Watt Meter & Charger Question

[Cyclist83]

Hi all,
I successfully wired up a watt meter to my battery (an accomplishment for this newbie!). All's great now that I can see how much I'm pulling while I'm riding but I now have a question...

Can I use the watt meter with my charger to see how much I am putting back into the battery? All of the connectors line up, but I'm paranoid I'll mess something up without double checking first...
So it would go like this AC=>Charger=>Watt Meter=>Battery Charging Port.

Thanks in advance!

 

[Hillhater]

Which wattmeter have you used ?
Most of the common wattmeter so are " one way" , iE , source>Load ....or Battery > Motor.
So if you want to measure the Watts ..Charger > Battery, .. You will have to reverse the connections on the Wattmeter.

 

[Cyclist83]

I've got the Lunacycle watt meter.

 

[dilkes]

Which wattmeter have you used ?
Most of the common wattmeter so are " one way" , iE , source>Load ....or Battery > Motor.
So if you want to measure the Watts ..Charger > Battery, .. You will have to reverse the connections on the Wattmeter.

For measuring the battery charging load, the Source is the charger output and the Load is the battery.

 

[dogman dan]

Exactly, the cheaper watt meters need to run one way.

A cycleanalyst can run backwards though, so you can just measure a negative number with that, or let it run back to zero.

 

[llile]

AFAICT nobody makes a wattmeter suitable for portable use measuring charger output on an Ebike that will handle up to 100V. I'm running 24S/82Volts. Most of the units I've been able to identify can handle up to 60V.


Now, I do have a cycle analyst, but it doesn't monitor the charger input, sop I'm not sure how one would go about using the CA to measure watts out of a charger.


Can anyone recommend a wattmeter or a hack that can handle up to 100V?



/EDIT the only hack I've found on Endless Sphere so far - I am using 3 Mean Well power supplies stacked to get my 82 volts supply for charging. If I just put an RC wattmeter like the GT Power wattmeter on one power supply, it will measure about a third of the total, depending on where the individual voltages are adjusted. This might be "good enough" but not ideal. I'd maybe print a chart next to it so I could quickly convert the reading to an actual wattage without a bunch of mental gymnastics.

/Edit Motomech put me on tothese- measures up to 90V, perfect for a charge meter:
http://www.ebay.com/itm/261131148479?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

 

[Jon NCal]

The cycle analyst can measure if you get the external shunt.

 

[amberwolf]

Can measure charging using controller shunt if you add a charging negative wire inside the controller on the non-battery side of the shunt and bring that out.

(adding a charging positive wire to the positive battery wire of the controller while you're in there is convenient and puts both wires right there).