AeroVironment Gt Charger ebike review

[tuxman]

Before I bought my GT Charger electric bicycle from Sam at electroportal a few years ago, I did a bit of research, and found several different types of ebikes.

The GT Charger was very attractive mainly because the motor drives the Shimano Nexus-7 transmission and it's price point complete. Also, I didn't want a kit with bugs to sort out. It was purpose built and well designed. Made in the USA. Powerful. http://www.electric-bikes.com/bikes/charger.html

I am very happy with my Gt Charger at over a thousand miles on the bike. After my controller stopped working, I fitted an aftermarket Curtis 1505 controller, potentiometer, on/off switch and battery charger using the stock battery pack. Not as clean looking, no longer vintage, but it's much more powerful than stock. Wired the headlight directly into the battery pack this time around.

After I set the throttle using the potentiometer, I leave it, then turn the power on/off at the push of a button. This allows me to fine tune the power of the motor to match my cadence. On the flip side, you have to peddle any time the motor is on. Being pedelectric I had to peddle to turn the motor on before these mods so this was nothing new.

I don't have a way to monitor the amp draw other than by the fuses I've blown. Was using the stock 20 amp fuse but quickly found out the new controller was much more powerful. 30 amps was fine for awhile, but it blew when I pushed too hard on a major hill in a higher gear than usual. Went to a 40 amp fuse and haven't blown one since.

My commute is 5 miles one way, 4% mean grade of rolling hills. With the 14ah SLA battery pack, an average 25ah draw, using the motor assist on every hill, it has been more than enough to make the commute. Have had 2 flats, blown fuses, chain pop off, but have not had the battery pack go flat in all these years.


I am happy putting the power to the peddle with my Gt Charger!




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[buzzfirst]

Thanks for the review on a turn key bike. Not everyone wants to or has the skills to build an ebike and this will be good information for someone looking for a turnkey. If I could have found a purpose built electric trike(tadpole) I would have, instead I have to build mine. Congrats on getting what you wanted.

 

[Starson]

Hey Tuxman,

I think it looks just beautiful! Anyhow, was wondering what your top speed is, before and after your modifications? Also what sort of hill climbing ability does this bike possess? Did you get the new controller as part of an upgrade kit from Sam at Electroportal? My understanding was that if the controller was upgraded, if I remember right there would have to be a new bottom bracket installation? If you found a way to replace the controller without changing out the bottom bracket it would be worthwhile knowing about.

Regards,
Gary

 

[dogman dan]

Ugly compared to what? A cyclone? A frankenbike with a homemade chain drive? An I zip with the motor hanging off the rear?

 

[torker]

I love the innovation. Sounds like you've done a great job making a better machine. For me the only dealbreakers would be no freewheel when the motor is on and no susp. Good review and updates btw.

 

[tuxman]

Hey Tuxman,

I think it looks just beautiful! Anyhow, was wondering what your top speed is, before and after your modifications? Also what sort of hill climbing ability does this bike possess? Did you get the new controller as part of an upgrade kit from Sam at Electroportal? My understanding was that if the controller was upgraded, if I remember right there would have to be a new bottom bracket installation? If you found a way to replace the controller without changing out the bottom bracket it would be worthwhile knowing about.

Regards,
Gary

With the stock controller, the motor was limited to 20mph before it cut out. I don't have a speedometer, but it's much much faster than stock up hill. I can choose a much higher pedal assist level now, which really helps when pulling my trailer and on the one major hill on my commute.

In 1st gear with the trailer I can tackle any hill.

So my bike has been sitting parked for awhile, $400 would have been plug and play easy, but for less than half of that I rolled up my sleeves and soldiered it in myself. By now I was a bit more comfortable and had more knowledge so I got the controller from http://www.electricscooterparts.com/speedcontrollers.html . It was quite easy to replace.

