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withalligators avatar image
withalligators asked

Battery SoC entering float at 95% within last few days with 150/85 and BMV700

Hey folks,

I have 981w of PV on my sprinter, going to a 150/85 and 400AH of lifepo (4 x 100AH battleborn units). Within the last few days, the charger has started floating the batteries at 95%. The system is just less than a year old.

Settings are 14.4V absorbtion for 1hr20m. Float at 13.6 for a while, it was floating about 0.2V higher, so I had it down to 13.4, but it eventually started floating at 13.4 so I turned it back up to 13.6 and it seems stable there.

Any ideas on addressing the 5% of the batteries the charger won't Bulk?

battery capacity
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2 Answers
nebulight avatar image
nebulight answered ·

What is your charged voltage, tail current and charged detection time set to on the BMV? It's not that the battery isn't charging to 100%, it's probably that the BMV settings need adjusted for it to register 100 SOC.

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withalligators avatar image withalligators commented ·

Charged voltage is 14.4, tail current is 4.00%, charged detection time is 3m. These are the settings Battleborn recommend for this bmv. It was reaching 100% a few days ago. The change is kinda sudden, and interesting it's a full 5 percent.

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nebulight avatar image nebulight withalligators commented ·

This is your problem; your charged voltage on the BMV is set too high. Per the manual:

02. Charged Voltage

The battery voltage must be above this voltage level to consider the battery as fully charged. The charged-voltage-parameter should always be slightly below the end of charge voltage of the charger

Since your absorption on the charger and your charged voltage setting on the BMV are the same, you'll never get above that voltage in order for the BMV to consider the battery to be fully charged. Battleborn I think suggests charging to 14.6v, so their recommendation of 14.4v is probably okay. However since you are only charging to 14.4, you aren't above that voltage on the BMV. Set your BMV charged voltage to 14.2 or 14.1v and you should sync to 100%

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withalligators avatar image withalligators nebulight commented ·

I somehow completely thought I had replied to thank you. I cleared this with Battleborn, and did it. I am now seeing 100% on my BMV. Thanks.

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nebulight avatar image nebulight withalligators commented ·

Glad you got it working!

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withalligators avatar image
withalligators answered ·

Now it's hitting float at 94% the last 2 days. I also don't think it's entering an absorb state. If it is, it's very quick and definitely not the 1hr20min it's set at.

Because it's not hitting 100%, it's reading my last discharge as one from several nights ago.

Guys, is this something I can nip in the bud before it gets worse? I'm starting to get concerned.

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klim8skeptic avatar image klim8skeptic ♦ commented ·

Look at the history of the Mppt, and what firmware version?

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withalligators avatar image withalligators commented ·

MPPT is firmware 1.37, here is the history from it:

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screenshot-2019-07-06-16-42-47.jpg (495.7 KiB)
screenshot-2019-07-06-16-43-04.jpg (315.7 KiB)
screenshot-2019-07-06-16-43-04.jpg (315.7 KiB)

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