Lipo Questions

Old 06-18-2009, 08:24 PM
  #1  
Tech Regular
Thread Starter
iTrader: (45)
 
active_sport's Avatar
 
Join Date: May 2009
Posts: 443
Trader Rating: 45 (100%+)
Default Lipo Questions

I am a newbe to the lipo scene. Given that I know nothing about them. In antipitation of going Lipo I have purchased a Lipo capable charger w/balancing.

I am just having fun with my HPI RS4 Pro w/Mamba Max 5700 setup w/4600 nimh 6 cell packs. This alone has made the RS4 insane. I have already melted 1 diff... I also just purchased A Traxxas Rustler XL-5 that I will be moving the CC Mamba Max system over to. I will be just bashing during the summer around the house, but maybe bring it indoors over the winter to race. (I know it's not a race truck.... I am just getting back into RC so I will hone my skills with it, then step up). I also plan to buy a Slash or SC10and race that in a spec Short Course class.

What I need is a recomendation on Lipo battery that I can bash with, but will be a decent pack at the track as well. I am not interested in a 3 cell at this time. What I would like is to purchase a cheap pack that will give me good bashing and good performance on track (as practice pack) and then once racing season comes around I will purchase a quality "race" pack.

I would be interested in some reading material (posted online) about the differnet ratings of Lipo. What to lool for, etc.

Thanx in advance!
active_sport is offline  
Old 06-19-2009, 08:51 AM
  #2  
Tech Adept
iTrader: (6)
 
Thirtybird's Avatar
 
Join Date: Jan 2009
Location: Metrot Detroit, MI
Posts: 240
Trader Rating: 6 (100%+)
Default

I don't know what configuration you are running for the battery in your RS4 - you didn't mention if you were running stick, side-by-side or saddle....

If you are running saddle, you will have a lot less to choose from as you probably have a height restriction and the majority of the good saddle packs are taller than the clearance you have (i.e. Reedy 4800). For bashing - the Trakpower 3200 saddle (20C I believe) would be alright and should fit. However, for about $70 on ebay, you can get an Intellect 4200 30C saddle pack, and that would be adequate for racing too. LRP recently introduced a saddle pack that may fit (check the measurements) in 4800 mah 40C.

If you're running stick, there are a ton of cheap, cheap LiPo stick packs on ebay that would probably be fine for bashing. For racing, an SMC or Thunder Power 40C pack is kind of the baseline now.
Thirtybird is offline  
Old 06-19-2009, 08:52 AM
  #3  
Tech Lord
iTrader: (21)
 
Join Date: Jul 2008
Location: Houston, TX
Posts: 11,530
Trader Rating: 21 (100%+)
Default

Lipo reading -

http://www.batteryuniversity.com/

and -

http://www.maxamps.com/lipo-care.php
Duster_360 is offline  
Old 06-19-2009, 12:41 PM
  #4  
Tech Regular
Thread Starter
iTrader: (45)
 
active_sport's Avatar
 
Join Date: May 2009
Posts: 443
Trader Rating: 45 (100%+)
Default

Originally Posted by Thirtybird
I don't know what configuration you are running for the battery in your RS4 - you didn't mention if you were running stick, side-by-side or saddle....

If you are running saddle, you will have a lot less to choose from as you probably have a height restriction and the majority of the good saddle packs are taller than the clearance you have (i.e. Reedy 4800). For bashing - the Trakpower 3200 saddle (20C I believe) would be alright and should fit. However, for about $70 on ebay, you can get an Intellect 4200 30C saddle pack, and that would be adequate for racing too. LRP recently introduced a saddle pack that may fit (check the measurements) in 4800 mah 40C.

If you're running stick, there are a ton of cheap, cheap LiPo stick packs on ebay that would probably be fine for bashing. For racing, an SMC or Thunder Power 40C pack is kind of the baseline now.
I will not be using the RS4 for bashing anymore, as bashing with an on road car = lots of broken parts. I hit a curb a few weeks back and broke the graphite upper deck..... I remade it using aluminum (now there is much less chassis flex). If I decide to race that old dog it will be in a stock classes. Right now I am using a "stick" pack configuration on the RS4, But height is a consirn as I can not go any heigher than a standard stick pack. ANy taller and it will rub on the belt for the front drive.

The Mamba system is going into the Traxxas Rustler. I plan to race the Rustler in a "stock" stadium class and a slash in a "spec" class. I hope to be able to run the same type of battery in both the Slash and Rustler.
active_sport is offline  
Old 06-19-2009, 12:52 PM
  #5  
Tech Lord
iTrader: (21)
 
Join Date: Jul 2008
Location: Houston, TX
Posts: 11,530
Trader Rating: 21 (100%+)
Default

I've been running Intellect 2S 30C 5000mah hard case lipos in my Slash with a Castle Sidewinder/5700 combo. Gives me about 25min of run time, fits the batt tray almost perfectly.

