portable LED floodlight , power source ?

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portable LED floodlight , power source ?

This topic has 19 replies, 11 voices, and was last updated 26 October 2019 at 17:07 by Hacksaw.

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24 October 2019 at 20:55 #434593
Hacksaw
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@hacksaw
Evening gents . A couple of years ago i bought 2 of those yellow portable rechargeable led work lights . A cheap one from Screwfix , and a fifty quid one from the newly opened Led lighting shop.. Guess which one still works ? Yep ,the cheap one !! The other one doesn't charge properly , or runs out of juice quickly anyway.. So rather than chucking it away , and assuming the "bulb" is ok , I thought maybe i could run it on a cable, to another battery ..but what voltage ? About 3v innit for leds ?? After a little dismantling , there's a circuit board in it too.

There's a red wire and a black going to the "bulb" , but connecting them to two AA cells doesn't make it work !! ? Does it need "special electric" from that board bit ? I'll take some photos in a minute .

Edited By Hacksaw on 24/10/2019 21:15:46
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24 October 2019 at 20:55 #32045
Hacksaw
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@hacksaw
24 October 2019 at 21:00 #434594
Hacksaw
Participant
@hacksaw
24 October 2019 at 21:15 #434597
Michael Briggs
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@michaelbriggs82422
If possible I would put it back together with the original electronics and measure the operating voltage. Alternatively connect a variable voltage power supply and increase the voltage to an acceptable level of brightness, taking care not to cook it. Michael
24 October 2019 at 21:30 #434600
roy entwistle
Participant
@royentwistle24699
What is the voltage of the rechargeable battery ? Or what is the rechargeable battery ?

Roy
24 October 2019 at 21:30 #434601
Nigel Graham 2
Participant
@nigelgraham2
Having opened the thing up, does the battery not tell you the voltage on its own label?
24 October 2019 at 21:57 #434605
Neil Wyatt
Moderator
@neilwyatt
Posted by Hacksaw on 24/10/2019 20:55:42:

Evening gents . A couple of years ago i bought 2 of those yellow portable rechargeable led work lights . A cheap one from Screwfix , and a fifty quid one from the newly opened Led lighting shop.. Guess which one still works ? Yep ,the cheap one !! The other one doesn't charge properly , or runs out of juice quickly anyway.. So rather than chucking it away , and assuming the "bulb" is ok , I thought maybe i could run it on a cable, to another battery ..but what voltage ? About 3v innit for leds ?? After a little dismantling , there's a circuit board in it too.

There's a red wire and a black going to the "bulb" , but connecting them to two AA cells doesn't make it work !! ? Does it need "special electric" from that board bit ? I'll take some photos in a minute .

Edited By Hacksaw on 24/10/2019 21:15:46

Closer to 4V for white leds, so three AAs. I've found a 4.2V lithium battery pack from an old phone works OK and has excess discharge protection.

Neil
24 October 2019 at 22:14 #434608
Hacksaw
Participant
@hacksaw
I took it apart a while ago..having had a rummage i've found the battery ..cells are 3.7v ,i don,t know if they are in parallel or series …and it unwrapping it reveals yet another i.c.!

And the other end !

Edited By Hacksaw on 24/10/2019 22:17:22

Edited By Hacksaw on 24/10/2019 22:24:58
24 October 2019 at 22:15 #434610
old mart
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@oldmart
Lidl have recently had two of these for sale, one battery and one mains, I bought the mains one, it was £14.99, I think the battery one was more. The mains one has 1500 lumens@ 20W and is intended for a security light, it comes with a remote control programmer. I intend to use it as a light for the mill, on an adjustable arm.

Those 18650 lithium cells are easy to get hold of if you need some.

Edited By old mart on 24/10/2019 22:18:34
24 October 2019 at 22:25 #434611
duncan webster 1
Participant
@duncanwebster1
Looks like series connection to me so you have 4*3.7 = 14.8v. The circuit board(s) probably deliver a constant (switch mode) current, connecting 14.8v direct to an LED without a series dropper resistor would release the magic smoke. You could try connecting the wires which now go to the batteries to a car battery, if it then works you have duff batteries, if not you have a duff circuit board. Both are repairable, but is it worth it? Make sure it is connected the right way round
24 October 2019 at 22:31 #434612
Hacksaw
Participant
@hacksaw
They are bright , no doubt about it , but it's a horrible cold light .. The warm white gu10 led in my kitchen is a much nicer light . I want ideally , to have it on a lead , with croc clips to attach to a 12v lead acid , Just not sure what voltage the bulb would be ..I didn't want to pop it trying !
24 October 2019 at 22:32 #434613
Lainchy
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@lainchy
Those are 18650 cells. eBay job, but buy the best ones you can. Should be an easy repair
24 October 2019 at 22:42 #434615
Frances IoM
Participant
@francesiom58905
LEDs are current driven (+ need a limiter unless you like a well lit but very fast puff of smoke) unlike old tungsten wire bulbs which are voltage driven – those LEDs marked as 12V etc for in-car use have an internal current limiter – likewise LION cells are relatively cheap but can(ie usually will) explode + catch fire if charged in wrong way (that’s the function of the circuits seen on the board – it measures voltage of cell + adjusts charging as appropriate) – shorting the cell is an extreme fire risk unless the cell has an inbuilt circuit to limit output current
24 October 2019 at 22:44 #434617
Paul Lousick
Participant
@paullousick59116
The light looks similar to the one which I have. Label on the back says that it has a 8800 maH, Lithium-ion battery and the charging input is 8.4VDC, 1000mA

Paul
24 October 2019 at 22:46 #434618
Hacksaw
Participant
@hacksaw
But the light only runs for an hour or so on the cells and then it's 8 hrs charge ! A 12 v lead acid would run it for ages..
24 October 2019 at 23:08 #434621
Hacksaw
Participant
@hacksaw
M.B , D.W . and F .I. thanks for the info on the constant current requirement ..

I have , (by re – using the circuit board bit ) and reconnecting the wires , hooked it up to a 16v drill battery ….And it works !! .. And the drill battery recharges in only an hour !

I've chucked the old battery pack on the bonfire…as its nearly Guy Fawkes night anyway

Edited By Hacksaw on 24/10/2019 23:11:17

Edited By Hacksaw on 24/10/2019 23:12:21
24 October 2019 at 23:19 #434624
duncan webster 1
Participant
@duncanwebster1
Glad it's fixed, but i'd take the old ones off the bonfire if I were you, one of those going off with a bang could take your eye out, and the contents are probably most unpleasant
25 October 2019 at 20:01 #434689
Meunier
Participant
@meunier
Posted by duncan webster on 24/10/2019 23:19:17:

Glad it's fixed, but i'd take the old ones off the bonfire if I were you, one of those going off with a bang could take your eye out, and the contents are probably most unpleasant

+1 and while the 'nominal working voltage" is 3.7V (minimum discharge voltage ) the fully charged voltage is 4.2V
DaveD
25 October 2019 at 20:04 #434690
Meunier
Participant
@meunier
double post – finger trouble

Edited By Meunier on 25/10/2019 20:05:32
26 October 2019 at 17:07 #434791
Hacksaw
Participant
@hacksaw
Thanks chaps , i know you'd have milled out a perfect flange to slide and lock the battery pack on .

I'm a cowboy, so i made it from wood, polymorph ,banana skins and bogies…but it works
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