The Museum of HP Calculators
HP Forum Archive 21
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|HP 41 Battery Pack Rebuild|
Message #1 Posted by John Ratard on 29 Sept 2012, 1:37 p.m.
I have been dealing with a company in China that manufactures custom LiFePO4 battery packs (3.2V/cell). I bought 2 packs for my NLS MS-230 miniscopes to replace the D cell lead acid batteries. These have performed as expected. The LiFePO4 (Lithium iron) advantages over lead acid and other battery types are numerous: approx. half weight and size of lead acid, double the capacity, longer lifetime (up to 2000 times), no liquid electrolyte, and much safer than Lithium ion. These cells can be manufactured to any size or shape, even to fit inside the space used by the 4 1/2 N cell Nicads. A limitation is shelf life without a recharge within approx. 3 months since there is a lower voltage below which the cell starts to deteriorate. The over and under charge protection circuit for these cells will be included in the battery on request.
I noted the post on 1/2 N cell NiMH batteries dated 2005. This is worth checking out for a group purchase including me. The contact is:
Tina Rong(America Team),
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