HP Forums

Full Version: Classics Battery Holder vs. Battery Pack
You're currently viewing a stripped down version of our content. View the full version with proper formatting.
Inspired by Mark Hoskin's battery holder for classics that take 3 AAA cells I built one myself.
But when I put it in an HP-67 with even freshly loaded AAA batteries that give together 4.1 V I get the low battery indicator on (650 mAh or 900 mAh cells, doesn't give a difference).
In contrary I lately re-designed a cell phone battery pack with 3 AAA 800 mAh cells in it and the low battery indicator does not appear also I measure only 3.95 V.

What is the difference here? Why do I get the indicator on using the holder but not with the pack? Different current flow given to the calculator?
Do you mean AA ? Anyways, it could just be a poor electrical contact someplace.
No AA but AAA batteries inside the holder and pack as well.

Search for "Alkaline Hewlett Packard Calculator Battery CASE HP 35, 45, 55, 65, 67 & 80" on TAS. It's Mark's offer.

OK, will try to connect from pack outside with some wires and measure whether contacts maybe bad somewhere.
Out of sheer coincidence I received a little package from Mark Hoskins only yesterday. Among other things it contained two classic batteries and one of his AAA battery holders for classics. The HP-35 that I used to try them out likes both of the packs equally well, I put rechargeable 800mAh NiMh cells into the AAA holder.
Today did a test to a small bulb.
As the AAA cells aren't new voltage under load drops significantly from near 4 V to near 3 V.
That makes clear the low bat indicator.
Voltage drop doing the same with the pack is 0.1 to 0.2 V.
Reference URL's