Headway 48v 10ah - EVcomponents.com
- Thread starter Ypedal
- Start date
Notice Sandy in the background sticking her tonge out at the camera !
And well.. that kinda sucked....... 
Quote EVC :
" Built in BMS with max continuous discharge of 60a Max cutoff discharge current 100A "
Well, this is an e-bikekit.com hub motor in a 20" wheel with a crystalyte 35 amp analogue controller, shunt soldered for 45~50 amps on the Cycle Analyst meter..
This BMS does not automatically reset, it requires disconecting the wires and reconnecting.. 1st overcurrent cutout i reset and checked the MaxA value on the CA and it says 36 amps.
I then used up 0.3ah more and managed to cut out on command at low speed ( less than 20 km/h ), if i ginger the throttle to 25+ i can slam the throttle and peak at 50 amps for a moment and then * bzzt.. cutout.
Next step.. solder up the shunt ! :|
Quote EVC :
" Built in BMS with max continuous discharge of 60a Max cutoff discharge current 100A "
Well, this is an e-bikekit.com hub motor in a 20" wheel with a crystalyte 35 amp analogue controller, shunt soldered for 45~50 amps on the Cycle Analyst meter..
This BMS does not automatically reset, it requires disconecting the wires and reconnecting.. 1st overcurrent cutout i reset and checked the MaxA value on the CA and it says 36 amps.
I then used up 0.3ah more and managed to cut out on command at low speed ( less than 20 km/h ), if i ginger the throttle to 25+ i can slam the throttle and peak at 50 amps for a moment and then * bzzt.. cutout.
Next step.. solder up the shunt ! :|
Lessss
1 MW
I have a 40 amp circuit breaker on my headway pack. I've seen my analogue battery level meter sag like SLA when I crank that throttle with the headway pack. No CA or anything but I suspected that they weren't putting out 100Amp (prolly due to BMS). It works for my bicycle, whether or not it will work for your motor driven cycles in another question. Curious to know if they truly do 100 amp when the bms is bypassed though.
El_Steak
10 kW
Lessss said:
I looked back at the tests done by doctorbass last winter and the batteries would sag from 3.35v down to 2.95v with a 35amps load. Does that seem consistent with what you are seeing?
If they sag that low @35amps, I wonder what it would be at the max continuous rate of 60amps.
redorblack
100 W
- Joined
- Sep 26, 2009
- Messages
- 142
http://www.evcomponents.com/ProductDetails.asp?ProductCode=38120S
They are rating the cells at 5C continous, 15C pulse, the BMS is supposed to be 60A cont, 100A cutoff... which part isn't working to spec? Cells or BMS (sounds like) or both (very well could be).
Keep us informed please.
They are rating the cells at 5C continous, 15C pulse, the BMS is supposed to be 60A cont, 100A cutoff... which part isn't working to spec? Cells or BMS (sounds like) or both (very well could be).
Keep us informed please.
I"m confident the cells are good, this is a BMS issue i need to sort out..
Lesss, the voltage LED indicator on your throttle is not a good indication of operating voltage, the BMS won't limit the amps, it will simply cut out if you exceed it's limits. I suspect your controller is not drawing all that much power ! :wink:
Once i get at least dozen cycles on this pack at normal rates i can bypass the BMS and hook it up to the RC for a 100 amp test..
Voltage sag is proportional to amp draw, as long as the cells stay above 2.7v under heavy load they will do the job. 2C stuff can't maintain 2.7+ and get into the 2.5v and less quickly....
Soldering iron ON !
Lesss, the voltage LED indicator on your throttle is not a good indication of operating voltage, the BMS won't limit the amps, it will simply cut out if you exceed it's limits. I suspect your controller is not drawing all that much power ! :wink:
Once i get at least dozen cycles on this pack at normal rates i can bypass the BMS and hook it up to the RC for a 100 amp test..
Voltage sag is proportional to amp draw, as long as the cells stay above 2.7v under heavy load they will do the job. 2C stuff can't maintain 2.7+ and get into the 2.5v and less quickly....
Soldering iron ON !
sparky
100 mW
Ypedal said:
Ypedal... another question on the video (not pack related...sorry): Your throttle appears to have some kind of external sleeve thing that you're using as a cruise control. What is it? My thumb gets tired on my throttle and I have been contemplating something like this... Please inform --unless I'm imagining it-- thanks!
Good stuff on the pack! Keep at it!
My left hand is controlling the NuVinci shifter, throttle is on the right hand not visible in the video ( camera is mounted to my chest and i can't see the screen when recording lol.. ) I can keep the throttle pinned and adjust the gearing with my left hand, kinda cool to ride and takes no time at all to get used to.. never inbetween shifts the Nuvinci is always hooked up.
So i opened the lid again and this is the shunt before solder :
So i opened the lid again and this is the shunt before solder :
Attachments
Nope.. not gonna work.I can manage to get 2000w from it ( voltage on the CA 46.5v, but i'm sure the BMS is contributing to this sag ) .. this BMS is gonna have to go !
