Headway. Which is it?

[tomjasz]

OK as I plan on another project I read all I can find on batteries. It seems Headway are a safe but expensive option. Some call them crap others claim longevity and reliability. Which is true? They surely seem easy to configure for a n00b.

 

[snowranger]

I got about 30,000 miles or around 1000 cycles out of mine. They are very durable but the large size and weight would be more suitable to a cargo bike that has the space to carry them.

 

[teklektik]

+1
Headways have a lower energy density than other contemporary options, but are certainly physically robust and offer very flexible reconfiguration options.

I have 9200+ miles and 320 cycles on mine and they run like the day I got them. I put them on a first build which was a 2WD cargo bike and frankly got them because they were a 'safe' proven product that would allow me to experiment with different voltages and Ah setups - and the weight wasn't that much of an issue. I tried 16s2p (not enough range), 16s3p (ample range - too much weight), and settled on 20s2p as a midway balance for range and weight.

My (much lighter) second build uses a custom NMC pack from EM3EV, which gives me exactly the dimensions and capacity I want in a lighter compact format. My big moose Yuba with Headways will still be truckin' when the NMC pack dies, but that's part of the tradeoff.

Leaning towards lighter builds, I can't say I would use Headways again, but for the cargo bike, the experiments I could perform, and their life expectancy, I don't regret getting them.

 

[chvidgov.bc.ca]

I like their reliability. I'm planning on using them to build a nice battery from my trolling motor. I've had no problems using them on a couple of ebikes for several years. Heavy though.

 

[tomjasz]

Looking for a weigh comparison. What would the Headways weigh compared to my NMC from cell_man in my sig?

Thanks

 

[tomjasz]

If you are interested for signed feedback there is no any.
Most young people seems to be willing to violate any law of physics, or manufacturer specifications, for a bit more pleasure regarding raised top speed.
Or they shown totally impassioned about charging their batteries at the suggested current by the manufacturer.
And some others do not use any BMS with those Lifepo4 cells.

Personally I am determined to play the game by following all rules, but my opinion is not here yet, it would come in some time.
http://www.ittsb.eu/forum/index.php?topic=963.0

Thanks! Nice build! I also like the Piaggio. I sold Vespa GTS 250 to build two EBikes.
I like batteries inside the frame better than on rear rack.

 

[dnmun]

Looking for a weigh comparison. What would the Headways weigh compared to my NMC from cell_man in my sig?

Thanks

lots heavier. not twice but seems like it, maybe 40% more.

 

[tomjasz]

FWIW interesting read and results.

http://endless-sphere.com/forums/viewtopic.php?f=14&t=41877#p612317

 

[Ykick]

FWIW - use careful torque measurement(s) on headway screw terminals or at least don't over do it. I've had a several HW cells which failed and was told by headway users it was likely my assembly which caused the failure. I dunno, 'been tightening screws all my life and don't think what I did was excessive???

I still have an old 4S1P HW block which I use for 12V auto accessories but that's about all that's left from 12qty purchased back in the day. But as already stated, not much, if any, size/weight advantage, IMO.

RC Lipo is scary but with qualification, monitoring and BMS I think they're reasonably safe while providing large amount of power in small size/lightweight package. ANY battery pack carries fire potential. Simply the nature of pushing large Amps in/out on regular basis...

 

[dnmun]

FWIW interesting read and results.

http://endless-sphere.com/forums/viewtopic.php?f=14&t=41877#p612317

this was chroot's fire. in the end it was obvious that the positive wire to the battery from the charger shorted out to either the frame which was shorted to the negative wire of the battery or it shorted to a wire inside the BMS.

none of the headway cans actually burned, the shrink wrap melted off from the heat of the fire caused when the nylon bag that chroot had his battery in caught fire and burned. you can look at the pictures and see that none of the cans vented solvent that caught on fire.

 

[tomjasz]

I read the thread rather carefully and it was obvious from lien and one other that having the cans rub has or can also be a problem. While your conclusion seems to be correct there are other build factors that seem to be worth noting.

Thanks

 

[dnmun]

those cans did not rub together because he used the plastic end holders. you can see the orange color, and those end holders are mostly what burned along with the bag to make so much soot.

you can see it burning still in the picture because the cells are most probably still red hot from discharging the entire charged battery into the short.

the short had to bypass the BMS too or it could never have created so much current.

 

[tomjasz]

Jeez, I didn't say they did, but again, several have pointed out that touching CAN be a problem. No?

For anyone using the Headway battery, I would recommend to verify the blue coating of the cells to ensure they are intact.


Regards,
Lyen

for the reason Ed Lyen has given, the metal connecting straps being slightly too tight and allowing two cell cans to be in contact.

