dankers

This is my first post here, found you guys via Google and it looks a great forum, I have a couple of question I hope you can help with?

I've had a Goped ESR 750 for a few months, it was a great solution for my commute to work except for the lack of range, I needed 20km on Turbo mode really so I converted the ESR to run on Lithium cells hence I now get that range.

Things have been going well for 2 months now, using the ESR to commute 20km per day, until Friday when the motor decided to let out its magic smoke. So now I need a new motor....

As I'm not in the US, I can't buy direct from Go-Ped, does anyone know a place to order a new motor from? The Australian distributor can get one but it will take a while and I'd like to get one quickly. Any ideas?

The one thing I think the ESR needs is a one way front sprocket, does anyone sell these as an add on?

Wimmig

Contact DDM and ask them;

http://www.davesmotors.com/index.htm
sales@davesmotors.com

They will ship internationaly, the shipping is cheap and in 99% of cases is cheaper than buying locally (private import vs. company buying).

goped man

I'm sure DDM can hit you up with a motor. Go on www.davesmotors.com then e-mail them asking for a spare ESR motor. Their shipping is very fast from the USA to the UK so it shouldent take much longer than 9-14 days for you.

jambeedavid

Do u think the lithium cells are the culprit for your motor getting trashed? Im curious as to how you converted, as i too would like to extend the range of my 750ex.

__________________
Owner/Builder - TS Carbon Fiber GSR60, TS TSI

Porsche tracking, Jetski Racing, Piranha Keeping, Harley cruising, Ducati riding, LandRover crawling, SVT 1/4 mile dragging, RC Heli hovering.....

Wimmig

Unless the lith cells are from gods own garden, i don't think they are the sole course for the motor dieing.

dankers

I've done a bit with the Lithium’s since I first did the conversion, it now has a BMS system which I use off-board, I think the initial conversion photo would be the most suitable to post as if anyone else wants to follow, this is an easy conversion. There is a picture attached. 7 x 7S Emoli packs connected in parallel via a busbar.

These 7S7P E-Moli cells give a total capacity of 21Ah, since this time I've change the pack configuration around to fit in more Lithium’s however that was a hassle and for 20KM turbo range 7S7P is fine. You might be thinking that 21Ah is only 2Ah more than the EX, well, not quite as Lead cells have what is known as the Peukert effect, it simple states that the more amps that are drawn out of a lead pack, the less capacity they will deliver. This is mainly why Eco mode has such an increase on range.

Lithium cells do drop capacity when pushed as well but it's nowhere near as bad as the Pb cells that the Goped comes with. 2nd, Lithium cells have a different voltage than lead, where as the stock config is 24v nominal, a 7S Lithium pack is 25.9 - two things here; first electrical power we actually care about is watts which is volts * amps, given the higher nominal voltage the Lithium pack contains a larger watt capacity. Also as the Lithium cells I'm using do not drop voltage under load as bad as the Pbs stock packs, I get more watts for less amp draw, as well as getting the full 21Ah out of the pack whereas the Pbs in the ex get something like 14Ah thanks to Peukert. Finally, my 7S7P is 5kg lighter than the stock 9Ah pack in the ESR750 so my watt hour per mile is less than the EX.

Some rough maths:

EX @ 50 Wh/mile on turbo = (24*14Ah)/50 = 6.8 miles = 11km

Lith @ 43 Wh/mile on Turbo = (25.9*21Ah)/43 = 12.6 = 20km

I have never ridden an EX, I'm not sure if those figures are right, just a guess given my stock ESR and based on the excess weight - I know my non-ex was getting just over 4 miles on Turbo mode. With the 7S7P config I consistently did 20km per charge. With my newer 7S9P pack, I've done 30km on a single charge, both these figures are in turbo mode constantly but not always flat out, only most of the time - The 7S7P pack that I'm using can supply over 8KWs (11hp), just need a 400 amp controller and a much larger motor. This shows how little I'm pushing the cells which is why they hold voltage so well and also why I get full capacity from them. I initially considered using A123 system's cells which I decided against due to their form factor, however 7S7P of these puppies could provide 18Kws (25hp) thanks to their power density.

