Electric conversion: Project ForkenSwiift

[Matt Timion]

Originally Posted by SVOboy

Matt will have to make a chargelog,

HAHA... That's not a bad idea. Is there a way to quantify how many Kilowatt hours are used to charge a char?

[JanGeo]

Hey you ever heard of a Kill-a-watt meter? It plugs into a regular outlet and measures amp hours, Kilowatt hours, voltage, frequency, amps, watts, power factor, volt amps, and time connected to the outlet.

[The Toecutter]

but... as of today i've sold enough stuff from the red swift that we've made our money back on it. (and there's still a perfectly good motor - with decent compression even - that nobody seems to want.)

Ebay.

[krousdb]

Yup, the kill-o-wat meter is the bomb. I had it from when I grid charged the Prius to record kwh. Now I use it here and there to see how much juice things draw. I got it on ebay for like $25 shipped. The only caveat is that it is rated at 120V, 1875 watts. If you are using standard 12V chargers then you should have no problems.

[MetroMPG]

chargelog. that's funny.

eventually if we want to truly compare our vehicles' efficiencies, we'll have to convert to common energy units. diesel will lose some of its apparent mpg advantage over gasoline, etc.

ebay the motor, eh? has anyone here ever shipped a motor? or received one shipped to them (you have, right matt)? i've specified preferred pick-up on teamswift - that may be part of why it hasn't sold (in addition to being the least desired motor in the suzukiclone pecking order after the 1.3 dohc and the 1.0).

thing is, i have no idea how to "package" it properly and would have to check international issues, since the buyer would probably be south of the border.

[MetroMPG]

Originally Posted by krousdb

Yup, the kill-o-wat meter is the bomb. The only caveat is that it is rated at 120V, 1875 watts. If you are using standard 12V chargers then you should have no problems.

i think we'd blow it up. even if we stick to automotive dumb 6A chargers on a 4 12v battery setup, that would be 120V x 6A x 4 chargers = 2880 watts. could do the calcs manually i suppose; just time how long we're charging for.

of course, then we have to debate whether to base calcs on total energy pulled from the grid or actual energy used that was stored in the batts...

[krousdb]

Originally Posted by MetroMPG

[i think we'd blow it up. even if we stick to automotive dumb 6A chargers on a 4 12v battery setup, that would be 120V x 6A x 4 chargers = 2880 watts. could do the calcs manually i suppose; just time how long we're charging for.

Methinks your calcs might be wrong. Is the 6A an input or output number. I think it is an output number. So 12V x 6A x 4 = 288W.

Edit: I just checked my 10A, 12V output charger. The input numbers are 120V, 1.9A. So 4 of these would be 120V x 1.9A * 4 = 912W. You could run eight 10A, 12V chargers off of one kill-o-watt meter.

[krousdb]

Also interesting to note is the conversion efficiency of 12V battery chargers.

Input: 120V x 1.9A = 228W
Output: 12V x 10A = 120W

Efficiency = 120/228 = 52.6%

[MetroMPG]

Originally Posted by krousdb

Methinks your calcs might be wrong. Is the 6A an input or output number. I think it is an output number. So 12V x 6A x 4 = 288W.

you're right. thanks for the correction.

and, what nasty charger inefficiency. very interesting. also, not surprising now that i think of how hot the charger gets when it's in use for any length of time.

[JanGeo]

If you are charging the 12 volt batteries in series in the EV then you are better off charging them with a single high voltage charger so you only get a diode drop power loss for one diode instead of many. I run a Variac/autotransformer rated at 20 amps through a 35 amp bridge directly to the battery and dial up the voltage and current for 3 or 4 - 12 volt batteries and run some Powercheq balancer modules between them to keep them balanced charged the same. This charger, although heavy to carry at around 30-35 lbs, get about 89-90% efficency which is just a little below (1-3%) the efficiency of the much more expensive chargers.