# A Basic Question - Right Battery Charger for Plug?



## Gary Woolard (Jan 2, 2008)

I recently picked up a used Accucraft Shay with R/C control. There are rechargeable batteries in the tender which drive the single servo, but I don't know what the voltage is. There is a small plug which you can pull out of the tender to recharge the batteries: it looks like this --










Experienced R/C users at the summer steamup seemed to recognize it as a reasonably standard plug, and one fellow showed me his charger -- it was a typical looking 'wall wart', a small transformer that plugged into a 110 wall socket, a pair of wires about a foot long that ended at a small plug that mated with this one. Unfortunately, I didn't look at it closely enough to see the specs on it.

So my question is this -- what kind of charger do I need, and where can I get it?

Thanks all, in advance!


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## TonyWalsham (Jan 2, 2008)

Most R/C systems use 4 x AA cells = 4.8 volts. However, some use 5 x AA cells = 6 volts. 
If the batteries are working the system, you can measure the voltage at the two pins. If around 5 volts it will be a 4 x cell pack 
If not working you will need to count how many cells. 
The other lead will be a charge plug for a TX. They are either 4 x cells or 8 cells. 
Your local plane, car and boat hobby shop will have the one you need.


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## Paul Burch (Jan 2, 2008)

Gary,
I think this might be the type of connector , http://www.all-battery.com/FemaleHi...80272.aspx
But before you look for a charger I would try to identify the type batteries and voltage that are in the loco.
All-Battery.com or Batteryspace.com probably has what you want. Or like Tony said,your local hobby shop that specializes in RC.


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## Semper Vaporo (Jan 2, 2008)

I think there are two basic types of those 4-pin flat connectors. One is just a rectangular piece with two of the corners on one of the long sides keystoned. The other type is about the same size, but, instead of keystoned corners, one of the short sides has a key sticking out. The idea behind the non-symetrical shape is to force the connector to be plugged into the socket just one way and not the other so the pins always align for purpose ("+" to "+" and "-" to "-", and not the other way around). 

The difference in the two shapes is for two reasons. 

One is because the purposes of the 4 pins are the same, but the order of the wires is different, (you don't want to force one connector type into another type socket... Not wired the same!). 

The other reason is for proprietary reasons, You can't buy brand "A" batteries and then spend money on a brand "Z" charger. There are, however, adapter cables that have one brand connector on one end and the other brand socket on the other and the wires are swapped around to produce the correct pin-out arrangement. 

As mentioned above, your best bet until you get the differences sorted out in your own head, is to go to a local hobby shop that does R/C and have them look at what you have and then point out the appropriate brand devices that mate with it. 

There is probably a web site that will have drawings to show all of this, if you want to search for the info. Personally, I can't think of a simple Google search term to enter!


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## Pete Thornton (Jan 2, 2008)

Experienced R/C users at the summer steamup seemed to recognize it as a reasonably standard plug, and one fellow showed me his charger -- it was a typical looking 'wall wart', a small transformer that plugged into a 110 wall socket, a pair of wires about a foot long that ended at a small plug that mated with this one. Unfortunately, I didn't look at it closely enough to see the specs on it. 
Gary, 

I'm pretty sure that's a standard r/c servo-rcvr cable, which you can buy at your local r/c hobby store. They have 3 wires, 2 carry power the the third is the signal. If just used for power, the signal wire is skipped sometimes. This is a switch to turn on/off power to a rcvr from the battery. 












I have a 'smart' charger (see picture below from batteryspace.com) and I have a 'servo extender' cable which is 6" long and has male-female connectors - designed for servos that are too far from the rcvr for the supplied servo cable. The extender has one plug removed (I forget whether it is male or female on your cable) and a Tamiya connector added [the big clear plastic one used on r/c car battery packs.) 

As Paul notes above on his link, you probably have a "Male Hitec connector with 22 AWG wire -Battery Side". (Hitec and Futaba are the two servo types.)

You have to sort out your polarity - rc servo cables have a red (+) that should match the (+) from the charger, like the center wire on your loco.

I don't have to worry what the battery pack is - the smart charger figures it out.


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## Greg Elmassian (Jan 3, 2008)

The smart charger also figures out lithium vs. nicad vs. nimih? 

Pretty darned smart.... in fact so smart that I have never seen one with only 2 leads that could do that. 

(now maybe it's a reasonable assumption that the receiver batteries are lithium, I don't think so but someone else might)

My advice is to open the loco up, and find out what type of batteries and how many cells. Then you can't make a mistake. 

Greg


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