dankers

It might not be PMW, could just be DDM was too busy to ask. I can't see them not selling the brushes, maybe PMW have bothered to put them on their site or made a part number? Doesn't anyone from PMW hang around on this forum? I would like to know for certain.

Anyway, failing getting new brushes from PMW, the place I have looking at my old sooty motor are trying to source some as well. I'll post here if they find anything suitable, there was some talk about brushes from a car window winder motor.

Getting very tempted to get a new scooter, nearly ordered a sport to get the replacement parts for this one, it was almost as cheap as the spares I ordered from DDM!

However, might buy a different scooter, maybe a GT? I like the look of the Go-ped but at least with the GT / Curries they can be upgraded to brushless and the build quality looks fairly good as well.

esr750

Judging from your shop appraisal, it sounds like a defective motor from the beginning. As long as the temp monitoring system was working the motor shouldn't have fried from overheating. The controller would prevent that from ever happening as well as log a fault code.

Specs indicate with no load (chain removed) the Goprammer or an amp-meter see no more than 4.2amps. Mine measured about 9amps the last time I checked so I suspect something not quite right inside my finned-monster motor or I didn't use the Goprammer correctly. Had to brush-up on my Hex math just to decipher the charging timer! LOL... I'll probably order a spare motor soon and have a shop take a look at the old one. Brushes, soft, silly $$$ brushes, if only they were available?

BTW - I tried to run the sled with Goprammer connected but it cut-out a couple times so I aborted that idea. Dunno if it was due to poor cable connection or what but it was interesting to see the motor amps flucuate for the few moments it did work under load.

There does seem to be some good mods for Currie/GT scoots but I worry about their chassis construction for folks over 200lbs. Hard to beat the Goped chassis construction and I suppose a brushless motor could be mounted somewhere over the existing 3" housing?

rricks

Sorry to hear our service for you recently has not lived up to your expectations. Can you clarify what went wrong so we can correct the issue ASAP?

dankers - unfortunately, we can only get the parts that PMW makes available for us to order in the Go-Shop - and the only option we can order is a complete motor . Have a look for yourself at www.goped.com

__________________
7-Star Go-ped Dealer
Go-Wagon
Remember - use coupon code 'gpn' for 5% off performance parts!

dankers

Thanks rricks, yeap, we checked the go-shop earlier in the thread, and I posted a note from Brad @ DDM that stated what you said also. Is there no way you can check with PMW, they don't seem to reply to their customers, maybe a dealer would get a response?

Seriously, if motor brushes aren't available, who in their right mind would buy an ESR? That's like buying a car and not being able to get replacement spark plugs.

My motor doesn't have a way to monitor the temp, I know some ESRs have them but mine never came with one, maybe the new ones don't have them?

esr750

Thanks Rick - I've already sent Brad an email detailing my problem and I will call Dale to go over this mess AGAIN once he starts answering the phone @ 11am MST. DDM really needs to understand this problem because it looks like one thing when it's actually something else - took me a while to figure it out completely and gather the proof I need to illustrate the situation. If these attempts fail, I will PM you and see if you would like to get involved before this implodes into bad juju for DDM...

Dankers - there was no temp sensor when you removed the motor from chassis? Sensor on my nearly year old sled is located between the power connections on the finned head of the motor. It's supposed to interrupt operation if it gets too hot and also displays motor temperature via the Goprammer.

dankers

Nope, no temp sensor and I questioned this with Jason at extremetoys when it was delivered as I noticed it when assembling it out of the box. He stated: "they must no longer put them on".

As I spent a long time deciding over which scooter to get, I viewed the temp probe as a bonus for goped as I thought it would protect the motor on it's slightly high voltage and long run times with the Lithiums. Hence fairly disapointing when it arrived without it, maybe they are cutting costs or maybe just missing from the factory?

esr750

What??? This is getting weirder by the minute and as I understand ECO revisions, the only things affected were charge time/mode parameters and the unused "brake stop" parameter. Perhaps now that the holiday is over somebody in-the-know can sift through this situation and find the problem or provide some SUPPORT?

btw - Sorry to hear about your country-mate Steve Irwin - very likeable chap and sad he bought-it like he did. I've heard the Barrier reef is a very dangerous place, in more ways than can be imagined. Some of the most dangerous/poisonous things in the world seem to frequent those waters. Irwin will be remembered as someone who left this world doing what he loved to do - nobody lives forever!

