GT i-drive 2.0 Build

[Alastor]

i thought that was ymittos! awesome. nice memories from there! nice to see you get a bit of air too.

You know Ymittos nice you should visit again too bad i was injured and could not step up the throttle as well in the near future i think we will have the chance to re film something more interesting hahahahaha

 

[GCinDC]

Have you ever consider filming while giving birth to one of this boxes?A lot of people might be interested.

I will try to remember to do so. I have to redo the one on my DH comp soon...

So I've been cleaning up the GT before releasing it into the wild. The buyer has been very patient, considering my limitations after surgery, but finally I finished and this weekend he came by to pick it up!

I wrote up a little user manual on how to bulk charge and how to balance charge etc. Yesterday he brought over his Hyperion balance charger (he does lots of RC stuff) and I helped him program the setting (lipo 5s @ 15A for 40000 mah w/ max 4.18V [min avail]).

I had balanced each of the 8 5s packs when I first got it and another time as a whole 5s8p pack after using a little of it.

But I discovered sometime over the holidays that I'd left my 4x BM6 lipo buzzer dongle attached for over a week! :x

I had made a nice pocket for it with the Velcro cover and had forgotten to disconnect it. Amazingly the cells dropped from only 4.2V to 3.87V over that time. But cells 4 and 5 got out of balance by .05V and .1V respectively.

This was very serious because after one charge w/ the new 1000W BMSbattery charger, a couple cell 5's got up to 4.23V, which I immediately dropped by riding the bike some.

In any case, the battery needed to sit on a balance charger for a long time and I helped him set it up so he could do it at home.

Only problem was that a couple hours later, he emails me with pictures of his mistake:

and the result of plugging in the 5s balance connector while the discharge leads are configured in 20s?:

he was very mad at himself, but i told him that it's the only way I learn... :lol: And you all know that's true. I did the exact same thing over three years ago when I was cutting my teeth on lipos...

so I'm going to rebuild the DB25 balance connectors...

Before that we had a nice ride together which I'd intended to film, but didn't get around to.

It was interesting to note:
- the GT is faster than my dh comp now (the batts were indoors, but are new compared to 200-300 cycles(?) on my dh comp pack?)
- the GT is much lighter, and obviously has a bigger rear wheel, but the dh comp strugged to get to 35mph on the flat and the voltage sagged more.
- the new GT lipo pack felt very stiff.
- after 7 miles, the dh comp had used 7Ah while the GT used only 4Ah!

 

[toft]

Almost twice Ah? thats huge difference... I really like your giant dh project but this ah differences... You should considering 15 ah solution in giant In facts I'll take this one with less ah consumption My next project sholud have less then 15-20 wh per km... Of course less average and max speed..and middrive... but we leave in differences towns... I have really more not two pass higway, rather small roads and path... And mayby buy go pro BUt there in Europe its as I thing more the 300$ so expensive...
Regards (especialy health in arms) MIKI

 

[GCinDC]

yeah, my dh comp is a hog. and it's just powered by an hs3540. seems everyone's getting 40xx's now... those must suck more current. i still think the 9C is the best value motor. lighter but peppy.

anyway, i got the battery back and started examining the parts. i'd soldered the tight-fitting solid 22g(?) wire into the db25 and was very impressed that there was no damage at all to them:

i've seen others solder the stranded wire into the db25 but i don't like that. if it ever gets wet and corrodes, those wires will snap off like nothing. these solid wires are in there strong!

the jst-xh's at the ends of those wires didn't look so good. a couple were stuck and hard to pry apart, so the connecting Y cables will need to be replaced:

when a bm6 was inserted, it need to be jiggled to make a connection but otherwise did not:

i regard these connections as sacred. one failure could be disastrous... hence the glue, and electrical tape around the connectors once joined...

back to the db25. when i pried i saw that only the ends were fried:

 

[GCinDC]

oh, and all the cells were balanced w/in 0.030V and sitting pretty much where we'd left 'em at 3.75V.

 

[Hyena]

it's just powered by an hs3540. seems everyone's getting 40xx's now... those must suck more current. i still think the 9C is the best value motor. lighter but peppy

I believe the 40's are well endorsed
I agree though, the 9Cs are good and their power:weight is tough to top. For my own bikes now I'm either going 9C style or H40.
The H40s CAN suck more current, but they don't have to. They can actually be really efficient if you don't punch it constantly. Because they're bigger with more copper they don't waste as much energy as heat and have more torque without needing to be as heavy on the throttle. I find for commuting my H4080 can be up to 30% more efficient than my 9C 9x7 .

As for the burnt series/parallel stuff up - don't you love that. I've had a number of people do that with similar set ups and no matter how many times you warn them sooner or later they'll still do it. I can't talk, I've done it once myself. But after you DO do it once the time it takes to remake all the harnesses prompts you to pay more attention in the future!

 

[Skippic]

Or you can just go bulk with a bms...

 

[GCinDC]

levelled with a cold this weekend, but managed a bit of progress replacing the fried db25 connections (and new parallel charge cables for myself..):

for the batt side, i clipped and re-soldered the existing balance wires (bottom of connector here) but it was way more work than cutting and inserting new (top):

don't worry, i didn't forget the shrink tube...

