New Lithium Battery Pack for my EV

Eight years ago I installed a pack of 36 Lithium cells in my EV. After about 50,000km and several near-death battery pack experiences (over discharge) the range decreased beneath a useful level so I have just purchased a new pack.

Same sort of cells, CALB 100AH, 3.2V per cell (80km range). The pack was about AUD$6,000 delivered and took an afternoon to install. I’ve adjusted my Zivan NG3 to cut out at an average of 3.6 v/cell (129.6V), and still have the BMS system that will drop out the charger if any one cell exceeds 4.1V.

The original pack was rated at 10 years (3000 cycles) and given the abuse we subjected it to I’m quite pleased it lasted 8 years. I don’t have a fail-safe battery management system like a modern factory EV so we occasionally drove the car when dead flat. While I could normally pick this problem quickly from the instrumentation my teenage children tended to just blissfully drive on. Oh well, this is an experimental hobby, and mistakes will be made. The Wright brothers broke a few wings……

I just took the car with it’s new battery pack for a 25km test drive and all seems well. The battery voltage is about 118V at rest, and 114V when cruising at 60 km/hr. It’s not dropping beneath 110V during acceleration, much better than the old pack which would sag beneath 100V. I guess the internal resistance of the new cells is much lower.

I plan to keep driving my little home-brew EV until I can by a commercial EV with a > 200km range here in Australia for about $30k, which I estimate will happen around 2020.

It’s nice to have my little EV back on the road.

2 thoughts on “New Lithium Battery Pack for my EV”

  1. Back in 1970 I toured a company that made mining company dump trucks. These things were huge. They were electric of course (like a locomotive), and we got to drive and steer them using console buttons. The motors were the wheels. The big engine just turned a big alternator.

    I’ve always been impressed with a design that makes the wheels the motor, rather than all the power wasting transmission and differential.

    I had an emergency generator that used a 5 HP engine to turn the alternator. It worked fine, but the noise was terrific, and my neighbors threatened to kill me. So I had an old Dodge truck, and the alternator fit under the hood. The truck had an excellent muffler, and was quiet at 1300 RPM.

  2. Hi David,

    I remain most impressed with your electric vehicle. Real user data from something that really works. Most impressive.

    I am commenting here about codec2 since comments there seem to be closed there.

    I am wondering about a WSPR type front end to your low bandwidth voice software? It seems to me such a software could coordinate both ends so they find an open channel with enough bandwidth for voice or data.

    Given the fast ADC HF receivers now available that do the whole HF band and a digital frequency agile mfsk transmitter, the whole thing could be a software load!

    A super cell phone for HF :).

    John

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