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Best battery for 17.5t blinky

Best battery for 17.5t blinky

Old 07-03-2014, 06:48 PM
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I just went through this same conundrum when upgrading from turnigy packs to something of higher quality 7000+ vs 6000.

Decided to drop my bikkies on LRP 6000mah packs (55/110C) due to better weight balance. I run 13.5T and I'm not expecting (hoping) any drop off as I was seeing it with the 5800 turning packs (45/90C)

Hopefully they arrive before next race meet!
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Old 07-03-2014, 07:13 PM
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Get the best possible pack. Lots-o-Cs. 5mm plugs if you can. If the mfg has options of different capacities in the same pack size, steer away from the highest mah and get the one just below. From my exp, the packs stuffed with mah tend to puff more.
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Old 07-03-2014, 07:21 PM
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Originally Posted by samnelso View Post
Get the best possible pack. Lots-o-Cs. 5mm plugs if you can. If the mfg has options of different capacities in the same pack size, steer away from the highest mah and get the one just below. From my exp, the packs stuffed with mah tend to puff more.
This was also my thinking. LRP offer a 6000 and 7500 in the same range.

Volker and co use both depending on the track it seems. Only last year they were using 5200-5700 packs as well, so should be awesome for my 13.5 races.

I've gone with two packs, I think that's good for rotation. Three would be better/ideal, but that's too much coin.
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Old 07-03-2014, 07:33 PM
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Originally Posted by cplus View Post
This was also my thinking. LRP offer a 6000 and 7500 in the same range.

Volker and co use both depending on the track it seems. Only last year they were using 5200-5700 packs as well, so should be awesome for my 13.5 races.

I've gone with two packs, I think that's good for rotation. Three would be better/ideal, but that's too much coin.
Mod guys don't care much about voltage or punch, they have more than enough with motor and boost, so they can run lighter packs for better balance, hence the 5700-6000 LRP packs
Most won't even charge their packs fully
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Old 07-03-2014, 07:40 PM
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Originally Posted by RedBullFiXX View Post
Most won't even charge their packs fully
Yep, saves even more weight
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Old 07-03-2014, 09:17 PM
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Originally Posted by cplus View Post
I just went through this same conundrum when upgrading from turnigy packs to something of higher quality 7000+ vs 6000.

Decided to drop my bikkies on LRP 6000mah packs (55/110C) due to better weight balance. I run 13.5T and I'm not expecting (hoping) any drop off as I was seeing it with the 5800 turning packs (45/90C)

Hopefully they arrive before next race meet!
Last week got 2 of the new LRP 6000's to replace my Turnigy 5600's that were going a little soft and I need 2 more packs anyway.
Their first run last week was good, a little better punch then Turnigy and no drop off, was running 13.5 blinky.

my best run I had my consistency down to 0.12 with worst 2 laps dropped, and 0.14 with worst lap dropped.

next run with them tonight...

Beth.
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Old 07-03-2014, 09:32 PM
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I can tell you first hand, if you do not have a low resistance battery in 17.5 and 13.5 you will be off pace. Try the Aero-Model 7600 90C, they have super low resistance and will give you the best possible lap times the entire race. These packs weight 330-340 but its worth the weight. If you cycle each battery pack people have talked about in this thread you will find your average voltage per gram is much better with the larger packs. Keep in mind this only works if you can get your car weight down to the min. weight limit of your particular race.

If you can not get your car weight down to the min. try using a lighter pack in the 290-300 gram range. Try the Aero-Model 6000 90c pack

Im my case with the awesomatix car I can get the cars weight to 1375-1380 with using the 7600mah pack. Normally I am still under weight and have to add 20 grams or so. This is usually placed on the opposite side of the battery as people have mentioned balance is very important. However voltage is more important with the spec classes.

Kyle Bergstrom
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Old 07-03-2014, 09:36 PM
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I agree with Kyle. The Aero-model packs are definitely worth it. What ever class, these cells get the job done.
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Old 07-04-2014, 03:44 AM
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Originally Posted by Adam B View Post
I will be a little partial to fantom packs. But in testing and cycling my batteries recently ranging from 6000mah to 7200mah, I found the 6000 to have the lowest internal resistance and higher average voltage. I do have some 7600packs, but have not tested them yet. The 17.5 blinky cars are only going to pull so much and create so much heat. The heat lowers internal resistance thus allowing more volts to the ESC. I feel the larger MAH packs would be great in MOD, or something that will really demand higher current flow, but in stock, we really are not working them. Weight balance can be a factor as well. But I think there is only about 10grams difference between my 6000 to 7600.
Umm, no.

