question

wineteam avatar image
wineteam asked

Solar does not reach 100% SOC

4 x 100Ah Battle Born

6 x 100w Merlin SRS100 solar panels

Victron Shunt

Victron MPPT 150/35

Solar provides plenty of watts, but MPPT drops solar use from Absorbtion to Float at 13.5V which is 60% SOC. I know there must be a mismatched setting but am unsure where and then how to change settings so that I can get the solar to provide 100% SOC. Any guidance is appreciated.

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SOC
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6 Answers
wineteam avatar image
wineteam answered ·

Below are the recommended setting from Battle Born directly:

Most Recent Victron BMV-712 and SmartShunt Settings:

Battery Capacity: Total AH of your bank of batteries

Charged voltage: 14.2v

Discharge Floor: 0%

Tail Current: 4%

Charged Detection Time: 3m

Peukert Exponent: 1.05

Charge Efficiency Factor: 99%

Current threshold: 0.10A

Time to go averaging period 3m

Battery SOC on reset- clear (if you ever see - - as a state of charge that means you need to fully charge the batteries for it to calibrate

State of Charge: leave alone

Synchronize SOC to 100%: Leave alone, this device will sync itself at the top of the charge

Zero Current Calibration: Leave alone

(Note these settings do not effect how your system performs)


Here are the MPPT settings:


12 Volt - Victron MPPT

Battery Voltage: 12V

Max Charge Current: Varies By MPPT Model.

Charger Enabled: Switch should be to the right and blue.

Battery Preset: User Defined.

Expert Mode: OFF (Switch should be to the left and gray)

Absorption Voltage: 14.4V

Float Voltage: 13.6V

Equalization Voltage: 14.4V or Disabled.

Automatic Equalization: Disabled.

Manual Equalization: NEVER PUSH BUTTON.

Temperature Compensation: Disabled.

Low Temperature Cut-Off: Disabled.

I have implemented these settings and am seeing better performance.

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kevgermany avatar image kevgermany ♦♦ commented ·
Great. It may take a few cycles before you get to 100%. Depends on how out of balance the cells are inside the batteries. Internal cell balancing is slow, and the BMS will use cell data to protect the battery.
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Sarah avatar image
Sarah answered ·

Hi @Wineteam we really need to see what the charging parameters are for the batteries and the charger configuration on the mppt - especially the absorption charge voltage. It could also be that your shunt is not configured properly and you are actually at 100% SOC.

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kevgermany avatar image kevgermany ♦♦ commented ·
@Wineteam

In the first image there's a cogwheel, top right. Click on it, brings up the settings, we need the battery settings.

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wineteam avatar image
wineteam answered ·

20240402-185105000-ios.png

I believe this was the default mode when I received the trailer. It took me a while to figure out that even if I went into Expert Mode, I needed to change the default mode to User Defined, at which point I could then start making changes to the setting.

Let me know what settings I should have. Thanks again for the help.


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Sarah avatar image Sarah commented ·
Knowing the config for your shunt would be helpful as well.
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Sarah avatar image
Sarah answered ·

Check the battle born manual which indicates an absorption voltage of 14.2-14.6 volts. You are at the bottom end of this range. I recommend you contact Battle Born for further advice before considering any changes to this setting. https://battlebornbatteries.com/wp-content/uploads/2022/10/BB10012-Manual-Edition.PIM_BB10012Rev020_08282023.pdf

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kevgermany avatar image
kevgermany answered ·

You have different battery voltages indicated by the shunt and MPPT. This shows there's a point of high resistance between the MPPT and battery or shunt. Could be a loose connection. Perhaps at the fuse in the red lead to the shunt. Possibility of a fault on the shunt or MPPT.

Battery is charging slowly because the MPPT is in float. There's also something loading the system by a couple of amps.

There's enough in the manual @Sarah provided to use expert mode. Generally you don't want to overcharge, but setting MPPT absorption and float to the mid point of the ranges specified will help. Manual also says that the internal balancing by the BMS only kicks in at 14.2V. Raising absorption will improve the balancing process.

Does look as if the shunt isn't properly configured.


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Sarah avatar image
Sarah answered ·

Glad to hear that you are getting better performance! It is amazing what a 0.2 volt tweak can do :-)

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