Horstmann Economy 7 Immersion Timer battery problem?

[JohnD]

The higher voltage ones will have the cells soldered together on the tags, it would not be wise to try to separate them. You should be able to find whatever size and voltage you need.

There really ought to be something printed on the green wrapper, or you could measure your unit accurately.

 

[Deleted member 267285]

@EcoGirl - did you try Horstmann?

 

[AndyPRK]

maybe this ?

https://www.ebay.co.uk/itm/153781415801?hash=item23ce162f79:g:Mf4AAOSwUxlbxaK4

EDIT: Oh its in USA. Not worth it

 

[ianmcd]

The battery is definitely dead, and apparantly they don't work when they have dead batteries, so could be both.

Im sure I read somewhere that the unit has to be powered for 30 mins before the battery will work as it has to charge

 

[Deleted member 267285]

Im sure I read somewhere that the unit has to be powered for 30 mins before the battery will work as it has to charge

Think it’s in the manual, I read it yesterday it states 15 minutes?

 

[EcoGirl]

The higher voltage ones will have the cells soldered together on the tags, it would not be wise to try to separate them. You should be able to find whatever size and voltage you need.

There really ought to be something printed on the green wrapper, or you could measure your unit accurately.

Nothing on green wrapper. How do i measure the "unit correctly", John?

 

[EcoGirl]

@EcoGirl - did you try Horstmann?

Good point - I think I did last time - it doesn't look as though it is meant to be replaced. And it's worth me trying them. Thanks

@AndyPRK - did you try Horstmann?

 

[EcoGirl]

Im sure I read somewhere that the unit has to be powered for 30 mins before the battery will work as it has to charge

My understanding is that that is at the beginning of it's life. A battery measuring 0.1V is dead, as in non-revivable. (and I have had it powered for months, just in case!)

However, this does emphasise that the unit won't work without a working battery.

I am sure I don't need the replacement to be the same size - but I need it to have certain properties, and not knowing what those are, I'm reluctant to substitute.

 

[EcoGirl]

Does anyone know how to find out what properties the battery needs to have? eg I imagine it must be able to function in a hot space, as the switch is in my airing cupboard. But I don't know what the mAh or voltage should be.

There's a number of button batteries that are NiMH, and 1.2V (If mine is 1.2V?) for example this one:

https://www.ebay.co.uk/itm/40229673...7779&msclkid=86f685d7a2bc1d6c1886e560460de51d

I don't want to risk putting one in that then damages the unit!

 

[JohnD]

Nothing on green wrapper. How do i measure the "unit correctly", John?

the spec I found says:

Type : Rechargeable Nickel Metal Hydride Button Cell
Nominal Dimension (with Sleeve) : Φ = 25.2mm H = 8.7mm
Applications : Recommended discharge current 3.2 to 160 mA
Nominal Voltage : 1.2V
Capacity : Nominal:320mAh
Minimum: 320mAh
Typical: 370mAh
When discharged at 0.2C to 1.0V at 20℃
Charging Condition : 32 mA for 16 hrs at 20℃
Service Life : >500 cycles (IEC standard)
Continuous Overcharge: 32 mA maximum current for 1 year
No conspicuous deformation and/or leakage
Weight : 14.1g
Internal Resistance : Under 200 mΩ upon fully charged
Max. Charging Voltage: 1.5V at 32mA charging
Ambient Temperature Range: Standard Charging : 0 to 45℃
Discharging : 0 to 45℃
Storage : -20 to 45℃

so for a single cell
25.2mm is one inch diameter (ish)
and the height of one cell is 8.7mm one third of an inch (ish)
(I bet those dimesions were tranlated from Imperial measurements.)
and gives 1.2volt

So if you have a battery an inch high, it must contain three cells.
therefore its voltage will be 3.6v

And so on.

The spec also tells you it is designed to function at
Ambient Temperature Range: Standard Charging : 0 to 45℃
Discharging : 0 to 45℃
Storage : -20 to 45℃

 

[EcoGirl]

Nominal Dimension (with Sleeve) : Φ = 25.2mm H = 8.7mm
Applications : Recommended discharge current 3.2 to 160 mA
Nominal Voltage : 1.2V
Capacity : Nominal:320mAh
Minimum: 320mAh
Typical: 370mAh

Charging Condition : 32 mA for 16 hrs at 20℃

Continuous Overcharge: 32 mA maximum current for 1 year

Max. Charging Voltage: 1.5V at 32mA charging
Ambient Temperature Range: Standard Charging : 0 to 45℃

Fantastic John, thank you. Now I need to find a battery that meets those parameters, I presume?

Could you see the battery in the thumbnail a few posts back? It is only one cell (1/3" ish thick).

 

[JohnD]

so you need a single
Model No.: 320BVH

not a battery bigger than that, or at any voltage other than 1.2v

 

[AndyPRK]

I didn’t contact horsemann

in the other thread of mine of voltage was suggested to be higher

 

[EcoGirl]

so you need a single
Model No.: 320BVH

not a battery bigger than that

Thanks for clarifying John,
Yes, needs to be same voltage. Why can't it be a bit bigger in size, or different shape? Plenty of space to attach.

 

[JohnW2]

Yes, needs to be same voltage. Why can't it be a bit bigger in size, or different shape? Plenty of space to attach.

As you imply, it's only the electrical characteristics which matter - physical size/shape, per se, are irrelevant.

However, in practice, batteries with similar electrical characteristics are likely to be of similar size, if not also 'shape'.

Kind Regards, John