Racing battery choices

[zeropointbug]

So I am trying to decide what size lipo to get for racing, in particular, those 30 min mains. I have come to three choices based on what runtime I was getting with my old Hyperion G3 vx, 25 mins for a 6s 4200mah 35C pack.

1. Thunder Power RC G6 Pro Power 65C 2250mAh 6-Cell

2. Thunder Power RC G6 Pro Performance 45C 2700mAh 6-Cell 419 grams

3. Thunder Power RC G6 Pro Performance 45C 3300mAh 6-Cell 515 grams


The small 2250mah would need 3 sets of packs for 10 mins running time each, which any lap time savings might be negated by the battery swapping TWICE. I am not sure on the 2700mah, whether it would last 15 mins running or not, it would be super close, and maybe too risky? The 3rd option seems like a solid one with almost 20 mins running time each, so only one battery swap during a race.

Anyone with some veteran racing experience is happily welcome to put their two cents in on what you think of each. BTW, I run pretty smoothly, fairly constant throttle over the whole lap, besides the straights.

thanks

[nitrostarter]

Are you overly concerned with weight for the reason of possibly choosing the smaller packs?

IMO, #3 would be a clear choice for one battery swap during the race. No need to put more times than you need to unless the rules state it. And I would hate for you to get 14 minutes of runtime on each pack of #2 and not finish the race.

[RC-Monster Mike]

What vehicle are you racing that gets 20 minutes of runtime on a 6s 3300mah pack? Hyperion packs get my vote - not just because I sell them, but because they are great packs and a great value. I use the 4200mah 5s packs in my buggy and truggy and couldn't get 25 minutes in a race situation even in my light 808 buggy.

[zeropointbug]

Yeah, I am just wondering if the light weight pack is going to give me any overall benefit over the larger packs, but counting the 2nd battery swap into the total time, maybe not a gain there. But, I also have to pit twice regardless of whether I need to, to make it fair for the nitro guys... But they say for the 2nd pitting, I only need to pit for literally 2 seconds and then off again.

Mike, I am racing in my converted Revo running my good old 1512/3D 1700Kv. and RX8, and at the track I was getting up to 25 mins on a 6s 4200 G3 pack, two 3s packs in series on each side of truck for cg and balance. So, going on that, the 3300 45C pack should be getting around 18-19 mins. I would only put back 2700-2800mah after 15mins running.

I am going for the Thunderpower packs this time around because they have a 2 year warranty, plus 50% off replacement for damaged packs. RCtoys or better known as draganfly are from my hometown here, so I don't have to pay for shipping cost, so they end up costing the same as Hyperion packs in the end. Hyperion would have been my 1st choice otherwise.

[RC-Monster Mike]

When I raced My ERevo, I used to do 30 minute mains with a "cheater" battery swap. I used a series connector between the ESC and batts and started with a pair of 2s 6000mah packs wired in series(4s). I could get 20 minutes on this setup in the ERevo and when I came in for a battery swap, I pulled the series connector and one of the packs out and installed a single 4s 3700mah pack in its place to finish. Basically, I only had to swap one pack this way, which saved me some time. The 2nd "pit" is basically a trip through pit lane.

[BrianG]

You just need to covertly install a high-power coil under the track and a matching coil/circuit in your vehicle that will pulse-charge your vehicle as you drive over it (albeit a very high power pulse). No battery swap needed!

You'd better shield anything else electrical in your vehicle though!

[zeropointbug]

4s 6000mah for 20 mins makes sense, and when I say 18-19 mins for a 6s 3300, that would be to pretty well 100% DOD. I would only want to run 90% max, preferably 80%, to make room for future capacity loss, and just to give you that headroom if you want to wait a few laps to do a pit stop. But didn't the weight difference after you pitted make a difference in handling?

I never posted the 370 gram weight of the 2250mah pack I was looking at, that's 145 grams weight loss, enough to make a noticeable diff, I don't know.

Probably 2x 3300 6s packs might be the best bet then as far as weight, 2 pits, and cost is concerned.

$300 total for 2x 45C 3300 packs, or
$390 for 3x 65C 2250mah packs... hmmm

[zeropointbug]

haha, yeah I could take my twin Tesla Coils and use them as transmitter and receiver! Although only tapping ~100watts from the circuit might not cut it.

[BrianG]

Originally Posted by zeropointbug

haha, yeah I could take my twin Tesla Coils and use them as transmitter and receiver! Although only tapping ~100watts from the circuit might not cut it.

It would if you put several of those coils throughout the track for multiple pulse-charges for every lap.

[RC-Monster Mike]

Originally Posted by zeropointbug

4s 6000mah for 20 mins makes sense, and when I say 18-19 mins for a 6s 3300, that would be to pretty well 100% DOD. I would only want to run 90% max, preferably 80%, to make room for future capacity loss, and just to give you that headroom if you want to wait a few laps to do a pit stop. But didn't the weight difference after you pitted make a difference in handling?

I never posted the 370 gram weight of the 2250mah pack I was looking at, that's 145 grams weight loss, enough to make a noticeable diff, I don't know.

Probably 2x 3300 6s packs might be the best bet then as far as weight, 2 pits, and cost is concerned.

$300 total for 2x 45C 3300 packs, or
$390 for 3x 65C 2250mah packs... hmmm

I left one of the 2s 6000mah packs in the ERevo and removed the other, along with the series adapter - the actual weight change and resulting impact on handling was minimal. The pit was basically removal of a single 2s 6000mah pack and series adapter and replacement with a single 4s 3700mah pack. I only had to mess with one side of the truck for the pit and didn't have to mess with the body at all(just push it out of the way during the pit).

[zeropointbug]

Hmm, that reminds me of an idea I had with the side of the body so I could just lift a flap and swap the pack out without messing with body clips. I made a full under body shield made of Lexan, which acts as a mud guard and skid plate which allowed me to lower the suspension a bit, pretty well a truggy.

Something I just thought of, what do you guys think of a sway bar kit for the Revo?

[RC-Monster Mike]

A sway bar is a must for racing - without it the ERevo is either too stiff or has way too much body roll - totally different truck with sway bars. I didn't bother modifying the body on my ERevo - just pulled it out to swap the pack.

[zeropointbug]

Oh well then I will have to get one. Even without it, all the top truggy guys drove my revo and commented on how balanced it felt and had good turn in. Which swaybar kit do you recommend? Tekno RC? Do you run the sway from and back?

[RC-Monster Mike]

I haven't used the Traxxas sway bar kit - the Tekno works well, though I always manage to lose the small set screws in the flanged rod inserts. I am sure either would get the job done.

[jhautz]

I was using the 6s 45c 2700mah Thunderpower packs you mentioned. Great batteries. I ran them in my buggy indoors last winter and they were super solid for a 10-12 minute race. I wouldnt push them for 15 minutes. If you need 15min then go with the 3300 packs. For 25 minutes you will really need to load up on battery. I personally would rather do the battery swap than carry that load around the track. You could probably get 25 minute race done on one battery swap at the 13 minute mark using 2 of the 6s 2700 packs. I really never ran them beyond the 10 minute mark but Im sure I could have gotten another few minutes out of them with no issue.

I agree with Mike, The Hyperion batteries are super solid and priced very fair. Certainly cant go wrong there.

BTW: Those 6s 2700 packs are solid enough to push my truggy around the track for 10 minutes too. I dont race the e-truggy much any more but I ran it a couple times in the last year using those packs and they handled it no problem.