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Old 04-01-2010, 08:22 AM   #54 (permalink)
bwilson4web
Engineering first
 
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Join Date: Mar 2009
Location: Huntsville, AL
Posts: 843

17 i3-REx - '14 BMW i3-REx
Last 3: 45.67 mpg (US)

Blue Bob's - '19 Tesla Std Rng Plus
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<forehead SLAP>GOSH I wished I'd thought of that!!
Quote:
Originally Posted by orange4boy View Post
. . . What I really need is a custom 14V battery or a set of Saft Ni-cads or a set of Prius cells. Only cheap.

Time to look up plastic welding.
. . .
I've ordered some 1/8" polyethylene welding rods last night for my NHW11 module refurbishment. I tested polypropylene last night, no good. I have some left over, battery case fragments but I'm not enthused about sacrificial case plastic ... unless I have a bunch of it.

Looking at a pair of NHW11 modules:
  • 1.2 V (nominal cell voltage) - 14.4 V
I have been looking for an application for refurbished NHW11 modules not in the traction battery pack. You've provided a perfect answer.

Your extra cell on the Pb battery is a brilliant solution. I've always hated the diode drop and have been thinking about more efficient buck power supplies. The diode was more 'proof of concept' and a permanent version would look at using Schottky to reduce the forward drop. But I like your solution better and I especially like the idea of using refurbished NiMH batteries to handle the 'plug-in' load. This is the type of application perfect for my purposes.

My only concern had been whether or not the inverter voltage control would 'suck' electrons out of a higher voltage battery. Have you tried using a current sense resistor to see if there is any reverse flow into the inverter? That will be my first test. <grins>

Thanks,
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

Last edited by bwilson4web; 04-01-2010 at 04:24 PM..
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