Headway Pack Builders thread

The Mighty Volt said:
Also......{not @Scott!!!}......who make the best BMS to go with these Headway packs? Thanks.
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Travis (Frodus) and I are using the eLithion Lithiumate BMS for our builds, and I've got to say - it's pretty impressive. :D
 
scoot said:
I am definitely tired of pounding these out out in my strap factory :evil:
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Hey scoot... did you consider knocking together some sort of a "squeezer" to flatten them out, like a large-scale nutcracker design... not sure if there is a generic term for a device like this:
nutcracker.jpg


...with the right leverage... long arms on the thing... maybe?
Lock
 
From the page:

"There is approximately 200 lbs of lead added to the bottom of the battery box to make up for the lighter weight of the lithium cells. Some of this is visible in the photo below."

Yikes! :shock: I understand why they have to do that (narrow, non-tilting design) but man, that's like carrying an extra passenger (and not a skinny one at that!)..

Oh, and I notice they have the cool new "octagonal" (or are they hexagonal?) building blocks... I want those! Frodus my man, when is EVComponents going to get them? =)

Eric
 
haha, we got them in with the last shipment of headways.

The holders are red. They'll be on our website fairly soon.
 
Wow Travis... just noticed the headway cells from EVC jumped from $17 tp $19 each... bummer :roll: That must have been just in the last week or so, eh? :cry:
 
frodus said:
Its not a $2 jump, its only $0.30. We removed the 10% fee for customs/freight ($1.70).
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That's awesome... makes it less confusing overall. I have always had it in my head since my initial order they were about $20 a piece when the customs and fedex shipping were figured in.
 
voicecoils said:
frodus said:
haha, we got them in with the last shipment of headways.

They're red. They'll be on our website fairly soon.
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red cells? any special sauce inside? :D
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The battery holders are red, not the cells themselves.

Eric
 
Corrected to be more clear, sorry.

Blue cells still, red holders, but they're 3-cell end holders and fit staggered.
 
frodus said:
Corrected to be more clear, sorry.

Blue cells still, red holders, but they're 3-cell end holders and fit staggered.
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ah yes.... that's what I wanted to see.... that is, the staggered stacking aspect 8) . Does one still need to strip off the heat shrink on the + end to help avoid splitting these new cell holders? or, are they molded with a better cross-linked polymer?
 
Hi that's my bms capacity from bmsbattery.com

bms%20capacity.jpg


It 's connected to 16 headway 38120 10Ah
The charger is a 400 watt charger for lifepo set at 58,4 v
After 1 hour charging, cells in the negative pack side go in over voltage.
This cause stop and go the charger. It's impossible to arrive to 58,4v because other cells are at 3,40v.
More one goes towards positive and the voltage decreases.
First cell in negative side is 3,9v and last cells is 3,3v

Is this a bad BMS ?
Why does this happen ?
 
alex_audi said:
It 's connected to 16 headway 38120 10Ah
The charger is a 400 watt charger for lifepo set at 58,4 v
After 1 hour charging, cells in the negative pack side go in over voltage.
This cause stop and go the charger. It's impossible to arrive to 58,4v because other cells are at 3,40v.
More one goes towards positive and the voltage decreases.
First cell in negative side is 3,9v and last cells is 3,3v

Is this a bad BMS ?
Why does this happen ?
Click to expand...

If this is the first charge the cells could be several amp-hours out of balance. Limiting the charging current to the shunt capacity of the BMS (don't know what that is), e.g. through a 10 ohm resistor would keep the charger running until the the low cells catch up. That could take one or two days at 50 milliamps. To shorten the time, clip 10 ohm resistors across the high cells and let the charger run at its preferred current.
 
the cell that reads 3.9V is shutting off your charging FET by reaching the high voltage cutoff HVC which is why it doesn't charge anymore once you get that cell to 3.9V so you have to drain some juice off that cell with a small power resistor, i use 5W 5 ohm, it gets a little hot but it will allow the charger to turn back on and fill all the other cells too.
 
Looking for flat braided copper for my 72v build, to be use at < 50A max discharge. Found several on ebay... figure the NINCO with a width of 0.3937 inches will work ok, but how about the rest?
http://cgi.ebay.com/NINCO-80103-SUPER-RACING-50cm-COPPER-BRAID-/380213355835?cmd=ViewItem&pt=Slot_Cars&hash=item58867b653b
http://cgi.ebay.com/Belden-cable-tinned-copper-tubular-braid-ground-strap-/270574371686?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item3eff7d4366
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320517455963&ssPageName=STRK:MEWAX:IT

Basing Current estimation on this Table from the Alpha braid brand.
http://www.alphawire.com/Products/TubingAccessories/FIT-Wire-Management/Braid.aspx
 
I suggest that you consider copper /tin plated braid rather than straps. The straps transmit vibration from the car and when one cell moves ( and it will !) with straps the force goes right to the next cell etc. With braid the braid absorbs the energy. You used to be able to buy braid already made into custom lengths from aircraft electronic suppliers but haven't looked into this for years. I will do so now as i am making some packs in the near future as i think that a good home built pack is probably better than most commercially available ones. At least you will know what you've got! If you buy braid in long rolls it wouldn't be that hard to to add copper washers and then solder them to the braid, I am sure there are other ways to do this too.
ron the motorman
 
Hi All,

I'm currently modeling my future headway pack, but I am missing the dimensions of the headway "two cells" holder (orange).
Does anyone have the dimensions of this part ?
Or maybe a cad file of it ?

Any precisions are appreciated.

Thanks,
 
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