question

jonathan-drewes avatar image
jonathan-drewes asked

Battery at 100% SOC ---> BAD

Setup: off-grid Victron 250/60 MPPT, Multiplus 3000W inverter, Trophy 48V/100Ah (installed 11/2022)

Here is my problem --
To keep the inverter from having a “High DC Ripple” alarm and then shutdown, the battery cannot get to a self-reported 100% SOC.
When it does get to 100%, it disconnects itself, mostly, from loads and will not reconnect until the MPPT stops providing current to the inverter for loads. When the MPPT does not provide power (sundown) and when the current demand is high, the battery reconnects reliably, then the cycle repeats the next day until/if 100% is reached.
The battery does provide low current, sometimes, to the inverter before sundown, but not continuously, or at a high amount of current.
During this disconnected state, the voltage at the battery terminals (also have the MPPT and inverter at these studs) is higher than the V reported on the battery display by 1-4V depending on the load. In this disconnected state, if I cycle a space heater on/off, I get a high DC ripple alarm which can shutdown the inverter (wife gets mad).
On a day when the battery does not get to 100% or earlier in the day while the MPPT is charging, I can cycle the heater without the alarm and the voltages all match.
This problem happens with and without the CAN bus data cable plugged in, no matter what charging parameters are set in the MPPT.

The attached screenshot is from the Victron VRM which shows the voltage disparity (red curve is the reported Trophy V, blue is the actual V), power (middle graph where a load cycled, and the High DC alarm created.

Has anyone else experienced this with the Trophy?
Does this kind of situation occur with other batteries/BMSs?
Talking to the SOK and EG4 dealers, they have no issues like this with their products.

I've been in contact with Dan at Trophy about this.

Any guidance here would be appreciated.

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MPPT Controllers
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5 comments
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Alexandra avatar image Alexandra ♦ commented ·
@Jonathan Drewes

I have not used the batteries you have but there are some pointers to work on.

1. Is there voltage difference fron battery terminals and inverter terminals not under load? If it is higher or lower adjust the charged voltage accordingly.

2. Maybe the voltage is overshooting on charge a bit and bms is sensitive, you could lower the set charge limit by 0.3 to 0.4v and see if that helps.

3. Lower the charge current to the battery to half what the battery says it can do.

The DC ripple alarm is from the way the bms is trying to disconnect. I had a battery do this once, had to strip and check all the terminals and found a few not torqued correctly. So it was badly assembled from factory. Not sure if yours can be opened non destructively to do this one and caution needs to be taken (VDE rated kit requured)

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jonathan-drewes avatar image jonathan-drewes Alexandra ♦ commented ·

There is no significant V drop between any terminals. Cables are only 1-2 ft. All connections are new, clean torqued.


I've tried lowering the charge V down to 55.5 from 56.8, same result.


Charge current is 20A max (100A allowed by battery) but this problem happens when there is 2-10A.


Also, once the battery gets into this bad state, its reported SOC does drop over the afternoon (to 90-95% ) and still stays in this bad state.


Thank you for the help.

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Alexandra avatar image Alexandra ♦ jonathan-drewes commented ·

@Jonathan Drewes

A sudden draw and a dc ripple and shut down, indicates a high resistance connection (or a bms that just can't hopefully not the case here.)

Do you have dc breakers in the system? Or any other disconnects

Maybe bypass them for now. Do a good 3k load test and see what happens to rule them out.

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jonathan-drewes avatar image jonathan-drewes Alexandra ♦ commented ·
With the MPPT breaker to the battery OFF after the battery gets full, the issue persists.


So all that it could be is a BMS issue ? That was my conclusion.

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Alexandra avatar image Alexandra ♦ jonathan-drewes commented ·
@Jonathan Drewes

I cant say for certain if i am not there doing the testing.

But if it cant do the current discharge/output it says, then it is no good.

If it cant take the charge amps it says it can, it is also no good.

A 3kva is not a monster inverter. (62.5A @48 v) As long as you have sized your dc cabling correctly and all your connections are good, then this can only be a battery issue.

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2 Answers
Paul B avatar image
Paul B answered ·

DC ripple is usually CAUSED by the battery cables being TO LONG or the cable size is to small.

OR its a battery that CANNOT supply the required DC Amps and hold voltage when high AC load is required.

read up on DC Ripple and cure this issue


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jonathan-drewes avatar image
jonathan-drewes answered ·

Its looking like a problem with the BMS not consistently delivering the current. The next step is to replace it with another. Thanks for the help everyone!

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