Turnigy Graphene batteries from HobbyK

[Old School]

A well known Hong kong based store has a special at present on discounted Turnigy Graphene 5000mah 4s 45C batteries. I purchased six of them but am a little concerned with the items received. The instructions state prior first charge to check the cell voltages are between 3.7 and 3.85 volts.

So far three of the batteries the cells #1 and #2 have been within the range but cells #3 and #4 below with battery #1 indicating cell #3 3.66v and cell #4 3.61 and battery #2 cell #3 and #4 were 3.65v. On battery #3 cell #3 was 3.55v and cell #4 3.61. On battery #4 all cells were 3.80v prior first charge.

I believed that the graphenes were supposedly higher quality and had matched cells. If the prices are discounted because the batteries are seconds quality then surely this should be highlighted. Are the above cell voltages too low, please? I am still to test batteries #5 and #6.

[fweasel]

I've been finding it more common that batteries are shipped with cells at voltages below that of storage levels. As long as they're above 3.4V, or even 3.2V, it's worth giving them a slow 1C charge to see if they'll balance. I'm sure they'll be fine. The first thing I do when I get a shipment of new batteries is put them on the charger right away, cycle them, and then bring them back to 3.8V.

[rol243]

give the new packs a full balance charge then re check each cell for voltages.

[Old School]

Many thanks gentlemen

[RaceMechaniX]

I have quite a few Graphenes and they do arrive at a low voltage and often not equally balanced, but all have returned to good states after a charge and balance.

[CraigP]

Tyler, where do you set the final charged voltage at? Do you push it all the way up, or do you used that extra room to safe guard the battery more? I've been looking at them, but haven't purchased yet... Any info would be great.

[RaceMechaniX]

For normal racing I just charge to 4.2V/cell. I will store cells anywhere between 3.5-3.85V/cell. Lower is usually better if the cells do not self-discharge. If they are prone to self-discharging I leave them at the higher level for margin. For time trial events I charge them to the legal limit which is usually close to 4.25V/cell. I don't recommend this for normal running.

If you have a discharger function on your charger. You can discharge the cells to 3.5V/cell.

[CraigP]

Great! I'll have to try a set... Thanks for the info

[Old School]

Many thanks for the information

[Bp9145]

I have quite a few Graphenes and they do arrive at a low voltage and often not equally balanced, but all have returned to good states after a charge and balance.

I agree with Tyler. Just cycle them a few times and they will balance right. I also have received a few of them at a lower voltage with some cells not equal but after a few cycles they were fine with no issues whatsoever. Great batteries. . .love them and you will too!

[Old School]

Many thanks