Victron Orion DC2DC with banks in parallel

[LifesBetterWhenYoureBeating]

Hi folks!

I'm going to install a victron Orion TR smart (non isolated) dc2dc charger so I can charge my LifePO4 battery from my starter battery, but I have a 1/2/off/Both switch that can put both banks in parallel (even though that's not a setting I intend to use, I don't see a way of physically stopping that from happening on the switch), and I'm wondering what will happen if the switch is accidentally set to Both while the dc2dc is operating. Could that damage any of the batteries or the charger?

Cheers

[smac999]

you might get a current loop through the orion. as the banks try to charge itself in a never ending loop.

how is this switch wired? you are going to need at least 2 switches. one for the starter and one for the house loads. time to redo it.

[LifesBetterWhenYoureBeating]

Originally Posted by smac999

you might get a current loop through the orion. as the banks try to charge itself in a never ending loop.

how is this switch wired? you are going to need at least 2 switches. one for the starter and one for the house loads. time to redo it.

The switch is wired with the output going just to the house loads -- the engine starter is hardwired to the starter battery. I want it like that because my house bank is LifePO4 and I don't trust its BMS 100%, so I want to be able to quickly switch to the starter battery for the house loads.

I don't understand how a second switch would help

[smac999]

Originally Posted by gsalgado

The switch is wired with the output going just to the house loads -- the engine starter is hardwired to the starter battery. I want it like that because my house bank is LifePO4 and I don't trust its BMS 100%, so I want to be able to quickly switch to the starter battery for the house loads.

I don't understand how a second switch would help

The engine is required to be switched. add an on / off switch on the starter line. If the starter gets stuck and you can’t shut it off the boat will burn.

You can also buy 1/2 / off. Switches with no both. Then you have a backup but can’t combine.

[LifesBetterWhenYoureBeating]

Originally Posted by smac999

The engine is required to be switched. add an on / off switch on the starter line. If the starter gets stuck and you can’t shut it off the boat will burn.

Ooops, I guess I have some more reading to do. I wasn't aware the engine is required to be switched and didn't think about what would happen if the starter gets stuck. The boat actually came with a 1/2/both/off switch next to the engine, but the battery is currently connected directly to the starter. I'll fix that

You can also buy 1/2 / off. Switches with no both. Then you have a backup but can’t combine.

That was my plan, but the BMS shuts off the LifePO4 when I put it in parallel with the starter battery, and the Orion has short circuit protection so I should be fine. I'm still trying to get a definitive answer from victron on that, though

[LifesBetterWhenYoureBeating]

Originally Posted by smac999

The engine is required to be switched. add an on / off switch on the starter line. If the starter gets stuck and you can’t shut it off the boat will burn.

If the starter gets stuck after the engine is running, what signs will it give so that I know I must disconnect the battery? With the engine running, would I be able to hear the starter still going?

Given that I'd only use the switch in this scenario, would it make more sense to use a fuse instead? If so, which type/size?

[CaptainRivet]

Originally Posted by gsalgado

If the starter gets stuck after the engine is running, what signs will it give so that I know I must disconnect the battery? With the engine running, would I be able to hear the starter still going?

Given that I'd only use the switch in this scenario, would it make more sense to use a fuse instead? If so, which type/size?

You will smell it and see the smoke from the Isolation lacquer of the anker…
The starter is not fused too, so it starts to be a glooming welding iron and catches fire if the cables won‘t do that before…

You also don‘t want to parallel an empty FLA with a full FLP bank, the current that’s floating then it’s massive and only Limited by the internal resistance of the FLA or the cable that’s melting then. That’s is high high resulting current still massive but if the FLA has an internal short of the plates which regularly happen especially due to sulfation that internal resistance is very low = floating current extremely high melting your cables and cause fire too.

So I highly recommend a off/1/2 switch or 2 switches