how to use a kill-a-watt meter

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Last seen: 11 years 6 months ago
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how to use a kill-a-watt meter

I purchased a kill-a-watt meter for charging my batteries. It reads a 120v from wall, 2amps when charger attached. I charged the batteries today and the charger turned off when I checked but it was several hours later when I checked it. It read that I used .21 kwh. How can I use this information to determine how long it charged the batteries for. If the charger uses 240watts(120v x 2 amp) can I just divide that by 60 which would be 4 watts a minute. Then divide that into the .210kwh or 210watts and determine that the charger ran for about 52 minutes.

Is there some way to determine the overall range of the bike from this information. I had driven the bike about a mile today but it had also sat for close to 48 hours since my last charge. My controller is attached to the battery pack and is turn on/off with the key switch but I believe it still draws some current even when not turned on.

Last seen: 4 years 3 months ago
Joined: Friday, December 1, 2006 - 09:01
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Re: how to use a kill-a-watt meter

Well, pretty much. The charger is a taper charger, so you can't tell the total time it's been on from the amount of electrons pumped into the pack.

.21 KWH is 210 watt/hours. That's the power consumption at the tap, so any inefficiencies in the charger will be included. The pack holds about 1 KWH (12*20*4=960 Watt-hours), so if you'd run the pack totally flat you would need about 1KWH to fully fill the battery.

reikiman's picture
Last seen: 5 months 3 weeks ago
Joined: Sunday, November 19, 2006 - 17:52
Points: 8447
Re: how to use a kill-a-watt meter

BTW it's fun to calculate the miles/gallon equivalent ... see: Equating "fuel" efficiency between electric, hybrid, and gasoline vehicles

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