Maytag's GT gets a BMC

[maytag]

When do you go to 72v?

Lets make sure we work out the kinks first before we start thinking crazy but I have to admit that I have done some number crunching already. Most likely if I were to bump up the V's I have 3 emoli packs to consider to build another 9Ah subpack to series up.

1) Milwaukee V18s (5-cells), = 73.3v and 43.4mph max speed
2) Ridgid 24v (6-cells), = 77v and 45.6mph max speed
3) Milwaukee V28s (7-cells), = 81v and 48mph max speed

Figures are based on my current setup of 54v and 32mph max speed. Going with either of these packs would make for an easy charging solution using their matching 1hr chargers.

Its cool to think a little on the wild side but I'd most likely put the money into an extended range pack on a beam rack and stay at 54v. I have 2 good Hawker 13Ah SLAs sitting around doing nothing, I might consider strapping them on for a quick registration into the 40+mph club...hmmm.

 

[knoxie]

Hi


Ha ha no no run it like this for a while!! he he you bad boy!! get some reliable miles under your belt first, its so tempting I know but its better not to rush, 30 mph+ is quick enough!! ha ha, keep us all posted, I have also got 4 days off work now to test the controller and the new Puma, should be fun!

Cheers

Knoxie

 

[D-Man]

Maytag, where did you end up getting the new fets and hardware at? Awesome bike by the way.

 

[maytag]

Maytag, where did you end up getting the new fets and hardware at? Awesome bike by the way.

Thanks for the compliment D-Man. I didnt replace the FETs, only the h/w. We have an electronics surplus store locally called Halted, been hitting up this place for projects the past 15+yrs. They sell the TO-220 h/w seperately or in a baggy kit. The baggy kit comes with what looks like an orange flimsy insulator pad, screw and the shoulder washer $.25 per kit. I didnt like the flimsy insulator pad in the kit so I just picked up mica pads for $.05 a piece and the shoulder washers for $.10 a piece and used the original screws.

Man, too bad I have to work otherwise I'd be putting on more test miles. Looked in the garage earlier and the packs were fully charged already, took about 2.5 hrs

 

[Ypedal]

Any chance you took pictures of the hardware in question as you were installing them ? would be most helpful for the rest of us ! lol...

Keep up the good work !!!!

( Oh . and about the video thing.. for those of us stuck in an office chair 8 hrs a day.. hell.. i'll watch anything remotely entertaining pertaining to ebikes !!! )

 

[maytag]

Any chance you took pictures of the hardware in question as you were installing them ? would be most helpful for the rest of us !

Sorry no detailed pics this time, I was pressed for time since we got back from dinner at the in-laws a little past 10pm. I wanted to just swap out the parts and get a quick ebike fix before bed. The fix happened at 1am, almost like drinking a cup of strong java before jumping into bed.

 

[Stevil_Knevil]

Stop me if I'm wrong.. but this is the modification that was well illustrated by Knoxies' 150V upgrade thread in the ebike technical section(?)



-S
P.S. Rawk on, Maytag!

 

[maytag]

Stop me if I'm wrong.. but this is the modification that was well illustrated by Knoxies' 150V upgrade thread in the ebike technical section(?)



-S
P.S. Rawk on, Maytag!

Steve, exactly to the T except I didnt replace the stock 100v FETs, just replaced the crappy plastic tubes and fiber washers with proper h/w.

 

[maytag]

Took Friday off from work so I had a full dose of ebiking today. Everything WAS holding up very very well, I'll get back to the "was" in a bit after I give some details of how well the Puma performs. This morning I made a bracket to mount a camcorder on the handlebars knowing I would be doing some range testing this evening with Joystix and Jondoh. I decided to try getting some video footage using the new bracket and thought a quick ride up the hills to a lake about 2.25mi away from my house would be neat. I started the camcorder and took off flying, might as well give the Puma the full treatment. It's pretty much 2.25 miles uphill, change in elevation from my house to the lake is 148ft to 590ft. When I got there I discovered the camcorder wasnt even on, coulda swore I started it. . . Sorry guys! I then rode over to Joystix's house then had lunch with Ric and John, we discussed what our route will be for our range test later after John gets off of work. After John had left back to work, Ric and I did 2 Puma vs X5 dragraces. We started side by side with a 5-6mph rolling start then we both jump on the throttle at the same time, once with me on the Puma then another pass after switching bikes. Drum roll please..... With me on the Puma I cant say that Ric on the X5 is eating my dust only because after a block the X5 was too far behind. Ric out weighs me by 40lbs. With Ric on the Puma it was much closer of a race but the Puma is still the clear winner. We took videos of both with 2 different cameras, I'll try gettting around to editing the 2 for a multiview video of the races but I have more problems to deal with so I cant make any promises to when it will get posted.

