Question about 6volt NIMH battery pack recharging

ampdude

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My Magcharger charging unit died. Has anyone ever tried charging a 6volt NIMH battery stick with a car battery charger set to 6 volts? I have an old Sears battery charger that has a lot of settings to it. I don't see why this wouldn't work if I set it to 6 volts and 1 amp, but somehow it seems like a dumb idea. Input please..
 

alpg88

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you need a bit more than 6v to charge 6v nimh pack, but you should be able to partially charge it, fully charged nicd cell is about 1.4v you got 5 cells, so you need 7v to charge fully, 7.2v wall ac adapter would work too, if you can find one, just time it, capacity + 50%more.
I've charged nimh nicd cells with wall ac adapter many times, no issues, just time it.
 

ampdude

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Okay, I just don't have anything to connect the battery to. The stick does say 6V, but I never thought beyond that thinking that it was actually 4.8V nominal. . I think most of my wall warts are 6-12volt, don't think I have a 7.2 and I did just look at the battery stick, yes it is 5 wrapped cells, for some reason I thought it was four. I guess I just really need to get another charging unit for it.

I just looked at the wart that came with the Magcharger originally and it says the output is 12 volts, so there must be a buck in the charging adapter itself. I saw a bit of circuits in there, but didn't look at them too closely when I had it apart. It's in the dumpster now.
 
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ampdude

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You may consider about using pair of 21700 and proper bulb.
Much brighter, lighter weight, longer run time and easy USB charger.
Thanks for the suggestion. What bulb would you recommend? I'm wondering if 26500's would not fit as well. They may be too short though. I'm a little worried about battery rattle with 21700's and it's not a format I've ever gotten into. A higher output bulb would be fine as I'm sure you're aware the Magcharger has an aluminum reflector and glass lens.
 

vicv

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You a get a hobby charger. That's how I charged my stinger battery until I got a cradle for it. Any bi pin G4 ~7 bulb will do if you go that route
 

alpg88

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Reflector and lens may be glass, but your bulb holder is still plastic, FM used to sell ceramic bulb holder, idk if he still does, that would work with high wattage bulbs, but if you stay within stock wattage you do not need one,.
 

ampdude

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You a get a hobby charger. That's how I charged my stinger battery until I got a cradle for it. Any bi pin G4 ~7 bulb will do if you go that route
I've always considered a hobby charger, but so confused on which one to get. What do you use?
 

alpg88

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B6 is the best bang for the buck, around 40 bucks, be aware of fakes thou, they are faked a lot, due to high demand, and popularity.
 

vicv

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I've always considered a hobby charger, but so confused on which one to get. What do you use?
IMAX B6. The small one with out an AC adapter. I just plug a laptop power supply into it. But about 10 years ago and it still works well. I actually am using it right now to charge a 12 V car battery.
Or if you want to get away with it really cheaply, you can buy something like this. I believe this is a 1S to 5S charger. Clearly one of my solder joints failed, but it will be easy to fix. It was only a few dollars if I remember. USB powered, so I cut a USB cable and soldered the end onto the power pad. On the other side or the 2 BATT wires and rare earth magnets are soldered on the other end.
IMG_1559.jpeg
 
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ampdude

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LoL.. thanks guys. I soldered a Surefire lamp assembly back to working shape the other day. Been a tick since I did that.
 

alpg88

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IF you do not care about ballance you could use this for Li ion. but it wont work with nimh/nicd since it uses delta V termination of charge method, this circuit is not capable of that, but for li ion, it is great, i used it many times in my builds. It is about 4 bucks on ebay
1705875903095.png
 

alpg88

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Now you have another problem how to connect those batteries to the charger. it does come with alligator clips, and round plugs, but it will do no good for individual cells, my advice get magnetic leads.
something like this
1705879306207.png
 

fivemega

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Thanks for the suggestion. What bulb would you recommend? I'm wondering if 26500's would not fit as well. They may be too short though. I'm a little worried about battery rattle with 21700's and it's not a format I've ever gotten into. A higher output bulb would be fine as I'm sure you're aware the Magcharger has an aluminum reflector and glass lens.
This is only one sample of bulb.
Pair of 26500 will fit but pair of 26650 will have more capacity.
Using pair of 26500 or 26650 or 21700 will need plastic pipe because MC tube has diameter of about 34mm while 26500 or 26650 has diameter of 26.5mm and 21700 has diameter of 21.5mm
So all mentioned batteries will fit in MagCharger but need spacer to hold in center with no rattling.
MagCharger reflector is metal but reflector base is plastic.
 
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