DNA 75 draining battery to 3.1V - is that bad?

[Tubbyengineer]

The 3.1v level will be fine, if you don't mind losing a little battery life you can raise the soft cutoff level to 3.19 in escribe if that will make you feel happier. The usual safe discharge level qouted for Li-ion cells is 2.7v, below that things start to become risky, and as already pointed out once below 3.0v or so the batteries start to suffer increased degradation...

 

[allen]

No probs buddy [emoji4]

I've only got lipo DNA200's and I can check the cell voltage in two ways:
1) I've got it set so that when I charge them via usb it displays the cell voltage whilst charging. I set this up on the screen section of escribe.

2) Connect the device and do the cell monitoring on escribe and it should tell you what voltage the cell is at.

Are you using an external charger or charging in the mod? Not that it really matters but if it were me I'd set the cutoff to 3.2 and still change out/charge when it gets to 10% ish.

I've set mine so %age shows in power mode, so i can check it by switching over briefly.
And yes i use an external charger still

@Tubbyengineer
I'm happy at 3.1v cut off as it's so near running out when it gets to 5% it seems a decent balance.
I can always buy more batteries anyway [emoji6]
Thanks for your suggestion, I'll watch and monitor and bear it in mind

 

[longy01]

Can I ask a question. Am I right in thinking that soft cell cut off is actually reading battery sag, and not the batteries current voltage level? Sorry if this seems like an obvious question but the dna 75 is new to me. When I first booted up the Ecsribe 75 software, the soft cell cut off was set at 2.75v even before I connected my Vt75 to it. With this in mind, why would Evolv have this setting as default if it was unsafe.

 

[allen]

Can I ask a question. Am I right in thinking that soft cell cut off is actually reading battery sag, and not the batteries current voltage level? Sorry if this seems like an obvious question but the dna 75 is new to me. When I first booted up the Ecsribe 75 software, the soft cell cut off was set at 2.75v even before I connected my Vt75 to it. With this in mind, why would Evolv have this setting as default if it was unsafe.

@Tubbyengineer gave a great reply above. with me looking up the spec sheet on my 25Rs too, this confirmed it.
they can go down to 2.7 and not suffer much damage but their overall life spam will be reduced a little bit

2 ways to extend battery life so far as I can work it out:
don't overdischarge them (why many mods e.g. pico, cuboid, RXs cut off at 3.2V
charge them slowly

but 2.75 isn't unsafe - it's just not great practice (although it means you charge less often)
and yes, the 2.75 generally kicks in will battery sag rather than actual charge in the battery. although at lower power settings the difference between sag level and actual level is unlikely to be very much

 

[longy01]

@Tubbyengineer gave a great reply above. with me looking up the spec sheet on my 25Rs too, this confirmed it.
they can go down to 2.7 and not suffer much damage but their overall life spam will be reduced a little bit

2 ways to extend battery life so far as I can work it out:
don't overdischarge them (why many mods e.g. pico, cuboid, RXs cut off at 3.2V
charge them slowly

but 2.75 isn't unsafe - it's just not great practice (although it means you charge less often)
and yes, the 2.75 generally kicks in will battery sag rather than actual charge in the battery. although at lower power settings the difference between sag level and actual level is unlikely to be very much

Thanks for the reply Allen. Was beginning to think people were avoiding me, lol. It was my thinking that, as you said in your original post, the soft cut off setting has nothing to do with the minimum discharge of the battery. This is the job of the discharge profile.

My profile is set to 3.32v at 3% remaining. Even though I generally swap my batts out with about 15 - 20% left.

Yesterday I was experimenting with different SC settings. With a 25r at 3.66v (50% charge remaining) and the SC set to 3.1v I would get a weak battery warning, cutting the wattage to 26w. This was with a simple single coil 0.5 ohm build at 30w.

When I set the SC to the default setting of 2.75v my device would continue to fire at 30w with no warnings until about 20% battery remaining (3.42v). I don't think 30w is a lot to ask for from a DNA 75, but I would still like to have it all the same, hence I'll leave it at 2.75v for now.

Sorry for the long winded reply lol.