no reading from wattmeter from battery output terminals?

[footpump]

hello all received my wattmeter yesterday the output wires are a bit thick at 12g.
I tried wattmeter using the load side + & - to a 9volt battery wattmeter works.

so I thought rather than fitting the wattmeter to my ebike all I will do is charge up my battery 36v 10.4 to see if I have 360watt when fully charged, use ebike and see whats left when one bar shows on lcd display.

I also have another battery 13ah and a spare frame mount, so tried wattmeter load +&- connected to the output terminals of frame mount but got no reading?

then realised battery was not turned on, tried again still no reading, removed battery from frame mount and tried on output terminals on bottom of battery still nothing .

not sure whats amiss?

thank you, ps also want to check if 13ah battery is actually a 13ah battery

 

[Kinninvie]

Source side + and - should be connected to your battery and load side - is connected to the negative wire from your motor as it goes back to the battery .Simplest way is to cut the negative wire going to the battery and put the wattmeter inline with the source side nearest the battery.
The red + wire on the load side is not used and should be insulated.

 

[Kinninvie]

Latest GT Power instructions show the positive wire connected through the meter to the load but it will work either this way or the way I describe above.
I have 3 of these wired this way between my bulk chargers and batteries.
http://www.ebbm.nl/Files/3/4000/4467/Attachments/Product/3psd5B2J2N9845S17920hf5438O194XB.pdf

 

[footpump]

thanks for info can get a reading from meter but no ah or watts
myhttp://www.ebay.co.uk/itm/New-FT08-RC-150A-Hight-Precision-Watt-Meter-Power-Analyzer-Backlight-LCD-UK-K1O7/162083199831?_trksid=p2054502.c100227.m3827&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908103841%26meid%3Db3d70559c3884d479b88d8e0a5e6eaf5%26pid%3D100227%26rk%3D2%26rkt%3D12%26sd%3D391310516149 meter from

seems similar toohttps://www.electricbike.com/%E2%80%8Bebike-battery-math-volts-amps-amp-hours-watt-hours/

 

[footpump]

here is a pic connected to 13ah but just shows 39 v

 

[awol]

Putting the battery on the load side as you have in the photo is for when you are reading the charge going into the battery and the charger's + and - are connected to the red and black on the source side. I use one for that sometimes.

 

[awol]

thanks for info can get a reading from meter but no ah or watts

The ah and watts increase when you are drawing power from the battery as these are calculated from what is actually being used in real time.

 

[Kinninvie]

As above Ah and watts are a measure of energy being used not stored.