Connecting 3S Lipo to EVX (diagrams inside)

[NickRummy]

Well I've been doing some searching on people running 3S lipos on the EVX. Seems like people have been trying the mod that makes the evx run off one battery pack then plugging the 3S into that. I haven't read anything about it working though. Has anyone done this?

If the EVX runs off 14.4v it HAS to work with a 3S. I just don't think you can run one 3S through one of the input leads. My questions is how would you have to wire the 3S through both the leads? It seems like the exv just takes the two inputs and connects the battery packs in series.

Here are my diagrams. The first being the normal single pack mod and hooking up the 3S that way. The second being an adapter to use both input leads. I think this idea will work but there are a few options on wires and i'm not sure which to pic. Ideas please?

 

[Kamikaze]

First thing you need is a voltage cut off, don't want to ruin that $$$$$ lipo by over discharging it.

 

[NickRummy]

thats no biggie, got a novak 3S cutoff for it

First thing you need is a voltage cut off, don't want to ruin that $$$$$ lipo by over discharging it.

 

[JohnRobHolmes]

Go with the single pack mod, with the 3s plugged into one side. Less wire that way, and no messing up and creating a dead short on your pack.

 

[STANG KILLA SS]

a simple idiot proof way would be a Y harness.

 

[hotwheels000]

I have been running the super duty which is essentially the same ESC with the single pack mod with no problems on a 3s Not exactly like your first diagram but the same concept.

 

[NickRummy]

Thanks a lot for the replies fellas. I just want to make sure I don't fry anything. I read some other guy used a 3S in the single input and lost power after about 3 runs.


John, that was my fear. I didn't want to short out the circuit and wanted to make sure I got the wires right making the loop. I'll just give the single pack mod a shot. thanks!

 

[floogldood]

The left diagram is correct.

 

[Kamikaze]

a simple idiot proof way would be a Y harness.

If you used a y harness it would dead short the battery.

 

[NickRummy]

I guess I just don't understand why they put the two battery inputs on the EVX then if one will do? They could have just put one battery input and then included an adapter to hook two batteries in sieries into the one input.

If you used a y harness it would dead short the battery.

 

[Kamikaze]

Basicaly the two seperate inputs are the series hook up, so by the diagram on the left you are just closing the circut so that one battery can be hooked up. But thats whay you can't make a y harness to hook up one battiery, cause if you do that you are hooking the battery up to itself and creating a short situation.

 

[Trikster]

If you used a y harness it would dead short the battery.

Unless something internally dead shorts the battery, this will not do it. The positives go to the positive input and the negative goes to the negative. Now, if the internals of an EVX just put things in series, then yes, a Y will make your Lipo inflate and most likely burst.

 

[Kamikaze]

If you plug in the battery to both +'s and both -'s it will short the battery if my reasoning is correct. If the input of the esc is 14.4 volts than there has to be a serries conection between the two seperate plugs, thats why you conect one set of plugs to run one battery, to complete the circut.
EDIT: Pardon the awful drawing but I was to lazy to go into cad. If you y-harness the two inputs you create a short. The big drawing is the y harness short, the little one is the way the 2 batts hook up. Please correct me if I'm wrong.

 

[HndsWthtShdws]

The left side works, the right side shorts. They both end in -orts but they arent the same thing.

 

[hunter306]

Only thing I'd be concerned about is the built in BEC. Usually Novak designs it to run off only 1 of the two packs that are plugged in (it's piggy backed off of only a single input).

If you run 3s on that single input that BEC is going to be getting ALOT more voltage than it's designed to handle.

Just a headsup, otherwise this idea would work fine.

 

[NickRummy]

Well I ran it today and the 3003 servo held up? how long do you think a servo would last at that voltage? It didn't seem any stronger. Maybe i'll throw a volt meter on it tomorrow and see what is going to the motors and servo.

 

[Kamikaze]

It won't be under any more voltage, it will just be harder on the bec to absorbe all that evtra voltage, stepping it down to 6 volt makes heat, to much heat makes smoke. Glad to hear it worked though.

 

[NickRummy]

Gotcha. maybe i'll look into running that MIP regulator then.