Re: A54 bow thruster seal replacement?

Dean Gillies

Hi Scott,

On Tue, Dec 15, 2020 at 11:53 AM, Scott SV Tengah wrote:
That said, lower than 22v is very plausible with normal batteries.
In an Amel, yes, but not always.
A fully charged 115Ah AGM (such as Rolls S12-128AGM) will deliver 67A for two minutes while retaining terminal voltage above 12V.  Put 12 of these in a 2S6P arrangement and you get 400A at 24V. That's almost 10kW delivered to the cable with terminal voltage above 24V. In an Amel the voltage drop at 400A would be around 2V, hence 22V delivered to the BT. However, in a boat where the batteries are located close to the BT, then the voltage drop in the cable can be much less, so the delivered voltage to the BT will be much closer to 24V. 

I find it difficult to believe Sleipner would produce a "24V" BT which does not operate reliably if powered with 24V which is exactly what LIthium batteries would provide in an Amel cabling setup.

Btw I didn't quite understand ... why (and where) did Amel ask you to install a shut off switch? I understand there is no breaker/fusing on the BT cables, which is interesting in itself.

Cheers, Dean
SV Stella A54-154

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