On Ni-MH Batteries

Want to know how something works? Harness the power of the Brainiacs!
Post Reply
User avatar
Shane
Posts: 710
Joined: Fri Feb 01, 2008 12:08 am
Location: Omaha
Contact:

On Ni-MH Batteries

Post by Shane » Sat Jan 23, 2016 3:31 pm

A 7.2V Ni-MH battery pack should output how much voltage (no load) after freshly charged?

I have one that is charged by what is called a trickle charger but I measured 7.8V on the battery terminals while it had been in the charger only a matter of minutes after crashing in a ham radio HT.
I'm wondering if I have ruined this battery. Not enough info here to tell that but I read on a site led to by a Google search, they should not be charged more than 10 hours. The radio I'm using this in has two choices of chargers: 1) included is the "trickle charger" which is supposed to charge it up full in 18 hours (seems crazy given the voltages I'm seeing here), or 2) a Quick charger that only takes 2 hours (which I do not have).

I'm debating whether to get another battery pack as a spare, get an alkaline battery case and use that as a spare, or both. And if this one is indeed trashed, then one more like it, too.

The radio is a IC-V80 2meter HT by Icom. The battery is rated at 1400mAh but the rig has a 5.5 watt output setting, which might be asking too much of this pack, I don't know.

Any ideas, opinions, or sendoffs?
Mike Shane, CBRE
---Omaha---

User avatar
Deep Thought
Posts: 3132
Joined: Thu Mar 20, 2008 9:23 am
Location: La Grange, IL
Contact:

Re: On Ni-MH Batteries

Post by Deep Thought » Sat Jan 23, 2016 5:28 pm

If you can find a ~10 ohm power resistor (5 watts will do) you could measure the voltage drop. If the battery is rated at 1400 mAh this would be half of the rated capacity and should not drop the voltage much until it gets close to the "discharged" state. It would at least give you some indication of the remaining capacity.

Most Ni-MH batteries want ~1.4 volts per cell for the charging voltage so your 7.8 isn't that unusual for a 7.2 volt battery just taken off the charger.
Mark Mueller • Mueller Broadcast Design • La Grange, IL • http://www.muellerbroadcastdesign.com

User avatar
Shane
Posts: 710
Joined: Fri Feb 01, 2008 12:08 am
Location: Omaha
Contact:

Re: On Ni-MH Batteries

Post by Shane » Sat Jan 23, 2016 10:34 pm

Thanks for those tips, Mark.
Mike Shane, CBRE
---Omaha---

Post Reply

Who is online

Users browsing this forum: No registered users and 1 guest