According to the spec sheet, a Multiplus will de-rate its output when the temperature exceeds 40C. Is there any way to see this is happening? Through VictornConnect? I sometimes see less than full battery charge current, and I suspect this is the cause, but can find no way to confirm.
Hi @billknny,
The internal temperature sensors readings are not visible, and at least for now it is not possible to see if the unit is de-rating itself with any software.
Hello, why you don't use a a Temperatursensor and mount this directly to the ringtrafo inside?
You can see it on VRM or yor display and you can start the fan when it's needed.
Controlled by your system.
I installed the same at my Inverter but without using the relay contact to run a external fan. I need this only to monitoring.
Best regards Robert
Guy,
Thanks for that answer!
One thing to consider: Add a MultiPlus assistant that would allow me to turn on an external cooling fan if the internal temperature reaches the point where capacity starts to cut back. On smaller systems—like on my sailboat—an external fan can impose a significant load and it would be nice if could be turned on only when needed.
I believe you can already do this with the Programable Relay Assistant. This will allow you to trigger one of teh relays to open or close when the internal FAN is either on or off. I have not yet tested, but created two Assistants, one which enables the relay when the FAN is on and a second to disable the relay when the FAN is off.
Like you I have installed on a sail boat and need to aid the cooling.
Bathnm,
Thank you! That's a step in the right direction. My greatly simplified understanding is that the internal fan comes on:
(when the temp is high) OR (when a high power draw is demanded)
So it is not a direct surrogate for the internal temperature, but it might help. I'll investigate further.
Guy,
Thanks for that answer!
One thing to consider: Add a MultiPlus assistant that would allow me to turn on an external cooling fan if the internal temperature reaches the point where capacity starts to cut back. On smaller systems—like on my sailboat—an external fan can impose a significant load and it would be nice if could be turned on only when needed.
Believe that the BM-712 has a relay that you can trigger by battery temperature, if that's useful in your case.
The inability to see the Multiplus temperature is frustrating.
@mvader (Victron Energy) would it be possible to make the MultiPlus II temperature available on the dbus?
Hi all,
The same question over here.... and some more....
The setup;
1 x multiplus 3000/24
1 × cerbo gx
1 x lynx distributer
1 x mppt solar
1 x 24v/280AH lifepo4 bat with emusbms(connected to BMS bus on cerbo)
This all built into a rack with 2 compartments. 1. Battery and bms, 2. Inverter, mppt and cerbo. Both compartments have there own fan group.
I have connected the 2 fan groups to the relais outputs on the cerbo gx. Also connected 2 temperature sensors(unfortunately forced to do this.....) ASS000001000. 1 is at the battery end negative, the other is mounted at the multiplus ground screw, to measure as close to the multiplus inside.
Problem;
I have to set the fan activation temp very low(I noticed the victron temp sensors are very slow responding, probably due to the big metal housing) to get them kicking in before the temp inside the multiplus has allready reached high levels, for example when it starts charging at full power. I noticed a delay for approximately 5 minutes before the temp sensor value reach 30 degrees(with 18 degrees outside temp). So now i have set the fan activation temp to 24 degrees to prevent the multiplus trigger it's high temp alarm before the case fans switch on... the big sideaffect about this; when the outside temperature goes over 24 degrees this fan group is running 24/7 while the multiplus fan switches off when charging is done and no big inverter power is needed..
So at this point i'm in desperate need of reading out the internal temperature from the multiplus at the Cerbo and be able to use it as a trigger for the relais..
The second and almost the same problem happens in the battery compartment. When charging starts and the bms has to balance some of the cells(through the little circuit boards mounted on each cell) temperature in a single cell or the balance board can rise very quickly while the overall temperature, measured at the last negative keeps low for quite a while, this resulting in a high temp alarm from the bms....
The difference with the other compartment is actually that all the data is allready readable in the Cerbo over can. The bms sends out a main temp value which is always the same as the highest temp measured over all cell modules who all have it's own temp sensor...
Sadly I can't find a way to trigger a relais based on temp values from the BMS bus...
About this i have found a little workaround, you can trigger a relais based on an alarm. After all, with this workaround the next problem resides... when there is a battery low voltage alarm(what i use to switch off the multiplus) the fans start running and draining the battery even further, resulting in the last alarm from the BMS itself switching off the power for the whole system to keep the battery from dying. Ending up wih a fully down system before the solar or grid comes up to charge again...
So please guys, i'm desperate for a fix on this. And as far as my knowledge as a developer go, i think this must be doable by some simple software changes??
Regards Joost.
