Re: Firefly batteries


Mike Longcor (SV Trilogy)
 

Without midpoint voltage monitoring, connecting the mid points is not recommended as it will mask a battery problem.

From Victron (BMV manual):
"Midpoints should not be interconnected: one bad battery can go unnoticed and could damage all other batteries."

We run our six Fireflys in series parallel with 3 individual balancers. Feels like overkill but it works well. With an upgraded battery monitor, I would probably connect the midpoints so loads and charges are more evenly shared.

Cheers,
Mike Longcor
SV Trilogy SM23
NZ


On Tue, Oct 12, 2021, 8:58 AM Scott SV Tengah <Scott.nguyen@...> wrote:
FWIW, my Victron batteries (Smart lifepo4 12.8v) documentation explicitly states "Do not interconnect the midpoints". See drawing on bottom of page1. FYI the gray lines are the data cables for the BMS.

https://www.victronenergy.com/upload/documents/Datasheet-12,8-&-25,6-Volt-lithium-iron-phosphate-batteries-Smart-EN.pdf

When I installed my system 3 years ago, I wanted to connect the midpoints and use a battery balancer and decided against it. 

Perhaps this is not an issue with Fireflies/AGM/Gel/FLA.

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

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