Beard Trimmer Battery Replacement - mAh & Voltage Advice

[BillyTheBob]

Hello folks

Hoping somebody here can share their wisdom.

My beard trimmer battery is nearing death and the trimmer model has long-since been discontinued, hence I can't just replace like for like.
It's in good nick and served me well, much like my arms and legs.
I dissembled it and found the battery is: AA - NiMH - 2.4V - 750mAh
These seem pretty hard to come by, in fact, most batteries are 1.2V here in the UK, unless I'm not looking in the correct corners of the net.
In respect to voltage and mAh, what rechargeable battery could I replace it with which likely won't effect performance or overload the circuitry? For example, what is likely to happen if I were to replace it with a NiMH - 1.2V - 1300mAh, or perhaps even a 2400mAh?

I know next to nothing about all this stuff.

Billy

 

[throbscottle]

Hi Billy, welcome to ETO!
Your 2.4v battery will consist of 2x 1.2v cells strapped together. They are probably in some kind of heat-shrink wrap.
If you can find out the dimensions of each cell you can identify what type they are, however if it says AA on the battery, without further information I'd say it is either 2x AA size cells, or the whole thing is AA size.
Here is a handy guide to sizes of cells: **broken link removed** however it's possible yours is another size not on here, in which case a photo and actual dimensions would help.
If you try looking for the trimmer itself on the net rather than just the battery you might have more luck.
Once you've identified the cells, chances are they are connected together by some kind of welded tabs. Your luck is in here, as you can get NiMh cells with the tabs pre-welded for you - you just need to solder them together into the pack size you need, wrap it up with tape or whatever.

Oh and to finish answering, mAh does not compensate inadequate voltage, you need to make a pack of 2x 1.2v cells in series. My own experience of replacing cells with higher capacity ones has been that the device was underpowered, even if the battery did last longer! So you probably shouldn't go much over the 750 (per cell). If you were to use a single cell, your charger would probably destroy it since its output is for 2 cells in series.

Hope this helps

 

[JimB]

Your battery has two cells in series, as throbs has commented.
To find all sorts of cells/batteries, have a look at these guys:
https://www.strikalite.co.uk/

JimB

 

[tronitech]

A couple of these in series is about the best I can come up with.

Only 550mAh but will do the job.

 

[audioguru]

Just now I replaced the AA alkaline battery cells in a thingy I made. The battery holder for two cells had bolts between the cells to hold the holder to the box, and the bolts cut through the thin wrappers of the cells which shorted one cell. Boy oh boy it got hot. The cell smelled and deformed. The battery holder almost melted. I replaced the bolts with glue.

 

[KeepItSimpleStupid]

Are we talking AA cells or AA cells with tabs? Is it a pack form? i.e. end to end or side by side?

There are actually two Different AA dimensions. One has a recessed button and one an exposed button. I have a rechargeable device that WILL not accept an alkaline AA and it contains the charger.

You should not try to solder to a non-tabbed battery. The tabs are spot welded.

 

[jpanhalt]

If the battery is the size and shape of a AA battery, it may be made of a pair of 1/2AA end-to-end in a single wrapper. Here is a chart that shows some of those less common sizes:
https://www.powerstream.com/Size.htm

Some battery vendors will have pre-made packs or will assemble a custom pack for you at nominal charge of a few dollars. The commercial way is to spot weld small nickle or steel strips to the battery ends. If you are good at soldering or know someone who is, you can do the same thing with copper braid and a good iron. I typically use a 25W Weller for battery packs. I would not risk doing soldering on the newer lithium chemistry batteries,* but I have done many NiCd and NiMH that way. Just be sure not to get the battery too warm.

John

*For lithium cells I use a battery tab spot welder.

 

[BillyTheBob]

Hello folks, thanks for the replies and links. Most grateful.

I should have given more detail in my OP.
The battery is a single cell AA, with tabs/tags, recessed button, and sits on top of the main chipboard.
It's a tight fit in there with no room for two cells side-by-side. By the looks of things only a AA will suffice.
The pic almost exactly resembles the battery in my trimmer.