Didn't require a new bottom bracket, I think you are talking about going to 36v? If you are talking about the stock wires and the removable pack brackets, I bypassed all stock wiring, and ran new wires to the motor. The pack is no longer removable like it was in stock form. Hence, it looks ugly as someone has pointed out. I broke the handle that latched the pack onto the bike, and zip tied it to keep it secure. After that I could no longer remove the battery pack anyways, so I didn't add quick disconnects from the battery pack to the motor etc.

Just remove the guts from inside the "removable battery/charger/controller pack". Connect a new battery charger to the batteries, the batteries to the new controller, and the new controller to the stock motor. Hook up your choice of throttle,then hook up the on/off switch.

As long as you supply the stock motor with 24v DC it doesn't care what controller you are using. Stuffed my new controller and battery charger in place of the old one and I was in business.

 

[tuxman]

Forget that gas powered rust bucket. Lets talk ebikes. No hub motor at legal power comes close in performance to the GT Charger on a 20% grade or pulling 100lbs on a trailer.

The only other instant bike on the market that comes close cost about $4,000 more.

 

[tuxman]

I love the innovation. Sounds like you've done a great job making a better machine. For me the only dealbreakers would be no freewheel when the motor is on and no susp. Good review and updates btw.

Sam told me he I could get a freewheel for the front chain ring, similar to the one the Cyclone uses. I declined, I need the exercise anyways, plus to save my batteries, I peddle the distance, and use the motor on hills.

You can see on his website pics of the bike with front shocks. You can add them for an up charge.

The advice to me was you don't need shocks for a road bike, and would be hard pressed to find a pro style road bike that had them. Honestly the 26" x 2.1" tires take the bumps quite well. If I were to go off road, I should consider it, then add them later as needed.

A few years later, still on the road, so I didn't need them after all.

 

[Starson]

Tuxman,
Just to clarify, when your modded charger bike is powered up and you are moving, do the pedals keep turning independent of your own peddling?

Regards,
Gary

 

[tuxman]

Tuxman,
Just to clarify, when your modded charger bike is powered up and you are moving, do the pedals keep turning independent of your own peddling?

Regards,
Gary

Yes. If you take your feet off while the motor is on, the pedals keep moving under the power of the motor.

 

[Starson]

Tuxman,
Just to clarify, when your modded charger bike is powered up and you are moving, do the pedals keep turning independent of your own peddling?

Regards,
Gary

Yes. If you take your feet off while the motor is on, the pedals keep moving under the power of the motor.

Hi again Tuxman,
Ok, I dug out an email response from Sam Wonderly at Electroportal. He talks about the pros & cons of upgrading the Charger Bike to a new controller with a new bottom bracket throttle based system. Although a more difficult upgrade, it would allow freewheeling of the charger bike (the pedels won't turn when the motor is on). The voltage stays the same at 24 volts. Apparently, upgrading to a different controller is the easier part. However changing over the bottom bracket to allow freewheeling is a different kettle of fish.

Hi Gary,

The Charger bike's controller is as vulnerable as any e-bike (or EV)
controller...though generally last for many years if customers heed our
advise regarding moisture issues (I.E., use the power pack rain cover in
rain...and if you don't have it, turn the system off until it dries out!)
I would suggest the same for ANY e-bike (even go so far as suggest you
make your own rain cover if it doesn't come with one).

The throttle controller kit consists of a 24V 30A controller with manual
speed regulator (half grip throttle), free-wheeling bottom bracket/crank
set, outboard 24V 2A charger, plus instructions on how to install. It's
not super easy to do the conversion however, since it involves removing
the original circuitry from the power pack, cutting some inner plastic and
part of the underside of the aluminium heat sink, then soldering wires so
they match up with connectors on the mounting plate. Changing out the
pedals and bottom bracket shaft/bearings also takes some bike mechanic
experience and special puller tools. Cost of the kit is $250.

We may be offering a throttle version of the bike (adapted with the kit),
but not until later this Spring when we've got the help to do it.

