Discharging Lipos

[Aire valley]

When discharging lipos to store......what is the best discharge rate.? 1. 1.5. 2amps..or higher..? Thanks..

[Cremegg]

if your charger has a storage mode....use this at it discharges the batteries for you

i think storage is about between 3.78 - 3.82 and half full

[neallewis]

Originally Posted by Aire valley

When discharging lipos to store......what is the best discharge rate.? 1. 1.5. 2amps..or higher..? Thanks..

I'd do them at the maximum your charger can discharge. It will certainly be a lower discharge rate than running them in the car at racing conditions.

[Aire valley]

Thanks Neil. good point...it will discharge at anywhere between 1 and 5 amps....just wondered what was best for the batteries ..

[Aire valley]

Originally Posted by Cremegg

if your charger has a storage mode....use this at it discharges the batteries for you

i think storage is about between 3.78 - 3.82 and half full

Yes I have a storage mode but the discharge rate can be set between 1 and 5 amps. I wondered what the best rate was for the battery..

[tomtom]

I would say 5A, max.

[The Dude]

Me too because it takes a lot of time and they are warm at the end.

[johnboy]

Any point discharging as they don't have a memory like the old cells used to?

[neallewis]

Originally Posted by johnboy

Any point discharging as they don't have a memory like the old cells used to?

if you have fully charged a pack and not used it in a race meeting, and won't be using it for a while. best not leave lipos fully charged.
I find packs after a heat or final are discharged enough to store.

[Aire valley]

Originally Posted by johnboy

Any point discharging as they don't have a memory like the old cells used to?

Yes....it is strongly recommended that lipos are discharged to "storage" which is around 3.75 - 3.8v per cell.......all good chargers have a Storage facility..which takes the lipos to this state..
My only concern is the discharge rate which can be varied..

[Big G]

my etronix touch charger "stores" at 5.0A although I've informed it they are 5700mah batteries. It takes them to 7.4v

[Aire valley]

Originally Posted by Big G

my etronix touch charger "stores" at 5.0A although I've informed it they are 5700mah batteries. It takes them to 7.4v

Yes... I understand that 7.4v ( 3.7v/cell) is the optimum point...I play safe and stop just above that..3.8v/cell........ It looks like the discharge rate is the same as the charge rate ...i.e 1c. I will stick to that..... Thanks guys..

[SlowOne]

Over-discharging cells can cause gas build up that makes them swell. Research shows that LiPo/LiOn cell failures are usually down to the variability of the chemicals in them, the manufacturing process variables and the materials used. Variations in the thickness of the separators, the slightest burr on the metallic elements, and gas produced due to high current rates causes the cell to swell and change shape. That may activate the fault and cause a problem.

Store them at just above nominal for long periods, more than that for short periods up to three/four weeks. As Neil says, the state of charge after a decent race length is just the ticket, so don't worry about doing anything else unless you are hibernating them for the off-season when discharge to 3.7/3.8v per cell is the best policy. Getting them there at a high discharge current is not necessary, and may cause gassing and swelling that leads to early failure.

Stick to 0.5C as a maximum discharge rate and you'll have cells that last and last. HTH

[Aire valley]

Originally Posted by SlowOne

Over-discharging cells can cause gas build up that makes them swell. Research shows that LiPo/LiOn cell failures are usually down to the variability of the chemicals in them, the manufacturing process variables and the materials used. Variations in the thickness of the separators, the slightest burr on the metallic elements, and gas produced due to high current rates causes the cell to swell and change shape. That may activate the fault and cause a problem.

Store them at just above nominal for long periods, more than that for short periods up to three/four weeks. As Neil says, the state of charge after a decent race length is just the ticket, so don't worry about doing anything else unless you are hibernating them for the off-season when discharge to 3.7/3.8v per cell is the best policy. Getting them there at a high discharge current is not necessary, and may cause gassing and swelling that leads to early failure.

Stick to 0.5C as a maximum discharge rate and you'll have cells that last and last. HTH

That's brilliant...... just what I wanted to know....thanks....