GT i-drive 2.0 Build

[GCinDC]

good fun:

[ambroseliao]

If you listen with headphones, you can hear his heart beating. Very cool!

[GCinDC]

hey guys, have you seen this?
count the number of tear-offs (as in goggle lens tear-offs)

fyi: 5.10 / Danny Hart: Hart and soul Trailer
gotta love the comments, too:

hart_unstoppable_with_mullet.jpg (13.91 KiB) Viewed 764 times

[full-throttle]

Yeah nice mullet

mullet.png (221.04 KiB) Viewed 728 times

Here's another vid that's too good not to share

[Sacman]

Here's another vid that's too good not to share

Wow! I've seen many vids of guys doing bike tricks but they were all BMX or MTN bikes.
This is the first I've seen where a rigid, carbon fiber ROAD bike is used.

[GCinDC]

so i'm back on the idrive this week, since the dh comp is in repair. such a different ride. so high up now! tighter suspension..

anyway, i had a long errand after work yesterday and had to ride 21 miles! and without a CA!

i was late for an appointment at the end, so i got a good workout, going on speed 1 (15mph max) most of the way. considering normal driving uses about 1 to 1.5Ah per mile and the old pack had maybe 8Ah tops, i was asking a lot, pedaling hard, knowing i could hit the cliff anytime...

thankfully towards the end, i remembered that i had my lipo buzzers which hooks up to the pack db25 and it alerted me in the last 1/2 mile that one cell was hitting 3.2V under load.

that pack always had a runt cell, so i wasn't terribly surprised, and my balance charge cable hasn't been working, so it hasn't been balanced since 2011.

here are the no load voltages at the end:

unbalanced_cells_after_700cycles.jpg (52.29 KiB) Viewed 499 times

and here's the video, fwiw, from which i got the numbers:

i think cell in the top left pack is the runt, and it'll be interesting to check the IR of cell 4 from the other packs.

why are they low? do they coincidentally happen to be runts in their cell groups?

or have they been working extra hard to balance up the runt from the topleft pack, and are consequently overworked? what's the explanation? i sort of figured that when cells were paralleled, they'd balance themselves out?

i kinda expected the runt would be in the top right pack, which looks likes it's been getting poked by the locknut!

i think this dent is somewhat recent, the pack may have gotten mishapen recently. anyway, they may be tougher than we thought..

after 3.25hrs on the balance charger (set to charge up to 4.2v/cell):



after 4.5hrs on the balance charger:

[methods]

FYI: I recently found that my iCharger was off by 40mV on one channel. Not that I think this is what caused your runt situation, but I suggest carefully calibrating your iCharger channels. The calibration routine is posted in the maga RCGroups iCharger thread.

In my experience when a group of parallel cells all show low capacity (like your runt cell) it is because at some point a single cell failed and after that the parallel group of 4 was driven down deep past 3.0V when the pack was not being monitored for cell level LVC. This happened to two packs we recently built here (that were not running cell level protection)

-methods

[GCinDC]

thanks, methods. i balance charge other packs with the icharger and haven't noticed a difference, but will pay closer attention to that.

isn't another sign of a runt that when hooked up to a charge, the runt cell's voltage will rise quickly, comparatively quicker than healthy cells? why is that, just out of curiosity?

it should be noted that under load, it dives far lower as well, so just doesn't seem as stable anymore.

i'm afraid these cells have seen the mid to high 2V's once or twice, or three times, from lack of protection and lazy monitoring...

[methods]

Low capacity or high internal resistance.

Higher internal resistance
Drive a current into it and it will show a much higher dynamic voltage (I * R = V)
Pull a current from it and it will show a much higher dynamic voltage drop as well

Same would happen for a lower capacity...
Cells would climb faster and drop sooner

Oh well... anyone who is serious about ebikes has piles of lipo around that has been abused. All of my lipo has seen 2V at one time or another Dont you hate that 45min push home just *knowing* your cells are sitting at 2V? Arg... I dont miss those days.

For real bro... test your iCharger channels with a Fluke. You may be surprised.... mine were WAY off and from what I understand that is somewhat normal for older units. Check it.

