Estes Command Control Launch control question

[Vance in AK]

I just picked up one of these controls & want to convert it to run off my 12 volt lawn tractor battery. The control has connections for two seperate 7.2 volt ni-cad battery packs, & will run on "low"(7.2 volts) power with only one, or "high"(14.4volts) with two battery packs.
The connecters for the battery packs are just a two wire plug. My question for you electrical engineers is do I need to run my battery leads to the plugs for both battery packs to get the full voltage from my 12V battery, or can I just run to one connecter in the control box. I'm thinking I could just run to one battery connector & I should still get my full voltage at the controls, but I don't want to miss something .
Anyone else made this conversion?
Vance in AK.

 

[mikeyd]

I have not pulled one of these apart, but to get the 14.4v they would have to put the batterys in series. I would go to an electric car rc shop and buy two plugs like what is on the battery side. In one plug I would wire a "loop", or short, in the other plug I would wire to a length of cable with battery clips on the other end to go to the battery. Make sure you keep the polarity correct, on the battery plug, as this unit uses led's which can be polarity sensitive. Then You plug in the two clips and it should work fine. Just make sure you are turned onto the "High" setting before connection to the car battery, as I do not know what the 12v would do to the launcher in the low setting, it might blow out the led's.

Happy Flying!

 

[Vance in AK]

Thanks Mike.
Now not trying to be argumentitive(sp), just trying to understand.
As long as you had the full 12 volts coming in thru the same lead that would normally run the control box on 7.2 volts for standard or "low"(single battery) power ignition, what would be the advantage to running the jumper on the second connecter to simulate series battery opperation?
One of my main concerns is whether or not there is anything in the system that would be zapped by twelve volts coming in on one leg. I can't picture a problem since it uses the same LEDs whether you are using one or two batteries, just more that light on the power indicator LED bar for the higher voltage.
Thanks.
Vance in AK.

 

[mikeyd]

This has to do with the "continuity" circuits. If you only used the one connector hooked up to 12 volts, and ran the switch in the "low" 7.2v setting, you would not have the proper voltage dropping components for the buzzers and led's and could burn them out. If you stay in the high mode and "trick " it into thinking you are using 14.4v, you use thier internal current resisting, or voltage droping circuits to prevent overload of the buzzers and led's thus preventing their early demise.

 

[mikeyd]

Vance, I went and got my unit, and removed the battery tray so I could see the switch. In looking at this, I see no leads that would indicate any difference in current limiting components to the led's. The short of it is, in looking at it it looks like you should be able to only use the one plug, and leave it switched to low, and it should work fine. I of course can not say this with all certanty, but I did test it by using one battery, to see the power level, then swithed it to high, and shorted the other battery connector, and the power level remained the same. Basically saying the same thing you did in your reply! Good Luck!

 

[Vance in AK]

Thanks for going to all the trouble Mike. I really appreciate it.
when you spoke of shorting the second battery lead, did you mean to just put a jumper between the red & black leads on the second battery plug?
Thanks again, Vance.

 

[mikeyd]

Originally posted by Vance in AK
when you spoke of shorting the second battery lead, did you mean to just put a jumper between the red & black leads on the second battery plug?
Thanks again, Vance.

Yes Vance that is what I did when I did my small test.

 

[Vance in AK]

Thanks again Mike. I'll pick up a plug & get to work.
Vance in AK.