The downsides are the cost of the cells and the fact you'll need a separate charger as well as keeping the cells in balance. The E-Moli cells I'm using stay in balance extremely well and this is one reason I'm using them however, the main reason is that they are much, much safer than normal Lithium-Ion cells that use Cobalt for the cathode. The Cobalt type Lithium cells have a better energy density so would have a higher range and be cheaper but, just aren't as safe.

To do this conversion to E-Moli Lithium’s would cost around US$650 so it's not cheap. Then you would need to add a lithium charger to that, the good news is that these cells can be charged safely at 3C which would be a full charge in around 20 minutes - my chargers can't handle that and charges at 1/2C which takes 2 hours for a full charge from flat.

It did cross my mind that the lithium’s could have caused the early death of the motor - the issue being that my pack fully charged is 29.4V compared to 27.4v for the stock lead acid cells.

Attached Images

IMG_1778.jpg (82.2 KB, 323 views)

esr750

Love it Dankers - thanks for sharing! Yes, check with DDM, they're very good about replying to questions and I'm sure they can handle overseas shipping. I'd strip the motor down and give it a good inspection. Ohm the windings and try to find the source of your smoke. My guess is that the brushes wore out.

At 225lbs my EX is lucky to get 5 miles in turbo 100% mode. I reprogrammed the controller so econo mode slowly (8% acceleration) reaches 80% top speed and that increases range to about 7-8 miles with stock SLA's. It depends a lot on grades, wind, plus starts & stops so...

Would love to get your range with that weight though even if it does eat brushes!

ride on!

jambeedavid

Is it tricky to charge it? could i get the chargers model? description of how its done. Thanks a bunch!!!!

__________________
Owner/Builder - TS Carbon Fiber GSR60, TS TSI

Porsche tracking, Jetski Racing, Piranha Keeping, Harley cruising, Ducati riding, LandRover crawling, SVT 1/4 mile dragging, RC Heli hovering.....

jambeedavid

would u recomend that programer? is it a big help in tweaking range and speed and all?

__________________
Owner/Builder - TS Carbon Fiber GSR60, TS TSI

Porsche tracking, Jetski Racing, Piranha Keeping, Harley cruising, Ducati riding, LandRover crawling, SVT 1/4 mile dragging, RC Heli hovering.....

dankers

The charging is the only tricky part really. The actual goal of this whole project was to develop a Battery Management System for Lithium cells, the intent is to convert a car to an EV in the future and why I need a BMS. The plus side being that I love my Go-ped but orginally just bought it to test the BMS.

So my charger is custom made and still under development and really aimed at scaling up to car sized packs. BUT, you could charge the cells with an RC charger, I fly RC helicopters and I started off charging the packs with a RC charger and flying RC is where I orginally where I cut my teeth with Lithium batteries. The massive downside here is you need a 12v DC powersupply so, even though the chargers are small the power supply isn't going to be. You will also have to keep an eye on each individual cell to make sure that it stays in balance.

There are some packs that are availible already that have a BMS built in and can also be charged with a regular Lead acid charger such as the onboard on in the Go-ped. These are meant for small EVs like electric bikes and I think you could get 40Ah in to an EX and still use the onboard charger. The problem being that these packs cost a fair bit but are comming down all the time. What I did was more of a learning experience really and took a lot of time.

rockyray

does anyone know where to get the brushes to rebuild an esr motor. my motor also gave out.

esr750

Yes, it's a big help tweaking the econo mode settings - 80% top speed is about right for me to kick the scoot along and/or up hills plus the acceleration parameter saves high current drains too.

The other things it does are simply a luxury - motor temp, current, charge cycle/time - all in all it's a lot of money for very little actual use of the programmer. Find a dealer with one who will re-program for a reasonable fee might be best. I'd be happy to loan mine to responsible types but it would have to somehow be secured for $250.

Dave's Discount Motors in Salt Lake should be able to get brushes from PMW or perhaps direct from Patmonts?

