# Headway high power lifepo4 cell - LFP38120HP (HW38120HP)



## Headway Headquarters (Nov 25, 2010)

Hello Pawiel,

Although my experience with them may be slighted, I think that they are great cells and are capable of specifications that are provided. Here are some tests that I completed using a 4S1P set-up for pulse discharge capabilities. Wanted something else to go off of, other than marketing materials and what was produced by the factory. 

Hopefully others that have had experience with these cells will post!


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## rwaudio (May 22, 2008)

Pawiel said:


> Hello.
> 
> Last time I was looking for opinion and info about A123 20Ah battery.
> Few weeks ago I saw an interesting cell (because of high current rate and probably good life-time).
> ...


I've tested the 10Ah non power version of that cell. It's the same physical size but higher capacity and lower power. Performance was decent but nothing compared to the A123 pouches. A few people have made car size packs out of Headyways, but again I'd choose CALB CA instead (I believe that the people who have done Headway would also recommend CALB CA instead). I still have a 4S2P pack that I use for a 12v battery here and there. I've used it to jump start half a dozen gas vehicles and other random uses when I need a small 12v battery. I would consider them for an electric pedal bike, or small motorbike/scooter but I wouldn't put them in a car. If you go WAY back in my blog you'll find my testing on them.


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## Ampster (Oct 6, 2012)

I have also used the 10 Ahr version on some electric bike conversions. 
I used Winston 90Ahr cells for my VW conversion


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## Pawiel (Sep 15, 2013)

rwaudio said:


> A few people have made car size packs out of Headyways, but again I'd choose CALB CA instead (I believe that the people who have done Headway would also recommend CALB CA instead).


Thanks for an answer.
I must ask you why you would chose CALB CA instead?
Discharge current recomended for that cell is 0.3C (continious). So, you shouldn't get much current from that cells (for a long period of drive).
Headway's max discharge current is 3C continious, lifetime is also 1500-2000 cycles. 
Are Headways generally not recommended for EV? Maybe cycle-lifetime is not the same as said in Headway's datasheet?

So, why you are saing that Calb is better?
Maybe energy density is quite good for the battery price or weight?

Greetings and nice weekend!


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## Ampster (Oct 6, 2012)

For me, the Winstons were cheaper per kWhr and required less assembly. I have returned to my bike project and the Headways are great for configuring a pack into a bike frame.


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## rwaudio (May 22, 2008)

Pawiel said:


> Thanks for an answer.
> I must ask you why you would chose CALB CA instead?
> Discharge current recomended for that cell is 0.3C (continious). So, you shouldn't get much current from that cells (for a long period of drive).
> Headway's max discharge current is 3C continious, lifetime is also 1500-2000 cycles.
> ...


Probably the biggest thing is actually testing the cells. Use manufacturer specs as a guide to help you narrow down cell selection, then test them with your own two hands. The cell that comes out on top in your mind for your application is the cell to buy.

Some chinese manufacturers underrate their cells in some areas. why? because even if the the normal cells drastically outperform this spec the not so good cells do too. What does that mean? No returns, no warranty claims, even an under-performing cell will often exceed published specs. I have a single CALB 60 with self discharge, all other cells in my pack can sit for 3 months with no noticeable decrease in SOC, that one cell does have a noticeable self discharge of approximately 1% per month, the others are so close to zero it's negligible. However 1% is less than the 3% published spec so the cell is just fine and CALB or any company of this type will not replace a cell that meets spec. The cell is no good to me, in a bottom balanced pack it's out of balance in a month, if you had a top balanced pack, it would probably work as all of the other cells would be shunting and it would probably put enough energy back in this cell to keep it up with the rest from cycle to cycle as long as the car didn't sit for long periods of time.

In the real world Headways perform well, they are a good cell, the 10Ah cells aren't quite as good as CALB CA's the 8Ah power cells might be slightly better than CALB. So given the extra cost, the cost and complexity of pack assembly I'd rather just step up to the next cell size and probably come out cheaper in the end anyway with the same power and more range.

A123's are very good, but the quality control was crap, the cells are hard to use, so again in the real world even though the specs are very good, it's not a practical cell to put in a street car.

For racing the rules change a bit, weight and power is critical so the design choices would be different.


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## Pawiel (Sep 15, 2013)

rwaudio said:


> Probably the biggest thing is actually testing the cells. Use manufacturer specs as a guide to help you narrow down cell selection, then test them with your own two hands. The cell that comes out on top in your mind for your application is the cell to buy.
> 
> Some chinese manufacturers underrate their cells in some areas. why? because even if the the normal cells drastically outperform this spec the not so good cells do too. What does that mean? No returns, no warranty claims, even an under-performing cell will often exceed published specs. I have a single CALB 60 with self discharge, all other cells in my pack can sit for 3 months with no noticeable decrease in SOC, that one cell does have a noticeable self discharge of approximately 1% per month, the others are so close to zero it's negligible. However 1% is less than the 3% published spec so the cell is just fine and CALB or any company of this type will not replace a cell that meets spec. The cell is no good to me, in a bottom balanced pack it's out of balance in a month, if you had a top balanced pack, it would probably work as all of the other cells would be shunting and it would probably put enough energy back in this cell to keep it up with the rest from cycle to cycle as long as the car didn't sit for long periods of time.
> 
> ...



Excellent answer!
Thanks!


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