Running two different rated batteries?
 

Small story, sorry!

Have a Senton and wanted to purchase some new 3s batteries, but SPC is sold out as usual.

Anyways, took out my other RC's with my son a couple days ago and sadly broke the transmission in my P2de, and then a 1987 Full size Chevy decided to park itself in the way and busted a hinge pin on my other.

Ordered my parts, but being my location even with paying for intimidate delivery, I am looking at 4-6 days before they arrive and still have to find time to actually sit down without kids trying to touch small parts.

So, I decided to pull both batteries out of the busted vehcile and use them in my Senton. Of course with extreme monitoring, one battery is a SPC 5000mah 40c 2s, and the other is Venom 4000mah 20c with 40c burst.

Everything did fine. Measured heat and voltage, etc. Made sure nothing was ballooning or swelling. At the end of the run, both packs had the exact same voltage per cell, and the 3s was warm to the touch, but nothing crazy, while the 2s was cool.

Anways, worked out, but is this 'okay' to do? Didn't want my batteries sitting there half used. Would love to do this again until some more 3s becomes available through SPC. Running 5s was great fun in comparison with 4s.

Only concern is the Venom peaks at 160 amps and the SPC 200amps. One has more capacity, but both stopped at the same voltage.

Thoughts? Everything I know about batteries from college says 'be careful'.

Guessing no one knows the answer?

Just spent a couple hours searching and piecing information together. Most of it coming from several flight forums, along with Traxxas forums.

Finding a lot of information going back and forth, mostly positive info stating that running two different size batteries is actually okay. They average themselves out and you drive accordingly to the lower MAH rating.

Although my limited experience shows they run into their LVC at the same time. With this being said, my best educated guess is the lowers rated 'C' pack will drag down the performance of the nicer pack. Therefore, rather than having a 160amp burst and 200amp continuous available. The nicer pack will now only use up to 160amps as needed when the other pack does so as well. Also, the MAH rating is only going to be rated what ever the lowest pack is rated, but as stated earlier, they hit LVC at the same time.


Any further input?

Should be fine as long as you don't run them to LVC. Obviously the smaller pack will hit empty sooner. LVC is only measuring total voltage, so if one cell in the smaller pack hits empty the ESC might not pick that up depending on what LVC is set to and you'll end up with a damaged cell.