Multiple Multiplus errors: Low Battery & Battery Voltage Ripple

[dgerfan]

For the last couple days I haven't been able to run any high draw appliances using a combination of solar, batteries and power assist (7 amp connection). My RV is located approximately 200 ft from the power pole and I'm using a combination of 10g and 12g extension cords. In the Multiplus I have the connection throttled down to 7A. This has been working well for several weeks as I can't get closer to the pole due to the soft ground (In another post I detailed getting stuck while trying to move the RV). Well for the last 5 days or so the Multiplus displays "Low Battery" every time I attempt to run the water heater or the microwave or the coffee pot (not at the same time of course). While a high draw appliance is running the DC lights in the RV constantly flicker.

Yesterday I contacted Battle Born and they recommended that I charge each battery individually, then put a DC load on the battery in order to verify correct functionality. I charged each of the four batteries to float stage and put a small load. One of the four batteries wouldn't charge so I removed it out of the bank and connected up the three batteries. I'm still receiving the Low Battery alarm and now I get the Battery Voltage Ripple alarm. Any help is appreciated!

Configuration:

Multiplus 12/3000/120V with 4/0 cable
(4) 100aH Battleborn Batteries with 2/0 cable
Universal Rotary Changeover Switch 660V 63A (this switch replaced the SPS because of the know stuck relay issue)
BlueSea Battery and Inverter switches
Morris Products Insulated splices for running the cables from the front bay to the Rotary Switch and Breaker Panel

I used the wiring diagram from All About RVs to wire in the Rotary switch and its currently in position two (single phase connection)
https://www.youtube.com/watch?v=_wjf...hFPJH&index=14
Diagram shown at 7:14 in the video.

In September of 2023 I removed the SPS and installed the Changeover Switch and I've been in this spot with the extension cords, 7A shore power and solar for approximately 2 months.

[ncitro]

Do you have a multimeter? If so, what is your voltage at the Multiplus terminals? What is it at the batteries? If they are the same voltage work from one to another looking for where you are dropping voltage. My guess is you have a high resistance connection somewhere dropping voltage to the MultiPlus.

[dgerfan]

Battery: 13.48v
Battery Busbar: 13.48v
Multiplus DC Terminals: 13.48v
Multiplus AC-IN: H-N: 119v H-G: 121v
Multiplus AC-Out: H-N: 119v H-G: 121v

[ncitro]

Okay so at that point the voltage looks good and does not seem to be dropping. Can you post screenshots of your MultiPlus settings? Have you done a firmware update recently that might have wiped out those settings? I am wondering if the alarm voltages are set too low?

[dgerfan]

ncitro This inverter was installed in 2020 and I haven't touched the settings or updated the firmware. I just purchased the MK3 yesterday to check the settings in case by some fluke something had changed.

[Jlawles2]

Do you have any way to measure amp draw when you try to run appliances other than the multiplus? Also try manually measuring voltage at the batteries when the multiplus goes into boost mode.

[ncitro]

ncitro This inverter was installed in 2020 and I haven't touched the settings or updated the firmware. I just purchased the MK3 yesterday to check the settings in case by some fluke something had changed.

Your Pre alarm is set for 11.5V, if you are getting 13.48 when its alarming I suspect a problem in the Multiplus itself. I would reach out to your dealer at this point for a possible warranty claim.

[dgerfan]

[QUOTE=Jlawles2;n130218]Do you have any way to measure amp draw when you try to run appliances other than the Multiplus?

The only other way that come to mind is to plug in a device to a kill-o-watt.

I turned on the Water heater and measured battery voltage and it was all over the map. Lowest reading was under 6v

[Jlawles2]

sounds like you have another bad battery in the mix. you can try disconnecting all of them and adding them back in one at a time until you start getting errors. Hoepfully the HWH is not electric and you are running it on the inverter. IIRC those are something like 1500+ watts.

[ncitro]

If your voltage is dropping when under load, I’d think you’re looking at a bad connection somewhere. Try to find a place that reads good voltage under load (start with the batteries) and’s work out from there while it’s under load and look for a place where voltage is dropping and that’s your bad connection.

Best tool for reading current draw is a clamp on amp meter. Make sure you get one that does DC.

[dgerfan]

Jlawles2 ncitro I put the volt meter directly on the battery posts while they the water heater was turned on. The readings were fluctuating between 13.4v to around 5v. I have never observed this under normal circumstances but would assume that the voltage would just drop gradually. I would like to isolate the batteries from the inverter by running a large DC loads but I'm not sure if there are any in the RV.

In the meantime I'm working with Battleborn and the supplier I purchased the Multiplus from. That supplier has already said that they believe its a battery issue.

[ncitro]

Sounds to me like a battery issue as well.

[Jlawles2]

Probably the easiest thing to do would be disconnect the negative lead on all but one battery then run the kick in the inverter phase of the multiples running something simple like a 100W light bulb in a 120V lamp. That should be about a 10 amp load on the battery. Do this for each battery and see if the problem persist while measuring the voltage of each battery.

In the mean time you may want to charge the batteries individually with a dedicated Li charger like the https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1 or higher amperage. No need to go all out and get a super high amp one. Once you get all of the batteries topped up with that, then repeat the test. If there are not issues, then I would suspect the Multiplus charge side has become damaged some way.

[Kathy&Jim_Imagine]

ncitro Neil, Dumb question as I'm still somewhat new to this but doesn't the 12/3000/120 need a minumum of 400ah of battery to function correctly? If one of the batteries isnt taking a charge... or if its been eliminated from the mix, would'nt that have a negative effect on the systems operation?

[dgerfan]

Probably the easiest thing to do would be disconnect the negative lead on all but one battery then run the kick in the inverter phase of the multiples running something simple like a 100W light bulb in a 120V lamp. That should be about a 10 amp load on the battery. Do this for each battery and see if the problem persist while measuring the voltage of each battery.

In the mean time you may want to charge the batteries individually with a dedicated Li charger like the https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1 or higher amperage. No need to go all out and get a super high amp one. Once you get all of the batteries topped up with that, then repeat the test. If there are not issues, then I would suspect the Multiplus charge side has become damaged some way.

I charged each of the batteries individually (except for the one that reads 0.00v) and waited till each was in float mode. Disconnected the negative and positive cables and checked voltage via volt meter. Each showed approximately 13.45v. I then connected the Viar Pump to each battery however none of the batteries were able to start the pump.