Considering 8s rather than 7s

Batteriapan

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Feb 20, 2017
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If I getbatteryuniversity.com right, then keeping my packs between 3.2V and 3.9Vgives me about ten percentage point less capacitycompared to3.2V and 4.0Vbut two to four times the longevity of life. Sounds like apretty good deal to me.

Given I have enough cells to handle the capacity loss and ifmy inverter run at 21-32V,why not run 8s rather than 7s?
 

Geek

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Aug 15, 2017
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Batteriapan said:
If I getbatteryuniversity.com right, then keeping my packs between 3.2V and 3.9Vgives me about ten percentage point less capacitycompared to3.2V and 4.0Vbut two to four times the longevity of life. Sounds like apretty good deal to me.

Given I have enough cells to handle the capacity loss and ifmy inverter run at 21-32V,why not run 8s rather than 7s?

That is an excellent suggestion. I guess it is the same as running 4s instead of 3s in 12v setups. Even better if you have to loose 1s due to maintenanceyou can still operate your system.
 

DarkRaven

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Sep 2, 2017
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1,235
Well, yes, you can do this.

However, two issues with that. First, not fully charging the cells doesn't change the nominal voltage so this isn't a 24V system anymore. And second, the voltage range is already big enough, so you can do this with a 7S configuration as well.
 

daromer

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Oct 8, 2016
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Even though you dont go higher than 3.9 i suggest 7s. What if you need those last % a winter night. You then have no chance of actually using it ;)
 
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