Lipo Torkinator ESR help required

[mattyb]

Hi all
I have a Goped ESR with Torkinator motor and 20ah of 7cell Lipo fitted. It runs on the stock controller, but charges from my Hyperion, via a neat single plug connection, that carries both the high amp charge cables and the balance leads.

I use it mainly for commuting to and from my local pub, around 2 miles away , and I think it's fair to say I love it ! For what I use it for it is close to perfect. It's capable of well over twenty miles an hour, and can complete the round trip with about 25% of the pack remaining.

Due to the fact I often ride it home in the dark off road, I wanted some good lighting up front, so I have found a 7cree led bicycle lamp on the bay. It's a great bit of kit with plenty of light, and comes with its own small battery pack and charger.

The question I have for the boards clever peeps is this, I have purchased a step down voltage converter, which works a treat, allowing me to run the light from the peds Lipo, but what I'm looking for is a way to connect it so that the converter is only powered when the peds controller is turned on. Although small, I want to avoid the current drain on the pack from the converter and the led on the light switch being powered constantly.
My guess is there must be somewhere on the controller that I can connect a relay to that would allow me to have the converter power up only when the ped is turned on.

Any pointers would be very much appreciated.
Thanks in advance
Matt

 

[mattyb]

Let me add a few pics to help make things slightly more interesting, we all know threads without pics can be dull

The light I'm looking to add



The charge end of the multipin connector I'm sooo happy with !



The converter that seems to work so well



Now where I get a bit out of my depth ! The underside of the controller showing the two relays which my guess is hold the key to my switching glory !



And the top side of the said controller



Any pointers, or for that matter even abuse is welcome

 

[mattyb]

Nearly 100 views but no comments, I'll bump it back up, someone must know a way to help.

 

[bandaro]

Couldn't you use a relay on the battery, before it hits the Y harness to run the controller and the inverter. That way the relay is a "master" switch and with it turned off the battery cannot drain. Solder/leave the motor switch on permanently, so it is the single relay that you use for the whole power up, instead of switching the esc and inverter off.

That being said, it would probably be cheaper to just run a low amp switch from the batteries for the inverter and flick that switch as well as the esc switch to turn off. If you mounted them next to each other it wouldn't be too much hassle for your drunken self when you get home.

Alternative options would be to see if the esc has an output BEC on it. These typically give out 5-6v at up to 2 amps, so it might power your light just fine by itself depending on power requirements. Check the user manual for this. Another possible method that should be possible is solder the inverter wires to the output of the relays/battery and it should work it all automatically. But alas I don't have the technical knowledge to tell you how it is done, so would go with my earlier thoughts personally.

 

[mattyb]

Thanks for your reply bandaro,
Your first point using a relay is a good idea, my only concern with that is the heavy current pull from the motor means a very large relay would be needed.
Yes a second switch would definitely be a easy cheap option, I am just being picky and want a clean install, but if a second switch is what I need to do, then so be it.
Picking up a feed from the controller is my favourite option but unfortunately like you it is above my limited technical knowledge

 

[bandaro]

You can get a Heavy duty truck (24v) relay rated for 80-100 amps from an auto store/ebay pretty cheap. That should easily handle your amp draw, unless you are running some crazy setup power. Otherwise best of luck figuring it out, have you tried taking an educated guess and poking about with a multimeter?

 

[brent]

Poking around with a multimeter is a good idea.
Or, can you take a closer or better focused photo of the board, perhaps so the text on each component is readable?

If you can figure out where there's a pin or something with a positive voltage only when your goped is on, it'd be easy enough to use it to charge the gate pin of a cheapo n-channel FET. Throw in a resistor or two depending on your configuration and you're basically done. A regulator output would be safer but getting power directly from the battery should be fine if you're careful not to short anything.


Judging from the huge copper fills, I'd guess that one of the three regions I circled is likely a battery power output that's only enabled when the thing is turned on:
http://i.imgur.com/1QzsAng.jpg

(I'd try the middle one first)