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.

Mike Longcor
SV Trilogy SM23

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.,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.

2007 A54 #69
SV Tengah

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