WM5 cell telemetry bypass information

General Discussion
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1

WM5 w/expansion board on 14S NMC using PHEV cells, 23.3kWh, CAN control of Victron CCGX.

Using round numbers, the WM5 can bypass 0.5A, so it would take 2 hours to bypass 1Ah or 1000mAh.

Cell telemetry
Cell telemetry796×458 282 KB

The screencap was taken at about 11:55am. These mAh numbers can’t possibly be correct It’s only been a little over three hours where a maximum of 1500mAh would be bypassed, yet the highest is showing 5293.1mAh.

What am I missing?

I’ve been running this system for probably about 4 years, and I’ve just never questioned it.

2

Hi snoobler,

There are two things that could be causing this:

  • The daily reset of accumulated mAh is not happening - this can be caused by an incorrect time set, so running through the steps here may help
  • Is there any chance you have the wrong cell monitor type selected in Hardware > CellMon?

Keen to get to the bottom of this one!

P.S. can you provision your device so we can see the balancing go up over time?

3

Hey James,

  • I recently time synced. Prior to the sync, there was about a 3 minute error. As of this moment, the error is 1 second.
  • Cellmon “WatchmonPlus wm5 15-10s”
  • BMS is provisioned

I can confirm the session counts appear to be resetting. I save snapshots every 5 minutes, and a spot check of that shows counts resetting when the date advances.

I recently increased my bypass voltage slightly. I’ve had minimal bypass since 8/1.

8/1/2026, 8:00am:

Bypass related information
ID Bypass Initial Session Amp
1 7/30/2026 9:49:16 AM 134.1 mAh 0.00A
2 7/31/2026 8:35:07 AM 389.2 mAh 0.00A
3 7/31/2026 8:30:23 AM 1948.2 mAh 0.00A
4 7/31/2026 8:32:50 AM 1547.1 mAh 0.00A
5 7/31/2026 8:34:20 AM 278.1 mAh 0.00A
6 7/31/2026 9:02:34 AM 3032.3 mAh 0.00A
7 7/31/2026 8:33:12 AM 3382.8 mAh 0.00A
8 7/31/2026 11:10:42 AM 61.5 mAh 0.00A
9 7/31/2026 8:33:46 AM 986.4 mAh 0.00A
10 7/31/2026 9:02:34 AM 687.9 mAh 0.00A
11 7/30/2026 8:20:21 AM 101.4 mAh 0.00A
12 7/31/2026 9:03:32 AM 208.5 mAh 0.00A
13 7/31/2026 11:07:50 AM 1670.8 mAh 0.00A

9:35am:
Bypass related information
ID Bypass Initial Session Amp
1 7/30/2026 9:49:16 AM 134.1 mAh 0.00A
2 8/1/2026 8:52:34 AM 262.6 mAh 0.00A
3 8/1/2026 8:41:00 AM 1975.2 mAh 0.00A
4 8/1/2026 8:44:16 AM 1148.3 mAh 0.00A
5 8/1/2026 8:48:07 AM 182.9 mAh 0.00A
6 8/1/2026 9:32:18 AM 89.7 mAh 0.00A
7 8/1/2026 8:44:05 AM 1575.7 mAh 0.49A
8 7/31/2026 11:10:42 AM 61.5 mAh 0.00A
9 8/1/2026 8:44:05 AM 524.5 mAh 0.00A
10 8/1/2026 9:33:44 AM 2.6 mAh 0.49A
11 8/1/2026 8:44:05 AM 341.3 mAh 0.00A
12 7/31/2026 9:03:32 AM 208.5 mAh 0.00A
13 7/31/2026 11:07:50 AM 1670.8 mAh 0.00A

10:05am:
Bypass related information
ID Bypass Initial Session Amp
1 7/30/2026 9:49:16 AM 134.1 mAh 0.00A
2 8/1/2026 8:52:34 AM 293.0 mAh 0.00A
3 8/1/2026 8:41:00 AM 1995.8 mAh 0.00A
4 8/1/2026 8:44:16 AM 1178.7 mAh 0.00A
5 8/1/2026 8:48:07 AM 203.5 mAh 0.00A
6 8/1/2026 9:32:18 AM 1344.5 mAh 0.00A
7 8/1/2026 8:44:05 AM 1751.4 mAh 0.00A
8 8/1/2026 9:44:26 AM 53.4 mAh 0.00A
9 8/1/2026 8:44:05 AM 545.0 mAh 0.00A
10 8/1/2026 9:33:44 AM 222.1 mAh 0.00A
11 8/1/2026 8:44:05 AM 387.5 mAh 0.00A
12 8/1/2026 9:46:29 AM 30.4 mAh 0.00A
13 8/1/2026 9:46:18 AM 20.5 mAh 0.00A

As you can see in about 30 minutes, #6 has accumulated 1344.5mAh of balancing - about 6X what’s possible.

Thanks,

Steve