Light Help

[Joshua Smith]

So, I own 2 Salvo can lights, purchased back when I had a job, and as a result, had disposable income. One 10w, one 21w, both HID. One of the chargers died, but it was identical to the other one, so I used it for both. my 21 has been my main light, and I keep the 10 around as a backup and a loaner. The other day, I decided to run the battery all the way down while I was soaking my 21 in a bucket. I thought you were supposed to do this once in a while, and I have done it more than once without incident. Anyway, I forgot about it for a few days, and when I fished it out, dried it off, and took the battery out to charge it, it was dead- the charger doesn't seem to know there is a battery there. (normally, I plug it in, and the charger shows red-green-red, and then shows a steady red as it charges, green when done charging. It does its little light show when I plug it in to the wall, but it doesn't show a red light when I plug the battery in any more. To be sure, I grabbed my 10w, and plugged it in. It worked just fine.

So- is my battery toast? Did I kill it by leaving it discharged for too long?

[Bric Martin]

[sarcasm][/sarcasm]

So, I own 2 Salvo can lights, purchased back when I had a job, and as a result, had disposable income. One 10w, one 21w, both HID. One of the chargers died, but it was identical to the other one, so I used it for both. my 21 has been my main light, and I keep the 10 around as a backup and a loaner. The other day, I decided to run the battery all the way down while I was soaking my 21 in a bucket. I thought you were supposed to do this once in a while, and I have done it more than once without incident. Anyway, I forgot about it for a few days, and when I fished it out, dried it off, and took the battery out to charge it, it was dead- the charger doesn't seem to know there is a battery there. (normally, I plug it in, and the charger shows red-green-red, and then shows a steady red as it charges, green when done charging. It does its little light show when I plug it in to the wall, but it doesn't show a red light when I plug the battery in any more. To be sure, I grabbed my 10w, and plugged it in. It worked just fine.

So- is my battery toast? Did I kill it by leaving it discharged for too long?

So you just want know what time it is?

[CaptnJack]

NiMH I'm guessing? It may be toast but potentially salvagable...
You need to trick the charger into "seeing" the battery with at least minimal voltage. Any chance you could use some alligator clips to put both batteries in parallel? (warning this is basically shorting the good battery into the bad, wires may get hot or spark) Then once the good has put a modest amount of voltage into the bad hook up the charger.

[Joshua Smith]

NiMH I'm guessing? It may be toast but potentially salvagable...
You need to trick the charger into "seeing" the battery with at least minimal voltage. Any chance you could use some alligator clips to put both batteries in parallel? (warning this is basically shorting the good battery into the bad, wires may get hot or spark) Then once the good has put a modest amount of voltage into the bad hook up the charger.

Yep, NIMH. I can try that. No problem doing it on my pile of oily rags next to all my solvents, right?

[H20doctor]

The pcb might have gone bad in the battery pack.. New ones are 9.00 , its prob not the charger

[Joshua Smith]

NiMH I'm guessing? It may be toast but potentially salvagable...
You need to trick the charger into "seeing" the battery with at least minimal voltage. Any chance you could use some alligator clips to put both batteries in parallel? (warning this is basically shorting the good battery into the bad, wires may get hot or spark) Then once the good has put a modest amount of voltage into the bad hook up the charger.

I'll be damned. I hooked them together for less than a minute, and it worked! Sitting on my bench charging away happily right now. Thanks a lot!

[CaptnJack]

NiMH I'm guessing? It may be toast but potentially salvagable...
You need to trick the charger into "seeing" the battery with at least minimal voltage. Any chance you could use some alligator clips to put both batteries in parallel? (warning this is basically shorting the good battery into the bad, wires may get hot or spark) Then once the good has put a modest amount of voltage into the bad hook up the charger.

I'll be damned. I hooked them together for less than a minute, and it worked! Sitting on my bench charging away happily right now. Thanks a lot!

Sweet. From completely flat its probably going to get warm to the point where the PCB cuts off the charging before its "full". So once its done just disconnect, let it cool overnight and recharge again tomorrow. Should be as full as it'll get at that point.

[Joshua Smith]

NiMH I'm guessing? It may be toast but potentially salvagable...
You need to trick the charger into "seeing" the battery with at least minimal voltage. Any chance you could use some alligator clips to put both batteries in parallel? (warning this is basically shorting the good battery into the bad, wires may get hot or spark) Then once the good has put a modest amount of voltage into the bad hook up the charger.

I'll be damned. I hooked them together for less than a minute, and it worked! Sitting on my bench charging away happily right now. Thanks a lot!

Sweet. From completely flat its probably going to get warm to the point where the PCB cuts off the charging before its "full". So once its done just disconnect, let it cool overnight and recharge again tomorrow. Should be as full as it'll get at that point.

Roger that. Thanks again!

[camerone]

Josh -

Better than trying another charge cycle is to cycle the NiMH pack a couple of time. It is possible that you may have a bad cell in the pack...over discharge on NiMH can cause cells to go bad, and it won't hold a full charge. Alternatively, the so-called "smart" chargers look for dips in the voltage or changes in temperature to indicate a full charge, and if you've had a bad cell or a over-discharge, it can get fooled and cut off too early. Sometimes you can bring it back, sometimes you can't. Better to use the pack than try to keep juicing it up, though...

If if won't come up, we can troubleshoot and try to find/replace the bad cell in the pack. NiMH is easy - no circuit board, safe to work with, etc. Lithium is a little more tricky, but not rocket science (the PCB does the cell balancing for you...)

For future reference -- NiMH does _not_ have a memory, like the old NiCad packs do... anyone telling you otherwise doesn't understand the chemistry of the cells. The reason for cycling the pack (above) is to make sure the charger worked, and the cells are still good. NiMH packs do not ever need to be completely discharged. The only thing you want to do with them once in a while is burn-test the pack after a full charge and make sure it's actually holding rated capacity or close to it.

