E-Bike Fuel Gauge

[RobF]

I hadn't realised that we had lost Jeremy as well !!

So can I now say without fear of contradiction: "Ebikes with 250W motors limited to 15.5mph are for all practical purposes legal."


...waits in anticipation...

 

[Old_Dave]

"Ebikes with 250W motors limited to 15.5mph are for all practical purposes legal."

practically

 

[flecc]

I hadn't realised that we had lost Jeremy as well !!

Nor me, that's very sad.

 

[Old_Dave]

Jeremys not exactly lost.... just gagged

 

[103Alex1]

Yes, it's a nice little project and looks quite neat, but it doesn't really do very much. If you don't already have a stock of standard electronic parts, so you have to buy everything individually from Maplin, it'll work out relatively expensive. IMHO it would be better to buy a ready-made one like the Cycle Analyst, which can do a lot more.

Those were my original thoughts, Dave, and been looking into it. Trouble is the CA display is just too big to be permanently mounted on the bike. I haven't got space on the handlebars for my phone mount if I get CA (Galaxy S3 is huge and has to go where the CA display would go ... and I need to be able to have my phone mounted for SatNav).

I'd kind of got reversed into a corner on all this before the Speedict option came along .... but now there are incompatibility issues with my phone there too it seems.If I have to take it out of the picture the whole thing just got very very complicated for an end package that's a big compromise.

So ... trying to map out a plan for if Speedict winds up being a no-go because of this Bluetooth bug without losing too much. Without Speedict or Cycle Analyst I'm missing a whole load of stuff needed to bring the back bike up to the sort of end result envisaged and is going to be a great deal more work than I'd hoped it would end up being.

 

[flecc]

Jeremys not exactly lost.... just gagged

That's still sad.

 

[rsscott]

I'm afraid to say that Jeremy took the moral high ground and lost the ability to post for his troubles


Sent from my iPhone using Tapatalk

Not true Dave, he can still post if he wishes. At no point was he told otherwise.



Sent from my GT-I9300 using Tapatalk 2

 

[flecc]

Not true Dave, he can still post if he wishes. At no point was he told otherwise.



Sent from my GT-I9300 using Tapatalk 2

Thanks Russ, that's reassuring.

 

[Old_Dave]

Not true Dave, he can still post if he wishes. At no point was he told otherwise.

Thank you Russ.

 

[NRG]

I'm afraid to say that Jeremy took the moral high ground and lost the ability to post for his troubles


Sent from my iPhone using Tapatalk

Jeremy has left of his own accord, he's not banned.

The Fuel gauge also acts as an ammeter as well, you change displays at the flick of a switch between remaining battery and instantaneous current draw.

The beauty of this design is its simplicity!!! Thats why Jeremy designed it as the ready made watt meters display too much information that is not easy to decipher quickly.

The reset switch can be remote mounted it doesn't need to be right next to the controller.

You'll need to talk the Jeremy about 20Ah battery but I don't think its possible with his current design.

 

[103Alex1]

Thanks NRG.

You'll need to talk the Jeremy about 20Ah battery but I don't think its possible with his current design.

Calling Jeremy, 1 ..2 .., come in Jeremy ....

 

[Electric-Bob]

Full credit for the idea goes to Jeremy Harris over on ES, a very clever, helpful and all round decent chap. ES thread:

Endless-sphere.com • View topic - Simple ebike 'fuel gauge'

This sounded such a good idea and something I’ve been looking for on my Peugeot, so I decided to give it a try.
The display is a 9 segment LCD ‘analogue meter’ set to give a visual readout of remaining battery capacity and instantaneous current draw readout. Full scale meter deflection (FSD) is set for 30amps and total battery use is set for 10Ah batteries. The unit utilises a Picaxe-08m microprocessor and Jeremy has provided the code / program needed to make it all work. The code can be tweaked to support other capacities up to about 18Ah. Max voltage is around 65v. A reset switch is included to reset the Ah accumulated counter.
Using Jeremy’s cct diagram I laid everything out on some copper strip board, the layout worked first time to my surprise but the board is a little big, as you will see later it only just fitted inside the controller...I did consider fitting it externally but managed in the end to squeeze it in.

The display mounts on the handle bar in a neat small box from Maplin and includes a switch to flick between the two display modes. A small resistor network (potential divider) is needed to limit the meter input voltage to just under 1v for FSD, I ended up with 58K in line and 18K to ground

Just 4 wires are needed to connect the meter and I used the USB cable form an old Microsoft Mouse! I drilled the cable hole off-centre to miss the handlebars and the meter itself was also off set in the box to proved room.

I'm hoping you can offer a little help on the simple fuel gauge project. I have all the parts and am trying to bread board this prior to going to a strip board. I have very limited electrical skills and am having a hard time transferring the wiring diagram to my bread board. I have the controller off my bike and opened. Can I do this with just the controller and the battery? or do I need the controller hooked up to the bike so the throttle and motor are all in play? Or can I simulate the motor load and do without the throttle? Hope these aren't dumb questions. Any help you can offer is appreciated

 

[Deleted member 4366]

He's using the controllers shunt to calculate the current and he's tapped into its 5v rail to power the device. The 5v is only active when the controller is switched on.

In order for yours to work correctly, you'll need to know the shunt's resistance. I haven't looked through the code, but he's using the voltage drop to calculate the current I=V/R. If your shunt has a different value to his (which it will), you'll have to adjust something in the code.

You don't need to use the controller at all. He's only used it for convenience. You can use a separate shunt of known value or a piece of 14g wire. You'll need a 5v supply for it that you can get from the throttle wire, but only when the controller's switched on.

IMHO, that's a nice project, but you can get the same a lot cheaper and easier by buying a cheap wattmeter and doing the remote shunt mod. I did a thread "the best value wattmeter" that explains how to do that.

 

[flecc]

The link for d8veh's thread.
.

 

[flecc]

the link here for d8veh's thread.
.