-methods

[GCinDC]

thanks, that helps my understanding. i always think chemistry and forget math.

so what fluke would i need? most cost more than the icharger ..

and while we're on the topic of IR, is there any reason i would not be able to measure the IR of my whole pack, reconfigured to 5s8p? i tried this and blew my last icharger, but i probably screwed up, since i seem to recall that several cells displayed 0 mohm and one had an impossibly high number... perhaps i connected the leads in 20s... ?

ps. did i also read somewhere that there's a little deviant method in the oven? if so congrats. i always buy a bunch of stuff for my own projects to compensate, so 5 cromotors seems like a good start.

[Skippic]

I say, if you have a couple of bad packs, just throw them out or replace them. I read lipo fire is nasty stuff!

[GCinDC]

how bout you come over and we do some lfp tests to smoke 'em in the alley?

i just got some brake cleaner which shoots pretty far and i think is a tiny bit flammable and could add to the entertainment.

[Skippic]

We would need to charge them to at least 4.5V...

[GCinDC]

no prob... you know, i originally wondered if it would be a good test for your bms! what do you think? voltage differences too big??

[grindz145]

That's so weird how all the 4th cells are low.

[GCinDC]

perhaps not for long! after at 6 hours charging, 4 of which was balancing @~1-2A:


i'll check the bm6 voltages before and after my commute..

[methods]

Just wait until someone you know (who has a good quality DMM) comes around. No need to spend a grip - I only justify owning a really nice DMM because I use the hell out of it.

Yes I do have a deviant in the oven... little bastard is going to be popping out in like 5 weeks. I am excited.
This is something I have avoided my whole life.... never thought I would be excited. Guess it must be the hormones

-methods

so what fluke would i need?

ps. did i also read somewhere that there's a little deviant method in the oven? if so congrats.

[Alan B]

Yep, Mom's chemistry prepares Dad. It's amazing. Everyone's on drugs and they don't know it.

[GCinDC]

all my ebike vids are public again, on my youtube channel.

see the right column for playlists, or jump from here:
highlights
jumps
offroad
scenic
and lastly, commutes

[GCinDC]

loaning the GT out for an ebike addict who had to ship his own ride home, so i fixed up some of the issues:
- CA not coming on (not sure if i fixed it entirely, but it seems to work, and this ebike addict in question has never had the benefit of a CA, and only uses multimeter, so i hope he'll see the light). remounted it properly.
- rear brakes: lever spring was broke, ebrake contact therefore cutting power, vbrakes scavenged away, and replaced
- wire fastening, ship shaping


poor unvented discless 9C... i'll fix you up later, ok sweetie?

um, yeah, reminds me of torque arm miseries. i might have concerns for the passenger if this was the hs3540, but the 9C stayed put ok:

yeah, the light mount broke, and let's face it, it's not like i'm selling it...

i think he'll be shocked at how narrow the handlebars are, from his kona dh ride! i might have cut 2" off each side way back when. half twist here cause we couldn't be bothered to mod the magura... ah impatience.

his tools are gone, so i wonder how long before he gets a flat.

[GCinDC]

pretty sure these are total GT idrive stats, except cycles which are just for second batt pack:

20120715_211524.jpg (64.25 KiB) Viewed 692 times

[full-throttle]

One more

[N!co]

all my ebike vids are public again, on my youtube channel.

see the right column for playlists, or jump from here:
highlights
...

Hahaha, that man @ 0:15.

[GCinDC]

my GT is about to have a new owner.

i got chased (on my dh comp) the other day for a couple miles by a guy who, as it turned out, wanted to ask what demon from hell i was riding! and where could he get one.

he came over this weekend. i told him about my bikes and we went out riding, him on my GT and now he's gonna buy it.

i checked the front axle, btw and it's fine. i tightened up the rear brakes and it's in great shape.

i'm going to buy all new batts and a bulk charger for him, and when that comes in, hand it over.

the cool news is that he is a pro cameraman who uses drones and a motored paraglider. can you just see my mind working....

ps. and in case you didn't know it from my other thread, i'm getting surgery in two days so will be off the bikes for a couple months...

[grindz145]

the cool news is that he is a pro cameraman who uses drones and a motored paraglider. can you just see my mind working....

Hah! No way! I expect to see his posts on this thread...

Good luck with all the Def Leopard stuff too this week... Have you got the reference yet?

I hope your offering him a crash course in bike electronics with the purchase as well