Given the availability of parts and the original pedal pressure controller
being a key reason why so many people have appreciated these bikes, I'd
say you're better off getting the orignial version and later deciding
whether to change it over after it fails (if it does...as some customers
have more than 15,000 miles without incident).

The Charger is an excellent bike, at a fantastic price of $800. Very hard
to beat.

Hope this helps,

Sam

Sam Wonderly
Sales and Product Develoment
Electroportal, LLC
236 W.Portal Ave. # 510
San Francisco, CA 94127
415-672-2645

There's some people over at Visforvoltage.com who have upgraded Charger bicycles. If you want to do a search type in "charger bicycle" in quotes, as it's almost impossible to do a search for "charger" because you will invariably get results for electric bike chargers. You could start with this thread which seems to cut to the chase in many ways
http://visforvoltage.org/forum-topic/bicycles-and-pedelecs/482-finally-reached-conclusion-my-charger-bicycle-saga

Be aware that these bicyles haven't been manufactured since sometime in the 1990's, so if your'e buying one, even though it's new, it is from that original stock. On the other hand, it was apparently very well designed with really good quality components. It can be upgraded, and it only costs $775.00. Where else are you going to get such a bike? By and large, the owners of this bike seem to adore it! Even in it's pedalic form, the magnet can be moved to a new location to get rid of the speed limitation. I don't have one, but I researched and really considered buying one. Got another bike and will be electrifying it instead. Or, I might just bite the bullet and buy one. There's a rental place in my city that have Charger bikes for years and they want to sell them off for $400 plus. I'd much rather get a new one for the price difference.

Personally, I'd really appreciate the non-hub motor guys discussing the advantages and disadvantages of this bike, but it never seems to happen here. Don't know why that is, maybe it's just that so little is known about the bike, or that some people consider it to be ugly, or maybe they know something that I don't cause I'm suh a newbie.

Regards,
Gary

 

[tuxman]

Hello Gary,

Much thanks for the info! Loved the part about the brother in law... http://visforvoltage.org/forum-topic/bicycles-and-pedelecs/482-finally-reached-conclusion-my-charger-bicycle-saga

My brother-in-law is expecting delivery on his $9,500 Optibike in about 2 weeks. His bike will obviously be better.

But will it be $8,000 better?

ha! That's good stuff.

IMO the advantages of the Gt Charger is in it's design. They had to work around SLA because at the time, no other battery in 1990 was mature or affordable enough. The key to their design with SLA was to use a transmission, keeping voltage requirements down, which kept battery weight down. With SLA every time you double the voltage, you double the battery weight.

Another advantage is any bike shop can true the wheels. My local bike shop won't touch a wheel with a hub motor in it.

One would think all the math required for the best results had been worked out before production, too.

 

[TylerDurden]

Personally, I'd really appreciate the non-hub motor guys discussing the advantages and disadvantages of this bike, but it never seems to happen here. Don't know why that is, maybe it's just that so little is known about the bike, or that some people consider it to be ugly, or maybe they know something that I don't cause I'm suh a newbie.

I only recall one Charger bicycle being posted here; ~2yrs ago.

The rear hub is somewhat intriguing. Looking at the spacing, dedicated freewheels might be do-able.

 

[TylerDurden]

Correction: ~2.5 yrs ago

http://endless-sphere.com/forums/viewtopic.php?f=6&t=3016&start=0

 

[Starson]

Personally, I'd really appreciate the non-hub motor guys discussing the advantages and disadvantages of this bike, but it never seems to happen here. Don't know why that is, maybe it's just that so little is known about the bike, or that some people consider it to be ugly, or maybe they know something that I don't cause I'm suh a newbie.

I only recall one Charger bicycle being posted here; ~2yrs ago.

The rear hub is somewhat intriguing. Looking at the spacing, dedicated freewheels might be do-able.

Hi Tyler,
So how do you envision installing that dedicated freewheel? What would need to be done?

Thanks,
Gary

 

[TylerDurden]

Hi Tyler, So how do you envision installing that dedicated freewheel? What would need to be done?

