Headway 40160S LiFePo4 Questions.

So,

I recently noticed the Headway 40160S LiFePo4 cells at EVassemble:
http://www.evassemble.com/index.php?main_page=product_info&cPath=2&products_id=151

And they claim 16Ah and a max discharge of 160A !

I'm after a 16-20Ah 36V pack that can handle about 80-100A Continuous and around 160-200A Peak (for at least a few seconds).
After seeing the above Headway 40160S specs I am starting to question my Lipo purchase.

I'd like to know what BMS can be used with a headway pack and still allow 5C continuous 10C burst rates.
(I read that 40160S 5C continuous and 10C burst on another site... which tells me the EVassemble spec of 160A is a "burst" spec)

I also noticed that Evassemble sells some cheap 35 dollar 5A chargers for LiFePo4 36V packs... which would be fine for me since I don't mind plugging in a LiFepo4 pack for a few hours.

Just FYI, running a cell at it's rated discharge constantly will result in quite a bit of voltage sag.
These cells may do 5C and short bursts of 10C, but if you run them at their limit constantly, they will have a short life. Remember, those 1000+ cycles are at a 1C draw ...

I would recommend nothing short of lipo or A123 for what you're trying to do.

I'm mainly switching from SLA for weight savings, the pack-size of LiFePo4 wasn't such a big deal to me, but the limited C rates were.
But if I can get a 5C 10C "burst" LifePo4 pack then I think that would work well for me. I wouldn't mind a life cycle of only 500. (assuming that's about what it would be if you run the limits of the LiFePo4's ??)

I also like that I can potentially get a cheaper battery system since I could run a cheaper charger on those LiFePo4 packs. And wouldn't have to mess with wiring up a Mean Well to a Hyperion to a Single-Plug adapter. (all of which are currently sitting on my desk already!)

You would really need to have a good size headway pack ( how would it fit on the bike, lol.. ) to comfortably output 100 amps constant. 30AH would deliver up to 300 amps, and you'd use a third of that, so i think that would be a pretty good rate.

15ah of cheap 20C lipo can do that too though, and take a hell of a lot less room.

p.s. evassemble is a pretty bad company to deal with from what i have read on the forums.

neptronix said:

You would really need to have a good size headway pack ( how would it fit on the bike, lol.. ) to comfortably output 100 amps constant. 30AH would deliver up to 300 amps, and you'd use a third of that, so i think that would be a pretty good rate.

15ah of cheap 20C lipo can do that too though, and take a hell of a lot less room.

p.s. evassemble is a pretty bad company to deal with from what i have read on the forums.

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Then I guess I'll just stick w/ a 20Ah 36V Lipo Pack, I just don't want these things to burn down my apartment. Since I don't have a garage (and I don't want these things outside) it would need to be stored inside. I'd also like to keep the pack permanently attached to the vehicle, so 'visual inspection" would be a pain.

If you're using 10S 20ah, you are talking to the right guy



Inside falcon EV bag. ( just took this shot )



Inside Topeak rear bag ( i like this method since it's clean, but bounces around too much )





Center mounted 30 caliber ammo box ( this didn't work out so well, mounting style needed improvement but i just gave up on it. )

I don't have a garage either. I am in an upstairs apartment these days.

Another option is the 20AH A123 cells. Spendy ($45-$50 before shipping ea.), but they will do what you want for sure.

thanks for all the pics.

Have you or anyone else here used the Flat LiFePo4 packs that HK sells:
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=17823

*they even sell them from the USA warehouse !

oh, and yeah... thats my exact set-up. I purchased one extra (9) in case a Lipo showed up bad.
Edit: I purchased Turnigy from the USA warehouse

The lifepo4 has a bad defect rate according to reports, and also does not live up to it's discharge claims whatsoever.

OK, going back to the Headway 40160S LiFePo4 cells:

Can someone please show me a BMS that allows you to use the full 5C and 10C "burst" ?
It seems the BMS's offered on the site bigtime limit the current.

Thanks.

EBJ said:

OK, going back to the Headway 40160S LiFePo4 cells:

Can someone please show me a BMS that allows you to use the full 5C and 10C "burst" ?
It seems the BMS's offered on the site bigtime limit the current.

Thanks.

Click to expand...

I'm Michael from EV ASSEMBLE.
Actually 10C is official specification of Headway. But there is not Data about cycle life V.S. C rate in high C rated.
So 5C continuous and 10C"Burst" will be the max we suggest to use. Better we can use high C rate sometimes but not always.
1500+ cycle life is 1C 80%DOD test report. 80%DOD means charge batterie again when 20% energy is left in cells.

When the batteries are new, use it in no more than 2C rate first. This is for synchronization and homogenization. Especially when the battery pack have a BMS system. This is a advice to all LiFePo4 or Li ion. No mater you use Headway TS or others.
Our cells are in stock, delivery is very fast. Check items page and there is shipping time. Right now we make everything more transparent so that no doubt will happen again.
Right now, we have a BMS connection diagram with large details so right now no longer anyone will make a wrong connections. Also some customers have made a thread about performance of the BMS which you can see what a good performance our BMS will be. If anyone want to make test for everyone here, contact me.
I strongly recommand Spacey to take one from us for test. I will like to make it all in our cost.

neptronix said:

The lifepo4 has a bad defect rate according to reports, and also does not live up to it's discharge claims whatsoever.

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david, it would help if you can document this. i consider the defect rate on the headways to be essentially zero.

i just read that someone has just twisted off the negative terminal on a headway cell they bot from michael, but it was not defective, they just used improper connections leading to damage of the cell terminal.

most of us consider the headway to be the best cells available for the money.

Right now, we have a BMS connection diagram with large details so right now no longer anyone will make a wrong connections. Also some customers have made a thread about performance of the BMS which you can see what a good performance our BMS will be. If anyone want to make test for everyone here, contact me.

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Well that diagram took many months to appear on your site after you had sold me several BMS's, I asked you 3 times for support with my wiring. All I actually asked you for was conformation that my wiring was correct, I even supplied you with all the details.

You refused to send me the wiring diagram, I asked you over and over for the wiring diagram.... you replied but only to say that these BMS were different. I believe that at the time you did not know yourself how these BMS were wired.

When a customer asks for support you give it, when a customer who has spent thousands of dollars with your company asks for support you damn well give it..... or at least have the correct instructions on your site.

I strongly recommand Spacey to take one from us for test. I will like to make it all in our cost.

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I strongly recommend that you blow it out your a*se I would not deal with you again if you were the last ev seller... luckily you are not the only one. Customer service and support is very important, I give it to my customers regardless.

Anyhow, Headways are good cells if you use them at about 3C continuous. They will sag a bit compared to Lipo and are a bit heavier but are sturdy good cells for the money.

5C is really pushing it on these cells.

Sounds like I just need to "man-up" and go with the Lipos that I already purchased.
There is a lot of good info on here about them, I'm just hoping with the proper care they don't explode.
haha.

dnmun said:

neptronix said:

The lifepo4 has a bad defect rate according to reports, and also does not live up to it's discharge claims whatsoever.

Click to expand...

david, it would help if you can document this. i consider the defect rate on the headways to be essentially zero.

i just read that someone has just twisted off the negative terminal on a headway cell they bot from michael, but it was not defective, they just used improper connections leading to damage of the cell terminal.

most of us consider the headway to be the best cells available for the money.

Click to expand...

I think he is talking about the HK- LiFePO packs. They aren't worth the money.
-Olaf

Headways are pretty good cells I think if you don't need more than 30amps discharge. Proper A123 packs like from Cellman would be better though.