Best for ebikes: multimeter or clampmeter?

[ebiker1]

i've been told that i should get a multimeter for my ebike. according to what i've read, multimeters are good for measuring ~20 max and clampmeters are better and safer for measuring high current. what is it that a multimeter can do that would make it more useful? fluke makes a clamp module that plugs in to a multimeter and that might be the way to go. the reason for wanting a clampmeter is to measure the discharging current of my system easily.

 

[Ariane]

i've been told that i should get a multimeter for my ebike. according to what i've read, multimeters are good for measuring ~20 max and clampmeters are better and safer for measuring high current. what is it that a multimeter can do that would make it more useful? fluke makes a clamp module that plugs in to a multimeter and that might be the way to go. the reason for wanting a clampmeter is to measure the discharging current of my system easily.

Wrong question , the best thing for any ebikes is a CA (Cycle Analyst) :wink: don't waste your time with cheap solution like clampmeter or voltmeter or wattmeter... good day!
Black Arrow

 

[amberwolf]

The multimeter is needed for troubleshooting all sorts of problems, and a clampmeter only measures current, and isn't sufficient for most troubleshooting--it doesn't have all the other functions you need.

If you want to measure discharge current, you are better off with one of the many kinds of wattmeters you can read about in many threads here on ES; some in the ES wiki, etc. It will do a lot more for you than just a clampmeter would.

A clamp on ammeter is still good for some things, like checking phase currents on multiphase motors, but mostly there's no real need to do that unless you're just plain experimenting. Troulbeshooting rarely requires anything like that.

 

[cohberg]

If you wanted both in a single unit

 

[Drunkskunk]

Forget the clamp meter. it can be used as Amberwolf described, but you will likely never need to do that.

You need a Multi meter that can measure Volts and Ohms. Most good meters can also measure Amps, but ignore that function. You won't use a normal multi meter to measure Amps on most Ebikes.

For Amps you want an in-line meter like a Cycle Analyst, or possibly a Wattsup or clone meter, but the Cycle Analyst is far too useful not to have. You also want it to be able to measure your wattage, which both can do, but the CA keeps a record of it, gives you your Wh/Mi, and voltage, and Amperage, and speed, and distance, and allows you to set peak speed and amp loads amoung other things.


So to break it down, you need:
1. A good Multi Meter
2. A Cycle Analyst

 

[wesnewell]

The main thing you want on your bike is a voltmeter so you won't over discharge your battery pack. Everyone deals with electricity in any form should have a multimeter for testing. Watt meters are nice but really aren't needed. The Cycle Analyst is the Rolls of watt meters, about $150. But you can get the more common functions of one in a $20 watt meter.
http://www.ebay.com/itm/Waterproof-Digital-Voltmeter-DC-15V-To-120V-Red-Led-Voltage-Digital-Panel-Meter-/170846310527
http://www.ebay.com/itm/60V100A-Battery-Checker-Balancer-charger-for-Voltage-Power-Watt-Meter-Servo-Test-/130731639478
http://www.ebikes.ca/store/store_CA.php

 

[ebiker1]

i already have a ca-sa that i bought off ebay about 2 yrs ago for a good price. it's the small screen version, no instruction manual and too small for me the mph while riding. i've have never hooked it up as my ebike has never run long enough to do that and i don't have an inline shunt. it should probably work for measurements, though. so, i guess, the bottom line is i don't need a clampmeter. DINGDONG!!!!! 8)

 

[teklektik]

• There is no difference between a CA-SA and CA-DP except the external wiring - see manual here. This means you can use the DP connector on your controller if it has one - no need for an external shunt. Also the CA is more than just an expensive meter - it can give you 'current throttle' or LMH switch to help tame a powerful motor or twitchy throttle. If you just want to use it for bench measurements, get an external shunt from Grin Tech or a meter shunt from eBay - something around 1mOhm is fine (e.g. 50A 50mv meter shunt or 75A 75mv meter shunt).
  
  
• For tracking down electrical problems, get a cheap DMM and as recommended above, you can ignore the current capabilities - not super useful for ebike stuff. Simple DC volts, ohms, continuity test, and diode test will provide for 99% of your needs.
  
  
• For quickly identifying motor/controller issues, get an ebike tester. You can get tester from ebay or Lyen. Here's a little writeup to show you the tricks it can do. After you get it, swap out the clips for mating connectors to your controller and motor so you can hook it up PDQ. Give it a go to see what 'good' looks like. Hopefully you will never need it, but if you do, you will be really happy it's in hand.

 

[amberwolf]

You can buy the shunt separately from ebikes.ca if you like, or you can wire it up as a direct-plugin to your controller, using the shunt that's probably built into it, and calibrate the shunt value and enter that in the CA. Or get a 3rd party shunt and do the same thing. (the wiring diagram is in the manual, which can be downloaded from ebikes.ca as well; if you're not sure which version it is, jjust hook up power to it based on the wiring diagram; or ask at info@ebikes.ca )