Tuesday, January 27, 2009

Retrospective: design decisions

Just over a year after getting the Volt914 running, I've spent some time thinking of "if I had to do it all over again...". First - choice of motors (AC vs. DC). I'm occasionally disappointed at the performance of the AC24 motor. So I played a "what-if" game - I found some power output curves of the original 1.8L engine in the 914, and plotted a curve of horsepower vs. speed (assuming that one would always shift to maximize horsepower). I added curves for the AC24 as well as the Advanced DC 9":

You can clearly see that the AC24 is lower performance than the original motor, not even taking the extra weight of the batteries into account. The ADC 9" is generally higher performance until you get to 60 MPH or so - probably even taking battery weight into account.

So, if performance is your desired goal - go with DC. I do believe the range of the AC option is greater - higher efficiency, lower HP in general, the option of regen braking. Given that I mostly commute with the volt914, I think I made the right choice.

The next "what-if" game involves batteries. I'm somewhat discouraged by the acid issues with the Zivan charger and floodies. So much so that I'm saving my pennies for an upgrade this summer. I'll either go with AGMs (and a new charger) or, optimistically, something exotic if the prices have dropped enough. Stay tuned.

Other than those considerations, though, I'm very happy I did this project.

Saturday, January 17, 2009

Sigh - more leaky batteries

I knew in my gut that the front batteries were probably leaking like the rear ones were. Last weekend, I finally got around to removing the front battery box so I could see how bad it was. Pretty bad:

The front box is a pain to remove because of all the relays, batteries, DC-DC converter, etc. that are attached to it. You can see all the little green masking tape labels I put on all the wires to make sure I got things put back together correctly.

Here is the front compartment after attacking it with a wire wheel on my angle grinder:

It was warm enough that day to put a couple of coats of spray paint on it, so I did:

I went to Sam's Club and got 4 12-pound bags of baking soda. I put about 6 pounds below the front rack (looks like snow!):

I put about 1/4" or so inside the front battery box:

For good measure, I put some below the middle battery box (not shown) and inside the middle battery box (that's the ElectroJeep in the background - sealed batteries, no acid leaks there...):

Hopefully the baking soda will neutralize the acid spills as they happen. But this is something I will have to check every several months.

Thursday, January 1, 2009

Electric New Year

Happy New Year! The Volt914 is still running well. Today, I mounted an "ELECTRIC" label on the back just for fun. I hope everyone's conversion projects are successful in 2009. In case you had not noticed, my activity is nearly 100% on the ElectroJeep these days - come on by!