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Old 08-10-2012, 07:36 AM   #75 (permalink)
bwilson4web
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Join Date: Mar 2009
Location: Huntsville, AL
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17 i3-REx - '14 BMW i3-REx
Last 3: 45.67 mpg (US)

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Sad news. Not only is there a delay but I was offered not only some blemished cells but worse, short tabs with one looking like someone had punched holes to the point of looking more like a sieve . . . too much metal removed.

My eBike application means vibration, motion and temperature changes. I am not willing to take a blemished cell unless there is some reasonable replacement for early failure and the tab with all the holes has too much metal removed.

I have a boat-load of NHW11 modules and seven would give 50.4V stacks close enough to the 48V lead-acid stack. If the bike controller doesn't blow up with 56V, I can fully charge them and I'll have 5.5Ahr per stack.

Alternatively, six modules fully charged to 8V would give 48V but discharged to 6V it would be 42V, close to the 41V cutoff voltage of the eBike motor controller. Not as good as the A123 but 'less bad' than the lead acid stack.

The nice thing is I can test the Zener balancing and battery management approaches without having to risk the more expensive A123 cells.

Bob Wilson
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2019 Tesla Model 3 Std. Range Plus - 215 mi EV
2017 BMW i3-REx - 106 mi EV, 88 mi mid-grade
Retired engineer, Huntsville, AL
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