Never take a 12V NiMH pack below 10V or you risk serious damage... if you are going to drain the pack to burn test, hook up a multimeter in parallel to the light or resistor you're using and watch for the 10V point then cutoff the test...at that point, you're done.

...and try not to forget about it

[fmerkel]

On a similar thread on this general subject you posted:

[Re: Can lights
Postby Joshua Smith » Sat Dec 31, 2011 12:43 am
Some people, when you ask them what time it is, will try and tell you how to build a watch.]

I had previously posted:
[Re: Can lights
Postby fmerkel » Fri Dec 30, 2011 12:41 pm
A little battery maintenance:
Using a NiMh pack to damn near dead is an excellent way to drain the weakest cell and produce a reverse polarity condition if you persist in keeping the power on. This WILL weaken that cell further and has a high possibility of killing it outright. This, of course, ruins the pack. When the light gets noticeably dim, shut it off.]

Pay attention to what camerone is saying. Never, ever fully discharge ANY NiXX PACK. You can if some sort of man-fable or religious battery zealotry of some sorts compels you completely discharge a SINGLE NiCad, but NEVER a NiMh, and never a PACK. This is complete BS and men seem duty bound to keep the misinformation alive at any cost.

You may have saved it, but you did damage it some more.

[Joshua Smith]

On a similar thread on this general subject you posted:

[Re: Can lights
Postby Joshua Smith » Sat Dec 31, 2011 12:43 am
Some people, when you ask them what time it is, will try and tell you how to build a watch.]

I had previously posted:
[Re: Can lights
Postby fmerkel » Fri Dec 30, 2011 12:41 pm
A little battery maintenance:
Using a NiMh pack to damn near dead is an excellent way to drain the weakest cell and produce a reverse polarity condition if you persist in keeping the power on. This WILL weaken that cell further and has a high possibility of killing it outright. This, of course, ruins the pack. When the light gets noticeably dim, shut it off.]

Pay attention to what camerone is saying. Never, ever fully discharge ANY NiXX PACK. You can if some sort of man-fable or religious battery zealotry of some sorts compels you completely discharge a SINGLE NiCad, but NEVER a NiMh, and never a PACK. This is complete BS and men seem duty bound to keep the misinformation alive at any cost.

You may have saved it, but you did damage it some more.

Thanks. And I'm sorry if I offended you in the earlier thread. My comment wasn't directed at you, and I probably should have kept that to myself in the first place.

[airsix]

So you just want know what time it is?

[fmerkel]

Here's some more 'watch building' info.
This one is ESPECIALLY for men who have historically thought you NEED to totally discharge batteries.
It's one of my pet peeves. It just does not want to go away even though there has been more than ample evidence it's wrong for decades.

Dan's Quick Guide to Memory Effect, You Idiots - http://www.dansdata.com/gz011.htm

[fmerkel]

More NiXX chaging info:

A bit simplified but there are essentially 2 kinds of NiXX chargers:
1. Slow and 'dumb' (simple and cheap). These generally say something like 'hook up, charge for 12-15 hours, remove from charge. Some of these may use a simple timer. The timed ones are NOT like the next category.
This kind uses a VERY slow charge rate. Often called 1/10th C (capacity of the cell/pack in milliamps). The charge is so slow it can almost be left on indefinitely without harm to the pack. Excess charge is converted to heat. In fact you can tell if the pack is full when it starts to warm up.
This is actually a pretty good way to charge your pack if you have the time. It's very safe as long as you are using a properly sized charger. On a brand new pack or a suspect pack this is the best way to charge.
The charge will not stop, and it does not care WHAT it is hooked up to really, it just sends out a low level of charge.
The trick CaptnJack had above could easily have been done with a slow charge also since it would not have cared that the pack was dead.

2. So called 'smart chargers'. These generally are faster and have a electronic mechanism to determine when the pack is full, sometimes referred to as Delta-V. Since they charge faster with more amps they have to shut off or risk damaging the pack with excess charge. The faster charge rate cannot be shed as heat once full and heat will damage the pack. Since they actually sample the pack charge state most of them will reject a dead pack as was Josh's problem. The dumb charger doesn't care about that.

It's useful to have both kinds of chargers around to be used for different purposes.

Another good use of a slow charger is to hook it up to a timer for ~ 1 hour/day and leave it on a charged pack. This will keep a full pack topped off indefinitely without harm.
As has been indicated a freshly charged NiMh pack will lose ~ 10% of it's charge in 24 hours and then settle down to losing 1/2-1%/day there after. There is a new class of NiMh called LSD that is significantly better at retaining charge. They are MUCH better NiMh batteries. Look up Sony Eneloops for the poster child of this class. The majority are AA but there are some other sizes appearing.

[Joshua Smith]

Here's some more 'watch building' info.
This one is ESPECIALLY for men who have historically thought you NEED to totally discharge batteries.
It's one of my pet peeves. It just does not want to go away even though there has been more than ample evidence it's wrong for decades.

Dan's Quick Guide to Memory Effect, You Idiots - http://www.dansdata.com/gz011.htm

Got it. Thanks. But, for some reason, the big hand is stuck between "3" and "4".

[CaptnJack]

try some of that aseptic mold that'll loosen her right up

[Joshua Smith]

try some of that aseptic mold that'll loosen her right up

It melted the crystal. Now Mickey has one arm pointing at his feet, and the other one fell off.

[Blow-N-Bubbles]

Better yet, I'll trade you a new WATCH ...DIGITAL !! for the can light and we'll all be happier !