Battery pack requirements

So, so more thoughts on the new pack.  I don’t want to have liquid cooling – I’ve already got enough problems with cooling the motor and controller. This takes out the Tesla batteries as well as the Volt/Bolt batteries.  Also, it just doesn’t get as hot in Santa Cruz as it does in San Diego.

However, it does get cold – we’ve had near freezing weather for the last few weeks, and that is not good for driveability (or for the number of amps you can draw).

So I’ll have to heat the pack somehow – this will be built into the pack from the start this time. My thought is to use some kind of ceramic heating pad (gardening shop here I come) under the batteries.

I also want a full-fledged BMS this time as well – the miniBMS did what it promised (tell me when something is wrong but nothing else) – but that isn’t good enough. I need to know which cell is failing, and to be able to do trending on the cells’ capabilities.

Research continues!

4 Responses to “Battery pack requirements”

  1. http://illuminatimotorworks.org/building-a-battery-warmer-for-a-wheego-life

    never had heat problems for any of our vehicles we have needed them warmed up to charge though.

  2. peter says:

    San Diego was a bit of a problem. I lived inland – away from the cool ocean breeze. We would frequently get weeks of 95F+ temperatures (once had a solid week of 100F+ temps!). Yeah, I know other places get hotter, but I didn’t live in those. 🙂 All I know is that I lost 6 cells to the heat, and not sure how damaged the rest are.

    If I can find a source for the Farnham battery heating pad, I may be in business! Sadly, KTA-EV is no longer in business.

  3. markbrems says:

    As far as a good BMS, and I assume you are okay with top-balancing, I highly recommend the Orion BMS. After frying one of my cells with the MiniBMS, I switched to the Orion and never looked back. If you like, you can bottom-balance the pack and then disable the top-balance function via the USB laptop connection, and still have all the other bells and whistles.

    https://914electric.wordpress.com/2013/01/13/battery-management-rethunk/

    Cheers.

  4. peter says:

    Thanks Mark,
    I’ve been looking at that system with great interest. Some questions though: can it handle 3 different groups of batteries? What is the maximum number of cells? Does it communicate well with other systems?
    Cheers!

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