Good luck and keep 'em running!

dankers

Just out of interest, what are the factory settings for turbo mode? Obviously 100% power but is acceleration also 100%?

esr750

Factory standard ESR750 and EX versions turbo mode is 100% power/speed and 100% acceleration. Sport model uses 100% power/speed but 75% acceleration in Turbo mode due to it's smaller tires resulting in slightly lower final drive ratio. It would come-on pretty hard at 100% acceleration so you would only do that if you were experienced handling one of these sleds.

I haven't left the goprammer connected for test rides yet but I will eventually do that to monitor motor current, temp and battery voltage. I often wonder about trying the connector cable that comes with the goprammer into my Powerbook ethernet connection to see if it can talk to the Mac? Probably not but with the right cable pinout and some software it might work with a lappy computer?

It's cool to have but cost a lot of money - I'm okay with that and it's nice to play with different controller parameters and better monitor the charging cycle of the onboard charger. I was experimenting with NiMh packs so I justified the expense for that purpose.

Even with 13Ah F cells, NiMh just can't produce enough 100% startup current for the ESR motor so I'm stuck with a pair of hefty NiMh packs that might find home on a bicycle soon. I just spend the money I would spend on gasoline commuting to experiment with this stuff. I love the ESR750 and even though it's a brushed motor, chain drive, limited range and fairly heavy it's still the best and most affordable serious e-scooter I've found so far.

Ride pro!

jambeedavid

thank you esr 750. you are a credit to gpn and v is for voltage.

__________________
Owner/Builder - TS Carbon Fiber GSR60, TS TSI

Porsche tracking, Jetski Racing, Piranha Keeping, Harley cruising, Ducati riding, LandRover crawling, SVT 1/4 mile dragging, RC Heli hovering.....

dankers

Just an update, DDM can't get the brushes as I tried this route. They need a PMW part number and I couldn't find one for the motor brushes.

I took the old motor apart, toast is an understatement!

Clock Ticker

ESR's are great!

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s25-ported cylinder, pistons, piston rings, expantion chamber-38.4 MPH

Sheriff Jon

I don't know the specs. but I believe that Steve Patmont had a "prototype" ESR with a more powerfull motor on a recent SF ride. If it turns out that your batterys caused the motor to fry maybe this new motor, if and when it becomes available, could handel the extra juice of your Lithiums. And I believe it fit into the existing motor case.

I have an ESR with a EX battery kit and I can get 7.4 miles in TURBO @ a verified 21 mph, and I weigh in at 215 or so. I love my ESR, but would love it even more if I could double or triple the range. A 30/30 (30 mph for 30 miles)electric scooter would be a real contender for a viable and practical commuter scoter. Even 20/20 would be fantastic.

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

GO GREEN
Torkinated and Slakinated

esr750

Yes, and what is toasted inside? Are the armature/field windings sound? How much brush was left?

Brushes are soft enough to file very easily and I've repaired other DC motors with automotive parts sized to the job. As long as the terminal is similar style and size, the brush can be shaped to your needs.

Have you had any luck contacting PMW? Wonder what they want for a new motor? I'd probably buy a spare to have on hand if it weren't much more than the Goprammer. Gimme time to repair or perhaps rewind the stock motor for slightly higher voltage.

But, I do follow ESR comments and it's been said that the stock motor doesn't do well running 100% for more than 30 minutes continuous. I don't know 1st hand but I'm considering a trailer battery pack and these comments concern me?

Let's face it - the future is high voltage 3 phase AC motors and sophisticated invertor/controller circuits to get this technology to a more practical level for commuting. I admire the ESR for it's 21st century chassis design but the electrics and drivetrain are about 75 years behind the rest of the platform.

if I find anything about replacement motors I'll post back with the info.

good luck

esr750

Ditto that if recharge only took a couple hours.

7.8 miles @ 21mph? Hmm? Maybe my ex BB batteries aren't the greatest but I'm lucky to see 5 miles and I dunno my top speed but it's around 20mph. I'm 225lbs, 6' 2" and a lot of starts/stops in Manhattan.

