Re: A54 bow thruster seal replacement?


Scott SV Tengah
 

Dean, 


I agree that at higher voltages, current should just go down. 

That said, lower than 22v is very plausible with normal batteries. Put that big of a load on even a big lead acid bank and I would expect a big voltage drop. 

Amel suggested I add the emergency shut off switch. I believe it's for that reason. 


On Mon, Dec 14, 2020, 14:32 Dean Gillies <stella@...> wrote:
On Tue, Dec 15, 2020 at 04:07 AM, Scott SV Tengah wrote:
Sleipner said that they spec theirs to expect 21-22 volts or thereabouts under load and we are closer to 24.5-25
Scott, that's an interesting point.  
The cabling to the BT is 70sqmm (according to Amel drawings), and the run must be about 10m or so?  The voltage drop in the cable at say 360A (8kW@24V) will be about 1.5V, plus a bit for connections and internal resistance of the battery. So the voltage will definitely be higher than 22V, but should be less than 24V.  However, I don't believe the BT will be damaged in any way by a 24V drive. It should just take less current.   Don't forget that many (most?) BT installations have dedicated LA batteries in close proximity, with minimal voltage drop in cabling. Amel's are a little unusual in having the batteries so far away from the BT.  If the Sleipner product did not work properly at 24V I would be very surprised. I suspect their comment reflects their view that it will "still work" down at those voltages rather than not working at 24V.

Lithium is still on my mind!
Cheers
Dean
SV Stella A54-154
 


--
Scott 
2007 A54 #69
SV Tengah
http://www.svtengah.com

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