New prices for Headway cells!!!!

[auraslip]

price seems to be the number 1 priority for most of the HC LiPo flock

That doesn't even make sense to me. Headway p 8 ah cells are PRICED the exact same as hk lipo. And you only need a charger, and an inexpensive bms (compared to dedicated LVC and RC chargers). These are 10c cells, so at a minimum you're looking at a 80amps continuous. What ebiker needs more than that? If you do, your gonna need enough AH for range. That means a bigger pack which means 160amps continuous.
Plus lipo life cycle is 300-500, compared to lifepo4 @ 1000-2000. That right there should tell most commuters that lipo is gonna end up costing them 4 times as much in the end.

And that's not even counting the batteries you'll ruin with what ever handy made BMS you rig up.

Then again most of the LIPO guys, they take pleasure in handy rigging BMS and playing with batteries. Playing with different voltages does sound very appealing and I definitely share their enthusiasm for how powerful the stuff can be, but unfortunately not a similar bank statement.

[neptronix]

Erm, the price is quite different.. here is a comparison

for 36v and 10ah;
headway 10ah cell X 12 = $216
zippy/turnigy 5s 5AH 20c pack x 4 = $164.84

nominal/peak amps:
Headway pack : 50/100
Zippy/turnigy: 200 / 300(?)

Weight difference:
Headway 10ah pack = 302g x 12 = 3624g
Zippy/turnigy pack = 700g x 4 = 2800g

Cycle life:
Zippy/turnigy = 300-600 cycles our use
Headway = ~1500 cycles?

Size difference:
? ? ? i know the cylindrical cells here are gonna lose BAD for sure..

p.s. you could use a BMS with lipo as well.. or you could use a hobbyking charger on lifepo4.. so the cost of the external stuff is a bit questionable. Lipo chargers tend to cost more because the stuff is more high amperage. You won't be charging that 10AH lifepo4 pack at 30amps, will ya?

Yes headways are a better value, but they have their downsides. Discharge rating, weight, and size are what attract me to lipo. It is not all about cost or cycle life.

[auraslip]

Do you know of a BMS that works with lipo?

[neptronix]

Do you know of a BMS that works with lipo?

Yes, and reasonably priced as well.
http://www.all-battery.com/protectivepcbsforli-ionandli-polymerbatterypacks.aspx

http://www.tenergybattery.com/index.php?page=shop.product_details&flypage=shop.flypage&product_id=378&category_id=25&manufacturer_id=0&option=com_virtuemart&Itemid=27

^-- only bad part with these is that they allow discharge to 2.5v per cell.. not acceptable.. maybe fixable by changing resistors?

Other manufacturers also sell BMS's.. with an option to do lifepo4 voltage or lipo voltage.

[auraslip]

The tenergy one says it's charges to 4.35v per cell - that'd be very bad for the lifespan of a pack charging that high. Most people here charge up to 4 or 4.1. I think those BMS are designed for different chemistries. I think the goodrum fetcher BMS can be used with lipo, but you need to replace some resistors. I wonder why no one is doing that?

Btw here is what I got when I checked cell prices from my sources:

36v 10ah
headway 10ah cell x 12 = 192
prebuilt pack headways including 5 amp charger 36v10ah = 315
15c hk lipo 5s 5ah x 4 = 172
cost to take care of lipo = ???
cost of time to take care of lipo = ???
jk about the last one

All prices include shipping.

Btw you vast overestimated the headway discharge rate. IIRC it's more like 3.5c for the regular cells, and 8c for the P "power" cells. So 35 amps and 80 amps respectively.

But then again, if you are building a serious commuter bike, you'll want range. So if you get a 20ah or 16ah pack your continuous power rating is much higher.

[neptronix]

The tenergy one says it's charges to 4.35v per cell - that'd be very bad for the lifespan of a pack charging that high. Most people here charge up to 4 or 4.1. I think those BMS are designed for different chemistries. I think the goodrum fetcher BMS can be used with lipo, but you need to replace some resistors. I wonder why no one is doing that?

I suppose that most lipo guys like myself are hobbyists and don't mind a little bit of inconvenience. Me, i just chop off a bit of the top and bottom of my charge.

Btw here is what I got when I checked cell prices from my sources:

36v 10ah
headway 10ah cell x 12 = 192
prebuilt pack headways including 5 amp charger 36v10ah = 315

If you can get them for that much, they are a deal, although it sounds like you would be getting them from ev-assemble or something, which i would avoid like the plague.. erm actually maybe we shouldn't be talking headway prices, to respect the original poster.

Btw you vast overestimated the headway discharge rate. IIRC it's more like 3.5c for the regular cells, and 8c for the P "power" cells. So 35 amps and 80 amps respectively.

But then again, if you are building a serious commuter bike, you'll want range. So if you get a 20ah or 16ah pack your continuous power rating is much higher.

Ahh, all the official specs i've seen say 5c but i figured that was a bit high.
Yeah, 3.5c isn't bad if you have 16ah.
The problem with 16ah is fitting the damn things in the frame though.
Meanwhile i can fit 20ah 10s into my frame, no problem. And the packs are so narrow that they don't interfere with pedaling.

Too bad they don't make pouch cell headways..

[auraslip]

you would be getting them from ev-assemble or something, which i would avoid like the plague.. erm actually maybe we shouldn't be talking headway prices, to respect the original poster.

Yeah definitely from China. Definitely no recourse in the event of a bad cell/bms. Definitely not directly mentioning cell prices out of respect

The problem with 16ah is fitting the damn things in the frame though.
Meanwhile i can fit 20ah 10s into my frame, no problem. And the packs are so narrow that they don't interfere with pedaling.

That is the biggest issue with headway. I've gotte a 6" wide ping in my frame triangle, and it makes pedaling a pain. I'm upgrading to a 5.2" wide 72v headway pack of the 10ah cells. It should be an improvement, but we'll have to wait and see. I suppose a small 36v or 48v pack of the 16ah cells could be done lengthwise in the frame. A 72v 20ah pack would weight something like 38lbs I mean, I used to carry 40lbs of lead in my trunk bag.......and this would be in the frame.....I don't know how I feel about that

[neptronix]

That is the biggest issue with headway. I've gotte a 6" wide ping in my frame triangle, and it makes pedaling a pain. I'm upgrading to a 5.2" wide 72v headway pack of the 10ah cells. It should be an improvement, but we'll have to wait and see. I suppose a small 36v or 48v pack of the 16ah cells could be done lengthwise in the frame. A 72v 20ah pack would weight something like 38lbs I mean, I used to carry 40lbs of lead in my trunk bag.......and this would be in the frame.....I don't know how I feel about that

Geez, 6" wide? I figured those things were big, but.. damn!
My 10s 20ah pack is about 3" wide with the enclosure and weighs about 11lbs.
That's why i was willing to accept the downsides of lipo.

I can't imagine carrying anything over than 20lb, and i am sure 40lb was terrible O_O