HP 22 - Batteries


Any help will be appreciated. I am looking for the mah rating for the HP 22. They appear to be the size of AA batteries and I would like to open the battery case and replace the batteries.

Thank you


i found a better way to replace the pack batteries than
cutting the side of the plastic. here:


this page is not finished. i'm still repairing the keyboard :-)

good luck.


The original HP AA nicads were 700 mah. These are still made by Sanyo, see the pages here on batteries. You can sub 1100 mah nicads as well, just allow for 50% longer charging times.

You can of course use alkaline and lithium AA's - but under no circumstances should the charger be anywhere near the unit when you do this.

You can also use the super-extended capacity ni-mh rechargeables at 1850 mah - but you must recharge externally. This is really the best way to preserve your 21 or any woodstock as plugging in a unit with a dead or missing battery is the most common way to kill it.


Although it is recommended that you always recharge a woodstock battery pack externally (to prevent possible overvoltage damage to the calculator electronics), NiMH cells recharge just fine in the machine... well as well as any NiCads. Since their capacity is three times as large as the originals, you need to charge them three times as long to get a full charge.

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