Re: Firefly batteries

Paul Dowd and Sharon Brown

Hi Bill,


That’s interesting. Our Amel came with them as 6 pairs comprising 2 batteries in series, then all 6 in parallel. I guess there are pros and cons for each method.





Paul Dowd

Managing Director
FGPS Limited
Tel: +44(0)7710 466 619

skype: pauldowd


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From: <> On Behalf Of Bill Kinney
Sent: 10 October 2021 21:19
Subject: Re: [AmelYachtOwners] Firefly batteries



Our batteries are connected like this:

(Except with 8 instead of 6).

You might want to check the information about the maximum battery back that can be created.  I KNOW that they do not recommend connecting more than 4 in SERIES (as you would if you were making a 48Volt bank), but I can think of no reason that the number of parallel batteries would be limited. My manual doesn't suggest any limit.

I found the terminals of the Firefly G31 batteries to be slightly taller than the Lifeline batteries they replaced, but our fitting isn't tight, so a bit of expansion in footprint I would not have noticed.  Generally, for any battery, it is not a great idea to have them pressed tightly together. They need a bit of air space to lose heat..  Firefly suggests a minimum of 1cm between batteries.

I might be labeled a heretic but do you really NEED 12 batteries? We have never been in a situation where we felt we wanted more than the 8 our boat came with.  The Firefly batteries are happy with a deeper discharge profile than the FLA batteries the 54 was designed with.

Bill Kinney
SM160, Harmonie
Annapolis, MD, USA

Ya Fohi - Amel 54 #98

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