Voltmeter

[allotmenteer]

Hello all

Now that I am the proud owner of a 36V Nimh battery I have a question. I'm using the battery with a controller that has a low-voltage cutout of 20.8V (since it's for a 24V kit). Obviously if I ran the 36V battery that low it would be ruined. Indeed 30V is the absolute minimum to go down to and I imagine much below 36V there isn't much juice left in them.

What I'm looking for is a small voltmeter that I can mount on the handlebars or somewhere visible that will let me monitor the voltage left in the battery. All it needs is a 3 digit (with one decimal place) screen with and maybe a backlight for night use. Does anyone know of such a thing.

Obviously I can play it by ear and stop using the throttle when performance starts to fall off but something more accurate would be ideal.

I've got some lights on my throttle which seem to be reasonably accurate but as I don't know at what voltage the minimum light goes off at I don't want to trust it - how could I test this?

Paul

 

[flecc]

The problem with this Paul is the perennial one of the motor dipping the voltage, so you'd need to shut the throttle to get a roughly correct reading. Here's something compact and cheap (£2.99) which could do the job. It measures from 12 to 50 volts DC. Plug the + wire into the probe with rigged connector, mount on the handlebars and hold the handle of the device to take the reading. It might read all the time once coupled to the bars. It's Maplin part number RM69A

.

 

[allotmenteer]

The problem with this Paul is the perennial one of the motor dipping the voltage, so you'd need to shut the throttle to get a roughly correct reading. Here's something compact and cheap (£2.99) which could do the job. It measures from 12 to 50 volts DC. Plug the + wire into the probe with rigged connector, mount on the handlebars and hold the handle of the device to take the reading. It might read all the time once coupled to the bars. It's Maplin part number RM69A

.

Thanks flecc that looks perfect (and cheap too).
So I tap into the +ve wire from the battery before it goes into the controller with a suitable connector? Would one of these be ok to tap into the wire? Maplin > Snap-Lock Connectors They're only rated at 8Amp though.

 

[flecc]

The current rating won't matter as only a few microamps needs to pass. As long as those connectors don't sever too much of the main wire to the controller they should be ok.

Let me know how you get on with it, I'm interested as it could be a substitute for dud meters etc.
.