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Battery Voltage Difference 100/30 vs Actual Battery Voltage

I've been having an issue with my 100/30's going into float way before absorbtion or even float voltage is achieved. I then noticed there is a thread about this issue on the Facebook Lithium on Boats page and decided to check out my system. The MPPT shows a battery voltage of 13.71v. Battery voltage measured at the controller's own battery terminals show a voltage of 13.48v, BMV-702 shows 13.48 voltage at my solar charge bus measures 13.48v. I and many users on the Facebook group believe there is a software issue with the MPPTs. FYI I'm running 1.37 and have just reinstalled this version to rule out software corruption.

MPPT - Solar Charge ControllerFirmware Update Issuesoftware
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7 Answers
CJtechSupport avatar image
CJtechSupport answered ·

hi there, you can always connect al devices to the smart networking function if you have Bluetooth devices and a BMV or Smart battery sense. This will make the Voltage from the BMV/SBS the standard reference for the entire system.

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thanks. Installed Smart Battery Sense and all is working fine!

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roostermt answered ·

Has there been any solution to this yet. Just installed a system and having the same issue battery voltage different the mppt. In that case charging is stopping too soon.


Rooster

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bigbillsd answered ·

My Smart-Solar 100/50 has a similar issue. I can discharge 150 AH of battery to around 70% SOC but after bulk stage finishes prior to solar noon it moves to Absorb for, at most 15 minutes then switches to Float stage. So it looks like the batteries basically stop getting a real charge around 80% SOC. Its switching to float before solar noon! I have added the Smart Battery Sense this weekend at someones suggestion and will be boondocking the middle of next month to see if that made any difference. My local Victron dealer acknowledged the issue and suggested I lower the Equalize voltage and manually run an equalize when I want to fully charge them. I am hesitant to do that, but if I cannot get the Absorb stage to run for the many hours required after a reasonably deep discharge I may have to resort to doing that.

Any other ideas how I get the absorb to run longer? My battery settings are shown below. They are set according my my Crown Battery support team suggestions for their CR260 Deep Cycle 6v LA batteries running at 12v. (2p2s for 12v).

520AH LA house battery bank, 4 x 160w (640w) solar panels feeding the Smart 100/50 controller.

All firmware is current.



Thanks for any help or maybe some clarification as to what is happening to prevent using all the sun power available each day that I discharge my batteries.

My take on this is once the batteries get charged to around 80% (is that my user defined absorb voltage setting of 14.5v?) Should I make that higher??

they should switch to Absorb for a number of hours determined by the battery voltage when the controller wakes up. <11.9=6hrs, 11.9-12.2=4hrs, 12.2-12.6=2hrs, >12.6=1hr Nothing says run in absorb for 15 minutes.

I am normally running the 2800w inverter with a load all day so when the controller wakes up it should sense the voltage lower than 11.9v at dawn as I have pulled around 150AH from the battery overnight and the inverter is still running with a load at dawn which would normally show the battery is a lower voltage than it would be if not being discharged.

Logging the Vb when it wakes up would allow an understanding of the potential Absorb time the controller should run.


Best Regards, Bill Connell San Diego CA, USA







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Lee avatar image
Lee answered ·

I think that the voltage and current shown in the App is the charging voltage and current. Not the voltage of the battery itself. Otherwise you would see the current in the hundreds of amp hours.

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Holle avatar image
Holle answered ·

Hi.

Sounds very similar like my issue: BlueSolarHistory from MPPT 100/30 shows a min voltage for the battery (300Ah LifeYPo4) of 11,xx V even the battery 's voltage never fell below 12,5V.

Also Bulk mode is finished and Absorbtion is run for only 1 hour even though battery capacity at end of day only reached 80%. There was enough solar power to fully load the battery when bulk would have run some hours longer..

System runs with Firmware V1.39

Thanks for ideas.

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Flip-Flops answered ·

Seems to be an issue with the latest firmware load. Tons of users complaining on various Facebook groups. This is a new issue for most.

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Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

I have also seen unexpected charge behaviour based on the temperature compensation.

Do you have this feature enabled?

Perhaps try disabling it for your testing.

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Temperature Compensation is disabled.

Problem solved?