I don't know, as yet... But if pics of the wheel removed from the bike ever get posted, I'd be glad to speculate.

 

[Starson]

When the prices for a li po battery pack are as much as sla, then I might consider a hub motor trike, until then I am happy putting the power to the peddle with my Gt Charger!

Hey Tuxman,
I know that you've replaced the stock controller (which apparently isn't available anymore), with a new board and so this probably doesn't really help you, as it covers making modifications of the original controller board. There are pictures of the gutted battery box and wiring and that may help. However it's very interesting stuff, (even if I don't understand it). I thought that I should put it up here, since it seems to be such a good resource and there aren't too many of those on the internet concerning Charger Bikes.

I'm pretty obsessive in trying to track down things I want to know about on the internet, even if the info is scarce. I'd saved a link from a fellow who works at AeroVironment, the makers of the original Charger Bike. Since that time, it seems that AeroVironment has become a player with other big companies in battery technology. He seems to be one very smart Dude and I'm suprised that he isn't on this forum! His name is Brad Hori and he has modified the original controller board on one of his Charger Bikes so that he can use a 7 cell lipo. This bike and the mods are featured at the following link http://www.evalbum.com/1077

Click on the pictures to your right, especially the controller board. He has the changes he made to that board listed at the bottom of the picture, apparently to accomadate a 7 cell lipo???

28.00 Volt, Lithium-Polymer
Old OEM pack 4 6v x 12 AH
Upgraded to (2) 28v 10 AH 7 cell LiPo from BatterySpace.com
Part#: HPL-9759156C-7S-WR

He has also installed lipo in another charger, but hasn't mentioned changing the controller board, so I don't know if that is because the other one was a 7 cell lipo. The link is at the top of the page, so that you can flip back and forth between pages to see any differences.

2, 28.00 Volt, Lithium-Polymer
(2) LiPo in Parallel 10 AH each weighing in at 3.62 Lb each.

Caution! - The stock controller board on the Charger seem to be really finicky, and tha'ts where I gather people can get into trouble and failures. Since they don't make the controllers anymore, if you fiddle with it and it fails ... tuff luck! :x You're now into adding a new controller with no freewheeling, or adding a new controller and changing out the bottom bracket (or so I gather)
Also, I have absolutely no technical savy whatsoever. I really don't understand the ins & outs of technical stuff, but my instinct says that this material may be valuable for those that do.

Regards,
Gary

 

[brad]

HI guys. Yes I am a member on this sight, but have not had time to check it till today after doing a Google search.
If you need info on how to modify the Charger, let me know. I (think) I have it written down!
I did some documentation on it.
It was a matter of fooling it into thinking there was a centertap for the battery and changing the shunt resistors for the extra capacity.
I believe the centertap was originally put in to charge the (2) 12 volt lead acid batteries (actually (4) 6 volt) instead of putting 24 volts across this and getting an imbalance.
I also disabled the internal charger, removed some of the guts to lighten it up to about 12 pounds.
Its an expensive mod but well worth the effort for someone who wants to ride 2.5 times the distance of the original.
I still believe the Charger is the best bike, not because I work for the company but it just works so well, because of what I call seamless, thanks to the torque sensor.
I have only modified one pack so far. I made this for my wife, but she has never ridden it, so I use it for now, riding back and forth to work occasionally.

Brad

 

[Starson]

HI guys. Yes I am a member on this sight, but have not had time to check it till today after doing a Google search.
If you need info on how to modify the Charger, let me know. I (think) I have it written down!
I did some documentation on it.
It was a matter of fooling it into thinking there was a centertap for the battery and changing the shunt resistors for the extra capacity.
I believe the centertap was originally put in to charge the (2) 12 volt lead acid batteries (actually (4) 6 volt) instead of putting 24 volts across this and getting an imbalance.
I also disabled the internal charger, removed some of the guts to lighten it up to about 12 pounds.
Its an expensive mod but well worth the effort for someone who wants to ride 2.5 times the distance of the original.
I still believe the Charger is the best bike, not because I work for the company but it just works so well, because of what I call seamless, thanks to the torque sensor.
I have only modified one pack so far. I made this for my wife, but she has never ridden it, so I use it for now, riding back and forth to work occasionally.

