Plugging Along: From Polyurethane Mounts to Battery Packs

This week we continue plugging along. Not a lot of activity. Actually we spent a good part of the week packing braided straps and meters. We received a shipment of 20 meters and had a bit of a backlog to fill, so it kept me busy casting shunt bases and Brain in packing boxes. We are also moving a lot of the braided straps. If this keeps up we'll have to order another brazillian.

And this is a bit of a business lesson. Whatever you are trying to do, be aware of signals that something else might be afoot. We've been struggling manfully to get some of these vendors to cough up fairly piddlin amounts for commercial advertising - 1 minute ads in our show. They've been oddly resistant.

I could be sympathetic, but recently had cause to learn what a huge discount they are giving to their dealers - often more than they make themselves from the product. I've written on the flattening effect of the Internet on dealer networks for many years. That we still had them going strong in EVland was kind of missed. And I have to say I don't get it.

But when in Rome.....

This week we received our polyurethane motor mounts that we are going to use on the Escalade. This is kind of an important issue. We need to hold 450 lbs in position, keep it from turning with 350kw of power applied, and ideally we do not want to transmit any vibration to the frame of the car.

This last can be a surprisingly annoying and often overlooked aspect to an EV build. We've never really talked about it although you've watched us do it build after build. Basically, you want some sort of rubber or urethane shock mount between any vibrating motors and your vehicle, to prevent the vibrations from entering the passenger compartment, traveling up the seat back supporting structure, and entering the fillings in your back teeth. This can be terribly annoying if you forget to do this.

And so, polyurethane shock fittings. Used for many years with ICE engines, which also vibrate annoyingly.

They basically absorb vibrations in the flexible material, isolating the vehicle from the vibrating or oscillating motor.

These cost $142 I think for two basically urethane cylinders with a top and bottom steel piece and a hole through it. A bolt through it holds it in position, and does transmit a bit of vibration, but most of the weight is carried on the flexible chunk which absorbs a lot of the vibration.

Not much happening on the flatten 'em series. I am building a 2x2 inch by 1/8th aluminum angle frame around the bottom section at the moment. We'll add the second section to that soon. Bottom balance both at 2.65 volts or thereabouts. Add a third section for a bandwidth of 4.5-5.0 inches. I may work in a Kilovac relay to allow me to turn this pack on and off remotely, and perhaps a separate fuse for it.

We tested our last 12v monolithic that we cast in the pink silicon rubber last week. It came in at about 117 Ah very nicely. Good battery. We may have to make a set of the terminal tops and some drawings and see what we can do with a machine shop to have some of those made up professionally as fas as the terminals go.

We did receive a new shipment of 500 of the A123 cells. We're gaining confidence in our Chinese supplier and the cells themselves. I guess I do NOT think these cells are as good a solution as a CALB 180 prismatic for an electric car. But the smaller granularity with the much higher power output offers a significant advantage - smaller battery packs of less CAPACITY that still offer the same power output at any given instant. As we've said numerous times, this opens the door to a pack of less expense, but consequently less range, while still retaining full operation of the vehicle.

The bad news is that you basically have to engineer a structure for the cells. And that is additional expense, effort, and time. If you can swap sweat equity for money, it can be a strategy. If you spend as much on the module as you would have with the CALB 180's in the first place, you lose all the way around. Not a great strategy.

Flatten em looks too heavy and too expensive to make sense. It's main advantage will be I can bolt it on underneath a car for testing purposes. It could be a model for a very light Speedster where that was the sole supply and we accepted a 35 mile range in the car in exchange for lightness which is of course next to Godliness in the land of the EV.

Nine or 10 of our monolithic 12volts would probably make more sense with a 120v pack of 115 AH. That would be more of a 50-60 mile car and more practical. Probably a lot easier to put together. But the resin is a significant expense. Nine of those would make a nominal 120.4 volt pack of 288 lbs and 115 Ah.

It was March last year when we first announced a little gathering at the shop that grew into EVCCON 2011. And so we kick off the season.

We had most of our sessions, our vendor area, and quite a few of the meals in my hangar at Cape Girardeau Airport last year. It's about 18,000 sf and it was pretty comfortable for the number of attendees we had. If that number were to go up even modestly, it would quickly become uncomfortable. And so we have purportedly contracted to take the entire Show Me Center Arena here in Cape for our educational sessions, most meals and the vendor area. It's about 32,000 square feet and so unless we just have a blowout event, it should be quite comfortable.

I see Willie Nelson is in Concert there April 8th. I think he'll have cleared the area by our September 26th event. What famous singers are associated with electric vehicles?

Jack Rickard