Usual Battery Charging Setup

[Fire99]

Hi all,

This has possibly been covered many times and I'm doing a lot of research on the topic but to help things along a bit, can someone explain the likely charging setup on a twin diesel engine mobo with house and start batteries + a bridge solenoid?

Reason I ask is that my battery setup has been on my list of to-do's to investigate as reading some email correspondence from a previous owner, the house and starter batteries have been bridged as one.

My Cat's run 115amp alternators each and I have Stirling battery charger, along with a Onan generator with its own starter battery.

Is there a 'usual' configuration for charging from the dual alternators and how would the charge be split between the starter and house batteries??

As I say this is a winter project for me. I did electrical engineering as a young guy so I have some experience but boats can be a bit of a pick n mix of ideas so any information would be helpful.

cheers,

Nick

 

[PaulRainbow]

Could be any one of several systems Nick, especially if previous owners have been tinkering. If the house and engine batteries have been bridged that's a definite no-no.

The mains charger could be a multiple output version, charging all batteries.
The generator is likely powering the mains charger ?

Engine charging could be split by diodes, one engine charging domestics and one engine batteries, or using a VSR.

Best bet would be to investigate what each bank of batteries do and how the various charging sources are connected and then make any necessary changes.

 

[Fire99]

Could be any one of several systems Nick, especially if previous owners have been tinkering. If the house and engine batteries have been bridged that's a definite no-no.

The mains charger could be a multiple output version, charging all batteries.
The generator is likely powering the mains charger ?

Engine charging could be split by diodes, one engine charging domestics and one engine batteries, or using a VSR.

Best bet would be to investigate what each bank of batteries do and how the various charging sources are connected and then make any necessary changes.

Thanks a lot Paul. I have a sniffy thought that that is exactly what they've done due to probably a slightly lazy starter motor that happens to live in an awkward (ish) place to remove.. Lazy mechanic-ing is on my mind. Crazy that this appears to have been done when the boat was just 6 years old!!
The clue was when I turned the engine DC isolator off and there was still 12v at the engines..

The mains charger (Stirling) is a multiple output charger so we're on the right scent there..

I'll do some digging.