The LiFePO4 Headway cell 38120P TEST REPORT inside

How come this, very useful, Headway thread has been taken over by bloody LifeBatt?

A few of us on here have purchased Headway cells without a hitch and at a heck of a lot lower price than LifeBatt cells, even taking into account the group buy of surplus cells that is currently underway. My 40Ah, 48V Headway pack is specced to meet my needs comfortably - I don't need the extra that LifeBatt might give. Just how much more would 64off, 10Ah Lifebatt cells cost me, delivered to my door, with taxes, here in the UK? I'm guessing that the price would be about double, even at these supposed group buy rates.

We have a free choice as to what we buy, in my case what I'm doing is probably a bit like the stuff many others are doing here - it's a bit of an experiment within a fairly tight initial budget. I can't see the merit in risking really expensive cells on a proof-of-principle project, others may take a different view. If it works, then I may invest in better parts, but you can be assured I will not, ever, buy LifeBatt brand cells, just on a point of principle.

As I've said before, nothing pisses me off more than a pushy salesman, in fact I simply never buy ANY product that is advertised in this aggressive way. I far prefer the quiet, honest and straightforward way many other sellers advertise their products, and am more likely to buy from someone who doesn't push the supposed benefits of their product over the opposition with such relentless fervour.

Jeremy
 
I agree Jeremy. Leave Headway be Don, theres no need to fight. You wouldn't like it if A123 did the same to you! Headway are alot happier to sell to us guys than lifebatt are too it seems, and Victoria is actually pleasant to deal with too!
Steve
 
Jozzer said:
I agree Jeremy. Leave Headway be Don, theres no need to fight. You wouldn't like it if A123 did the same to you! Headway are alot happier to sell to us guys than lifebatt are too it seems, and Victoria is actually pleasant to deal with too!
Steve
Is this Victoria's contact: chcj55 [at] hotmail.com ?
 
The email address I have for Victoria is chcj55 (at) gmail.com, rather than hotmail.

Jeremy
 
I believe she uses the hotmail address for chatting on MSM with customers. (nice service!)
 
Heres a pic that Victoria sent me recently..
 

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Has anyone tried there smaller sized batteries similar to A123/emoli?
found this -
http://headway-cn.en.alibaba.com/product/0/201274488/Others/26650_2200mAh_high_power_lithium_ion_battey_cell.html

nice to get there bigger ones but it won't fit in my battery slots.
 
noob question...

what happens if you over discharge the 38120L at 60Ah continuous, will it burst or just shorten its life cycle?
 
olaf-lampe said:
Thanks for the picture, but I was talking about the new tabs on the "L" types. There seems to be a knob or something on top and bottom. Is there a thread in it?
I'm also interested in them (38120S):

38120l10ahlifepo4lithiubt4.jpg


shinyballs said:
Has anyone tried there smaller sized batteries similar to A123/emoli?
Apparently getadirtbike uses them in his LiFePO4 packs. I'd say they'd be much the same as the larger format.
 
Well, I ordered a hundred of the 10AH cells a couple of days ago and got a significantly better price than expected..... And considering what seems to have happened with the yahoo LiFeBatt group buy, that may have been a good decision.
 
If the "s" model is indeed a screw terminal version I want to get some of these also. Can anybody confirm or deny that this is the case yet??
 
Looking at the photo, the only thing I can think that those "tabs" could be are screw terminals.

I don't think Headway have released any more information at this point, though.
 
headway said:
vanilla ice said:
Thats what I'm thinking too. I emailed them asking this, but have no response yet. I'll post if I hear.

Yes, they have screw terminals, which will make the connecting of many cells for bigger packs.

Victoria

Dear Victoria,

thats what you answered me to this question:

The tabs of our cells just make the welding easier for connecting of the cells into big packs.

I'm confused...
-Olaf
 
This is what Victoria emailed me about the screw terminal cells-

"And here I'd like to inform you very honestly, at present we don't make mass production yet, it's still on trial production. Next month, we will make mass production for such cells when the testing is good."
 
Well, test run or not I've just received 100 of the 38120L 10Ah cells. From a random sample of a dozen or so each cell read 3.330V +/-0.002V max, most read 3.329V. 8)

Total cost came to £11.56/cell (~$23).

I'll post pics when I start building the packs up.
 
These are just the bare cells I got today, no tabs, no screw terminals. Will definitely post progress reports, I just need to get a CA now (when funds become available) so I can have a better idea of how these cells fare.

I can't wait to increase the range of the moped from the measly 10miles at present to hopefully something more like 50.
 
olaf-lampe: there are two cell types, the 38120P (8Ah) and the 38120L (10Ah).

See the zeva report. I don't have the kit myself to do accurate capacity tests (yet).
 
I know.
The headline says 38120L report. So I could expect 10Ah.

See yourself in the answer from ggracer

http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=5056

Just some numbers of the first cycles from that sheet:
I'm not sure if these numbers are alternating charge/discharge capacities because every second number is 8.5Ah ish

Final capacity Ah

11282.26

9091.105

8899.135

8842.834

8598.087

8872.718

8531.143

8861.885

8542.537

8864.274


-Olaf
 
That apparent 12-15% drop in rated capacity after half a dozen 0.5C discharge cycles is rather shocking! If it does turn out to be the case then I dont think I would have bought these cells. :? Maybe shallower discharge cycles will help to maintain capacity for longer??

Anyone in the UK got a battery analyser who wants to test a couple of cells?
 
olaf-lampe said:
I'm not sure if these numbers are alternating charge/discharge capacities because every second number is 8.5Ah ish

Final capacity Ah

11282.26

9091.105

8899.135

8842.834

8598.087

8872.718

8531.143

8861.885

8542.537

8864.274


-Olaf

Original datasheet:
http://www.endless-sphere.com/forums/download/file.php?id=11064

0.5C discharge capacities:
1. 8842.83
2. 8872.72
3. 8861.89
4. 8864.27
5. 8851.3

1.0C discharge capacities:
6. 8711.71
7. 8694.98
8. 8733.99
9. 8745.03
10. 8739.4
11. 8740.14
12. 8716.67
13. 8717.19

@flip_normal
That apparent 12-15% drop in rated capacity after half a dozen 0.5C discharge cycles is rather shocking! If it does turn out to be the case then I dont think I would have bought these cells. Maybe shallower discharge cycles will help to maintain capacity for longer??

These results are not so dramatic.
Both at 0.5C as well as at 1.0C rates the capacity is almost flat for few cycles.

1.0C discharge capacities after 700 test cycles done:
706. 7550.46
707. 7545.06
708. 7544.66
709. 7538.86
710. 7533.47
711. 7539
712. 7544.49
713. 7550.23

So after 700 cycles we see 1160-1200 mAh capacity drop = 13% drop.
It is not bad.
But ...
we still dont know what the temperature was for all these cycles.

What would hapend if the ambient temperature will be 10'C less or 10'C higher ?

We should also to know test results for 2C and 3C discharge rates as well.
As long as these cells are 5C rated.

It would be good to know discharge results for 1C, 2C, 3C rates at ~80% DoD . This mean 7000mAh-6000mAh discharge at 1C rate for first 700 cycles.
 
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