Rick - As usual, your guys are right on top of things and we got it figured out. Thanks for your concern and I gotta new order pending as we speak. The original chain finally gave-it-up yesterday exploring the QB bridge bike/ped path. No worries, kicked it home freewheeling (nice bearings!) and had 2nd chain from you guys soaking in sticky oil - all back-up and ready to go in minutes...

cheers!

dankers

Well that is strange, I'll be a little upset if it was meant to have a temp sensor and mine was missing. Would be good to get some of these point clarified.

Sad loss with Steve, I can imagine him trying to hitch a ride on the thing though, stingrays are not aggressive unless really threatened and even then, there has only been one stingray death recored before in Australia and that was in St. Kilda in Melbourne in the 1940's. Think it was a case of too little fear on his part, great bloke though, he did a load for conservation.

What's the story with the bearings? Ca the stock ones be replaced with better ones?

esr750

Naw - well maybe? What I meant was that with the chain off, stock bearings were really smooth. Don't get to sense that too often and my other experiences with different designs never come close to the quality and CAPACITY of the ESR chassis. Gotta keep an eye on that motor sprocket though - someday 'wished there were a belt solution and more of a D shape to the motor sprocket hub?

That's why I'm interested in your Lion packs - surely you've lifted the ESR empty and noticed how light it "could be" without the SLA's? If PMW doesn't come through soon, might be a few "developer" kits in my future, ya know?

But, for a heavier sled I've been parallel wiring my 24V 13AH NIMh packs mounted on the deck with great distance results. Mixing the battery chemistry during discharge seems to provide some range/performance benefits. The SLA's seem to better handle the high current start-up drain while the NiMh appear to provide more top-end benefit and mini-charge flow to the SLA's when at rest. Might add some diodes to prevent flow back into the NiMh's but so far I'm keeping everything straight with the connectors and the voltages seem to cooperate with each other during disharge. Plus, I got 2qty NiMh packs anyway so I swap them constantly on busy days allowing for time to cool before charging under controlled conditions on seperate charge system.

If I learn anything more about the motor/temp stuff I'll be sure to pass it along...

all the best

ysrelement

Just to clarify, his name is Ryan Ricks.

PM PatmontS on this site, that is Steve the creator of Gopeds and PMW. If anyone can be of assistance it's Steve. He normally responds to PM's within a couple days if not sooner.

__________________
2001 Porsche Boxster<>2008 Toyota Tundra Limited<>2000 BMW 328i

esr750

Totally my bad - I always have trouble dealing with two 1st names.

Everything is good on my end with DDM - as expected they were on top of things and I really appreciate Ryan's help/interest.

Yeah, I was hoping patmonts might see this thread and offer some advice - he has been very gracious to me before but this isn't really my situation. But the PM is probably a good idea and surely wouldn't hurt anything.

visiontim

Interesting thread, I've been having very recent trouble too and its almost the same thing, sudden loss of power then less power overall. I am hoping its the new batteries I put in and not the motor. Luckily I have over 600 miles on mine but I would still be pissed if this (ESR750 Sport) just crapped out on me.

By the way, I ordered the new batteries from Dave's and got one used in the delivery which was very odd. Luckily one phone call and they sent a replacement right away - definitely a new one too (matched the batch numbers on the 3 good ones).

I'll keep you informed as to whats going on with my motor.

dankers

Well, small update. Called in the motor place to pick up my motor on Friday, not very confident as I asked the dude if he could try and source a brushless motor of tha size and he stated I'd need a very long powerchord <smirk>. Acting dumb I said, "oh, I thought they made DC brusless motors? "Nah mate, no such thing".

Ran the rebuilt motor to work on non-turbo all the way. Got there and it was fairly hot and had a faint burnt smell, it could have been from it's previous promblems but didn't fill me with confidence. Comming home, just made 1km and it fails, white smoke and exactly has it failed before. Fantastic, at least the stock motor lasted 2 months.

To be realisitic, unless you want under 5 miles max range, the ESR is not worth looking at. You can't buy the brushes for the motor and there is no support a all. Go-ped have not answered 5 emails now, this is unacceptable. I'm confident this motor was faulty or used when I recived it and not only that it was missing the temp sensor.

When the brand new motor gets here from DDM, I' putting it in, the stock lead acids are going in it and then its for sale. All I can say is this has been a real eye opener, a waste of money and time.

PatmontS

Sorry, we somehow left that part number off of GoShop by oversight.
ESR motor brushes are available on line, or through your friendly GoPed dealer.

