GTech Battery & Controller Upgrade

Crambie

Finding my (electric) wheels
Dec 8, 2018
11
3
23
Even though I didn't expect to I really like the gtech especially after a few upgrades and tarting up of the boring paint. However there are a couple of things I wouldn't mind improving. One's range and the other's the max assist speed, it cuts off a bit earlier than the limit which is understandable for the little battery, and ease of changing modes. Just for extra range I could buy a 2nd battery (it's a 5.6AH and £299) but that doesn't change the other two things.

It's a Bafang (rear) motor marked BFY1604H14298, 250W 36v. The pedal sensor's inside the bottom bracket.

So would there be any problem adding a 3rd party controller and battery (10AH or so would really be enough) I presume it's just a standard motor badged up as Gtech's? I'm not sure if the sensor would be usable too, the wires isn't plugged, they just go in to the controller. It doesn't use brake cutoffs. I'm not sure if that's because the way the controller's setup or what, would I need them?

Anyway If I can then any recommendation on both plus a dinky head unit (or whatever you call them), without importing from China? Thanks.
 
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Crambie

Finding my (electric) wheels
Dec 8, 2018
11
3
23
Thanks. You mean "just" taking the battery pack to bits and swapping out the batteries for higher capacity ones? That could be an option depending on how easy it is to take apart and what batteries it currently has. I've not found a proper internal view so don't know what it currently uses so it's possible that you can't get bigger ones (just been searching and you almost definitely can). It's a good thought.
 
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vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,985
Basildon
All motors work the same. You can swap out all the other electric components, not including the battery, to standard Chinese ones for about £60, then you can use whichever battery you want and get whatever speed you want. if it were mine, I'd be looking at 48v for the increase in torque, which will help a lot on a bike without gears. Your old pedal sensor won't be compatible.

To do the conversion, you need basic electrical and DIY skills because it's not going to be plug-and-play, though if you have those skills, it's nothing difficult.
 

Crambie

Finding my (electric) wheels
Dec 8, 2018
11
3
23
Thanks. The motor is plugged as usual and I'll be adding panniers so could shove the stuff in one of those. It looks like I would need a different bottom bracket as I doubt the non-drive side has the space for a sensor, it's a couple of mm gap. So it would basically be a kit content minus the motor/wheel.

What about brake cutoff? The current controller must use the sensor to cut power. On a 3rd party one would that be the same? I'm sort of guessing not or they wouldn't be supplied with kits.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,985
Basildon
Thanks. The motor is plugged as usual and I'll be adding panniers so could shove the stuff in one of those. It looks like I would need a different bottom bracket as I doubt the non-drive side has the space for a sensor, it's a couple of mm gap. So it would basically be a kit content minus the motor/wheel.

What about brake cutoff? The current controller must use the sensor to cut power. On a 3rd party one would that be the same? I'm sort of guessing not or they wouldn't be supplied with kits.
You don't need a brake sensor with a KT controller because it has such a fast response to the pedal sensor, but the one you have will most likely work if you want to use it.

There are always ways to fit a pedal sensor without having to buy a new BB. it just takes a bit of imagination. All you need is some magnets rotating around with the crank, and the sensor positioned where they'll pass closely.
 

Crambie

Finding my (electric) wheels
Dec 8, 2018
11
3
23
I think a new controller would be easier than trying to get the integrated one working, for me anyway. So it just depends on the controller, one without cutoff's makes it that much neater. Thanks.
 

Bjn201

Finding my (electric) wheels
Oct 26, 2019
7
0
Even though I didn't expect to I really like the gtech especially after a few upgrades and tarting up of the boring paint. However there are a couple of things I wouldn't mind improving. One's range and the other's the max assist speed, it cuts off a bit earlier than the limit which is understandable for the little battery, and ease of changing modes. Just for extra range I could buy a 2nd battery (it's a 5.6AH and £299) but that doesn't change the other two things.

It's a Bafang (rear) motor marked BFY1604H14298, 250W 36v. The pedal sensor's inside the bottom bracket.

