I remember those times. The big reason that the chargers aren’t recommended for those battery types is that too many people had their batteries explode, with all the damage and acid burns that go with it. Also, the more you charge ‘single use’ batteries, the more likely they are to have a catastrophic failure. IF you are going to recharge that type of battery, make sure that the battery/ cell is in a sturdy container that will mitigate the damage if it leaks or explodes. My RC racer friends put their batteries in the freezer while charging to keep cool and mitigate damage if they explode. The down side to using the freezer, though, is that freezers are expensive compared to batteries.
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In short, assume that you will eventually explode a battery, take appropriate safety precautions, and you should be fine.
Jon Cole, N0OFJ
On Jan 27, 2021, at 11:15 AM, Tim Spurgeon <tims173@...> wrote:
Thanks for the reply. What amazes me is that this is not widely known.
It is like a secret that battery makers don't want us to know, so we keep
buying more "use once" batteries.
The key, as you also discovered, is to keep alkaline batteries from getting
too hot during the charging process. So why were battery chargers not
available 40 years ago, with timers that would allow short term charging,
followed by a timed cool down? Think of the money and resources that
could have been saved - money that went into the battery companies'
pockets. I am very pleased with the MFJ battery charger that I purchased
several years ago, and I am glad that I found the same charger (different name)
still being sold by another name on Walmart/Amazon.
Tim E. Spurgeon
----- Original Message -----
From: "Bob Ackerman" <RNAckerman@...>
To: "main" <main@CMRA.groups.io>
Sent: Wednesday, January 27, 2021 7:33:10 AM
Subject: Re: [CMRA] I found a universal battery charger dropped by MFJ.
Yes you can recharge Alkaline Batteries, but be careful. They can get
hot so charge slowly, can leak or split (then throw away), or pop or
explode. A general rule to charge at no more than 180-190mA for AA
batteries, and 90-95mA for AAA batteries. Just searched the Internet
quickly and a couple of sites said to charge briefly, then let sit. One
said 10 minutes on, 50 off. Another said 30 minutes on, 6 hours off.
Here is one site I found with good information (in my opinion):
On 1/26/21 8:45 PM, Tim Spurgeon wrote:
CMRA gang and Richard (W6RKK):
Several years ago, I bought a universal battery charger, mainly for the purpose of recharging Li-ion 18650 batteries that came in my Rig Expert AA600.
It wasn't until a week ago I tried a new feature on the charger; to charge alkaline AAA batteries. Over a couple of days I slowly recharged three batteries
out of one of my flashlights, and sure enough it worked. I don't know any more than it worked on alkaline batteries that I use every night.
I don't know how many recharge cycles I can get from alkaline batteries, but I did get one, so the price I paid for the AAA batteries is now halved. I am
When I went to the MFJ catalogue, the recharger was no longer listed.
However, I found it on Amazon and WalMart listed as: Universal Smart Battery Charger, or search for FC997, approximately $37 (don't get the batteries).
Then you will be set up to recharge any small battery commonly used in your gear.
I know that we should not use our CMRA site to sell stuff. However, batteries are part of our gear that we all must have for radio sport
and I thought this information would be useful. It has sure helped me!
Tim E. Spurgeon