Heat raises internal resistance.

More current out of higher capacity batteries is another legend. Until I see bench tests run I don't buy it, and practical experience shows no correlation. Yes, some batteries have lower internal resistance and they're better, but how many have any of the people here measured recently?

Back to our friend, 17.5 would rarely see more than 15-20 Amps, most likely under braking. This means his batteries are more than alright for the class (even the lower capacity one).
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Old 07-04-2014, 04:27 AM
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We are all talking about low-IR here but can someone put a figure on what a good pack's IR should look like? I have the ability to see what the IR is on my Orion Advantage Pro charger and my packs are all around the 5mohms.
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Old 07-04-2014, 05:06 AM
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I would ASSUME my Orca 90c 7500 has a better discharge curb than say a 6200 Orca but I have never compared back to back. It would be interesting to see the 7500 vs. 6200 (using lead to equalize weight) lap times and total race time in 17.5 sedan. Would there really be a difference in lap times? How about over 10 laps? Would the 6200 start to drop off?

For now I am just sticking to common sense and will continue to run the largest capacity, highest C rated cells I can get my hands on. Since I only run stock, any extra voltage is hugely welcomed!

As long as you can get down to 1380g, run the big packs. Even if you don't race ROAR rules, if you ever decide to expand your horizons and hit up a big race you will want your car to weigh and handle the same as you are used to. (Running 7200 LRP and LW Protoform bodies I could get down to 1305g in my 418 but I never ran that light)

I would choose cells that have 5mm female plugs instead of 4mm. Again, I have no proof that they are "better" but common sense tells me more surface area = less heat & less voltage loss due to resistance.

And there are ALWAYS ways to balance the big packs. In my 418 I have had to mount my 333g Orca so its almost touching the pinion gear, along with mounting the electronics overhanging the chassis plate by a good 1/2" AND mounting some lead on the electronics side. It can be done.
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Old 07-04-2014, 06:00 AM
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Originally Posted by kyle478 View Post
I can tell you first hand, if you do not have a low resistance battery in 17.5 and 13.5 you will be off pace. Try the Aero-Model 7600 90C, they have super low resistance and will give you the best possible lap times the entire race. These packs weight 330-340 but its worth the weight. If you cycle each battery pack people have talked about in this thread you will find your average voltage per gram is much better with the larger packs. Keep in mind this only works if you can get your car weight down to the min. weight limit of your particular race.

If you can not get your car weight down to the min. try using a lighter pack in the 290-300 gram range. Try the Aero-Model 6000 90c pack

Im my case with the awesomatix car I can get the cars weight to 1375-1380 with using the 7600mah pack. Normally I am still under weight and have to add 20 grams or so. This is usually placed on the opposite side of the battery as people have mentioned balance is very important. However voltage is more important with the spec classes.

Kyle Bergstrom
They are great lipos best I have tested and used. You have to love rebranding.

The 7600 is 335g, the 6000 is 295g, previous generation 7200 was 330g.

In my case the 335g pack is enough to put the balance off and require lead to correct it.
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Old 07-04-2014, 06:04 AM
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Originally Posted by niznai View Post
Umm, no.

Heat raises internal resistance.
Lipo IR reduces as temperature increases within the operating temperature range.

Hence why people use warming pads higher charge rates ect to warm the cells.
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Old 07-04-2014, 06:08 AM
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Originally Posted by dan_vector View Post
We are all talking about low-IR here but can someone put a figure on what a good pack's IR should look like? I have the ability to see what the IR is on my Orion Advantage Pro charger and my packs are all around the 5mohms.
The best lipos I have tested have IR in the range of 1.2-1.5mohm per cell depending on temperature.

Poorer brand name lipos that are currently used by racers IR is in 3-5mohm per cell.
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Old 07-04-2014, 09:58 AM
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100% right !!!! That would also mean that the lower capacity packs would heat up more when the the max amp charge rate has been fixed by the event officials...I see that most events limit everyone to a 14 amp max charge rate, which will not heat up a 7600mah pack, but will crank the heat in a 2700mah/3300mah pack.....
Originally Posted by frozenpod View Post
Lipo IR reduces as temperature increases within the operating temperature range.

Hence why people use warming pads higher charge rates ect to warm the cells.
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