How to get specification of an unknown rechargeable battery?

Thread Starter

cardiology

Joined Feb 8, 2009
12
Am I suppose to throw this LED light away as it is dangerous to keep it charged 24/7 with the 220V supply on these crappy batteries??
 

Søren

Joined Sep 2, 2006
472
Hi,

No, you don't have to throw it away.
You have to decide whether you're gonna make minor or major changes.

The easy way would be to get 1206 SMD resistors of around 15..22 Ohm, cut each track leading to a LED and bridge the cut with a resistor.

You have to find out how to lower the charge voltage a little and check how well balanced the batteries are (by disconnecting each of them and measuring them unloaded and while driving the entire circuit alone (just 1 batt.).

To find the resistors, you will have to find the current needed to give you the amount of light you want and the LED's voltage drop at that current too - the rest is Ohms law: (U_batt - U_LED) / I_LED = Ohm

A variable current supply will be the easy way to measure a LED (after disconnecting at least one lead of the LED.


Another way would be to hook all the batteries in series and drive more than one LED in series, but then the charge circuit would have to be changed as well.
 

SgtWookie

Joined Jul 17, 2007
22,230
I agree, it's a terrible design.

Unfortunately, in order to correct the design would require either making entirely new circuit boards, or doing a LOT of cutting and jumpering on the existing boards.

On the board with the switch (060-1), what are the markings on the two semiconductors in the upper left corner?
 

thatoneguy

Joined Feb 19, 2009
6,359
It seems like your batteries are fine from what has been stated.

There are 3 useful/good parts to the light

1) Power supply to step voltage down
2) Batteries
3) 60 LEDs in a Nifty Case.

It depends on how much you spent for the unit to decide how to proceed.

I don't think the term "rewire" covers all the changes that could be made for it to be a reliable lamp. "Re-build" is more fitting. A short list:

  • Seperate LEDs from one giant parallel array, feed independent LED strips with a constant current source.
  • Dedicated SLA charging/maintenance circuit or IC to keep the batteries alive longer. (constant voltage, current limited, temperature sensing)
  • Connect batteries in series to power long strips of LEDs at a constant current.
  • Low battery light to remind you to plug it in.
As Is, the only thing you NEED to do is stop the unit from boiling the batteries. Only plug it in when they are low, then charge for a few hours so they are full.

If the light automatically turns on when unplugged, a switch can be added, so that it can remain plugged in, but not charging. This could be combined with a thermistor and a couple parts to switch off the charger when the batteries get warm as well.
 

Thread Starter

cardiology

Joined Feb 8, 2009
12
Is there a simple way that I could change these batteries (in parallel) to one more reliable battery so that I do not need to worry about the fact that they would get overcharged and creat the bubbling sound or smell?
 

Thread Starter

cardiology

Joined Feb 8, 2009
12
I finally manged to find the specifications of the 4 SLA batteries in parallel:

4X 4V0.7Ah SLA

please advice on a new SLA battery spec that could replace the 4 so that I could buy a new one that is more relaible?
 
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