After 2 years of running non-stop with a DIY 16 kWh battery and a JKBMS, my inverter has failed. I’m getting error 54 and it no longer wants to discharge the battery.
I found a post on the old forum that mentions two blown fuses.
I opened up my RS and, sure enough, both fuses are blown. However, I’d like to know under what circumstances the fuses can blow? (I suspect it’s an overcurrent), but what could be the cause inside the device, from an electronics point of view? I’ve ordered some replacements from RS, which should arrive soon.
Thanks in advance if anyone who’s had this problem can shed some light and share their experience.
Once I’ve replaced them, I’ll post an update here.
Here’s the fuse part number in case anyone else has the same issue: Littelfuse 0326020.MXP
They can also heat derate and then blow
So a 20A fuse is not always a 20A fuse…
So yes over current blows fuses, but under what circumstances.
Heat accumulation at the top of the unit would not be helping the situation.
The first series had slightly undersized fuses, and during periods of heavy use, a fuse could blow.
You need to check whether they are 20 A fuses and not 15 A.
If they are 15 A, there’s no problem with replacing them with 20 A fuses, and that should solve the problem.
If they are 20 A, we need to try to understand why they blew, because normally that shouldn’t happen, even if the Multi RS is at its maximum.
Yes, they are 20 A. I checked VRM and there were no loads running in the house when the power cut happened. It was in the morning, at around 9:50, and my installation faces due west. I’m in Île-de-France.
To be on the safe side, I reduced the battery BMS output current. Because 20 A × 230 V is 4,600 W, and sometimes I could draw a little more — unless these fuses have nothing to do with the backup output.
I’ve just replaced my fuses; so far, so good. The house has switched back to the battery, which was at 80% when the power went out a few days ago.
Final conclusion tomorrow during the day, to see whether it holds up during solar generation.
Out of interest, these are the two fuses located right next to the MPPT inputs, aren’t they? So they monitor the current from the PV? If so, I don’t understand the calculation of 20A x 230V.
20A x PV voltage sounds more logical.
Also, the maximum nominal current per MPPT is 12A and the maximum power is 3000W per MPPT.
3000W / 12A = 250V. Perhaps your PV voltage is higher, so the current is lower.
While I’m at it, I’ll add to this post: everything is working perfectly. The weather’s really sunny, so it’s producing power without any issues.
Still, it’s a bit strange for this fault to happen after two years of running non-stop. To be on the safe side, I’ve limited the current on my jkbms a bit more.
A bit disappointed by this fault on a Victron system. Luckily, there was an old post about this topic on the previous forum. Hopefully this post will be useful to others.
