Ben Nelson's Electro-Metro Build thread

[Derek Pater]

Hi Ben,
How about a 2004 Toyota Highlander 7 seater?, manual gearbox do they have them in the U.S?

Most people can relate to a crossover like this one and its not to big.

[bennelson]

We have Highlanders over here, but it might be hard to find one with a manual transmission.

I just needed a car for me to zip around in locally. I really don't take up seven seats.

If a person wanted to convert a crossover or SUV to electric, there's nothing stopping them. There was a commercially built version of the RAV-4 electric, and Toyota and Tesla are working together to bring back a new version of it.

I do think an SUV would be rather ambitious for a first-time EV converter. You would want to keep the clutch on a setup like that.

[Derek Pater]

Hi Ben,
Thanks for your feedback, very interesting info on the RAV4 I did not know that, yes you are right big project a 7 seater EV.

Do a search for Stair Square Derek Pater, you can see my project.

I did move my large shed with 27 Army friends and other projects, if I get the right people involved will make it easier.

[electricman]

My Dad once worked on a team at a military base, that build a ten person bicycle to get around the base, the frame was more like a motorbike frame than a bike frame for tube sizes and wall thicknesses, and they had a serics of gear setups to they could pedal it up to about 50 - 60 MPH!

Considering the Highlander or other such sized vehicle, if you went with a DC Motor - I would think the Siamese twins would be the best approach - made by Kostov as well as others. White Zombie's new 9" Siamese Twin can dump out over 1100 pound feet of torque - might not even need a tranny with this arrangement!

Interesting enough - I have not yet heard of any AC Motors being packaged in a Siamese twin (Tandem) arrangement - must be an issue with the Controller logic challenges! (Inverter matching & sync!)

Ben - did my info on the Lead Acid vs. LiFePo4 batteries make sense financially for your motorbikes next set of cells? (Whitepaper #1, or #2)

[bennelson]

That lithium info was very interesting.

The big downside to lithium is that initial investment.
Even if they DO last that much longer, you still have to shell out the money in the first place.

Maybe if I sell enough Electric Motorcycle DVDs, I can save up for a set!

I did meet a guy this summer who built a VERY nice electric motorcycle with lithium batteries. I'm hoping he brings his cycle up to our EV meet tomorrow. It is his second motorcycle design. The first one was a 36V lead-acid cycle.

One thing good about working on projects like these, is that they really do build both knowledge AND confidence!

I think a cycle would be a better first investment in lithium than a car, just because of the smaller pack size and lower cost. The other thing with lithium is that if you screw it up, it's a more expensive pack you just killed!

I'm sure that whatever my next project is, it will involve lithium batteries. I just may need a sponsorship for it!

[bennelson]

I really like the "Siamese Twin" concept as well.

Unfortunately, the Electro-Metor is a front-wheel drive car, with a transverse engine (ahem, now motor.)

The single 10" motor only fit in there after chopping the tail-shaft off.

I would love to do a siamese twin on a rear-wheel drive project! A while back, a bunch of us in the local EV group went to the junk yard to pull out forklift motors. We got 3 HUGE matching DC motors. TWO of them are now going into two different Ford Ranger pickup truck conversions.

I have my eye on the third one. I was originally thinking that TWO of those motors in one project could create some AMAZING acceleration!

[electricman]

Hey Ben - did you know - that one of the leading Tech Team on the Tesla started first with a 944 Porsce with two motors linked (either by belt or chain, can't remember) but Lead-Acid Batteries! Lots of GO! But not very far! That lead to conversations, connections, and the move to the 18650 cells and the formation of a team building the first Tesla Roadster!

Sure - they have a head start - but there is till room for the rest of us to Blossom!

About the details - I think you mentioned the four new Yellow tops cost you $800. That is for a 48V Pack with a (Theoretical) Energy storage of 55 Ah. Since I can not get the hard data for the Yellow tops, and can only guess, I used a reference of the Power Battery specs for a 55 Ah AGM from a UPS Set I got from work.

They are rated at 55 Ah (20 Hour) but just 33 Ah for one hour, and even that is pretty good for PBA! Also - just over 20 Ah for 2 hours (20.5 Ah) - this from a battery weighing it at 44 lbs: Power-Battery_PRC-1255S.jpg.

Per my Whitepaper #1 - the 40 Ah ThunderSky Cells can be bought from a fair number of places for $50 per cell, and at 4 per 12V set = the same $200 per 12V, but - they can deliver a 40Ah result in the one hour time frame.

Both of these energy values are for a 100% DOD for which the Lead Acid is good for about 300 - 400 cycles, but the TS for 1000 cycles. Dropping back to 80% DOD - still gives you 32 Ah from the TS cells, and now you get about 2000 cycles, vs. the 3-400 cycles for the 33Ah from the Power Battery. Other battery specs attached for additional references.

Also attached - a fairly easy to find Lead acid AGM - the BB Brand, EP33-12.
33 Ah at the 20 hour rate, but just 19.2 Ah deliverable in the 1 hour time frame of reference that I use in my whitepapers!

So - the BB would require two of them to deliver the energy equal of four of the TS-40AH cells in a 12V pack. Refurb UPS sells knock offs of them for $70 - so yes - they would be cheaper than 4 x $50 TS 40Ah cells ( a bit!)

Atbatt - sells a variety of them for a good price too!

But - back to yellow Tops - The Robot Market Place sells them for $249.99! Just a little over what wall mart was selling the Blue Tops for here in Toronto!

On the Other Hand - WallCann - sells them for ..... $365! So your price of $200 each was a very good price! And looking at walmart.com - I can't even find them!

Surrette data in next post - too much data for one post! Robert

[electricman]

OK Ben, after trying to get this file attached - and trimming and squeezing it - I still had to scale it to 90% to fit the file soze limits here, but - hopetully it is radable enough to see the issue of EV Current Draws versus Lead Acid Batter Specs!

The Table Represents going through a stack of pdf files from Surrette, and gleaning this data out, and putting it into a spread sheet! Still - after looking at the data of 10 of their batteries, it is easy to see why I am bugged by Lead Acid Batteries being used in EV's!

Robert

[bennelson]

I know a guy who has some used lithiums for sale.

Must..... scrounge....up..........money!

[electricman]

I KNow a Guy who has NEW Lithiums for Sale! And - he will be exhibiting at EV Fest 2011!

Plus - I have a new Flickr page - with some Battery Data images posted there I could not attach here - RobertWeekley1