So would there be any problem adding a 3rd party controller and battery (10AH or so would really be enough) I presume it's just a standard motor badged up as Gtech's? I'm not sure if the sensor would be usable too, the wires isn't plugged, they just go in to the controller. It doesn't use brake cutoffs. I'm not sure if that's because the way the controller's setup or what, would I need them?

Anyway If I can then any recommendation on both plus a dinky head unit (or whatever you call them), without importing from China? Thanks.
Hi Crambie,

Just wondering if you managed to remove the speed limiter on your gtech?

I have one now, and looking to remove or derestrict the 15mph cutoff, for use on private land only.

Thanks!
 

Mefmotorsport

Finding my (electric) wheels
May 26, 2020
12
0
Hi all, I have 2 Gtech city ebikes which were recently subjected to intense heat in a serious garage fire at home. The bikes have fared well, just smoke damaged but one had its battery fitted which is partially melted and has failed completely. The bikes both work fine on the other good battery which was in the house. I rang Gtech about buying a replacement B1 battery but they don’t sell them any more so the bike is useless.

I was wondering about fitting an aftermarket battery and controller (I am an electronics engineer so I’m not daunted by this task) so I’m interested in anyone’s thoughts on such a conversion.

I see that the motor controller circuitry is enclosed in the battery holder and there is considerable circuitry inside the battery too.

If I don’t sort something out then the bike is scrap which is a shame as it was superb for me and my wife’s requirements.

Any comments welcome!
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
19,992
8,173
60
West Sx RH
You could use a Hailong battery with integrated controller if the combo will attach to the bike though they will be heavier and larger, add a lcd with five assist levels for better power control. The main issue is the motor connector and if it is a standard ebike hub one used or not, other wise wiring it should pose no issues for you.
 

pauland

Just Joined
Jul 2, 2020
3
0
Hi all, I have 2 Gtech city ebikes which were recently subjected to intense heat in a serious garage fire at home. The bikes have fared well, just smoke damaged but one had its battery fitted which is partially melted and has failed completely. The bikes both work fine on the other good battery which was in the house. I rang Gtech about buying a replacement B1 battery but they don’t sell them any more so the bike is useless.

I was wondering about fitting an aftermarket battery and controller (I am an electronics engineer so I’m not daunted by this task) so I’m interested in anyone’s thoughts on such a conversion.

I see that the motor controller circuitry is enclosed in the battery holder and there is considerable circuitry inside the battery too.

If I don’t sort something out then the bike is scrap which is a shame as it was superb for me and my wife’s requirements.

Any comments welcome!
It is still possible to get V1 batteries but they have supply issues.

I have wondered about wiring up a different battery using the base of an existing V1 battery to plug into the controller. As far as I know there is nothing special about these batteries so I wonder if plugging in a generic 36V ebike battery with a higher capacity via the V1 battery base connector would work.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,985
Basildon
I'd chuck all the electrics apart from the motor. £200 should be enough to get a lightweight battery plus mounting, a decent controller plus throttle, PAS, speed sensor and LCD. You're then master of your ebike instead of slave to it.
 

pauland

Just Joined
Jul 2, 2020
3
0
I'd chuck all the electrics apart from the motor. £200 should be enough to get a lightweight battery plus mounting, a decent controller plus throttle, PAS, speed sensor and LCD. You're then master of your ebike instead of slave to it.
That's not in my plan and I'm not a slave to it.

I may well try substituting the battery at some stage. I'm happy with the bike but would like to know if an alternative battery could just as well be used.
 
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peddler13@

Just Joined
Aug 30, 2020
1
0
That's not in my plan and I'm not a slave to it.

I may well try substituting the battery at some stage. I'm happy with the bike but would like to know if an alternative battery could just as well be used.
So has anyone successful swapped the Gtech battery ft or a different one yet please?
 

pauland

Just Joined
Jul 2, 2020
3
0
So has anyone successful swapped the Gtech battery ft or a different one yet please?
I'm not aware of anyone doing that. After making my original post I realised the standard GTech batter includes circuitry not only to control the battery but also to set the two ride modes (eco or full) so it would take more than a simple battery swap.