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Ac Adaptor - How To Know What Voltage To Use.?


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#1 b_sdaddy

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Posted 26 September 2017 - 06:00 PM

I've got a patio parasol light device, that wraps around the pole.

 

It comprises of 4 lights, 'similar' looking to a std. GU10 bulb.

 

each light has x6 small LEDs.

 

THE AC adaptor required for charging is lost. The instruction book gives no indication as to the voltage.

 

 

Q: if i disassemble the unit, will the bulbs have information to help in establishing the voltage for the charger.?

 

or

 

does the size of the charging adaptors' socket indicate to this (ie. are they all different sizes?)

 

 

 

It's for my mother-in-law, and not that important, but she did ask if I could 'repair' it for her......

 

 

cheers as always



#2 phillrulz

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Posted 26 September 2017 - 06:24 PM

Id google the item and somewhere it will probably tell you an input voltage. 



#3 RedRuby

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Posted 26 September 2017 - 06:26 PM

If you have the make of the parasol try google'ing it and see if you can get information that way possibly the manufacturer then you could e-mail them for information.

#4 b_sdaddy

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Posted 26 September 2017 - 06:46 PM

That's what I did, and came up with a french company who seem to have stopped selling this model. They sell garden kit still, but have dropped this from the catalogue. E-mailed them anyway.

 

Just that it's only half a dozen pozi screws, and if there was  a way of calculating V from the bulbs.?

 

I seem to remember that V equals I over R or something very close, from physics lessons, some 40 years ago!


Edited by b_sdaddy, 26 September 2017 - 06:48 PM.


#5 phillrulz

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Posted 26 September 2017 - 07:02 PM

That's what I did, and came up with a french company who seem to have stopped selling this model. They sell garden kit still, but have dropped this from the catalogue. E-mailed them anyway.

 

Just that it's only half a dozen pozi screws, and if there was  a way of calculating V from the bulbs.?

 

I seem to remember that V equals I over R or something very close, from physics lessons, some 40 years ago!

Doubt it will be that easy, you need to know a few things, if its a simple direct drive aka power supply just feeds the LEDs no drivers then you need to know

  1. Voltage drop of a diode
  2. Rated current of a diode
  3. Number of series parallel strings. 

If you had a variable power supply i guess you could tweak it till you get thew brightness you remember it being, higher the voltage brighter it gets till they pop. 



#6 b_sdaddy

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Posted 26 September 2017 - 07:27 PM

I've opened her up!

 

there's 3 rechargeable batteries: ZLG Ni-MH SC 2600mAh 07,12

 

googling this gets RC car rechargeable batteries!

 

Seem to be in parallel.

 

I 'assume' they're 7v.?

 

Any more thoughts on what AC adaptor/charger is needed.?

 

 

cheers again



#7 dyshipfakta

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Posted 28 September 2017 - 05:33 AM

3 cells in parallel of rc batteries is only 1.2 volts. In series 3.6 obviously which seems more likely. I say give 3.6v at whatever amp rating you can find a go

#8 Mervyn

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Posted 28 September 2017 - 07:40 AM

If they look like GU10 but are DC hey're probably MR16 bulbs so you need a 12v adapter

 

 

Merv



#9 Spider

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Posted 03 October 2017 - 08:09 AM

Seemingly simple question, but the answer isn't straight forward.

 

If the cells are in parallel, then they'll have a voltage of 1.2 Volts and for many LEDs, while they 'current' rated, a voltage of 1.2 Volts usually sets the current in about the sweet spot.

 

Now the AC adaptor is a charger for these cells if I read that right.

 

So, you'll want an adaptor of around 1.3 - 1.4 volts at approx 2.5 amps, However,,,,, being Ni-Mh Cells this won't be a straight out adaptor but a charger - unless the charging electronics are in the device?

 

Ni-Mh Cells are pretty fussy on how they are charged, they won't tolerate trying to be charged like a Lead-acid battery for example, they only tolerate low ripple charging and has to be at particular rates - that change over the charging cycle. Ni-Cads are much less fussy and you may do better to swap the cells over to these - if you can find them.



#10 b_sdaddy

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Posted 06 October 2017 - 02:19 PM

I have a 5,4v adaptor in my toolbox for a x24LED torch.

 

First I drained the garden parasol unit which took 60 hours!!

 

Then I took the units into my garden shed that uses an independent circuit from the house & charged for 12 hours.

 

No explosions, no heat, just lovely, bright LEDs.

 

For something that my mother-in-law uses a few evenings every summer, think I stumbled upon a non-scientific solution, or is it an accident waiting to happen.?






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