Sure, I have a version on the PC here I think.
For 7 cells, you just wouldn't connect to the cell 8 tap.
The input voltage range of the cell-log is 1.3-4.9V (and so is the alarm range). Obviously, you cant hook up a 12V battery to a channel, you would fry it!
So what to do... Divide it by 4. Use a resistive divider, with an opamp buffer (ie. gain of 1) powered off the 36V tap of the battery with a series zener diode of 6.1v (the opamp is rated for 44V max) . The reason for such a high voltage rail for the opamp is that the 8th output at 15V per cell (worst case) divided by 4 (3.75) and multiplied by 8 is 30V, and the opamp is not rail-to-rail, and so needs some headroom.
You get a voltage range of 2.5 (10.0V, dead empty for a 12V AGM) to 3.75V (15.0, highest cyclic charge voltage). You can use the alarm output to turn off your charger while the zener shunts (if you do this with your AGM's) do their thing, or warn you when you hit the LVC (or you have a single battery drop like a stone, or a massive imbalance occur - delta V).
The resistor values are calculated so that you have battery voltage/4. I have a PCB design around here somewhere as well.
At the highest voltage level (120V) the resistors will only be losing 0.9mA - and dissipating 0.1W.
Yes, you will unbalance the batteries eventually, but if you pulled from the whole pack voltage with an amplified zener reg, this would not be an issue. The dividers drop less than the self discharge rate anyway, so they are negligible.
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New evil decided - GNG offroad build on Craftworks DHR with 12S4P lipo. Aim - Light, balanced, powerful, able to climb a tree.
Project Vectrix restarted. Status - BMS + Charge control redesign (read faffing with batteries again)