How to test with multimeter?

[lotrwiz]

My ebike is a bit iffy, it keeps powering on then cutting out randomly, I can't find an loose wires or connections though

How do I go about testing it with a multimeter in order to find out whats up? If someone can point me towards a guide or help me out, I'd really appreciate it! thanks

 

[Ypedal]

that's like telling us you have a muscle ache without telling us witch muscle....

what type of kit, battery, motor etc....... pictures of you bike would help...

 

[dogman dan]

To test plugs with a multimeter, find the + and - wires. Detect voltage where it comes from, then look for the same voltage on the same wires on the other side of the plug.

This will work easy on the wires that have constant current when the bike is turned on. Battery to controller, controller to throttle, and controller to the red and black halls wires.

Mostly, I just find bad plugs by close looking or wiggling. See if contacts appear to be backed out of the housing, that's the classic plug fault. Lately mine's been doing it on the throttle plug. No obvious fault, but I think it's become time to replace the plug. The actual throttle is about 5 years old now. I need to just snag a new one and replace the whole thing really.

 

[lotrwiz]

that's like telling us you have a muscle ache without telling us witch muscle....

what type of kit, battery, motor etc....... pictures of you bike would help...

I believe I have fixed the problem, tested voltage from battery through till I found a half melted capacitor, replaced it with a new one, and it's right as rain!
this thread can be deleted now, thanks a lot though

 

[lotrwiz]

Pleas read next message. VV

 

[lotrwiz]

Well, I don't know how, but that wasn't the problem Any ideas as to what mgiht be causing this??

 

[Ypedal]

still not telling us exactly what you have... ... come on man... you want help, we need more info about your setup.

 

[John in CR]

With such a lack of info, I say measure the voltage at each series level in your battery to make sure one isn't low and tripping the BMS.

 

[lotrwiz]

I have a 250w 36v hub motor kit, front, brushless. it's using a 250w rated chinese cheapo controller, but that was replaced like, a week or two ago.

I can't find any loose wires now, but when i go over bumps, it's still resetting itself! it cuts out randomly even when on smooth ground though and wont turn back on, but then when i bump it up a kerb and back down, it'll turn on again, sometimes briefly sometimes for a good while.

 

[dogman dan]

If you didn't find the easy fix, a backed out plug contact, then it sounds like you have bad connections in the battery.

It sounds like you opened the controller, but did not find anything visually obvious there, like a bad solder on a wire leading in or out of it.

You have looked at the wires coming out of the hub? No cuts at the axle? I had a bike act funny for some time, till I noticed a wire rubbing a tire. It rubbed only when I was on the bike, but when off the bike, the fork stood up an and wire did not rub then.

Look again, with as much seeing happening as you can do. Big difference between looking and seeing. Only 10% of people see naturally.

If you do a good solid contact of your voltmeter to the battery outputs, then ride, you will see if the intermittent power is located in the battery or not. If it's elsewhere, you will get the cutout without seeing the voltage blink on the meter.

 

[lotrwiz]

Thanks for the reply dogman, but i found the problem, the battery is messed up somehow, heres a video detailing the problem that I recorded earlier : https://drive.google.com/file/d/0B-JQA4XlZN5QbFk4dld1Z3F6Tnc/edit?usp=sharing

 

[DAND214]

Pleas read next message. VV

Read the next message?

WTF, you must be lookung for post numbers!

It still sounds like a battery connection in or out of the pack.

We still haven't seen any pics of the setup. What kinda battery and from where/who?

Dan

 

[lotrwiz]

Pleas read next message. VV

Read the next message?

WTF, you must be lookung for post numbers!

It still sounds like a battery connection in or out of the pack.

We still haven't seen any pics of the setup. What kinda battery and from where/who?

Dan

I just posted detailing the problem, please see that post

It's a 36v 9AH Water bottle battery, I bought it from 8funbike.

 

[Ykick]

Judging by the result of the bump with your foot probably bad connection inside the battery. Need to open it up and find where the circuit path is failing.

 

[lotrwiz]

Judging by the result of the bump with your foot probably bad connection inside the battery. Need to open it up and find where the circuit path is failing.

As it's still in warranty, I'll be sending it off to the seller tomorrow, have already communicated with him, so that should get that sorted!

As I'm going for a new system with new power requirements, if anyone wants to help me out with a 72v system using these, and the appropriate way of charging and BMS's, then I'd love to get in contact with them, either over skype chat or PM, thanks a lot!!

http://hobbyking.com/hobbyking/store/__32162__ZIPPY_Flightmax_5000mAh_6S1P_20C_UK_Warehouse_.html

 

[Ykick]

These are much better deal and easier to assemble into larger packs IMO:

http://hobbyking.com/hobbyking/store/__15521__Turnigy_5000mAh_4S1P_14_8v_20C_hardcase_pack.html

 

[lotrwiz]

These are much better deal and easier to assemble into larger packs IMO:

http://hobbyking.com/hobbyking/store/__15521__Turnigy_5000mAh_4S1P_14_8v_20C_hardcase_pack.html

Hmm, okay, thankyou very much!