Christmas decorations, technical help required.

[Russdl]

Definitely not self build related, but hopefully one of you wise (wo)men will help me out.

 

My good lady wife has a Christmas decoration powered by 4 AAA batteries (it's haemorrhaging our savings keeping it fed on batteries, so a tenuous self build link!)

 

I've an old adapter that outputs 7.5V and 350mA, will that make the motor spin really fast and the LED's burn really bright or will it quietly smoulder in the corner whilst I do a runner?

 

Russ.

 

 

[ragg987]

Rechargeable NiMH or similar? If you have kids these become essential.

 

They also have much larger capacity than alkalines, so will need changing less often.

[SteamyTea]

https://www.hotukdeals.com/deals/uniross-multi-voltage-universal-adapter-for-500ma-100-poundland-875171

 

Must get myself some

[Russdl]

20 minutes ago, ragg987 said:

Rechargeable NiMH or similar?

 

No, currently using disposable AAA batteries. It has an adapter socket but didn't come with an adapter, so I'm wondering if an old adapter would work and not kill it?

 

20 minutes ago, SteamyTea said:

https://www.hotukdeals.com/deals/uniross-multi-voltage-universal-adapter-for-500ma-100-poundland-875171

 

Must get myself some

 

Good grief! That's ridiculously cheap, thanks for that link Steamy

 

[Barney12]

11 minutes ago, Russdl said:

 

No, currently using disposable AAA batteries. It has an adapter socket but didn't come with an adapter, so I'm wondering if an old adapter would work and not kill it?

 

 

Good grief! That's ridiculously cheap, thanks for that link Steamy

 

 

That deal expired in 2011

[Jeremy Harris]

4 AAA cells when brand new will be around 6.2 V, when effectively discharged they would be around 5 V, so a 6 V supply with the correct plug should do the job.  Hard to know what the current demand is, but as the cells are only AAA, which are not that high a capacity, I'd take a guesstimate that a supply capably of delivering at least 1 A should be fine.

[Russdl]

1 minute ago, Barney12 said:

That deal expired in 2011

 

Doh!

 

1 minute ago, JSHarris said:

4 AAA cells when brand new will be around 6.2 V,

 

1 minute ago, JSHarris said:

I'd take a guesstimate that a supply capably of delivering at least 1 A should be fine.

 

So...  what I understand from your reply Jeremy is that if I plug this old adapter in it's unlikely to kill the decoration? Did I get that right?

 

(If it does kill it then my life will be on the line!!)

[Jeremy Harris]

13 minutes ago, Russdl said:

 

Doh!

 

 

 

So...  what I understand from your reply Jeremy is that if I plug this old adapter in it's unlikely to kill the decoration? Did I get that right?

 

(If it does kill it then my life will be on the line!!)

 

 

Yes. 7.5V is too high, the maximum voltage it will normally see with brand new batteries is around 6.2 V.  350 mA is probably a bit on the low side, too.  The other thing to watch is that the polarity of any supply you use is correct.  The normal convention is now that the centre pin is the positive, but this isn't always adhered to so is worth checking before you plug anything in.  To add to the problem, there is a wide range of different sizes of power plug, and even common external barrel diameter ones, like 5.5mm, can have either a 2.1mm or 2.5mm internal pin/socket, making them incompatible with each other in some cases (some have springs that may make up the 0.4mm difference in pin size).

[Russdl]

Thanks all, for your replies. 

 

I think I'll go looking for some rechargeable batteries, seems like the simplest solution.

 

 

[SteamyTea]

Just been to Poundland and they are currently not doing the variable voltage adapter.  They may be doing it in the new year.

I also had a look in B&M and Poundstretchers, neither of them have them either.  So may be a supply problem.

[Onoff]

Mods,  apologies if this is seen as a plug but ref batteries and chargers I can highly recommend this seller:

 

https://www.vapextech.co.uk

 

I've known the proprietor and his family for 20 years but am not involved in any way. Paul's a top bloke.

 

Edited December 20, 2017 by Onoff

[Jeremy Harris]

+1 to the above from @Onoff, I've also used them for years, in fact three of my torches are still running on their cells and they must be at least 6 or 7 years old, maybe older.