Brad

Hello Brad,

I checked and noticed that this is your first post. Welcome to E.S. I think it would be really great if you could transcibe your notes and maybe even write a review of your Charger Bike! Especially since these electric bikes are still available for sale, and there is so little known about them. Also, there are people out there who have these bikes, and would like to increase the range, as you have done. If nothing else, then for posterity, so that the knowledge is recorded somewhere.
As you can see, there hasn't been a big response to the topic though. I would imagine that it's because a lot of people aren't that familiar with the bike, or something like that.

Thanks,
Gary

 

[tuxman]

I seem to be going against the grain on endless-sphere, very few members have the same requirements I do. Because I have to stay street legal, have 4% grades and often pull a trailer, I am going to stick with a non-hub w/transmission. Can't do gas, and hubs lack any real pulling power.

Thinking it's time to upgrade my battery pack and add a free wheel for the front cranks. Also want to change out the red push button to a finger trigger style. I would also like disk brakes and front shocks.

Upgrade or new bike?

 

[brad]

Hey guys, sorry for the really really late post on this subject.
For some reason I just got an e-mail from this sight, maybe 5 months late?
Anyway if there is something that you would like to know about the Charger Bike, let me know, if I ever get the message.
I will also write something about it later (when I remember).
As a matter of fact, I am working on a Charger now.
Someone contacted me who owns one.
Its getting new batteries and a tune up.
It seems that there are quite a few people who bought them and never used them.
They let the battery packs sit and after a half year, the pack is dead and they don't know what to do.
I still think they are great bikes, if not for the pedic (did I spell that correctly?) function, but also the Nexus 7 speed hub, which I like a lot, compared to a derailluer, which I don't like at all!

BH

 

[sk8norcal]

saw one on the street recently..

www.electroportal.com in sf
http://abc.eznettools.net/D300013/X300109/ChgrAccess.html

 

[tuxman]

Rather than upgrading my AeroVironment Gt Charger I've added an iZip Zuma to the fleet. Since the Gt Charger does exactly what I need it to do, it was better to invest into a new bike.

Each bike is well suited for its task; the iZip Zuma for daily commuting since it has all the upgrades I was looking for. And the Gt Charger as the grocery getter since it has the motor coupled to the transmission for hauling the trailer.

 

[klausbh]

Hi all,

I thought I would chime in with another endorsement for and alternative approach towards modding the GT Charger. Some years ago I bought one for $50 via craigslist, that was both mechanically and electrically in very poor shape. After some (ok, ... a lot) of internet research, I refurbished it as follows:



- 14.8V, 10Ah Lipo batteries (hobbyking)
- wattmeter / power analyser (hobbyking)
- marine grade DC circuit breaker (don't remember the exact specs)
- freewheeling cranks (sickbikeparts)
- no motor controller or throttle needed!

This setup worked surprisingly well, because the Nexus 7 hub allowed speed control via shifting (under a moderate load). In first gear I could start the bike from standstill without the inrush current triggering the breaker. In top gear, on the flats, with my 190 lbs self, and no pedaling, the bike got to about 17 mph. At maybe 20 mph the motor would run free, providing no help, but also drawing very little power. Low speeds down to about 7 mph could be dialed in using the lower gears. When time came to turn the motor off, I either reached for the switch (if the situation allowed for it) or simply applied the breaks, causing the circuit breaker to pop before any damage to the batteries occurred. Range was about 8 miles purely on batteries, which was enough to get me to and from work. I sold the bike to an acquaintance when I moved overseas, but as far as I know it is still running. If I were to start over again (and I might when I move back to the US) I would probably try 18.5V batteries (5s instead of 4s), but otherwise do everything the same way.

-Klaus