Samsung 30Q ideal Max/Min Voltages

[mitchm33]

It's pretty clear from a little research that I should charge my 20S25P pack of Samsung 30Q cells to between 4.0V-4.1V but I can't seem to find any consisticany about a minimum voltage. I want to balance longevity and range but I've heard widely varying answers from 2.5V-3.5V. Can anyone provide some additional clarity here?

Thanks in advance.

 

[amberwolf]

The spec sheet will give you the factory design limits.

Other than that, there are a number of threads about various packs and BMSs and balancing circuits discussing LVC limits.

Myself, with non-lifepo4/lto, I wouldn't run below 3v during max load, or say, 3.3-3.5v with no load. Others would go a lot lower to get more range at teh cost of lifespan. The lower you let it go, the harder it is on the cells, and the less lifespan they will have.

 

[spinningmagnets]

I don't have any good references, but from my study of this, I would never go below 3.0V per cell. I have a large pack, so I rarely go below 3.3V per cell.

3.0V to 4.1V is much better than anything outside that operational envelope. 3.3V to 4.0V is better, but narrowing the operational voltages more than that don't seem to have any beneficial effect beyond that.

 

[john61ct]

There is no significant actual mAh capacity between 3V and 2.5V anyway.

Frequently letting DoD get anywhere near **resting** 3.0V will shorten cycle life drastically, way too close to severe damage even instant scrap.

"Live" measurement of Voltage while discharging at high C-rates vs gentle usage,

shows a completely different correspondence to SoC level.

The earlier you stop on average, the longer lifespan is.

 

[Punx0r]

The 30Q seems to suffer a shorter cycle life compared to most other cells so anything you can do to avoid deep discharge ought to give a noticable improvement in the life of the battery.