Alternator upgrade KAD44 do i need isolated ground?

[nfluester]

I am looking to upgrade the alternator on one of our KAD44'S in readness for lithium battery install.

The balmar alternator i am looking at come in 2 varieties a case ground or isolated ground.

The engine is grounded but the original Valeo alternator has a dedicated ground cable.

Would there be any issues connecting the ground cable to the alternator case or should I buy an isolated ground alternator

 

[ARE]

Normally you only need an isolated ground alternator on a steel or aluminium hulled boat.

 

[nfluester]

great thats what i thought so next question is does anyone know where / how the voltage alarm is fed? does the EDC just measure the battery voltage or is there a need to wire in the D+ / Lamp in somewhere? so i dont get an alarm i'm pretty sure it's the brown wire but not sure what i need to feed it if i'm using external regulator

 

[petem]

great thats what i thought so next question is does anyone know where / how the voltage alarm is fed? does the EDC just measure the battery voltage or is there a need to wire in the D+ / Lamp in somewhere? so i dont get an alarm i'm pretty sure it's the brown wire but not sure what i need to feed it if i'm using external regulator

I'm not aware of a voltage alarm but the KAD series ECU's get their power in various ways. The early ones get their power from the alternator, the next series get them direct from the battery and the last series get them from the alternator via a 12v / 12v converter.

I would be extremely careful making any modification that could cause voltage fluctuations as you run the risk of blowing an ECU (VP have no stock and are looking for a new manufacturer so there will be a delay that is likely to last for months). A new one, when available, will cost you £3k.

 

[nfluester]

I'm not aware of a voltage alarm but the KAD series ECU's get their power in various ways. The early ones get their power from the alternator, the next series get them direct from the battery and the last series get them from the alternator via a 12v / 12v converter.

I would be extremely careful making any modification that could cause voltage fluctuations as you run the risk of blowing an ECU (VP have no stock and are looking for a new manufacturer so there will be a delay that is likely to last for months). A new one, when available, will cost you £3k.

Yes i have read that on here recently and that's does worry me slightly, my plan was to leave the engines operating off the lead acid batteries but have the alternator of one engine connected directly to the lithium bank and charge it controlled via an external voltage regulator

thoughts?

 

[Beneteau381]

Normally you only need an isolated ground alternator on a steel or aluminium hulled boat.

VP did a lot of their engines negative isolated block. The MD22 and some of the MD20X0 series that I know of. They were fitted in many fi glass boats. They went to a lot of complicated solutions to address the stop solenoids and glow plugs which were grounded through the block.