question

@Jamie Robinson

I had this recently with a set of UP5000. It refused to have comms with the GX at all. Was starting to question my own sanity.

Ended up making my own (a few actually because I tried connecting all the pins first thinking it was the cable) cable with only the 3 wires connected and it worked like a charm. It is early days still they have been up and running for about 4 days now, but does seem to be the issue.

It does seem stupid though.

Thanks Alexandra.

Really helpful to see someone else has had issues here as well.

On the 2 systems I did, they communicated and worked fine except the batteries went into intermittent fault due to occasional high cell overvoltage.

Also have made some new cables which will get installed tomorrow. Let's keep everything crossed and see what happens.

Would anyone from Victron like to comment on this??

I've always made mine with just the three wires because I remember it written somewhere in the Pylontech documentation to leave the unused pins "empty".This does seem dumb though, the inputs shouldn't be so sensitive that an open wire causes enough of a problem. They should be pulled up or down inside the battery to prevent this very issue.

Thanks for all the comments everyone.

I have used many sets of both BYD and Pylontech batteries in both off grid and grid parallel set ups and this is the first problem I have had with the victron cable. Have sent new 3 wire cables exactly as wkirby has mentioned and these will get fitted when they arrive on site. Will share the results once we have run it like this for a few days.

Wkirby is right I reckon. It is an over sensitive system which is affected in this way by induced voltages in an open cable. Will let everyone know if this fixes the issue.

Hello together,

when i was installing my new ESS this week i found out, that for the Pylontech Type US 3000 (without "C") the type A-cable is required.

For my installation, the Pylontech US3000C(!) is the type B-cable required!

Hope that helps.

HI Tristan.

That is not what the Victron manual says.

It is quite clear that for a US3000 (No C) you need a B cable.https://www.victronenergy.com/live/battery_compatibility:can-bus_bms-cable

The data is transferred via the same 2 cables but it seems the issue is where to ground the system The C type batteries seem to have ungrounded BMS and the pins 1, 2 and 3 of the BMS must not be connected to anything.

HI All.

Not surprisingly the new cables didn't work and I am still getting exactly the same faults as before. Looks like it is back to Pylontech for some more grief from the technical help guys!! This is my first issue like this but it makes me very wary of installing Pylontech in remote areas. All profit from this job and more has been used up in return visits.

NIGHTMARE......

I had the same issues a week ago with my new (and first) ESS.

But i think, that was not a problem with the cables (B-type for US3000C).

The problem was solved for me, running the ESS-assistant again and reducing the voltage-currents, depending of the loads, in the last step of the assistant all to 48V.

Since that there were no more alarms in my system.

You can try this and i hope, thats helpful.