Uniden sc150 charging

[Jason705]

I'm fairly new to this guys, so bear with me.

I just got a uniden sc150 scanner with a couple extra batteries. I am looking for some way to charge the nicd battery packs externally with some sort of smart charger so as to not kill the battery packs by over charging them. The spare battery packs are 4.8v 700mah and have the uniden plastic plug on the end of the lead.

Is there a way to Jerry rig a smart charger to charge these outside of the radio (which has no charge indicator or overcharge protection)? I was looking at rc battery pack chargers that supported the lower mah but I'm not 100%. If you guys have any ideas, I'd be glad to ear them. Charging 3 battery packs using the radio without over charging is tedious.

Thanks
Jason

 

[k3cfc]

You don't need a smart charger a simple light timer will work. get one that can be modded to shut off when the time is up read the back for instructions. look around for something you can rob the female charge part out of that your wal wort will fit. this plug is smaller than most so this will be a challenge maybe radio shack could be helpful. solder two stiff wires on the socket find pos/neg and mark as such this will get you going for now. i set my timer for 10 hrs for a 2200 amp/hr battery. plugging the batteries in and ouy may present a problem with breakage at the plug.

Hope this helps.

 

[Jason705]

Thanks k3cfc. I appreciate the response.

Ill throw out my theory here - let me know what you think....

In theory, if I was able to directly connect the wall wart to the battery pack for 10hrs using some sort of a timer, they should be fully charged. The replacement batteries I got are 800mah. I was just worried about over charging them and being no good.

My thought was to get one of those good smart chargers (like venom pro - I've got a line on one cheap) I could properly charge and not worry about over charging again. I'd just attach the alligator clips to the leads, program it an away I go.

Thanks for the response.

 

[nanZor]

The easiest solution would probably be this charger:

Tenergy 2.4-6V (2-5S) 300ma nimh charger

I've seen them on Amazon and elsewhere.

There are other airsoft nimh chargers, but many have too much current to handle those 700ma cells, even on their low setting.

The manual for this Tenergy charger suggest -AV auto voltage detection, short protection, high-impedance / alkaline rejection and 15 hour safety timer. Strip a few wires to mate to your Uniden packs, and I think this would be a good bet.

It would charge your batteries up in about 2 hours or so if they were fully depleted. Not sure if it has a trickle, so I would test with it plugged into a timer - despite the built-in 15 hour safety timer just in case.

 

[k3cfc]

Thanks k3cfc. I appreciate the response.

Ill throw out my theory here - let me know what you think....

In theory, if I was able to directly connect the wall wart to the battery pack for 10hrs using some sort of a timer, they should be fully charged. The replacement batteries I got are 800mah. I was just worried about over charging them and being no good.

My thought was to get one of those good smart chargers (like venom pro - I've got a line on one cheap) I could properly charge and not worry about over charging again. I'd just attach the alligator clips to the leads, program it an away I go.

Thanks for the response.

Good deal Jason. what ever works for you but at least your on the right path.

Good Luck

K3CFC

 

[Jason705]

Thanks for the information

Again, thanks for everyone's feedback.

I picked up one of these:

TowerHobbies.com | Great Planes ElectriFly AC Park Flyer Peak Charger

I stripped half the plastic from the charge end with the plug and the pins are small enough to slide right on the plug of the battery pack.

Since the charger has a variable rate to charge, any ideas on the number? I was thinking of starting at 400mah and see how that goes for charge time and heat.

Thanks
Jason

 

[k3cfc]

It is never good to charge any battery too fast. i would start at 200 mils and note the time. i didn't know this scanner won't work as long as it is plugged in so i modded it so it will. it went dead the other day in my van and this is when i discovered this. i also use a switching power supply to charge it in my van.

 

[nanZor]

Since that charger uses a peak-detecting circuit, to get an *accurate* peak detection from the cells, the current should be at least 0.5C, so 400ma (for 800ma cells) would be the minimum. If you used less, say 200ma, then the peak would not be accurately detected, and you risk overcharge - even though it physically feels cool. This is especially prevalent in new cells that have not been cycled.

In any case, while 400ma would be the minimum, I would NOT go past 1C, or 800ma if you feel tempted to charge it quickly. You'll get an accurate peak, but follow the max current spec of the manufacturer. Since those cells are held tightly together inside heat shrink, I personally would not go past 0.5C / 350-400ma charge. They can probably take more, but without adequate cooling could lead to wrapper melt.

Whatever you do, don't charge them inside the 150 now that you know you need 0.5C to get that peak detection.

Low current levels are only used for initial 16-hour forming charges at 0.1C, and when part of a capacity-determining charge/discharge routine and use a timer since there is essentially no peak to detect. Other than this usage, most manufacturers spec sheets show normal cycling in the 0.5C to 1C charge range.