Boat wiring and charging

[mitiempo]

I stand corrected. Only the dual sensing will draw .01 amps continuously as it is not only sensing from both sides but is connected to both banks at all times.

 

[mcframe]

Normally one would hope that the engine start battery is pretty well charged so you can quickly replenish the juice used for starting, then within a very short time anyway the VSR will cut in and the house bank will be charging.

If the house bank has priority and is low it could be some time before the starter battery is topped up. The engine may not even run long enough for that to happen! Therefore make the starter battery the priority and then you know it's recharged. The short delay before the house battery is on charge is not important.

That's exactly my reasoning.
(Recent fit of Odyssey start battery & bridging of existing 2 for house bank - not tested in the water yet.)

The VSR[1] deals with *all* DC charging (alternator & solar - and maybe wind in future).

For rarely-used shorepower AC, my Merlin All-In-One (bought well before recent price rise) has two charger outputs - one to start & one to house - I'm told that should be OK even 'tho one bank is 8Ah and the other 170 Ah...

If I were doing serious blue-water stuff, then I'd consider another small AGM, mounted high, next to the VHF with appropriate DC-DC charging and wiring to a non-ColRegs masthead strobe.

With a standard (Sterling reg'd) alternator on my 'easy starter' 1GM10, I'm wondering exactly how far I'll be from my mooring before the start battery is replenished - I reckon about half a mile ;-)

[1] BEP has red LED; that must draw current, but I simply interpret it as "Start Batt Full"

 

[mitiempo]

There is no question the start battery would be up to full in short order as a start seldom uses more than an AH or 2. But as Stu said earlier with the start battery being a priority all house charging goes through the VSR. Because of this the connecting wires should be a heavier gauge to deal with this. Were the house bank the priority the wiring could be considerably smaller as not much amperage would be going to the start battery to bring it up to full charge.

 

[cimo]

I just love my 1-2-both selector switch. great for charging thru!

(sorry, couldn't resist)

 

[VicS]

Were the house bank the priority the wiring could be considerably smaller as not much amperage would be going to the start battery to bring it up to full charge

but you must allow for the situation in which the start battery is somewhat discharged. I''d say that both connections to the VSR must be able to safely handle the maximum alternator output.

(The connections to the batteries, the emergency linking switch and the engine must of course be able to handle the starter motor current)

 

[mitiempo]

VicS
Personally I agree and have gone heavy with all wires but some like to go with the minimum required.