 

[pucksterpete]

The look of pain, I feel for ya bro. Take it easy

 

[GCinDC]

haha, how long did it take you to grab that shot! :lol:

thanks, tho. i'm MUCH better now! i should probably not have been rebuilding the pack after 3 wks, but thursday will be 12 weeks and i can do 90% percent of what i NEED to do, even though i've only got about 60% of the range of motion (and working to get the rest is a pia).

 

[GCinDC]

switching out the old db25 with a new one:

fixed charge cables (5s8p)

and discharge, fyi (20s2p)

 

[Skippic]

Scary monster!

 

[GCinDC]

this might be less scary, but i'm not sure how much time it would save:

can't remember who discovered it but i'm tempted to buy a couple anyway...

 

[GCinDC]

just got a package

and right to work charging to 3.85 each 10ah pack.

the most pleasurable balancing experience i think i've ever had once i sorted out the menus.

whoever discovered these really deserves some credit. unless it was hyena.

 

[Hyena]

the most pleasurable balancing experience i think i've ever had once i sorted out the menus.

But now that it's done (and really it's simple once you've done it once) you'll never have to touch it again. Turn it on and hit one button and you're off. So simple you could train a monkey to do it.

whoever discovered these really deserves some credit. unless it was hyena.

Haha what an asshole

 

[chroot]

Yes, it was Jay (Hyena) the first discovered this awesome charger BCM168. You will enjoy the best charger that charging thru the balance lead.

 

[GCinDC]

lol. of course he discovered it! hell, i thought he designed it!

was a little hyena bait joke which he apparently swallowed whole in response to this.

 

[spinningmagnets]

I apologize for the newbish question. These look pretty good, for 44V / 12S would I need two of them, one for each 6S string? I believe there are power supplies that can feed two chargers.

IF I need two of them for 12S, would you have a suggestion about a good power supply to feed two of these chargers? Thanks in advance...

 

[Hyena]

haha yeah I knew you were baiting but a hyena rarely passes up an easy meal

spinning magnets, see my thread in the FS section - that's where most of the discussion about these chargers is happening.
(that's not a sales pitch, you can get them elsewhere for cheap now) Short answer, there has been a few issues with isolation between multiple units that resulted in my blowing up 2 of them. But methods thinks it'll be OK if the earth of the power supplies are isolated (possibly not even an issue in the US)

 

[chroot]

You will need 2 of isolated power supply feeds into 2 of BCM chargers, and you will able charging 12S as each charger charging 6S as while both are in series 44v.

Let's not littering this thread relate the chargers. You can check @ http://endless-sphere.com/forums/viewtopic.php?t=41107

I apologize for the newbish question. These look pretty good, for 44V / 12S would I need two of them, one for each 6S string? I believe there are power supplies that can feed two chargers.

IF I need two of them for 12S, would you have a suggestion about a good power supply to feed two of these chargers? Thanks in advance...

 

[GCinDC]

thanks, chroot, but i hope you don't mind a question since the topic is up (and it's my littered thread ):

can i plug in 4 5s jst-xh connectors into the attached dongle? for example, now that the four 10ah packs are all exactly balanced, can't i insert all 4 jst-xhs and balance charge them from there? can't that board basically parallel 4 packs?

another thing that was cool: when i first plugged it into my MW350 it was beeping like crazy but i finally noticed that it was showing 16v INPUT and only operates on 11-15v? anyway, i grabbed a phillips head and dialed down the meanwell to 15v and all was good. cool to see the input V.

 

[Hyena]

can i plug in 4 5s jst-xh connectors into the attached dongle? for example, now that the four 10ah packs are all exactly balanced, can't i insert all 4 jst-xhs and balance charge them from there? can't that board basically parallel 4 packs?

Definately. Infact you can plug in any combination of packs you damn well like Eg you can plug in 2x 4S + a 5S and a 6S if you wanted.
Oh, as long as they're all a similar state of charge - otherwise they'll try and balance into each other via the balance taps and will melt if there's big voltage differential.

But yeah, they're rad for doing that and are especially good if you've already got a set charging voltage/battery layout and then decide to add another booster pack. I'm running my stealth fighter on 18S currently because I was charging in multiples of 6S and I could fit enough for 24S. But I've got a bit of spare room so could fit another 3S to bump it up to probably 21S and still easily do the odd balance charge with this 8)

 

[GCinDC]

awesome! so then i can do this... (as long as discharge plug isn't in of course )

and i don't really need the cables i just built (top, tho they are for the new bike owner...):

 

[chroot]

Jay (Hyena) beats me, You can charge as long as it's parallel and your recent post seems you got it right. Greg- so your GT bike already sold? Damn.... You should have keep the bike and put up for the museum "The classic reckless GT ebike from D.C."

 

[GCinDC]

new owner is pretty cool. rode motorcycles all his life, often thru hectic paris traffic. he's also WAY deeper into professional/broadcast video than me, tho that also makes him so damn busy that he's hardly ever here. just spent 10 days in haiti and returned only to fly somewhere else... so you could say he's a risk taker! thankfully he didn't get kidnapped!

we'll definitely ride together and that will be fun. he also joined ES to tune but i'm not sure how much he'll post.

so life will go on for this bike. 8)