Thursday, December 24, 2009

Lithium Batteries Finally Arrived!

Thanks to the hard work of EV Components I finally have 40 TS-LFP100AHA cells for use in the Gizmo. I placed the order in September 2009 but due to several circumstances out of their control the shipment didn't arrive until now. Fortunately they were able to find a shipper who would ship to Seattle and customs didn't take a full month like it did on earlier shipments. Dave Kois, of EV Components was kind enough to let me drive up to pick them up today. I arrived while the truck was still unloading. They sure have their work cut out for them. Look at all those boxes of cells!

While unloading the forklift ran out of propane so they had to run fill the tank. They are anxious to get an electric forklift so this doesn't happen and also so they don't have to breath the fumes. Below is another picture. You can see the brand new Toyota RAV4 that Dave is converting.

Below are pictures of my cells in my 2000 Honda Insight. It was definitely over gross. I'm glad I'm not that heavy of a person. There wasn't much spring travel left.
The box in the back is the battery box out of the Gizmo. I took it out and had it sand blasted. The bottom and corners were badly eaten by battery acid. It will last much longer with Li batteries in it. I'm going to paint it black inside and out. I'm also planning on plugging the drain holes so that water doesn't get in from the bottom. I still need to put in a splash guard in front of the box so the batteries stay clean and dry. Last time I had the batteries out I put baking soda on the bottom of the box. When I pulled them out the entire bottom was wet with baking soda crystals on the sides of most of the batteries. I determined that most of the water entered from the two front drain holes which are right where the tires would splash water on the box.

Well, I'm off to get my batteries ready to install. I still have several things to do.
  • Primer and paint the battery box
  • drill mounting holes in the battery box to match up with some threaded holes in the frame of the Gizmo so the box doesn't bounce around. Even 500lbs of batteries would bounce on some of the bumps I've hit.
  • clean off the battery posts and coat with NOALOX. I'm going to use a very fine file for this with NOALOX on the file so the aluminum won't have time to oxidize.
  • Run an M8x1.25 bottoming tap down each hole to clean the threads. I'll use NOALOX here too. The BMS I'm planning on using will mount to the top of brass bolts which hold the connecting straps so I want good conductivity through the bolts.
  • connect the batteries up in parallel and give them their 4.2V initial charge. I have a lab power supply I can use. I also picked up a 4.2V Chinoz Smart Charger from EV Components to do this.
  • Rebundle the batteries in the arrangement I need to buddy pair them.
  • finalize my mounting design and mount the the batteries to the battery box.
  • It may not matter much but I'm going to put NOALOX on the ends of all of the connecting straps. They are four layers laminated with some shrink wrap. See the picture below.

I have several other things to do but I'll post about them later.


Ed said...

Nice project! It looks like a lot of battery for a Gizmo. I'm interested to see how it performs with these batteries. Ed Castro Valley, Ca

Gizmo said...

Yes, it is a lot of battery. There were two reasons I had for going with essentially a 200Ah pack. One is to keep the current well below the peak 3C rating of the batteries. The other is that the batteries are a ballast for the Gizmo. It was originally designed for four 12V batteries. I didn't want to have to add dead weight to keep it stable.

I'll be posting my energy usage from the wall for 8V Trojan T-875s, 6V Interstate U2200UTL, and the Li pack. Surprisingly the 6V pack uses less energy than the T-875s for my hilly driving.