question

@Rob Beckers

Have you verified with a meter?

If it is exceeding absorption voltage it is very likely the batteries are shutting down to protect themselves.

Also using dip switches is a black art. Their current positions does not indicate how it is programmed in any way.

It is best to have a gx device in the system and an mk3 to usb adaptor used with ve config or victron connect, to make sure things are set right in software and are functioning correctly.

Thank your for your reply Alexandra!

The absorb/battery Voltage was verified by the customer using a multimeter. Unfortunately they are 4000km away from our shop (clear across the country), and they don't have a MK3-USB. So I cannot personally verify what the internal settings are. The MultiPlus is a brand-new unit just out of the box, so we can be pretty certain nothing was set in memory besides the defaults, which best I understand means it should honour the DIP-switch settings.

-Rob-

Alexandra, just read through your link about programming by using the DIP-switches; it's a little different from how I thought this was working and very informative! I'll give the customer a call and see if we can talk her through setting some explicit charge settings using those switches, and storing them.

Will report back with the result.

Thanks again!

-Rob-

The customer and I sent over setting the charge parameters, following the instructions. While I cannot verify what is set, I am confident she did everything correctly, and we should have the unit at 14.1 Volt for bulk/absorb.

Despite that, charging via the still runs the Voltage up to 16+ Volt (and to a point where I'm pretty sure the BMS switches off the batteries). Screenshot from the BMV-712 attached.

-Rob-

The multi looks to be in float.

There's a 12:12 Orion in there. Is that wired to charge the house batteries? Did the customer set/check that?

And interestingly the starter battery is shown close to zero volts. Is that not wired in, or incorrectly wired?

The orion is a DC-to-DC charger for when the engine is running (charge from alternator). The screenshot is when the engine is not running, as were the earlier measurements. Solar is not hooked up, the only charging source is the MultiPlus.

Noticed the zero Volt starter battery as well. I've not asked but assume it's just not hooked up.

-Rob-

Hi,the owner didn't run the batteries down to low voltage disconnect by any chance before charging on mains?

Cause this happened to me with lifepo4 in an easy solar unit everything was sweet for months until i decided to test battery capacity.I ran them down until disconnect,im not sure whether it was easy solar or batts that shut off first as im on a learning curve :-) i then plugged into 240v and at absorption the voltage went nuts until bms disconnected.

I took to victron installer/rv mechanic,they just did a firmware update,set parameters again,monitored unit and it came good,so i dont have a specific reason only that a reset/update of unit fixed it.

Cheers.

From the picture you dont seem to have a voltage Vsense connected

check the Multiplus Reference voltage connections are on the correct battery bank, and are connected on the NON battery side of any shutoff relay and that its getting the correct voltage reading

The customer went to a local Victron shop (and also got an MK3) and we're starting to get a better idea of what's going on here. Somehow the Voltage the inverter is sensing is a full 1 Volt less than the actual battery Voltage measured at the inverter's terminals. So, a setting of 14.4V for charging would mean the inverter actually runs the Voltage up to 15.4V, and that will most definitely kick in the over-Voltage protection on any lithium-ion battery with a BMS. Please have a look at the pictures illustrating this.

Has anyone seen this before? The inverter has been updated to the latest firmware, just in case. Battery temp sensor is disconnected.

-Rob-

Hi,since this thread and microwave one i bought a mk3 also,to learn and noticed charge curve on my easysolar is set to fixed, unless you've been informed otherwise this is best for lifepo4 then you can set a fixed absorption time,ie recommended by battleborn of 30 minutes per 100ah so 2hrs, battleborn also uses fixed charge setting.Something to help you get one step closer to happy.

Good luck.cant help with voltage readings

Hello, i have finally found a problem that matches mine.

I have gone from a Easy Solar with AGM that just worked and behaved, to upgrading to Lifepo4 and a shunt so now, Easy solar 24/3000/ with smart shunt 500A, now this is where the problem starts after the upgrade. i am seeing the same problem i have 4 Lifepo4 drop ins and i am seeing at absorption 28.4 and the battery's are going up to 15.56 and going in to overvoltage protection kicking out the absorption. every thing looks fine in bulk charge the mid points are with in 0.1 up until abs. i am seeing a 1.5 ish volt difference. about 15 minuets in to abs the problems starts.

the Easy Solar and the shunt and the seem to see 26v but the battery's are 27v i have run a multimeter over the setup the voltage is the same with in + - 0.3v before the shunt and after the shunt are the same as the batteries i have checked the fuse in the mid point connections of the shunt and are 1a not 100ma. i cannot work put why the multi is 1v out but its casing problems.

so as a work round for the time being would it be worth dropping the abs and float down a volt to compensate?

look forwards to seeing more input on this as its baffling me

Paul