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bbeng89 avatar image
bbeng89 asked

BMV-712 settings for solar and RV converter

Hello, I could really use some help figuring out the settings I need to use on my BMV-712 for my RV setup.


I have 2 group 24 flooded lead acid batteries, that add up to 124 Ah. About half the time I'm charging them from my RV converter (usually via a generator), which is a Progressive Dynamics PD4045KA. The other half I'm using a portable Renogy 100W solar panel with their Voyager charge controller. I left the settings on the BMV at the default and it seems to work well when I'm just charging off the converter. But when I switch to solar, the SOC often jumps right up to 100%.


I looked into my solar and converter specs and with the solar, the absorption voltage is 14.7V and the float is 13.6V. My converter seems to only do 13.6V. I'm thinking that since my settings on the BMV have the charged voltage at 13.2V, when the solar gets up to the 14.7V for absorption it is setting SOC to 100%.


I'm pretty new to this stuff and feel a bit out of my depth. Can anyone help me figure out what I should have my settings at so that the BMV will give me an accurate SOC with these two charging sources? Thanks in advance!

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3 Answers
Justin Cook avatar image
Justin Cook answered ·

@bbeng89, please see the user manual, specifically Section 2.3 regarding common problems and section 4.2.1 for programming the device properly for you battery bank.

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bbeng89 avatar image bbeng89 commented ·

Hi Justin, thanks for the response. I've read these sections, and the source of my confusion comes from the fact that my solar panel will go up to 14.7V but my converter on the RV will only go up to 13.6V. So I'm wondering how I should determine the Charged Voltage?

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JohnC avatar image
JohnC answered ·

Hi @bbeng89

Your BMV can only 'sync' to 100% SOC when it meets the set parameters for how much current the batts can accept. So with an applied V above the 'Charged V' setpoint, and measured A below the 'tail %' (for x minutes), then sync will occur.

So the 'tail' is important. In a solar-only setup I don't see much point in syncing in Abs mode, rather wait for Float to be reached, and when charge tapers off and flatlines, then sync is due. For me that'd be ~1-2% tail, and a Charged V set a little below Float V. A high tail setting will cause premature sync, and won't show that 100% truth.

There's a lot more than sync to setting up a BMV though, enjoy the learning curve..

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sglad avatar image
sglad answered ·

Your converter will do 14.4 in "boost mode" 13.6 in "normal mode" and 13.2 in "storage mode". This is from the product's manual.

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bbeng89 avatar image bbeng89 commented ·

Ahh, you're right, I just looked it up in the manual myself. I've never seen it go this high though... It usually seems to be 13.6. that said, would it make sense to set my Charged Voltage somewhere around 14.2 then? I've set my tail current to 1%

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sglad avatar image sglad bbeng89 commented ·

Try 14.3 with 2% tail and 95% efficiency and see if this provides more realistic SOC.

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bbeng89 avatar image bbeng89 sglad commented ·

Ok, I'll give it a shot. If it seems to be working correctly after a couple days I'll mark this as the answer. Thank you for all your help!

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