So we all regathered at 6pm for the range testing ride. We plotted out a 18.5mi ride and planned to keep our pace to 20-22mph peddle asisting only from stops and any moderate incline. We all made the 18.5mi route then John and I decided to keep riding to get a true full range test. We were both at 21.5 miles when John's BMS's let him know it was time to quit. Mine felt like it still had more left in the tank, my setup bypasses the BMS's but I pressed the gauge button and it showed a blinking single bar. The pack voltage at this point was 50.4v, 3.6v per cell which is the perfect LVC for emolis.

Okay now for the bad news. John recharges his V28s and Ric comes up with an idea for John to hook up 4 of his V28s (2p2s) on his X5 and John to hop on and try joining the 40mph club. We strapped on a GPS to the bike and off he went. I drove while Ric camcorded him, he went WOT for a long stretch but never made it 40mph (did 39mph on GPS). Well after watching how close John got to the elusive 40 a devil popped up on my shoulder, you guys are going to hate me for this especially Knoxie after telling me not to give into temptation. I thought somebody has got to join the 40mph club tonight so why not me. I strapped on one of John's V28 packs to the GT and wired it in series with my pack, total voltage was 83.1v . Powered on the controller and gave it a little throttle with the tire off the ground, it spins and gets my heart pumping. I put on Ric's motorcycle helmet and jacket and coasted it down the driveway and onto the street. I gave it a tiny bit of throttle then ZAP, Ric and John were behind me as I stop and turned to them giving the cut-throat signal. Well we just found out the V28s are good for 2 in series through the BMS (2s) but theyre definitely not happy running 3 in series (3s). John's BMS in the V28 got toasted. John had to leave and I'm sure the ride home wasnt pleasant knowing I just fried one of his V28s. Well John theres some good news and some bad news. The good news is that I've already replaced the FETs on the BMS and ditched your original smelly battery case with a brand new one, for some reason I had 6 empty cases on hand :wink: Your battery is fully functional again 8) . Now the bad news , when your BMS smoked it also took out my Crystalyte controller. After you left I went to connect up the battery on the GT then ZAP again, made a mess of the controller's and pack's black power pole connectors. Measured a dead short on the controller's (+) and (-) connectors. I peddled my way back home through 6 miles of hilly terrain, guess I deserved it. Cracked open the controller, looks like only 1 of the phases set of FETs are fried. Now I'm debating if I should just go ahead and replace all 12 FETs with 4310s for the lower ON resistance or just pick up 4 of the stock 4710s to fix the 1 bad phase. Guess I'm down and out again, but guys (Ric and John) you guys have to admit that this Puma is one kick a$$ little motor

 

[maytag]

Jondoh,

Sorry for smoking your battery but the surgery went well and its back to full strength. I can pass by and drop it off tomorrow if you like, guess I'll have to drive a car tho -haha

 

[BiGH]

Fantastic comparison. I think you've sealed what motor i'm getting now (and damm i'm excited!)

I'm especially pleased on the range you got (18mi) out of 9aH of batteries (i am correct on that right?)

I'm really sorry to hear about your controller going up in smoke though

I think its almost worth while getting two controllers, so that if one blows you have a backup (to run at stock speeds) until the other is fixed.

 

[Lowell]

Great news on the Puma hub. Do you have any time to speed numbers for it? I'd like to see a Puma vs X5 comparison with both running at peak performance. An X5 that can't do 40mph is either a bike carrying extra motor weight for nothing, or an unfinished project

 

[fechter]

My guess is the BMS tried to open and the increased voltage fried the FETs in the BMS.

