Anyone buying these 305ah envision cells?

[Kornbread]

Why would you want more of those cells when you can get others for <$60, if willing to wait for the boat.

 

[houseofancients]

Why would you want more of those cells when you can get others for <$60, if willing to wait for the boat.

because that <60 doesnt include shipping, nor import taxes into EU, nor a local contact where i can swap a cell within 30 minutes if something isnt right ( at least for me with NKON )
not to mention, a pickup time of 30 minutes after paying isnt too bad either

 

[Ajgball]

My input on these cells, I purchased some from a UK company called Fogstar, Envision 305Ah grade b.

After receiving the cells, checking each visually, running an Internal resistance check on each cell to compare against the name plate rating and finally a top balance of all cells to 3.65v per cell in parallel before assembling the pack in to a 16s configuration in the supplied Seplos case with 200Amp BMS. unfortunately these do not perform very well at all at anything over a 0.2c discharge rate when the SOC is around 50%, barley 210Ah usable before low voltage cut off at 2.9v per cell, after cut off they bounce right back up to 3.1v per cell showing these are very low grade cells possibly heavily pre-used and re wrapped. I repeated the test after a full charge to 3.60v per cell then a further discharge with a 0.1c discharge rate and achieved a little over 279Ah this time. They seem to perform better at higher discharge rate around 3.3v per cell and then it all goes downhill once they are around the 3.2v mark. Appreciate they are B grade cells but not being able to pull 50Amps at a 50% SOC before a low cell warning isn't what i expected. I have tested and built many different cell types and manufacturers / grades and these are very very poor quality.

For some reason my review on their website keeps being removed.

Did this get resolved for you?

 

[shavermcspud]

Did this get resolved for you?

It actually turned out to be a bad batch of BMS units with duff firmware, both BMS units I tried had the same issue and wrong reading of cell data. they have been working fine ever since and I can pull around 300Ah no problem.

 

[Ajgball]

It actually turned out to be a bad batch of BMS units with duff firmware, both BMS units I tried had the same issue and wrong reading of cell data. they have been working fine ever since and I can pull around 300Ah no problem.

Thanks, I’m really tempted to go with these due to the lower price point than the eve grade A. Any thoughts on if they would be less safe than a grade A cell?

 

[HughF]

I had zero safety concerns using these. I’ve got one pack built with EVE grade A and one with Envision grade B, both perform fine

 

[OffGridForGood]

Safety for a DIY pack is the same no matter what cells you sourced.
Get a good BMS, (I use JK many members recommend JBD, Overkill etc.)
Install class T fuse on each pack - remember if one cell shorts in an ESS with ten battery packs, ALL of the packs feed current to the short unless a fuse/breaker opens the circuit and cuts that energy flow.