In-wall plug in charger for GP645 battery

[tony22]

I just bought another GP645 type battery for my floodlight, and while waiting for it to arrive I decided to see if the old simple wall charger still works. I plugged it in and it reads 12 VDC. I was wondering if anyone knew how these crude chargers work. It's the kind that plugs directly into the wall and the other end into the floodlight. Does it get loaded down to 6 VDC when it's hooked up to the battery? Is it safe to charge a GP645 at 12 VDC?

 

[tony22]

Just raising the flag again, hoping someone can explain if what I'm seeing is correct for this simple type of charger. My new GP645 arrives Tuesday and I want to be sure this charger won't kill it.

 

[Mr Happy]

How much did the floodlight cost?

I mean, you are making a big assumption when you use words like "works", "correct" or "safe". How do you know someone didn't just stick a halogen bulb in a case with a reflector and a battery and wire it up to a 12 V wall wart?

I don't remember the history, but do you have a link or description for the particular make and model of light you own?

 

[tony22]

Mr.H, I'm at work at the moment so I don't have the specifics, but this is a genuine retail flood that came with the said charger and does work. My F-I-L bought it about 8 years ago and he and I both used it many times. When he moved into a new community he unloaded a lot of stuff and that's how I got it. I will get the specifics of the light later today.

 

[tony22]

Okay. It's a Lectro Science, Inc "500,000 CP Cordless" lamp. It came with a plug in charger which is a simple transformer type that plugs directly into a 120 VAC socket and has a cable which plugs directly into the lamp. The charger is rated (as printed) at 6 VDC out, 300 mA. But when I read it (with DVM) unloaded it is 12 VDC. I can only assume this is a constant current type charger which maybe loads itself down to something close to 6 VDC when connected to a working battery that needs a charge. I'm hoping I'm right.

 

[Mr Happy]

Is the light like this one? http://www.shipstore.com/SS/HTML/LSI/LSICE5400GF.html

 

[tony22]

Why yes, it looks suspiciously similar. 🙂

 

[Mr Happy]

If I were you I would take the light apart and see what the charging arrangements are inside it.

Reasons to be suspicious about the design:

• only 15 minutes of light from a 24 hour charge
• powering a 6 V 55 W bulb (9 A) from a little 5 Ah battery
• SLA batteries are not really designed for high power use and continuous charging and discharging

Does the charger say on it that it is a "sealed lead-acid battery charger" or does it say it is a "DC power supply", or does it say nothing like that? They might just be trickle charging the battery to destruction, or there might be a charge controller inside the light. The best answer is that either the plug in module contains a proper charging circuit or the light does.

To be frank, there have been many of these "stick a bulb and a battery in a case and call it a spotlight" gadgets around, and they are not really well designed items. I think if you get a few months of bright light out of them you have got what you could reasonably hope for.

 

[tony22]

If I were you I would take the light apart and see what the charging arrangements are inside it.

Did that when I had to see what the old battery was. What charging arrangements? The receptacle that accepts the "charger" plug just seems to be hot-wired to the battery. Based on what I remember it is not designed to be used while the charger is plugged into the lamp.

Does the charger say on it that it is a "sealed lead-acid battery charger" or does it say it is a "DC power supply", or does it say nothing like that?

Neither. It just says Plug In Class 2 Transformer, and the input/output ratings. Based on what I've learned about better flashlights I suspect you're right about this just being a "who cares" trickle charger.

Well, I already bought the replacement battery. Really mostly because my wife wanted to have it back in running order.