__________________
Sincerely,
Steve Patmont

PatmontS

Dear Dankers,
I apologize that we're having a hard time keeping you satisfied.
To clarify the temp sensor issue;
We've tried for years to protect motors through this strategy, but alas, temp sensors only bring new additional problems, while not properly doing their job as planned.
On brush type motors, the rotor is the place all the heat is generated. It's also the place a practical heat sensor is not practical. On the 2004 ESR750, we originally installed a programmable thermister on the inside of the fined heat sink. Even at a sensitive setting, it is possible to burn up the rotor under extreme conditions before the heat is even sensed at the thermister. At that same setting, under normal use, the thermister will shut down the scooter for a given cool off time too frequently, so we set it at higher settings, rendering even less motor protection.
It became clear that simpler is betterer, so we did a few tricks to make the motor even more capable of withstanding high temps, and eliminated the temp sense link and those potential problems.
That was my call so you can blame me if you think it was a bad decision.
Meanwhile thanks for any and all of your positive efforts with the ESR750.

__________________
Sincerely,
Steve Patmont

dankers

Thanks for clarifying the temp sensor issue and the brush issue, I have never stated that it was a wrong move, I just wondered why I didn't have one and was getting conflicting information. Given that in both my motors, the casing was always cool I agree with your decision. The case of the motor only ever got hot after the scooter was turned off for several minutes as the heat in the windings was convected to the motor case.

I have no complains about the ESR, I took a product and modified it as such I took a risk, the motor seems to be designed for the limits of the ESR and the ESR EX, this is good lean design. The stock controller is limited to 35 amps I believe(?) and this allows 800 watts to the motor, because of the extra voltage of my Lithium setup, I can push 900 watts in to the motor and not only that, I can do it for a much longer period than the stock ESRs.

Glad the brushes are available and that is fixed. I accept full responsibility for modifying the ESR and the issue I have with it, I created. The only issue is that its hard to get the real information, if you read earlier in the thread (see the top post of this page) you'll see that I thought the lack of brushes was an oversight but when dealers tell me that if its not on the goshop then you can't buy it, that’s the best info we have. Same thing with the temp sensor, the dealer I bought it off told me that "maybe they don't put them on anymore?", yet earlier in the thread you'll see there is conflicting information.

I've also learnt that there is no point getting the motor rewound as the magic that you guys added to make it last longer will not be replicated but the motor shop.

Thank you sincerly for putting all the issues straight, it certainly helps me with my options which are:

1. Find a way to keep the winding's cool - maybe forced air cooling over the windings. This seems fairly complex, if it's possible at all.

2. Removed a series cell for a 6S 22.2v nominal setup, I would lose some top end speed but to be honest it would still be fast enough.

3. Find a larger motor that will fit in the stock frames. Tried this approach and have yet to find anything suitable.

PatmontS

Dear dankers,

You are somewhat correct about how much the motor can take, but way off with the numbers.

Your numbers closely represent ESR cruising energy usage which the motor can take all day long, and therefore it's 750 designation.

The controller however is designed to manage somewhat more than that, and why the ESR750 is head and shoulders above the rest in that department.

The limiting factor is as you have discovered, the batteries.

The SLAs do not quite have enough energy per charge to destroy the motor. Your LIONs do.

Knowing this, with that increased on board energy, you can either be a better energy manager, and tread more lightly on the throttle, or develop a way to cool the motor more efficiently if you can't find a more suitable motor replacement.

Keep it up, you're a pioneer getting a glimps into the future.

__________________
Sincerely,
Steve Patmont

PatmontS

Interestingly, though the ESR 750 was introduced back in January of 2004, after several hundred thousand units, we're just now getting requests for motor brush replacements.
Not bad.

__________________
Sincerely,
Steve Patmont

Chumlee

Good job!

esr750

That is good news although I don't believe brushes wear very quickly it's nice to know they can be sourced if needed. 'Sounds like the Danker motor was dealing with heat more than brush wear.

Nice fore-thought by PMW to have included brush replacement procedure in the Goped service manual. Too bad brush motors in general seem to have heat issues but that's simply the physics involved and let's all hope to see more brushless motor designs reach consumers in the not too distant future.

Any tips from the PMW gurus about additional cooling techniques? I have started using extended range batteries so I'm concerned about overheating my motor. Even though I have the external temp sensor, based on your generous background about the design evolution, it seems best not to rely on that.