I've been thinking that if you want to put more than two drill packs in series, it might be a good idea to just solder a jumper across the BMS FET to bypass it. It's going to explode if it tries to open anyway. The jumper will reduce the resistance as well. The BMS will still be able to balance during charge. I'm not sure if the overcurrent protect FET does anything during charging???

Don't use 4710's... It will just blow again.

4110's rule. I've never tried any 4310's. They have a higher gate capacitance, so could possibly have drive issues, but I think they would be OK. At least they have them in stock and they are much cheaper.

Any signs of motor heating? That Puma sounds like it's going to kick butt, as long as those gears hold up. Are replacement gears available?

 

[TylerDurden]

Excellent report!

PLUS, We have another pic for the fried-food gallery, and more on the way... :lol:

It still remains to be seen how the damaged pack performs. I'm wondering if any other components on the BMS got zapped. (I am sure you still have a few BMS boards.)

Selfishly, I am pleased to know Jon's Milwaukee packs are handling up to 56V without the FETs blowing; I may try 48V at some point with less fear of 'KFP'. 8)

MANY thanx for your reports and fine pix!

 

[Stevil_Knevil]

Yes, excellent report Maytag!

That was the classic "Good News, Bad News" story.

Puma motor honks on X5 -CHECK. (but bro's X5 was running on NiMH )

Whether or not the stock FET insulation is sufficient at rated voltage is another that seems to have been answered by this destructive testing (damn those shoulder-sitting, ear-whispering demons).

Running above 60V practically requires a full FET swap for reliability -Check.

Sorry you're having to go back into the controller, but hey.. just think of all the headroom that you're going to have after swapping-out the stock FETs for phatter ones!


:wink:

-S

 

[maytag]

Placed my order for a dozen IRFB4310's thru Digikey this morning, couldnt find any IRFB4110's in stock anywhere but judging by how the Puma was running even with the stock FETs I'm sure I'll be happy with the 4310's which have less than half the On resistance of the stock 4710's. I had all day yesterday to thrash the Puma and it performed like a champ. What was most impressive was the climb up to the lake near my house, a lot of full throttling and when I got to the lake controller/motor/batteries were all only luke warm. Damn, too bad I screwed up on getting the video footage. I did get the video cruising down tho, maybe I'll get around to posting that footage so you all can get an idea of the climb coming up. Of course I'll have to tackle this climb again once I get the FETs replaced, and this time get the damn video right stupid! :lol:

My confidence was running so high on the Puma setup that when it came to strapping up Jondoh's V28 pack for the 40mph attempt the only thing on my mind (and I told John this) was "I'm just worried if the V28s BMS can handle 3s" NOPE. I'm almost sure if we would have somehow bypassed the BMS on John's pack I'd have already posted something in the 40mph club thread. I'll be back - fo sho

 

[joystix2]

Yah I'm here to defend my Phoenix motor. I agree with Steve, I have Nimh at 48v compared to 54v of Lithiums. Can we say "VOLTAGE SAG DISADVANTAGE"........ But on the other hand my next motor is going to be a Puma. That DAM thing has some torque..... I like them both but for practicality and transportability I would go with the Puma/Milwaukee combo. Another advantage of that combo is 2-3 hours of charging from dead compared to 10-12hrs with my Nimh. But my suggestion would be you have to go 50+ volts for the Puma to be fun cause at 48 it doesn't do 30mph. Now I am going to put a 12v12ah SLA in series with my Nimh pack to try and get into that 40mph club.

 

[maytag]

Hey guys,

I just calculated my average speed going home from Ric's house last night, I did 6 miles in 36min. That's an average pace of 10mph which I am damn proud of considering I peddled the whole way through some wicked hills and all nonstop, not bad for a 39-1/2 year older past his prime. Only problem is the motor got super hot, smelly and sweaty. hahaha :lol:

 

[maytag]

Fantastic comparison. I think you've sealed what motor i'm getting now (and damm i'm excited!)

I'm especially pleased on the range you got (18mi) out of 9aH of batteries (i am correct on that right?)

I'm really sorry to hear about your controller going up in smoke though

I think its almost worth while getting two controllers, so that if one blows you have a backup (to run at stock speeds) until the other is fixed.

