Handheld radio charging volts

[Skipper]

Have an old SH HX260 handheld VHF.
Works good. Battery good.
The battery is a 7.2V 750mAh NiCad. However, the supplied AC charger is rated at 10v.
I never had the factory 12v lighter plug (CLA) for this radio, but awhile back I found a 90's cell phone car-cord in my closet with the correct output plug for the VHF. It's pass-through 12v, but I figured it's close enough to 10v.
It worked. I've used it once, to charge for about 30 minutes. Mostly just to test it.
Although I'm thinking if the boat battery charger is on, or solar or engine running, it's getting more like 13.6+ volts, which is nearly double the radio's battery voltage.

So my questions are:
Is there an operating range for this radio?
Am I damaging the radio or battery with the increased voltage?
Why is the radio battery 7.2v but the factory AC charger puts out 10v?
I'm looking at getting a selectable-voltage buck-down DC to DC converter, but the regulated voltage selections are 3, 5, 6, 7.5, 9, and 12v. Can I charge the radio's 7.2v battery with 9v, even though the AC charger is 10v?

 

[Don S/V ILLusion]

Skip
Charge voltage may vary depending on how long you leave it on with the caution of heat generation above 10v becoming more critical. The manual is pretty explicit on this warning. Obviously, charging at 12+ volts will warm things up pretty quickly.

 

[Skipper]

Skip
Charge voltage may vary depending on how long you leave it on with the caution of heat generation above 10v becoming more critical. The manual is pretty explicit on this warning. Obviously, charging at 12+ volts will warm things up pretty quickly.

Thanks Don.
That info is not in my manual. It only says not to leave the AC charger on the radio longer than 16 hours.
Is there another handheld manual that has details?

 

[Don S/V ILLusion]

Thanks Don.
That info is not in my manual. It only says not to leave the AC charger on the radio longer than 16 hours.
Is there another handheld manual that has details?

It's in the online manual I found. Think near the end in a section describing battery replacement.

 

[Ken Cross]

You don't want to overcharge nicads. It will shorten their life.

Ken

 

[Skipper]

From Yaesu (Standard Horizon):

"The radio (has) an internal regulator to bring that down to an appropriate level to charge that battery. Most all of our products can accept an input voltage from 10-15 volts dc. This would also apply to that model radio (HX260)"

I guess I should have emailed them to begin with :-D

 

[Don S/V ILLusion]

From Yaesu (Standard Horizon):

"The radio (has) an internal regulator to bring that down to an appropriate level to charge that battery. Most all of our products can accept an input voltage from 10-15 volts dc. This would also apply to that model radio (HX260)"

I guess I should have emailed them to begin with :-D

They certainly know more than me but in looking at the schematic of the radio, there is no voltage regulator. For what that's worth...

 

[Skipper]

They certainly know more than me but in looking at the schematic of the radio, there is no voltage regulator. For what that's worth...

Where are you finding all this?
My paper manual and the online manual from SH show nothing about battery temp above 10v, or schematics: http://www.standardhorizon.com/down...me=HX260S.pdf&FileContentType=application/pdf

 

[Don S/V ILLusion]

There is a warning in bold somewhere around page 17 as I recall. The schematic is from my collection of old CDs because I at one time had some SH test equipment. I'll PM you a copy if I can extract the relevant section.

 

[Skipper]

There is a warning in bold somewhere around page 17 as I recall. The schematic is from my collection of old CDs because I at one time had some SH test equipment. I'll PM you a copy if I can extract the relevant section.

Nice! Thanks Don.
If it's difficult don't sweat it. I believe your description.

I found the warning about overcharging (plugged in too long). I'm guessing that's what you were referring to.

 

[Don S/V ILLusion]

Nice! Thanks Don.
If it's difficult don't sweat it. I believe your description.

I found the warning about overcharging (plugged in too long). I'm guessing that's what you were referring to.

I can't get the CD to reproduce but will consult my ITguy (my grandson) tomorrow.

 

[jssailem]

Don. It is always grand to have a convenient tech expert near by in the family.