Thursday, January 3, 2013

Goodbye lead!

After arriving back in SLO for the impending winter quarter at Cal Poly, I dropped the four large packs of lead batteries out of my car. After having sat uncharged for three weeks during winter break the pack voltage had sunk so low that my charger would not start charging presumably because it couldn't even detect that the battery was there. Oh well they're coming out anyway.

Here you can see all 24 of the deep cycle lead acid batteries (US battery model 31DC-XC). Each battery weighs 54 pounds by itself, add on top of this the steel frame each pack is supported by and the cables and bolts between every battery and you have yourself a quite near 1 ton battery pack. The corrosion left behind from spilled acid during charge cycles due to overfilling was formidable. I spend about two hours with a chisel and hammer breaking powdery chunks of corrosion off of the (at one point painted) steel frame in the back of the car that will house one of the PVC boxes for lithium batteries.
Looking down into the rear battery box frame. Rust and corrosion aplenty.

The next step is to measure for the second battery box that will go under the car, which now has significantly more ground clearance because the boxes underneath are gone and it is almost a ton lighter. I had originally put in heavier suspension to compensate for the added weight and it worked very well. It remains to be seen whether I will need to switch back to the stock suspension to make the ride bearable.

I've ordered the BMS from Elithion and it should be here in the next few days. That will be my next project along with modifying the charger to allow the BMS to shut it off and change it's current. Until next time... this is KK6ADS signing off.

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