Granite Running batteries in parallel

[Cuzboss]

Hey guys, so ive been researching and come to find out running two 3S 5000mah batteries in series doesn't give me 10,000mah in my 6S emaxx but parallel will. But, if I run parallel its really only 3S but 10,000mah so, in my Granite 4x4 BLX if I run two 3S batteries in parallel will I have longer run times without burning anything up including the batteries for the sake of LVC?

 

[Overpowerrc]

Yep parallel is same voltage double mah
Series is same mah double voltage

 

[Cuzboss]

So will the ESC know how to hit LVC so neither one of the batteries get damaged? I will buy a Y harness parallel adapter tomorrow. I just don't want to fry an ESC or a battery. I am currently waiting for a BLX 120 and id love to know how to make it a single EC5 without ruining a EC5 lead.

 

[Overpowerrc]

The blx 120 should have a sensor for lvc. The power going into the esc after the adapter has already been combined so there’s only one battery connection in the esc mind

 

[arrmadillo]

You will have to worry about heat in the electronics trying to dump 10Kmah.

 

[suchtragedy]

You will have to worry about heat in the electronics trying to dump 10Kmah.

I assume this is because batteries in parallel means you also double the amps?

 

[arrmadillo]

I assume this is because batteries in parallel means you also double the amps?

Yes

 

[nino]

Why? Is it so hard to swap a battery after 15-20 or whatever minutes? You'll stress the components more with the extra weight + increase the likelihood of one of the cells getting ruined if the packs aren't matched.

You don't exactly double the amps, you double the amp-hours and peak current available (if theyre say 30C packs now you have 30*10=300 theoretical amps available instead of 150A). The ESC will pull whatever it needs. But longer running without a break will cause more heat to build up.

 

[suchtragedy]

Yes

Correct me if I'm wrong but I thought amps drawn depends on your ESC and motor demand and heat is coming from a deficiency in current. That seems to make sense being that everybody recommends a minimum C rating but never a maximum C rating.

You don't exactly double the amps, you double the amp-hours and peak current available (if theyre say 30C packs now you have 30*10=300 theoretical amps available instead of 150A). The ESC will pull whatever it needs. But longer running without a break will cause more heat to build up.

Okay so that makes sense, basically diminishing returns on cooling effectiveness over time.

 

[rflx]

The only two advantages I see:
- you don't have to swap batteries
- you can draw more amps if you are using bad lipos

I personally don't mind changing batteries. And if you have decent Lipos, a single one can handle the current draw.

The disadvantages:
- Emptying 10.000 mAh without a break might cause temperature issues
- If your Lipos have different internal resistances, they will not discharge at the same rate. In that case, LVC will happen too early for one pack and too late for the other. This might be no problem at all, but could also lead to serious damage, but depending on your cells.
-You add weight to the car which decreases speed and runtime. Since it's all on one side of the truck, it might also affect handling negatively.

Personally, I wouldn't do it.

 

[jondilly1974]

The added weight will make the ESC and motor overheat. Do yourself a favor and just a take a 5 min break and swap packs.

And to answer your safety question, yes you can draw down one pack lower than the other. There is nothing atopppng that from happening.

 

[Cuzboss]

You learn something new everyday! I appreciate the insight. I just wanted to make sure the ESC wouldnt fry right away or something.

 

[Soppy]

Hey guys, so ive been researching and come to find out running two 3S 5000mah batteries in series doesn't give me 10,000mah in my 6S emaxx but parallel will. But, if I run parallel its really only 3S but 10,000mah so, in my Granite 4x4 BLX if I run two 3S batteries in parallel will I have longer run times without burning anything up including the batteries for the sake of LVC?

When you make up a cable to parallel the the packs , be sure to make the wires the same length to avoid unbalancing the load on the packs. If the batteries are identical , you should have no problems. Both packs will discharge at the same rate and to the same voltage.