Charging AAA batteries on housephone handset

[james01]

I use pairs of rechargeable AAAs in rear lamps to supplement my dynamo lights. A simple method of recharging is to put exhausted batteries in handsets, assuming they use this size of battery, and put the fully charged ones in the lamp. We're a 3 handset household so there's always a ready supply of fully charged AAAs. (This is such an obvious tip that I apologise in advance to anyone who has already posted it on the forum )

[Mick F]

What an excellent tip.

Our old phone system had two handsets and when we replaced the system, I kept the batteries.
We had a few solar powered garden lights, and they had AAA batteries, and I kept them after the lights went to recycling.

The batteries in this things are not very good ones, and these days I have Envelops ............ and a charger, but instead, I could use the phone!

[Paulatic]

Beware!
This will not work for all batteries in all handsets. Often BT handsets are very particular as to the maH of the battery. They are built to use ~500-700maH.

[RickH]

The quality of the charging circuits in the phones may not be as good and may "fry" the batteries by not backing off the charging once they are charged.

I've been using low self discharge MiMH AA & AAA cells, mostly Ansmann max-e with an Ansmann Powerline "Delta V" charger. I use them in bike lights and also wherever possible around the house. Although the cells aren't cheap I've not yet had a failure & pretty much all of them are 2008/2009 vintage.

[Mick F]

Our phone just sits there until it's used.
It's been there for years, and the batteries still work. They are a pair of 650mah AAA.
Sometimes, the handset is sitting on the cradle for weeks on end as we rarely use the land-line phone.

I can't believe that the phone manufacturer would put the batteries at risk.

[james01]

Our phone just sits there until it's used.
It's been there for years, and the batteries still work. They are a pair of 650mah AAA.
Sometimes, the handset is sitting on the cradle for weeks on end as we rarely use the land-line phone.

I can't believe that the phone manufacturer would put the batteries at risk.

Agreed. Same in our house, our outfit must be 5 years old and still going strong. I conclude that a BT handset is a very happy place for an AAA battery

[Paulatic]

A few years ago I was having battery trouble with an old digital set. Can't remember the name now but I think they were Seimens. Searching at the time I discovered the maH issue. A quick look this morning and I can't find the same site I was looking at but I found this one similar in information.
http://www.techanswers.org.uk/answers/r ... hones.html

Edit: to add I see James phone relatively new being only 5yo. Mine were a DECT model from the 90s.

[james01]

A few years ago I was having battery trouble with an old digital set. Can't remember the name now but I think they were Seimens. Searching at the time I discovered the maH issue. A quick look this morning and I can't find the same site I was looking at but I found this one similar in information.
http://www.techanswers.org.uk/answers/r ... hones.html

Edit: to add I see James phone relatively new being only 5yo. Mine were a DECT model from the 90s.

Thanks for the link. My BT handsets (which I now realise are probably at least 8 years old) have the identical Kaifeng 550 mah batteries. It seems that I was lucky to have used them with Tesco 600 mah batteries rather than something more capacious. Incidentally, I get around 30 hours runtime when used in my Smart half watt flashing LED rear lights. So I have an easy charging regime which doesn't need any monitoring as the batteries in the handsets are always ready and fully charged.

[hamster]

If you have an AA charger, the tip of a USB plug is just the right size to fit in the charger and make up the extra length to run AAAs in it.

[NATURAL ANKLING]

Hi,
On economy.

If you too have old chargers for hand sets that get warm, I worked out that they suck £30 IIRC of juice a year each on mine

Use a timer so they are charged for a few hours a day (the main handset might need to be on all the time) .

Not sure if efficiency of switch mode chargers today would save much?

[james01]

Update. Sorry doomsters ( ), but after nearly another 3 years I'm still using this charging regime, the old Kaifeng 550 mAh batteries still holding charge well and now at least 10 years old.
Ref the cost of mains recharging. I've always fancied buying a plug-in mains ammeter, especially one which is sensitive enough to record the very low current drain of some appliances (TV standby, phone handsets etc). Any suggestions ?

[NATURAL ANKLING]

Hi,

Smart meter?

[james01]

Another update for anyone interested. My ancient AAAs are still holding a healthy charge using the housephone batteries in rotation. This is particularly useful as I've now with some reluctance joined the daytime flasher brigade, lights on at all times.

[philvantwo]

Welcome to the club! They should be compulsory along with bright visible coloured jerseys.

[mjr]

Welcome to the club! They should be compulsory along with bright visible coloured jerseys.

Why do you want to hurt cyclists like that?

Also, where can I get an invisible jersey? It would help with stealthy removal of some things...