I hate the plastic film on cells like this, as it isn't very abrasion resistant and it causes a cascade failure when there is a problem. If a small short developed between two cell cases, caused by a bit of wear from vibration, then the resulting heat would cause the insulating film to shrink and expose a greater area to short, which in turn causes more heat and starts to shrink back the film on adjacent cells, creating a cascade failure.

I had exactly the same thing happen to me with some film insulated NiMh cells in my very first ebike back. A single cell cooked (my fault - I over charged it) and that then damaged the insulation on several surrounding cells, creating a similar fire to this one.

Perhaps one thing to learn from this is that even an outwardly very well built battery pack has the potential to catch fire, no matter what the chemistry. Personally I prefer cells that have cardboard sleeves (like the older Headway cells) as these are less likely to fail in this way.

 

[dnmun]

of course, but i was sticking to the true facts about that fire. it was not caused by the case shorting between individual cans.

it is possible that the positive charging lead to the B+ spot did rub through the plastic sleeve of one of the cells where it ran out of the bottom of the battery bag over the rear stay where it appeared to have shorted. or it could have shorted to one of the copper connecting bars. but it was a good enuff short to melt the tips of the individual conductors like that and then it could have continued producing high, but not full short level currents after the initial fireball since the weight of the pack in the nylon sack kept pushing the shorted spots together on that rear stay. that would have allowed the remainder of the stored charge to continue heating that wire until the nylon ignited.

 

[tomjasz]

of course, but i was sticking to the true facts about that fire. it was not caused by the case shorting between individual cans.

And I'm still learning and the bits that were guesses and proved wrong, in this instance, still hold some relevance and are worth noting in the process of learning about this battery option. Which is why I started this thread. Not to rehash the particular thread, but to learn more about using Headway kits.

Thanks for the input.

 

[dnmun]

it helps for others to read it too. so many people think the batteries will just explode spontaneously when they are charged up, but they never focus on the fact that many if not most fires are caused by shorts.

shorts in the sense wire harness on the BC18 charger fires, and shorts in the parallel wires on that lipo pack in the longboard on that other thread, i have melted the insulation off of 10AWG cable before i could cut the wire when it shorted, so hot it melted through the sense wire insulation on the battery, so i know shorts can happen.

i think after chroot's fire i kept recommending people use a fuse right at the battery for that red charging wire. in a way it is more useful on the charging lead than on the discharge because the BMS will turn off the battery if it shorts normally through the output.

 

[tomjasz]

Thanks Kiriakos. I had hoped to take an electronics class this year but I could not. I will in the future. In the meantime I appreciate all the input and the feedback from reposting and visiting old threads. I have learned to take things slow and learn before jumping in. It appears that since Headway sells cases for their sells without the plastic dividers that something has changed or improved since the fire thread and the comments by Lyen and others regarding chaffing of the plastic body.

 

[tomjasz]

It appears that since Headway sells cases for their sells without the plastic dividers that something has changed or improved since the fire thread and the comments by Lyen and others regarding chaffing of the plastic body.

Dear friend I will have to strongly disagree, the outer metal of these cells is electrically active, one layer of thermoplastic around them is all that they have as isolation so no electrical contact to be made among them.
While the thermoplastic layer protects the cells regarding safe handling by the people, the plastic spacers is a definably a must to use method.
In the Hedway rear rack, the cells are separated by special isolation carton, and the carton is hot glued between the cells.

Both methods offer superior protection.

In power tools with Ni-CD cells, its one cell has a sleeve of carton around it.
If the large Headway cells was have such a sleeve? They will look like been dressed up with a carton tube coming from a toilet paper. :lol:

When I looked at your build I missed the protection around the cells you speak of. I must look again.

 

[dnmun]

some people who build packs with the headway 38120L style will use double stick foam tape about 2mm thick and apply the short strips about 8mm wide of this double stick foam tape in the spots where the cells make contact in the close packing form. then the tabs are spot welded to hold the battery in that fixed position. it is effective and cheap. you could do the same with the screw tops if you used a solid wire between cells so they would be rigid, and soldered the wire to the ring connector under the screw to make the electrical connection. i used construction adhesive, like the stuff used to glue the flooring down, the 4x8 sheets of flooring. i put a bead of construction adhesive along that close packing contact surface and put all 12 cells together, glued in two rows as 12S.

anyway that pack is solid as a rock. and the construction adhesive provides insulation at the contact surface. so the square blocks are not needed. i have a 48V20Ah headway pack that is all plastic end caps, with spot welded tabs. it is easier to remove a cell, but that is not something you do with those cells often.