# A (rechargeable) battery question.



## Dave7 (22 Apr 2021)

2 questions really.
These are for the cordlesss land line.
We have 2 stations.
The one downstairs was giving problems and upon checking I found the 2 batteries were 1.5 V NONE-rechargeabl......so I changed them. Works fine now.

I then checked the upstairs one to find that they were 1.5V rechargeable.
Obviously, in the past, someone (moi ) had put standard 1.5s in the downstairs one.
Sooooo......
Q1.....is it ok to interchange standard and rechargeable.
Q2.....the shop I tried only had 1.2V rechargeable... could I use them instead of the 1.5s.
Thanks.


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## ebikeerwidnes (22 Apr 2021)

As far as I know they can be interchange - but it is bad idea to mix them in one device
personally I have given up on them -They don;t seem to last long - the power drops off so some devices don;t work after a short while - and it they are not used for a while (e.g. bike lights) they don;t have any power remaining when you need them.

I bought some a while ago and most ended up getting used a few times and then replaced with normal ones.


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## Tenkaykev (22 Apr 2021)

ebikeerwidnes said:


> As far as I know they can be interchange - but it is bad idea to mix them in one device
> personally I have given up on them -They don;t seem to last long - the power drops off so some devices don;t work after a short while - and it they are not used for a while (e.g. bike lights) they don;t have any power remaining when you need them.
> 
> I bought some a while ago and most ended up getting used a few times and then replaced with normal ones.



The IKEA rechargeable batteries are reported to actually be rebadged Panasonic Eneloop which sell for a premium. If you buy decent rechargeable batteries they have very low “ self discharge “ and will keep the charge for years when going unused.


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## icowden (22 Apr 2021)

A battery is a battery. The problem with putting ordinary batteries in a cordless phone, is that the phone is designed to recharge, so you are essentially putting batteries that can't be recharged into a charger. I believe this can cause problems such as small risk of explosion etc.


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## Dave7 (22 Apr 2021)

icowden said:


> A battery is a battery. The problem with putting ordinary batteries in a cordless phone, is that the phone is designed to recharge, so you are essentially putting batteries that can't be recharged into a charger. I believe this can cause problems such as small risk of explosion etc.


Well, so long as its only a small risk .


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## Dave7 (22 Apr 2021)

Any thoughts on 1.2V as against 1.5V ??


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## icowden (22 Apr 2021)

Dave7 said:


> Any thoughts on 1.2V as against 1.5V ??



The voltage is the pressure if you like, whilst amperage is the rate of flow. Its the amps that kill you :-)

This is the rationale for battery explosion:



> *Why Alkaline Batteries Explode*
> When an alkaline battery heats up or is exposed to a strong electrical current, the energy releases hydrogen gas inside the battery sheathing. As the vapor pressure inside the battery reaches a critical point, the sheathing ruptures. In most cases, the battery will simply leak, but if the vapor pressure is high enough, it can explode.
> Alkaline batteries from reliable manufacturers are vented to allow built up heat and energy to dissipate. Because of this, they seldom explode, but they might when used in a high-heat environment that doesn't allow the energy to dissipate. They can also explode when subjected to a high or persistent electrical current. This might happen to a battery installed in a smoke detector, which is hardwired to an electrical circuit. An explosion is also a possibility when you insert a nonrechargeable battery into a charger or when you install one the wrong way in a device that takes two or more other batteries.



So if you have a good quality battery that can vent, you are OK (well you might get a leaky battery), but if you get a pressure build up - kaboom.


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## Low Gear Guy (22 Apr 2021)

It is possible to buy AA batteries which are specifically intended for cordless phones. Presumably these are designed for continuous charging.


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## Tenkaykev (22 Apr 2021)

Low Gear Guy said:


> It is possible to buy AA batteries which are specifically intended for cordless phones. Presumably these are designed for continuous charging.


I think they act as a sort of “ float” battery. With our cordless phone there’s the larger base station/ answerphone which is connected to a power supply and the incoming phone line, and the “ satellite” station which sits in a small recharging dock. The rechargeable batteries just keep themselves topped up with a trickle charge while in the base, and the batteries are fully used when the handset is taken off the station/ charger.
They all have battery monitoring/ charging /temperature sensors circuitry built in.


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## figbat (22 Apr 2021)

AA/AAA rechargeables are generally only 1.2v anyway, so if that is what the phone was designed to use then no problem.


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## ebikeerwidnes (22 Apr 2021)

icowden said:


> A battery is a battery. The problem with putting ordinary batteries in a cordless phone, is that the phone is designed to recharge, so you are essentially putting batteries that can't be recharged into a charger. I believe this can cause problems such as small risk of explosion etc.


Good point - I was assuming that the phone was designed for non- rechargeable and they would be taken out for recharging - but this is an important point!!


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## PaulSB (23 Apr 2021)

ebikeerwidnes said:


> As far as I know they can be interchange - but it is bad idea to mix them in one device
> personally I have given up on them -They don;t seem to last long - the power drops off so some devices don;t work after a short while - and it they are not used for a while (e.g. bike lights) they don;t have any power remaining when you need them.
> 
> I bought some a while ago and most ended up getting used a few times and then replaced with normal ones.


Very much with you on this one. I don't think we've ever had a satisfactory outcome with rechargeable batteries in most domestic uses. We have some in the landline phones which are OK but we hardly ever use the phones.

I have a Lezyne front light with an 11 year old battery. Still as good as the day I bought it. Now that's a seriously good battery.


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## JohnHughes307 (23 Apr 2021)

On the1.5V v 1.2V thing (see what I did there 😃)... The non-rechargable batteries start at 1.5 but rapidly lose their capacity to maintain that voltage, so spend a fair amount of the time at 1.2V ish. The rechargeable ones never get as high as 1.5v but stay at 1.2V until shortly before they run out of charge. Most equipment is therefore designed to run on the normal range of the batteries, which is the same in both cases, rather than the maximum voltage.


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