I have had an issue with my WM5 since purchase. It usually only occurs in summer when I have plenty of sun. I was able to record this in action. When multiple cells are in bypass, there are fake phantom high voltages detected. (over 5v!!!). The video can be viewed here: Batrium Phantom Voltage Detection.mp4
Here is a screenshot!
Hi Slimf,
Generally this points to a high resistance in your balancing wires. Could you double check your terminals, bus bars and in-line fuses to make sure all resistances are low there?
With this ruled out, we can look into any potential hardware problems with your WM5.
Could you share some photos of how you have everything wired?
EDIT: Our software engineer has pointed out that this could also be a bug specific to the WM5 that is fairly easy to squash if present. Have you emailed us yet? (just making sure you are the same one in our inbox over there)
Another possible cause for the problem can be if you use the same wire to the cell for Batrium and some third party active loadbalancer. If you’re using such an active load balancer, it must have its own wires to every cell.
Hi
Yes, I emailed yesterday I think… I will get some photos together and send through.
I use the supplied fuses and folders and recommended gauge wire + ferrules.
No other balancer on the wires either.
Got the same fake high voltage reading ever since. This only occurs in bypass mode. Looks like a software glitch. Wiring is fine.
I switched off bypass and use an external Neely balancer
Hi,
same problem here with 8xWM5,
i tough i had misconfigured my setup but i’ve measured manually cells when this happen and voltage is ok …
Wiring seems ok, fuses too, no non-batrium external equipment connected to cells.
I hope it can be fixed, i don’t want to buy 8*Neyyyyyy active balancers 
https://www.swisstransfer.com/d/24a4e4ae-4a14-4edb-8ea7-87f00caaa5e1
This is somewhat frustrating - Its a problem across hardware models, across years of software and firmware versions and across chemistry (i.e different voltages). The primary function of the BMS is to detect the cell voltage and make decisions based off it - If it cannot reliably detect cell voltage then its not fit for purpose.
Batrium have admitted on several occasions they are working on it, and think they have solved the issue - but it remains.
In winter, not so much an issue - but now the sun is starting to peak again - its becoming an issue…
Batrium - Can you please elaborate on the issue and what is being done to fix it?
Hi Slimf,
We’ve dug deep into the WM5 and we think we have found the problem. We’ve also upgraded our test hardware with larger cells that should highlight future problems better.
There are things outside the BMS that can cause voltage spikes like a blown balancing fuse or poor busbar connection, or active balancers sharing a loom with us.
If you want us to use our logging to look into your spikes more, DM me your serial number and I’ll take a look
Hi James - I will DM you my serial number.
I have no active balancers - the ONLY thing connected to my balance wires is your supplied fuses and the WM5.
