Hello. My install is 24v offgrid, 1 smart solar 100/15 with pv, old multiplus compact 24 800 , connected with 0.5m of 25mm2 to two 12v agm batteries in serie, and venus os on raspberry (connected to multiplus via usb-mk3), and two yamaha efs3000ise generators.
All is working quite good BUT:
In venus os or victron config, the values seems wrong : with no ac in, battery current while inverting or ac load are sometime ok, but most of time no.Same for the ac in load when generating.
In all mode, The battery voltage seems to be between 0.7 to 1.1v above the reading on the smartsolar or my multimeter.
I changed the 25mm2 wire from batt to multiplus for new ones, in case of bad connectors or dammage cable, with no luck.
I updated the firmware to 1913 159, with no luck on the values.
I am little bit surprise all is working accordingly to the need, the only real drawback is charging with the generator: the multiplus switch to absorption earlier than expected.
Now, my last two option are installing an old bmv600s i have laying there, and (1) only read data from the bmv screen ( the most important Vbatt and Ibatt) and adjust the voltage on the multiplus to match my charging parameter, or (2) keep the venus os, connect the bmv to it, and and config the vdcc.
Not having ac loads values bother me a little bit and obviously searching any tips to have them.
By the way, battery temperature is not shown or available in vemus os, but seems to work. Is the data available from this old multiplus?
Do you have the temperature sensor connected to the battery bank and the t sense terminals of the inverter?
Yes, the temp sensor is inside a connector, bolted to the minus of the battery bank, directly on the battery pole and the two wire from the temp sensor are connected to the multiplus. The mp should fire an alarm in case of disconnected or damaged temp sensor
It seems that the incorect value for ac loads could be related to the inverter generator, supplying 2 phase 110v without neutral instead of single phase 220v with neutral, witch seems to be my case.
Could be…after reading and poking around…
Whatever, this don’t resolve the bad dc voltage reading nor the battery temperature
No one to tell if there is an offset on the dc values on the mp compact?
I haven’t found anything like this on the manual or anywhere.
The bmv i have is used on the 24v generator and bother me to take it from it to assume a mp faulty fonction, without speaking that power drawn by the mp , pi and buck converter, is exceding my powers need for lighting and computers and phone.
Rethinking about that, i think i am going to get rid of the mp compact, for an separate inverter, 24v generator to charge the battery bank and powering the inverter when needed.
220v ac generator will be kept to power the shop
hi
if you think your multi plus has a problem I’ll give you the pre-RMA victron documentation.
multiplus___quattro___testing_and_diagnosing.pdf (8,3 Mo)
Thanks a lot, ive been around this, the only thing this documentation gave me help with is a reminder to check internals bolts. That’s what i call poking around, findings interesting tips but without effect on the actual problem
Have been mulling over this. It may be that component aging may be affecting the reading. I don’t really know.
There is no programmed offset that i know of.
But you could adjust the charger settings to compensate for the overreading.
Thanks for the info about the offset.
Adjusting the parameter is annoying for lot of reason. But this made me think about the whole set.
Simplier and safest way is ditchind the multiplus, switch the 220v inverter generators for 24v generators, switch for 24v appliance any possible appliance, and 2 phoenix inverter for redundancy for 220v appliance.
For low power use 24v dc and full usb-c is good enough and plenty of appliances on the market.
At the end, cost is a third for the same power use… shame i begun my install the other way
Hi, i think you are missing 2 components 
- A smartshunt that will give you correct data from the battery, the mp sees the boat with all electrical loads and tries to charge these.
- A balancer for your batteries
In total 150$ usefully invested
Exactly. The bmv is a very useful. mine is is wired with a 24v alternator to be able to control the charge. The bmv open acess to Three stage charge, solar charging priority naturaly built-in, relay for autostart, the bmv is worth to the last penny wired with the 24v alternator.
I was planning to avoid the bmv with the mp, but no.and the bmv is too useful to the geny.
the mp need an cerbo or venusOS in addition to be able to see data. And if data are wrong…
but power consomption of all this set up is the real deal breaker.
the diy 24v generator with bmv+smartsolar+phoenix inverter is globally more efficient than inverter generator +smarsolar+mp+cerbo+bmv in my range of power usage.
And sure, i wouldn’t have done fine power metering if the mp had good values…
Edit : and yes , i forgot, there is a battery balancer in the battery pack ( 2 x 100ah in serie)