HP-1: Home Patrol 1 no power from batteries

[Ubbe]

My HP-1 dies when I remove the external power and the HP-1 charging says Battery Charge Error.
The batteries are fine, I usually charge when needed with an external charger and they indicate correct
with voltage and ampere when checked with a battery tester.

I've bent out the metal pieces that make contact with the batteries positive pole just to be sure but there
seems to be some internal contact problem. Is there a fuse that can have gone bad from age?

/Ubbe

 

[jonwienke]

Try different batteries. When they age, the internal resistance goes up, which causes the voltage required to charge goes up, and that is most likely causing the error message. That also lowers the discharge voltage. A battery tester designed for alkaline batteries will not see the problem until it is severe. But the scanner will shut down when each individual battery is over 1V.

 

[wtp]

when you say external charger

is it a dumb charger or a smart one?
the dumb ones can overcharge every time you use it.
a smart charger will only charge until full and can even give you the true capacity of each cell.
sure they cost more, but are worth it.

 

[Ubbe]

I always use a smart charger that keep track of voltage and temperature.

When I put in freshly charged batteries it shows a green battery symbol. After 2 minutes it says batteries are low and needs to be charged. If I then choose to start a charge in the HP-1 the batteries goes hot after 10 minutes as all charge current transfers to heat as the batteries are already fully charged.

It must be something with the voltage sensor in the HP1- that causes this, or a high ohm connection somewhere.

I probably have to disassemble the HP-1 to find the problem.

/Ubbe

 

[SteveSimpkin]

As mentioned above, try replacing the batteries with a new set. All of the symptoms you mention can be caused by one or more bad cells.

 

[dispatch235]

One or more batteries are bad...batteries are a tricky thing: i've never found a "foolproof" tester yet. Any time they heat up with charging you are close to having an exploding battery situation and they should be replaced.

 

[jonwienke]

Heat during charging indicates excessive internal resistance. The charging energy is being converted to heat rather than charging the battery.

 

[CommLt]

Power up with AC adaptor then remove the battery cover and try a reset.

 

[Ubbe]

Thanks. A simple push of the reset button helped. The cpu somehow was stuck in the voltage sense and discarded all batteries?

The second set of freshly charged batteries now worked ok. The first set actually had one battery that was acting bad in the HP-1 and needed to be replaced. It was showing up fine in the battery tester and worked ok in another scanner but not in the HP-1. Is it draining more current from the batteries? I haven't really tested for how long the batteries can power the HP-1. Thanks for the help everyone.

/Ubbe