I see extra spots for more fets on the aluminum chunk, from the digital camera closup i can see that there used to be fets in there.... leaves me wondering what's up with that... :|
liveforphysics
100 TW
Heck yeah! Run the leads to the controller straight off the cells and watch that thing try to prematurely stop the power party
Good work Ypedal, and I bet running that CVT hub is a kick.
Good work Ypedal, and I bet running that CVT hub is a kick.
Doctorbass
100 GW
Ypedal, Could you measure the voltage on the neg wire between in and out of the controller ( the switched one) ?
It would be interesting to put a multimeter with Voltage Peak hold on that and to try a short ride at high power and then watch that recorded voltage drop and to compare with the C-A measured current.. then you could get the equivalent resistance loss across that BMS..
That could give you some answer about that voltage sag... I think that the voltage drop on the BMS in and out need to be checked.
Doc
It would be interesting to put a multimeter with Voltage Peak hold on that and to try a short ride at high power and then watch that recorded voltage drop and to compare with the C-A measured current.. then you could get the equivalent resistance loss across that BMS..
That could give you some answer about that voltage sag... I think that the voltage drop on the BMS in and out need to be checked.
Doc
Well.. after pondering my options a bit more, decided to have a look at the back side of the BMS...
Gotta love how the heat sink screws are stripped out, and that solder blob on one pad on the right seems suspicious, then the surface mount resistors between the fet legs on the left...
The Thermistor is inside a plastic sleeve, then on top of a G10 board, by the time this thing trips the cells are already in melt-down territory lol.. but the BMS won't allow that much juice to flow anyways so i guess it's a non-issue :| .
Gotta love how the heat sink screws are stripped out, and that solder blob on one pad on the right seems suspicious, then the surface mount resistors between the fet legs on the left...
The Thermistor is inside a plastic sleeve, then on top of a G10 board, by the time this thing trips the cells are already in melt-down territory lol.. but the BMS won't allow that much juice to flow anyways so i guess it's a non-issue :| .
thanks for the review. This is the pack that I'm looking at and was going to use a 35 amp controller too. Does evcomponents know about their crap BMS? I think we should look for ways to use lithium without BMS. A battery pack is only as good as it's BMS and that's a shame.
Lapwing
100 W
morph999 said:
The BMS seems to be the weakest link. Pretty much why Gary's open source boards are in such demand.
Perhaps in a few months when EV Components has the pick and place machines coping with the demand for there Zilla their might be a niche for a surface mount production version or two. I think that one BMS board aimed at A123-2.3Ah up to perhaps 15ah Headways and a second for the 40-200Ah Sky Energy bricks would sell really well.
There was talk some time ago of getting an open source surface mount version of the BMS designed. Anyone?
It might be fun?
46v at 46 amps ! and No cutouts this time !
Waiting for the rim to cool off so i can do this with my PSI pack for comparison.
Waiting for the rim to cool off so i can do this with my PSI pack for comparison.
liveforphysics
100 TW
Ypedal said:46v at 46 amps ! and No cutouts this time !
Waiting for the rim to cool off so i can do this with my PSI pack for comparison.
Right on
Running dirty LiPo style with the LiFePO4 I like it, and you are a user with the experience and skills to not ruin the pack from no LVC/HVC.
None of my personal packs have BMS's, but i monitor with care .. and accept the risks.. problem is that this pack was not meant for me, it was supposed to go into the hands of someone with zero E-knowhow...
With BMS removed, after my road tests and bms tweak testing, all 16 cells read 3.330v at rest.. all exactly 3.330 , i like !
edit : Oh !! and the PSI pack will hold 47v on the same 46 amps ! ( full 7 second count under load ), the psi are larger and have slightly more capacity than the headway cells so given C rate at capacity they are pretty much on par with eachother at almost 5C rate.
With BMS removed, after my road tests and bms tweak testing, all 16 cells read 3.330v at rest.. all exactly 3.330 , i like !
edit : Oh !! and the PSI pack will hold 47v on the same 46 amps ! ( full 7 second count under load ), the psi are larger and have slightly more capacity than the headway cells so given C rate at capacity they are pretty much on par with eachother at almost 5C rate.
Lessss
1 MW
like I said, no CA but I would venture yes.
northernmike
10 kW
Holy cow.
Would Gary's BMS work with this pack?
17*16= $272, I could do without the box and a useless BMS...
But I accept that my needs really DO include a "plug and play" charger..
Would Gary's BMS work with this pack?
17*16= $272, I could do without the box and a useless BMS...
But I accept that my needs really DO include a "plug and play" charger..
liveforphysics
100 TW
Garys BMS + headways cells = win. His new LiPo board is extra slick, and by changing a couple of resistor values it can be setup for LiFePO4.
