 192947


…. on the engine battery connection to the unit and noticed that there is an intermittent voltage drop across the breaker which prevents the charger from seeing a high enough alternator voltage and so doesn’t charge the house from the alternator.

Firstly, I think the breaker has developed a fault, but since its terminals are marked ‘battery’ and ‘load’, it got us to thinking that in this situation the charge could be going in either direction, so which way would you consider it should be connected?

A simple blade fuse would avoid any issue but I hate them.

Chris

Putting the terminals on the other way around cannot reverse the current flow, I'd say the breaker is faulty. Blade fuses are used in all sorts of applications by the million and would be perfectly fine in this application. There should be a fuse at each battery, as close to the batteries as possible.

 

[Boater Sam]

We have a Renogy onboard combined mppt/dc-dc charger that manages the charging of both house and engine batteries from solar and alternator where it will charge the lithium house from alternator when it detects 13.2v in the engine battery feed and engine from solar once house batteries full.

We have a generic 20 amp circuit breaker like this….

View attachment 192947


…. on the engine battery connection to the unit and noticed that there is an intermittent voltage drop across the breaker which prevents the charger from seeing a high enough alternator voltage and so doesn’t charge the house from the alternator.

Firstly, I think the breaker has developed a fault, but since its terminals are marked ‘battery’ and ‘load’, it got us to thinking that in this situation the charge could be going in either direction, so which way would you consider it should be connected?

A simple blade fuse would avoid any issue but I hate them.

Chris

Those breakers are nasty Chinese junk and often go faulty or set on fire.

 

[ianabc]

We have a Renogy onboard combined mppt/dc-dc charger that manages the charging of both house and engine batteries from solar and alternator where it will charge the lithium house from alternator when it detects 13.2v in the engine battery feed and engine from solar once house batteries full.

We have a generic 20 amp circuit breaker like this….

View attachment 192947


…. on the engine battery connection to the unit and noticed that there is an intermittent voltage drop across the breaker which prevents the charger from seeing a high enough alternator voltage and so doesn’t charge the house from the alternator.

Firstly, I think the breaker has developed a fault, but since its terminals are marked ‘battery’ and ‘load’, it got us to thinking that in this situation the charge could be going in either direction, so which way would you consider it should be connected?

A simple blade fuse would avoid any issue but I hate them.

Chris

Probably knock off unit intended for car audio.