John and I both did 21.5 miles but I do remember John peddle assisted a little more than I did on his gohub kit with the same 54v/9Ah pack. The guidelines for the range test was to maintain 20-22 mph and peddle assist only after stops and for moderate inclines in the route, we tried to make the route as flat as possible. I have video of our route to the halfway point where we caught a bite to eat but I've always thought range testing videos to be pretty boring but I may post it up just for Buzz.

What's the best way to upload long 20+ min videos onto youtube? Or does anyone have any better ideas how to share videos on the web?

 

[Mathurin]

You can on youtube, just get a director account, or producer I forget how they call it, it's free, but standard accounts are limited to 10m

 

[BiGH]

John and I both did 21.5 miles but I do remember John peddle assisted a little more than I did on his gohub kit with the same 54v/9Ah pack. The guidelines for the range test was to maintain 20-22 mph and peddle assist only after stops and for moderate inclines in the route, we tried to make the route as flat as possible. I have video of our route to the halfway point where we caught a bite to eat but I've always thought range testing videos to be pretty boring but I may post it up just for Buzz.

What's the best way to upload long 20+ min videos onto youtube? Or does anyone have any better ideas how to share videos on the web?

Not sure if i asked this - what is the top speed (on the flat no peddling) you've managed to wrangle out of the puma?

as for posting on the web- i'd say youtube, or possibly google video (not sure how to) unless you have a dedicated hosting page - then its really easy.

 

[maytag]

Not sure if i asked this - what is the top speed (on the flat no peddling) you've managed to wrangle out of the puma?

as for posting on the web- i'd say youtube, or possibly google video (not sure how to) unless you have a dedicated hosting page - then its really easy.

I've managed 31.5mph on the GPS, that was on a chilly night on the batteries 1st cycle before the 1st controller died. I've since done maybe 3-4 cycles on the batteries but havent tried another top speed test. It may be safe to say the Puma can do at least 32mph max in a 26" wheel.[edit] on my 54v/9a emoli pack.

 

[maytag]

Fantastic comparison. I think you've sealed what motor i'm getting now (and damm i'm excited!)

Dont forget that I put a lot of labor into modding the stock wires, you might want to hold off a little bit longer for Knoxie's report on the 3rd revision of the Puma he has on hand. If this new rear hub performs anything like the 1st revision (front hub) the performance will be even better than what my modified Puma is getting, now there's something to get very excited about.

 

[BiGH]

its ok i'm holding off until i've throughly researched it - im just saying i'm leaning towards this motor.

I'm already intending on re-wiring the stock motor - the wires look hella small. thats the main thing i'm worried about. it would be good if the wires could be made to come out both sides of the motor - supporting larger wires.

Either way i invisige having two electric bikes over time - its more of question which one will be first (i want a reliable light commuter bike) and a high speed "fun" bike.

 

[knoxie]

Yo

I wont say I told you so :lol: its not funny though what a shame!! grrr you should have got more miles under your belt though to make sure it was all good first, what a pain.

I had my BMS fry as well on one of my packs when it failed at 72V, I think Like Richard says its the high voltage that is damaging the fets when they open, it properly toasted my BMS.

I suspect you can connect those packs like that its just that if the pack BMS opens it will do damage at that voltage, the fets more than likely blew because of the high voltage like I have found also, I would still be a little worried with 100V fets though as they could still be vulnerable even though they offer less on resistance and have higher current capacity, this is why I opted for 150V fets, its worth a try though, remember you also need to go around and check the gate resistors and transistors, these often blow when a phase goes, you could change the fet and just have it blow again as soon as you turn it on otherwise.

I would change the gate driver transistors as well as they are so cheap you may as well do it, its a time consuming business doing the mod so you will have to plan it well, dont rush it either, top tip make sure you glue the capacitors down last else you will struggle to tighten the fet screws! he he.

I have now fitted my Trek with one of the new Pumas and am running it on my old faithful xlyte controller, it has great low down torque but it is geared slightly differently and tops out at about 22mph on the flat which is a little disappointing however it has more torque which may be good for some folks, ill run it for a few weeks to see how I like it.

Good luck with the controller mod

Knoxie