SmartSolar - Why does my battery voltage go above my Absorption value

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dave-hartley asked Mar 12, '24

SmartSolar - Why does my battery voltage go above my Absorption value

Hi Newbie here, please be gentle :-)

My setup is a smart solar 100/50 12v

connected to a bank of 4, Gel Lead acid 110AH
2x 410W panels
Narrowboat
Engine not running ( not alternator input)

I am trying to understand why the battery voltage is not clamped at the absorption voltage value as set in the app settings ( see picture) 14.4v.

How is the absolute maximum output voltage set on this controller

Many thanks in advance for any thoughts

smart solar set-up help

ss1.jpg (117.2 KiB)

ss2.jpg (82.0 KiB)

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Alexandra ♦ commented · Mar 12 at 09:25 AM

@Dave Hartley

Check temperature compensation.

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dave-hartley Alexandra ♦ commented · Mar 12 at 09:47 AM

Thanks Alexandra.

I failed to mention I have a Smart Battery Sense fitted and connected to the SmartSolar.The temperature got up to 18c yesterday in the batter compartment.

Will higher temps raise the voltage delivered?

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nickdb ♦♦ dave-hartley commented · Mar 12 at 09:51 AM

25C is the base temp, for each degree below this it will raise charge voltages by the value it is set to. Once above 25C, it will reduce the charge voltages.

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Answer 1 · 2024-03-12T09:55:41Z

dave-hartley answered · Mar 12 at 09:55 AM

Sorry I was wrong, those charts are for days when no engine was running and the battery box was about 8-9c

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klim8skeptic ♦ commented · Mar 12 at 10:13 AM

@Dave Hartley do the math.

-(temp difference from 25c) X -(temp compensation volt value for battery)

That will give you the amount of variance from programmed set absorp volt value.

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Answer 2 · 2024-03-12T12:39:35Z

dave-hartley answered · Mar 12 at 12:39 PM

Thanks both for a simple explanation

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