New traction battery, what I've discovered about regen and range

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Supersleeper

Well-known member
Joined
Aug 7, 2017
Messages
124
Location
SF Bay Area
So, my new battery has been in for about a week now, and what a difference! So, as many know already, when your battery degrades (loss of bars), it's due to the loss of cells in your battery. The pressure plates and/or temp sensors on the packs, etc with their proprietary algorithm for cell depletion permanently shut down cells for safety.

While driving on a full charge, you may have noticed that the regeneration bubbles are mostly disabled to prevent battery overcharge. No matter how fast you are going, if you hit the brakes, you will be lucky to get two regen bubbles. As you drive and deplete energy, more bubbles become available for regeneration.

What I've noticed from the old battery to the new is that I'm able to start higher regeneration much sooner (say 10-15 miles or so) than from the old pack at a 100% charge. Theoretically, older packs, with less bars could potentially overcharge much faster due to the fewer cells available (less capacity charged faster at the same rates). Therefore, I rarely, if ever, saw 5 bubbles of regeneration, or if you are watching LeafSpy or the Energy screen on the navigation, rarely saw more than 20-25kw regen.

So as it seems, this makes a HUGE difference in range. Battery loss from bars will not have a linear effect on range, but rather more of an exponential effect. On my new battery, I've noticed that nearly 10-15 miles out of a full charge I can start regen at 30kw or greater. Massive difference.
 
That is excellent news. I can't wait to get my car back with the new battery installed. The regeneration on our LEAF with the old battery and our 2016 Volt is a night and day experience. Over the years the LEAF degraded to the point where as you said I only saw 1 or 2 regen bubbles even if I completely discharged the battery. Sometimes under braking I would get more regen bubbles to appear, but it would quickly go back down to 2. It just has the effect of compounding the range loss problem when you start losing regen. Good to hear your car is as good as new though.
 
So, as many know already, when your battery degrades (loss of bars), it's due to the loss of cells in your battery. The pressure plates and/or temp sensors on the packs, etc with their proprietary algorithm for cell depletion permanently shut down cells for safety.

Normal degradation is the loss of capacity in each cell, not the loss of cells. The above scenario describes a defective pack with bad cells, or an old pack reaching its actual end of life state, not just the loss of 40% capacity.
 
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