I have a multiplus ii 24/3000 120 volt and Honda eu7000is. Offgrid system. Recently when I start the gen to charge the batteries it will ramp up to 62 amps charging then stop wait a few seconds and do the same thing all over. Reduced input amps to 10 amps and same thing.
Ok tried a couple things. I had updated the firmware so I double checked settings. Made sure it was set to lithium iron phosphate and set to charge 70 amps, I even set weak ac input. Charge was reduced to 42 from 62. Charged for a short period then same thing.
What are your batteries? And is their a GX Device in the System?
I have 8 280 ah lithium iron phosphate batteries in series with an overkill bms
I have a raspberry pi running Venus os.
Hmm, I assume the Overkill BMS is not communicating with the Multiplus via DVCC on the Venus OS then.
In that case, verify SmartShunt settings. Ensure all System Negative Cables land on the System/Load side of the Shunt, and check your Generator for any issues.
Got it sorted. Was settings in multiplus and bms. Working now.
Glad to hear it. Would you care to share what you changed? I am curious for learning’s sake.
First I turned dvcc off and added weal ac supply. Worked for a bit at lower charge rate but same problem.
Changed multi charge setting to Absorption 29.2 V, Float 27.6V, Charge current 70 A, Repeat absorption time 0.25 hours, Reapeat 7 days and Absorption time 1 hour. Smart shunt setting Charge Voltage 28.9 V.
I also think in the 10 days I was away the bms and smart shunt drifted significantly so batteries were closer to full than showing. I also have one cell that reaches 3.65 early, the overkill is a good bms but lousy balancer. I have a JK bms to install but first to figure out what is wrong with my well pump. Thanks for your help.
Glad to hear things are working better. A few tweaks I would recommend.
Absorption = 28.8v (3.6v/Cell)
Float = 27v (3.375v/Cell)
Charged Voltage = 27.8 (3.475v/Cell)
This should help avoid the 3.65v overvoltage you are seeing on one of the Cells.