Having searched high and low, I view my problem is that they no longer sell single cell 2.4V batteries, they're 1.2V, moreover, the majority in the 600-800mAh range are AAA; nonetheless, from a couple of the links provided in the replies there is one 1.2V 600mAh AA available, and a 1.2V 550mAh AA available.
Would a 1.2V battery simply be half as powerful as a 2.4V and make the trimmers performance lame?

I watched a few videos online and these fellas carefully desoldered the tabs from the battery and then replaced it with a regular buttoned rechargeable battery and Bob's your uncle the trimmer worked just fine.
Here is a link to such a vid:

Billy

 

[audioguru]

The mAh of a battery is not its power, it is how long a charge will power your device. Since the original battery had two cells in series then each cell is a little less than half the length of a new single AA cell. A new single AA Ni-MH battery cell has a capacity of about 2300mAh which is a little more (because modern cells are better than old cells) than double the original 750mAh.

A DC electric motor with half the voltage runs slower with less power. It might stall easily and might not start running.

 

[KeepItSimpleStupid]

<deleted-Not applicable>

 

[Nigel Goodwin]

The battery is a single cell AA, with tabs/tags, recessed button, and sits on top of the main chipboard.
It's a tight fit in there with no room for two cells side-by-side. [/QUOTE]

As everyone has said,it's NOT a single cell - it's two 1/2 AA cells in series to give the 2.4V - and two 1/2 AA cells in series looks like a single AA but has twice the voltage.

So you could make one with two of these in series:

https://uk.rs-online.com/web/p/speciality-size-rechargeable-batteries/0199652/

 

[BillyTheBob]

Please forgive my prolonged slow moment. I understand it now. 1/2 1.2v AA + 1/2 1.2v AA = What I need.
It was the "in series" bit which threw me, and I kept picturing a pair of AA's side-by-side in a wrap.
In fairness I did write that I know next to nothing about this stuff in my OP. I guess I'm living, breathing proof some folks are just that dumb.

Now I know what's needed, firstly I will do a ring round locally and find out if they can sort me out, if not, the links you folks have steered me toward will be grand.

Thank you very much for the help and advice.

Billy

 

[jpanhalt]

You don't' say where you are, but judging from your strange language, I suspect it might be the UK. If, on the odd chance, you are in the US, let us know. There are several places in the US that will assemble that 2X1/2AA for you for a very reasonable price.

John

 

[Musicmanager]

You don't' say where you are, but judging from your strange language, I suspect it might be the UK

Coming from the UK as I do John, I ressemble that remark !

S

 

[KeepItSimpleStupid]

John:

In post #1, the OP states

1.2V here in the UK

To the OP:

1/2 AA + 1/2 AA = 1 AA
1.2 V + 1.2 V = 2.4 V

Both are series. One mechanical and one electrical.

 

[tronitech]

You don't' say where you are, but judging from your strange language, I suspect it might be the UK.

Strange language! It's called English and something you lot in the USA took over like everything else!

 

[jpanhalt]

Strange language! It's called English and something you lot in the USA took over like everything else!

Talk about holding a grudge!

John

 

[audioguru]

I speak Canadian English. Some hillbillies, cowboys and Southern drawlers in the US are hard for me to understand. Some dictionaries mention "dim-witted".
We get some TV shows from the UK and their accents are so strong that they should have sub-title translations for me to read. Many of their spoken words do not even resemble the written words.

 

[Nigel Goodwin]

I speak Canadian English. Some hillbillies, cowboys and Southern drawlers in the US are hard for me to understand. Some dictionaries mention "dim-witted".

I hate to disappoint you, but over in Europe we can't tell the difference between an American accent and a Canadian one

(with the obvious exception of the French/Canadian accent).

We get some TV shows from the UK and their accents are so strong that they should have sub-title translations for me to read. Many of their spoken words do not even resemble the written words.

Just as with any country there are certain strong regional accents, and a very small number of TV shows seem to exaggerate them.

What is unintelligible is accents in American made shows, where they have some totally bizarre accent that bears not the slightest resemblance to any English one.

Personally I come from an area that linguistically is the most neutral and closest to correct English (according to Linguistic departments at Universities), although even then we can drop into broad 'Derbyshire' if the occasion calls for it, but no one really talks like that on a day to day basis (Ay up me duck ).

 

[moty22]

Just as with any country there are certain strong regional accents.

I agree, I live in Kirkby only 3 miles away from you and I have very different accent.