This right?

[Bigmaxx]

My esc only has one plug for a battery, I have seen the traxxas adapter that allows you to put two batteries on it. My question is can I put a 4s lipo an a 2s lipo together? It for a Emaxx if that helps

 

[MudSlinger33]

Is it the brushed emaxx? If so then your esc will only handle 4s lipo. Traxxas does sell a parallel and a series connector for use with two batteries.

 

[Greywolf74]

If you ESC can handle 6S you can do that but you'll need to put a low voltage alarm on your 4S pack because it will drain completely down and start puffing before the 2S gets to 3.2V/C. If you dont have a LVA than I sugget sticking to 1 6S pack or 2 3S packs

 

[trax de max]

What's the specs and age of the two lipo's in question.

 

[Greywolf74]

It doesn't matter, if you run a 4S and a 2S even if they are both the same brand, same age, same mah, same C rating everything else the same the 4S will completely drain down to 2.2V/C by the time the 2S reaches 3.3V/C. I have my LVC set to 3.2V/C and I've ruined one 4S lipo and slightly damaged another one buy running them in series on my LST2-E. The first time I thought it was a fluke the second time I was keeping an eye on it more closely and caught it before I completely ruined it. That pack has just the slightest puff now but I think its ok. The IR of the cells went up from about 1.3milliohms to about 2.1 so I think it may have damaged it a wee bit but I think its still usable.

I think since the 4S has twice as much voltage it pushes out its power faster than the 2S pack making it drain much more quickly than the 2S pack. So one feel free to correct me if I'm missing something here but thats been my experience.

 

[trax de max]

i don't know how the esc could tell the difference between a single 6s or a 4&2s joined together. Unless they are different specs/condition.

 

[Greywolf74]

I'm guessing its because since the 4S has twice as much voltage as the 2S it pushes it power out faster than the 2S. As far as the ESC is concerned it doesn't care. But I've tried running 4S/2S combo twice now and both times I had the same result. Ruined the first 4S pack but draining it down to far and damaged the second 4S pack by draining it down to far. in both cases the 2S pack wasn't quite at the LVC level and the 4S packs were a full volt below LVC which in my case is 3.2V/C.

 

[Bigmaxx]

Thanks, i won't be trying that out. But if I put a lva it will be ok?
The 4s is a nano tech 5000mah 45-90c discharge
The 2s is a Turnigy power systems 5000mah 40-50c discharge

 

[Greywolf74]

seeing as how they have different c ratings Id probably put a LVA on each of them just to be careful but yeah with LVAs you would be ok and I'm guessing if you just had one LVA on the 4S pack youd probably be ok but Id check the 2S pack often with a volt meter just to be safe.

 

[Bigmaxx]

K thank you all

---------- Post added at 2:51 AM ---------- Previous post was at 2:46 AM ----------

What brand would you suggest I go with on the lva?

 

[trax de max]

I'd try to keep everything the same, but alarms should help.
I don't know if how the 4s and 2s drained one more than the other. The only reason i can think of is which wire was connected to the ESC connector. maybe the 4s was on red side and 2s on black side and the 4s dumped some into the 2s keeping that up. Or a different way around I don't know.
But would be interested in trying to find out more about this.

 

[hamz9561]

Your best bet is to run like cell counts at any one time. If you don't, the ESC will tend to drain the higher cell count pack lower as the circuit will attempt to equalize the voltage between the two packs. It probably best to run the 4s cell alone and 2 2s cells in series if you're running 4s. If you want to run 6s get 2 3s or a single 6s pack.

 

[Greywolf74]

Thanks Hamz! I figured it was something along those lines!