Headway life cycle

[CroDriver]

So, for how long do you have your Headway cells? How many cycles have you in them so far? How do you charge and discharge them (to what SOC, C-rates, with BMS or not etc.)

 

[deardancer3]

So, for how long do you have your Headway cells? How many cycles have you in them so far? How do you charge and discharge them (to what SOC, C-rates, with BMS or not etc.)

Not enough cycles to be meaningful, maybe 50.

A Headway 8s2p 24v 20ah screwtop pack wrapped in lots of closed cell foam.. the pack is charged using the BMS; discharge -no Bms just a low voltage light and a 30 amp fuse that the system has never caused to blow. I dont think it has ever been discharged more than 50%. When I got the pack, I manually balanced all the cells and made sure all the screws were tight.

I have possessed my Headways for about 9 months. Been using them about 4 months, I charge with the stock 2 amp charger but tweaked up 1.5 volts. the load is a 360w Cyclone that I doubt ever draws more than 20amps for more than a few seconds.

d

 

[RPA]

I'd like to know the same information. I'm only on my third cycle on a 29s2p 38120S pack. I'm just breaking them in now. Right now I'm charging them all at about 1.5A manually until I get the BMS working. I've been discharging to around 2AH per cycle. I'm limiting the current with a CA to 20 amps. Very impressed with the cells so far. They've been staying within .002V of each other.

 

[adrian_sm]

Here is my data:
http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=14528

Pack seems like new to me.

I am more intrested in how much voltage sag people are seeing under load. Mine seems alot more than what the spec sheet would suggest. Can the BMS cause a big drop in addition to the cells?

- Adrian

 

[RPA]

So far the max current I've pulled from the pack is 38A. I had about a 4 volt drop at this load (3.8C).

 

[Mark_A_W]

Here is my data:
http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=14528

Pack seems like new to me.

I am more intrested in how much voltage sag people are seeing under load. Mine seems alot more than what the spec sheet would suggest. Can the BMS cause a big drop in addition to the cells?

- Adrian

As we discussed, my 20 cell pack (64v nominal pack) will sag to 55v under a 35-40A load straight off the charger.

That's 2.75v per cell.


It pretty much seems to behave this way until at least 6AH is used.


Most of the cells are 18 months old, the original paper 10Ah cells, however 5 are newer blue wrapped cells. Done about 6000k, or about 400 cycles.


I still get 9Ah out of them, which is all I ever got.