critterhunter

I've got a JR Sport SX600 computer radio. While the price can't be beat and I'm very happy with the radio, the supplied TX battery pack (which I think is 700MA) doesn't last very long. I get maybe two or three flights before the transmitter starts warning me the battery is getting low. I have drained and charged the Nicad pack a few times and left it on the charger for about 24 hours without much improvement. I've got several Energizer 2500ma Nimh 8 packs laying around doing nothing and would rather use them. These batteries are a great buy at Walmart (be sure they are 2500ma and not the lower ones) for about $10-$15 an 8 pack. Question is will a "inline" (4 cells end to end with another 4 cells) battery holder from Radio Shack fit inside the TX battery compartment? Also, is that two pin mini plug on the pack that plugs into the radio something I can find at Radio Shack? It looks like the kind of plug found on wireless phone battery packs which I could cut one off of. Also, off hand, does anybody know what size DC plug that jack on the side of the transmitter uses so I can wire up my own charging jack to my Piranha Digital Peak charger and use it without removing the pack from the TX? I know the polarity on the JR radio charging jack is reversed and thus I'll have to wire the DC jack backwards for it.

critterhunter

Well, went up and found the answers to my own questions. Radio Shack does sell a 8 AA holder that will fit inside the JRsx600 battery chamber. You have to have the holder flipped on the proper side to clear the cover. If you still think things are a little too tight you can grind down the plastic on the Radio Shack holder just a bit but I didn't need to. As for the little plug that the battery plugs into the TX with, the guy had junk wireless home phone batteries laying around that customers brought in to exchange with the same exact plug. He gave me one for free. I also found a DC charge jack that will fit the plug hole on the side of the TX. The way I understand it the DC jack on JR TXs is wired backwards so use a volt meter to be sure. Now I'll have 2500 Energize Nimhs in my TX and should be able to charge them from my Piranha Digital Peak charger while still in the TX. I think I've read that the TX has a 2 amp fuse in it and that you shouldn't charge at a higher rate than that. Not a problem since I like to slow charge those 2500ma nimhs at around .3 amps to give them a safe charge that will last longer. I usualy set my charger for 3000MA capacity since these batteries might go higher than 2500 and will false terminate at the MA setting you choose if it is lower than what the battery will take. I also set the m/v threshold to around 5m/v, but be aware that at such a low setting these batteries might false terminate once or twice near the start of the charge. You could raise it to 8 or so but I prefer to keep it low since nimhs don't drop much in voltage when full charge is reached (m/v threshold of 5 means 8 cells x5m/v= a 40m/v drop in peak voltage will be required before the charger will terminate). Set it too high and the charger might not see that the voltage has dropped and the pack has peaked.

panzerd18

critterhunter I am in some what of the same situation as you. I have a JR 2610 6 ch and recently bought a 9.6V Sanyo 2500mah transmitter pack. I thought when they said a JR connector that it would work with my Tx. How wrong I was and I have found the same 2pin connector that the standard pack plugs into. I have been looking around for one to plug my 2500mah pack in. I had nearly given up and was going to cut the JR nicad 600mah pack plug off but now I will go to my local electronic store and see if they have it.

Also when I bought my charger I bought a JR transmitter charger cable which is the one you made. All I do is plug the connector into the side of the Tx and it charges without having to take the battery out.

critterhunter

Glad to hear it. Just ask the clerk at Radio Shack or some other store that exchanges wireless *home* phone batteries if you can have a junk pack or two. The plugs should be the same. Be aware, though, that the battery pack I cut my plug off of had the positive and negative wires reversed! It's a lucky thing I looked at the connector inside the JR battery compartment and it had a little "+" and "-" sign next to the proper pins. In other words, in order for this plug to fit properly into the TX it would have had it's red wire going to the negative terminal. I simply soldered the wire ends of the plug to the proper negative and positive posts on the 8 AA "inline" holder I bought at Radio Shack. You could also do this a bit cleaner by using a 9V battery plug to plug into the posts on top of the 8AA holder and then solder it's wires to the proper wires on the end of the mini two pin plug you snagged off the phone battery. I saw no need for this and I don't like the idea of a 9v battery plug coming loose off it's connections in flight.

proptop

My Feedback: (8)

You might have a problem with your charger "seeing" the Tx. battery? There's usually a diode in the Tx. so nothing comes back out of the charge connector to give the charger any feedback.

critterhunter

I've heard that but my Pirahna Digital Peak charger had no trouble charging the pack via the jack on the side of the TX. If you do have problems simply remove the 8AA holder and then plug a 9V battery plug onto it's top posts and hitch the wires to your charger.