It fits the "limited" bill for now and maybe someday PMW will wheel-out some of that cool stuff they've been working on?

'pleasure to visit with y'all...

hobbyholic

Yes the following is book sized, but you wont ever forget it, especially after working on a lucas wiring system (jaguar, land rover, triumph, mg, etc)
ELECTRICAL THEORY OF SMOKE...BY JOSEPH LUCAS

Positive ground depends upon proper circuit functioning, the transmission of negative ions by retention of the visible spectral manifestation known as "smoke". Smoke is the thing that makes electrical circuits work; we know this to be true because every time one lets the smoke out of the electrical system, it stops working. This can be verified repeatedly through empirical testing.

When, for example, the smoke escapes from an electrical component (i.e., say, a Lucas voltage regulator), it will be observed that the component stops working. The function of the wire harness is to carry the smoke from one device to another; when the wire harness "springs a leak", and lets all the smoke out of the system, nothing works afterwards. Starter motors were frowned upon in British Automobiles for some time, largely because they consume large quantities of smoke, requiring very large wires.

It has been noted that Lucas components are possibly more prone to electrical leakage than Bosch or generic Japanese electrics. Experts point out that this is because Lucas is British and all things British leak. British engines leak oil, shock absorbers, hydraulic forks and disk brakes leak fluid, British tires leak air and the British defense establishment leaks secrets...so, naturally, British electronics leak smoke.

Author Unknown


The Theory Explained through Discussion.

When wires smoke, how come the smoke is not the same color as the wire?

This is not completely true. When the smoke is in the wire, it is under pressure (called voltage). The pressure difference causes the color to change from the normal color we are used to. Not unlike the blood in our veins and arteries changing color due to the oxygen content. When the smoke escapes the wire and is exposed to air, the pressure is released, and the color reverts back to what we commonly recognize as smoke. The wire then changes to the color of the smoke that escaped.

I hope this helps you understand.


I would only question the last sentence of that description. It has been my experience that the wire turns a color directly opposite of the smoke.

Not always true, I think it must depend on the composition of the smoke in question.


I should have made it a little clearer; the color the wire becomes, is directly proportional to the escape velocity of the smoke. Higher velocities generate higher heat. This heat tends to burn the wire and affect the coloring. The statement was meant to be a generalization, indicating the fact that the color of the wire does in fact change. Sorry for the miscommunication.

I was speaking of electrical smoke which is generally white. The spent smoke casing generally assumes a color somewhat near black after the smoke leaves.

I can't stand it anymore! If, as you say, light bulbs suck up darkness and convert it to smoke which is transmitted (via wire) to a power source for recycling...why do car batteries go dead when lights are left on? Do car batteries (and flashlight batteries for that matter) have a limited amount of storage capability? Is it like a hard drive that gets so full that you have to double-space and then lose all data?

Now you're getting it.......

I thought you guys were smarter than this. Of course the battery stores the smoke. In fact it can store so much smoke that if you open the top and light a match, the resulting explosion can do serious damage. I'm sure you are aware that usually where there's smoke there's fire. If you connect the battery to a charger, the smoke is then returned to the wire (Remember, a light bulb wont work unless it is connected to a wire system) for the utility companies to use. Your hard drive analogy is a very good example.

Our hardware guys might be onto something in their quest for superior wiring. I have noticed the unique method of of series/parallel wiring the power strips on our systems seems to prevent the smoke from getting out of the wires. A "Smoke Loop" of sorts. In the case of the "smoked" workstation recently, you should notice that this was a conventional single power strip installation.

Since color is percieved by the cone shaped receptors in our eyes, and cones require more light that their rod shaped counterparts. Is the sky blue at night?

At night the process including contraction of the pupil is visual purple by which the eye adapts to conditions of increased illumination when facing 300 candle power redeflecting devices.

Since there is a spectrum of light that we as humans cannot see, I support the theory that everything is going up in smoke, we just can't see it. This may explain why the neighbors dog barks for no apparant reason.