Thanks for feeding our curiosity and for the ESR750 - good luck to Dankers too!

Sheriff Jon

I am always amazed and pleased at the general profile of the majority of ESR owners. For the most part they are older, more mature, very articulate, eager to share knowledge and eager to help others, and present company excluded, quite knowledagable about the mysteries of electronics. I can understand 'plug it in' and 'push button,' other than that I am completly dumbfounded when it comes to matters of watt vs. ohm vs. volt. But I sure do LOVE my ESR.....ZOOM ZOOM

__________________
"HOW we ride today, may determine IF we can ride tomorrow"

GO GREEN
Torkinated and Slakinated

v tach

Well the part number is there but now they're listed as being out of stock.

v tach

Its a tiny motor and with such little mass will heat up quickly under excessive load. The most sensible solution if heat is an issue is to have the controller reprogrammed to further limit the peak current. The only other thing I can think of is forced air cooling with an electric blower and some type of ducting. Probably be a little difficult incorporating such a setup and still keep the nice aesthetics of the ESR design.

esr750

In lieu of electric fan I wonder if a wheel driven fan could be added and ducted to direct air flow to the rear of the finned motor head? The motor fins should be helpful even with an electric fan but as patmonts described, the heat can/will peak deep inside the rotor long before it convects to the fins.

Luckily, I do mostly stop/go city street riding so I don't think I'm getting too hot even with the extended run ability of the external battery pack. But, I will remember that and I already have an 80% econo mode programmed for those long runs across bridges or along bikepaths if I suspect things getting too warm.

Please, please, please consider a belt drive for future improvements? Chain is cheap, solid and good value but these sleds find their way inside a lot of homes/apartments/buildings and a properly lubed chain is a messy chain. I've been looking at several sources for synchronous belts/pulleys - haven't found the right parts yet but it's gotta be out there. CDrive is using some belts on bicycles that look about right? I might see what Gates would charge for a custom build? Probably be worth $200-$250 to me since I've already spent $40 on chains and it's so messy.

Ride pro!

Sheriff Jon

I used to have a picture of a belt drive conversion on an ESR that Jason of COAST PED tried. Although a well designed belt drive does sound intreguing, his makeshift experiment didn't yeald great results, as it was no quieter than a chain drive and it seemed to create more drag than with a chain.

__________________
"HOW we ride today, may determine IF we can ride tomorrow"

GO GREEN
Torkinated and Slakinated

PatmontS

I think you're over doing it on the ESR chain.
The intensive lubing of this HD#25 chain is important with our much more powerful GTR46, especially when driven off road. The ESR chain drive system is under much less stress in a much cleaner environment, and I've personally never seen one wear out if lightly lubed with White Lightening bike chain jube, or even a light treatment of WD40. Just relube when it seams to be drying out. Soaking and heavy lubing is not recommended, and will cause the problems you would like to eliminate with a belt drive. Also heavy lubricants actually attract and hold sprocket and chain wearing abrasive debris.
With such a small drive sheive, a belt system will require a very tight and touchy power robbing adjustment if you don't want it to skip teeth at every excelleration. Lower powered designs continually had this problem, which would be exagerated with the more powerful ESR750 motor, and we feel a bigger problem than what would be eliminated.

__________________
Sincerely,
Steve Patmont

v tach

Forced air cooling would have to be a flow-through setup to be of much benefit. Fresh air in one end of the motor can and out the other, not across the fins. Obviously the ends would have to be drilled or vented in some manner. Electric powered ducted blowers have been the most successful setups I've seen. Small dc blowers are readily available, easily ducted, and draw only a few milliamperes.

The ESR I've been able to ride belongs to a friend. We're both over 200 pounds and his motor has faired well with the machine always in turbo mode. With the stock gearing, controller, and larger 12ah batteries, he has not had any concerns with the motor after many miles. He keeps trying to convince me to buy one but I'm waiting for more updated technology to show up in the ESR model. The current range of the ESR isn't practical for my needs and its a bit too expensive for a novelty.

PatmontS

V tach,
I hope youre not suggesing we upgrade the ESR750 to the superior and not so simple Segwayesque technology.

(I just had to get that in there)

__________________
Sincerely,
Steve Patmont

Sheriff Jon

I heard on the news that Segway is recalling ALL of their PTDs due to a possible hazzard issue.

__________________
"HOW we ride today, may determine IF we can ride tomorrow"

GO GREEN
Torkinated and Slakinated