Author Topic: Battery burner (Read 1357 times)

Nixter · « **on:** April 14, 2005, 11:17:12 AM »

In a topic called "unscientific battery test" someone mentioned a battery draining box.

I am interested in building such a box but have almost zero electronic/electrical component experience. Could a simple schematic be posted? With the individual components ID'ed for us newbies?

Thanks in advance...

Nixter

Siskiyou · « **Reply #1 on:** April 14, 2005, 06:34:06 PM »

Simple enough: Go to an electronic supply store such as Radio Shack or Fry's and purchase a battery container(box) for 4 AA batteries. This may require the purchase of a snap-on battery connector(+ -). The connector normally comes with a black(-) and a red(+) wire. Solder the red wire to the positive end of a 12v backup light bulb. Solder the black wire to the side of metal base on the bulb.

When you place four batteries into the container the bulb lights up and drains down the batteries. You might prefer to build one with a 2-cell battery box. I happen to use what I had on hand.

Oops! Simpler yet is go to an automotive supply store or Wally World and purchase one of those lights designed to light up a camper shall. I believe you can find them that use two or more batteries. I should note that I tried to use my Mag lights to drain batteries. I gave that up because I was burning out to many bulbs and it takes to long.

I believe my original drainer works best because the large 12v bulb draws more juice and drains the batteries faster.

Siskiyou · « **Reply #2 on:** April 15, 2005, 05:48:09 AM »

Radio Shack:

Item Battery Holder (4-AA) with wire. #270-409
Item Battery Holder (4-AA) w/snap connection # 270-383
Item 9V snap connection Item 270-325
Item Battery Holder (2-AA) Item 270-414

Price for list items is less them $2.00 ea. Provides you with a number of options.

Ka6otm · « **Reply #3 on:** April 15, 2005, 06:51:49 AM »

Siskiyou,

The battery discharger you have described will work all right but there's one other thing you should look into: Voltage monitoring.

If NiCd or NiMh batteries are discharged lower than 1Volt/cell they can develop polarity reversal. Having said that, in my experience if you run them down to less than 1 Volt and then IMMEDIATELY put them on charge, they won't reverse. If you discharge down to absolutely 0 Volts, they will develop reversal. Found out this is true the hard way. Also found a way to reverse the reversal that I won't even mention here as it's pretty hazardous.

The Commercial units monitor terminal voltage and when it hits the 1 Volt/cell mark, they shut off the discharge and go to charge mode.

When they hit the delta V or Delta T point (depending on manufacturer), they go to trickle mode (C/10 or less).

Ka6otm

Siskiyou · « **Reply #4 on:** April 16, 2005, 05:05:49 PM »

Ka6otm: Thanks for info. I have not had the problem with over discharging. I suspect that is because I check it once and a while. The light is normally out when I pull the batteries. I recently used the discharging, recharge, discharge, recharge, discharge, recharge cycle as recommended on one of the manufactures web pages. While this might seem time consuming it was the first time I did the multi-cycle process on these batteries in three or four years of service. I had preformed the one time discharge process a number of times.

When I was on the job we had a machine that did the discharge/recharge cycle. I still hated the NiCad batteries. The nickle-hydride batteries are a vast improvement over the NiCad rechargeable batteries.

I just went back and checked < http://www.Lenmar.com > regarding discharging batteries. The recommendation is to fully discharge the battery. There is a lot of information on their support page. To bad I do not care for their batteries. Lenmar provides more information then what I have found from other manufactures of re-chargeable batteries.

darrell8937 · « **Reply #5 on:** October 01, 2006, 05:32:30 PM »

Voltage reversal is a definate concern. I am a mechanic and had a call one day. for the battery sparking. I made a house call. rere these days, I still do though. Found the battery polarity was reversed. battery was flat and coustomer charged it, swears he hooked it up correctly and I beleive he did as a charger needs the intial charge to get the polarity right. Replaced that old battery and all was well. would have had to do some wire swapping and maybe It would have started on the backwards battery but not worth the trouble.