I think your basic understanding of smoke systems is remarkable. However I find a flaw with your theory. The battery is a reusable storage device for smoke. therefore, one would assume that some sort of one way valve (we can call it a diode) should be needed to prevent pressure flooding back into the system while at rest. Unlike the A/C system, the smoke system is collecting darkness at the headlights and converting it to smoke. This causes the system to fill up. The battery can contain much higher pressures and volumes than the wires. If this pressure exceeds the capacity of the wire, it will cause a rupture as you described. The rupture can be controlled by a sacraficial device known as a fuse. But this still doesn't eliminate the problem. Perhaps a two way valve (zener diode) is used to allow a small amount of pressure to return to the system, and partially equalize. I find this theory unlikely though, due to the increase in the force required to start the pump (which is now under pressure) working again...

The smoke continues circulating through the system, due to the pressure differential in the battery (smoke pressure/vacuum reservoir). When the reservoir becomes depleted, the pressure simply equalizes everywhere in the system (similar to an A/C system when it's turned off) and stuff just wont work. Notice the relations: Work (W) = Force (F) x Distance (D); Force (F) = total difference in pressure (Dp) x Area (A). Therefore, the work done in a pressure system is: Dp x A x D. If the pressure differential (Dp) is reduced to zero then W = 0 x A x D = 0.

The smoke only escapes the wires when a path is created between the pressure differential areas (@ either the reservoir or the pump) that has too little restriction. When this happens, the smoke travels through the wires so fast that the friction between the smoke and the outer walls of the wiring heats the wires until they rupture. The smoke continues to escape until its pressure is equalized with the atmosphere, or until the conduit that provides the path between pressure areas is severed. When this happens, the sudden drop in pressure allows the wires to "collapse" slightly and, being soo hot, as the edges of the ruptures and severed ends touch, the material becomes fused, sealing the system and retaining the remaining smoke.

Don't forget, when the system is at rest, all the valves, (switches and relays) are closed, keeping the pressure areas separated. When restarting the pump, as long as everything is OK, the smoke pressure is equal on both sides of the pump and there is no net force on the pump when it begins operating again. Also, within the pump there are pressure/volume actuated one-way valves with restrictors built in, arranged in such a way that they keep excess smoke volume recirculating through an integral smoke loop, which maintains the pressure within manageable limits.

The excess smoke, created by the light/smoke converters (headlights and other darkness absorbing devices), is changed back to darkness and dissipated in small unit concentrations so its dark effect is not locally observed. The smoke pump impeller (stator), converts smoke into magnetic flux which does work on the engine. Some of the excess work energy is dissipated through the cooling system and exhaust in the form of heat, while the remaining work energy is converted back to smoke and distributed evenly in small concentrations as you drive. This maintains the total quantity of smoke in the system at an average that does not change over time.

dankers

The windings looked like they had been thown in a fire for about 30 minutes, black ash with little bits of copper wire inside, totally had it. The brushes were fine and slightly worn however, one brush had broken free and that is what cased the final failure, I wanted to post pictures but I took it in to a motor repair shop and that where we opened it. Glad I did as it was fairly sooty in there.

The motor tech thinks that the motor was orginally a bit dodgy and had an intermitent broken winding from the commutator, this first started the heating issue. The final failure was when the brush broke free, it shorted the windings and also gouged the comm a bit.

This is the sad part, I'm new to goped and dispite sending a couple of emails never got a reply from them - OK products but shunning customers is totally unacceptable and downright rude. If it wasn't for you guys I wouldn't have known where to get spares from.

What I did do was leave the old motor at the motor repair place and asked them to fix it - they were convinced that it was a cheap Chinese motor even though I explained that Go-Ped's are totally USA made. I have also ordered a brand new motor from DDM, it was around US$200. This way I have a new motor and a spare.

Be warned ESR owners that you can NOT buy brushes for the ESR motor, according the DDM, their is no such part availible - so depending on how heavy you use your ESR, you could be up for a new motor when the brushes are worn.

