I have a multiplus 12/3000 inverter charger with a batter smart shunt and Cebro GX wit 70 display. I also have the 100/50 Smart MPPT and 400 watts of solar.
The battery charger is charging 400 am hours of Renogy AGM batteries, and start battery.
The charger was setup to charge up to 80 amps. Renogy can support up to 60 amps sustained where the batteries are in parallel so should support 120 amps.
The charger was working then stopped working when my Seafrost 12VDC compressors turned on. The fridge and freezer are seafrost and but combined pull 15 amps of current.
It worked before and now it doesn’t.
When I set to default configs on the Multiplus shut off all power to the Multiplus then wait three minutes the repower the inverter charger.
My Cebro GX shows the charger going through bulk, absorption, and float. It takes about 5 minutes to transition them all.
During the charging cycle with batteries at 66 percent there is no charge current coming from
The battery charger.
I’m not sure the battery charger is actually sensing the battery SOC. It sure if it ever has.
Because the inverter powers up and requires DC voltage to power up, I’m assuming I have connectivity to the 12v system so the charger should sense SOC.
Any advice would help. The inverter charger is brand new.
The 12V compressors may be 15A in normal operation but they draw a larger start up current, perhaps 100A = 1300W so they should not have caused problems on the Multiplus.
Does your Multiplus invert OK and supply ac power if you disconnect shore power. If it generates ac and you try a large load does it work or does it give low voltage error.
The charging on the Multiplus does not work off the SOC, it only works off voltage.
You may have a poor connection between the inverter and the batteries with a high resistance that is allowing enough power through to start it up, but not enough for higher current charging. Check your cables, connections, isolators, fuses etc. Use a multimeter to check for voltage drop.
Hi Bob,
You know the saying. A picture says more than a thousand words. So.. How long are your battery cables, and what is the diameter? Also. You said that it worked before. Something must have changed. Changed some settings, wiring? Are the batteries fresh? Have a clamp meter? If yes. How much power does your compressor actually pull?
Thank you for responses.
Understand the startup current issue and yes it should not have caused any issues with the Multiplus or my battery bank. I checked and tightened all the connectors going to the batteries and to the inverter. They are ok.
The batter charger now never comes on. The batter charger lights on the front of the multiplus remain off all the time now and the Cebro GX shows the charger is off.
I’ve reset the multipuls to default and repowered it. The battery charger never attempts to power up.
The inverter is inverting and works off the battery or shore power so is properly functioning and supply power to house loads.
I’'m beginning to believe the charger is defective in the unit. It’s pretty hard to mess up hooking up the battery charger. It’s two wires that are very well marked in the multiplus.
Before it seemed to completely die - it would transition through all the battery phases very quickly with no output where before it was outputting properly. Its like it slowly died. It worked, then stopped outputting, then no charger at all.
I’m calling the rep at this point as I’m kind of out of options, outside tearing into the charger and testing the recitifiers in the charger itself. Most likely it’s the SCRs that are going in the battery charger itself.
I believe when this is finally fixed i am installing a built in Victron battery charger to backup the not so great ones in the multiplus.
V/r,
I believe the batter cables are fine in length. They are the same ones I used on my Magnasine 2810 inverter. I’m outputting less charging current than the Magnasine as it put out over 100 amps charging as well. I set the victron 80. When I started having issues I dropped it down to 30 just to see if its an heat issue which indications never changed. This occured with or without the fridge freezers working.
The Multiplus uses the same AC/DC conversion circuitry for both charging and inverting. If the unit is inverting fine from the battery then hopefully the power electronics are OK and it is something peripheral that is causing a problem. I hope I am not offending by saying to check the Cerbo is not set to inverter only, but sometimes these things can catch us out. The other thing is downloading the settings file from VRM and check it out in VE Configure if you have a laptop or PC to make sure that there is not a corrupt settings file.