Totally agree - the scooter is great, the DC controller isn't half bad but really, brushless is the way to go and it's the way I would go *if* I could find one to fit. The closest I can find is an RC motor that is $1000 (search for a plettenberg predator) but its $1000! Although it's a 3" dia motor, its also an outrunner if it wasn't I would buy it.

rockyray

what kind of shop in the yellow pages repairs the esr motor? i have b&b 15 ah batteries in my esr and i have gone thru two motors already. luckily the first one was under warranty . so far i have only had to buy this new one but i would like to get the old one rebuilt and maybe they can do a better job on it. the original motor lasted 2 months and the second motor lasted about a year.

hobbyholic

the best place to take it would be boyle future tech located in auburn
the addy & # is...
Boyle Future Tech
12325 Locksley Lane
Auburn, CA 95602-2006
Phone: (530) 888-6290
call and ask. they might not do gopeds.
they do exellent work on electric components......motors, alternators, generators, starters, electrical repairs, etc.
ALL the dealerships, auto shops, city & county repair facilities use them.
every shop I ever worked at used them, or ended up using them after I told them about the place. They have rebuilt every starter or alternator that has ever failed on me. I have been there 100+ times easy. I used to work in the auto complex 1/10mi down the road.
they can even turn commutators, and stators, and custom build motors (more or less turns, larger or smaller wire, bearings, rebuild fried motors, etc.
they warranty the work too!!
I live in citrus heights. maybe you could bring it over and we can look it over and get the parts you need or take the motor up to them.
Idk?

dankers

Good to hear that I'm not alone and I think that the ESR motor is just capable of working with the stock batteries. I pass a motor shop when I work at one customer's site, its called Airport Electric Motors, what you are looking for is a place that does re-winds and servicing, basically the same kind of place that hobbyholic states above.

hobbyholic

yeah, this place I am talking about is pretty much at the end of the runway to Auburn airport.....kind of random that yours is called airport electric motors and my place is right next to an airport.

dankers

If I had the charger that could output the current, my 13 mile range Lithium ESR could in theory recharge in 20 minutes, I know people who are recharging at 3C with these cells without issue. Commonly Lithiums are charged at 1C so this means that it takes just over 1 hour for any pack to recharge as long as you have the charger that can put the amps back in. My charger isn't beefy enough to do 21amps, only 12 amps so my scooter from a full discharge takes 2 hours to recharge.

Even with the lead cells, the limit is the Go-ped inbuilt charger as quality lead cells can be bulk charged very quickly - if you need fast charging, you could always buy a switchmode (nice and light) 24v 8 amp charger that would charge an EX in just over 2 hours. Not all chragers are equal, by 8 amps, I mean constant current, like a Soneil. In fact their 8 amp 24v charger might even fit onboard as it's really small.

esr750

Dankers - Thanks for the gory details and hopefully some of us can learn from your situation. I finally found p/n for the motor on GoPed's site but nothing for the brushes which is odd since the factory service manual details brush replacement? DDM should be able to get an answer and/or somebody from Goped should address this problem ASAP. I understand modifications can't be warrantied but to not offer brushes for that DC motor?

If that's the way they're (DDM/PMW) gonna be, I might as well plan on an upgrade and just use the best part of the ESR - the chassis. Throw that "unsupported" motor away!

Hobbyholic - thanks too for your motor rebuilder info. Together perhaps we can keep these sleds running despite the lack of factory/dealer support.

DDM also screwed-up my order recently and I'm trying to be patient with them but it's frustrating. I wanna support these businesses and builders but if they don't even TRY to do right by their customers, it sure makes it hard to keep a positive attitude.

'Sorry you have to spend another day without your e-sled...

dankers

That's interesting, although everyone seems to like DDM here, I wasn't totally impressed, I had to pre-pay for the entire order I made with them before they would even special order the motor from Go-ped. I hope they get mine right, especially being here in Oz. Seems I'm going to be a long time without my scooter, not good for only getting 8 weeks worth of use. Anyway, here's the e-mail received from a guy called Brad at DDM when I asked about the brushes:

I get the feeling that E scooters are not a priority for Go-ped, its a shame but it just reflects the amount of users of the E scooters Vs gas.

Any ideas on how to keep the motor cool when I fianlly get a new one?