Hard cased lipos are made to same size as a 6cell pac so that would be a good way to go and would be more rugged and less prone to probs running offroad. They have wires coming out the top side of the lipo (as opposed to teh end or side) so just be sure that won't be prob. I'm not familar with a Rustler
Duster_360 is offline  
Old 06-19-2009, 12:58 PM
  #6  
Tech Regular
Thread Starter
iTrader: (45)
 
active_sport's Avatar
 
Join Date: May 2009
Posts: 443
Trader Rating: 45 (100%+)
Default

I guess my confusion is what type of battery do I need. I am looking for something in the 5000mah range, but do I want 20C, 30C, 35C? Will a battery that will hold up the my Mamba Max system be suitable for a much milder brushless or even a brushed motor?

What is the difference between 20c, 30c, 35c etc. I have read some technial info, but I am currently on a lot of pain meds(just had back surgery) so I am not getting it 100%....

I just need a simple explination. What would be the ral world difference in performance in a car if using a 5000 mah version of each.
active_sport is offline  
Old 06-19-2009, 01:13 PM
  #7  
Tech Lord
iTrader: (21)
 
Join Date: Jul 2008
Location: Houston, TX
Posts: 11,530
Trader Rating: 21 (100%+)
Default

With a good BL setup, the lipo should get only warm. If amp draw is 80 or 90% of the batt capacity, it will make the lipo run hot and you won't get much for cycle life. The cooler your lipo runs, the longer they will last. We are in the middle of a new generation of higher C rates, higher recommended charge rate lipos and on top of that, thay are cheaper than ever.

I would get something like a SMC 24C 5000mah. This will be a solid, cool running lipo. When you do want to run brushed or a milder BL setup, it will handle that with no probs. SMC rates their lipos conservatively so their 24C would be some else's less conservative 28-30C.

https://www.ssl-stormerhobbies.com/c...s&pn=SMC5224LD
Duster_360 is offline  
Old 06-19-2009, 02:04 PM
  #8  
Tech Regular
Thread Starter
iTrader: (45)
 
active_sport's Avatar
 
Join Date: May 2009
Posts: 443
Trader Rating: 45 (100%+)
Default

I appreciate the suggestions and help, One more question. What is the average charge time on a Lipo (i.e. 24c 5000mah 2S). Is it possible to use a Lipo pack twice in a race day/night. Maybe 1st heat/3rd heat, 2nd head/main. Just trying to figure, when race season is here how many packs per vehicle I would need.
active_sport is offline  
Old 06-19-2009, 03:23 PM
  #9  
Tech Lord
iTrader: (21)
 
Join Date: Jul 2008
Location: Houston, TX
Posts: 11,530
Trader Rating: 21 (100%+)
Default

Lipo uses a 2 step charging protocol - CC/CV. The 1st part, constant current lasts until the cell max voltage of 4.2v/cell is reached. Charger then switches to constant voltage to top off the batt. About 90% of the charge goes in on the 1st part and its the shortest time wise. A total charge takes about an hour. Some chargers offer a fast lipo option that basically cuts off the CC part of the charge to speed things up, this option would less than 30min. This all assumes a 1C charge rate too, with the newer lipos allowing a 2C charge, you reduce time even more (1C charge = capacity/1000, so a 5000mah, 1C charge rate = 5amps, 2C = 10amps, etc).

This is for a complete charge where you've run the batt down to near the voltage cutoff (~3v/cell recommended min voltage, don't overdischarge below this, poss damage). You'll be using a lot less for heats, races so your charge times will be less. Lipo will let you charge them as much as you need to without the limitations seen with NiMh batts.

I'll let one of the racers tell you about the number of batts they use since I don't race. This is another advantage of using lipo, you don't need that many.
Duster_360 is offline  
Old 06-19-2009, 03:37 PM
  #10  
Tech Regular
Thread Starter
iTrader: (45)
 
active_sport's Avatar
 
Join Date: May 2009
Posts: 443
Trader Rating: 45 (100%+)
Default

The CC Mamba setup has Lipo cutoff programable. Not sure if my Chargery 1010B has 2C charging or not. But being able to top off between heats will be nice. That means I maybe able to have 1 battery for heats, then use the 2nd battery (really good one) for the main. Ofcourse these numbers are based on one truck, so adding a slash would double the amount of batteries. I have a few good Nimh batteries that I could use for the practice rounds. So I maybe able to get away with 4 Lipos. I will wait for a racer to pop in and leave a comment. I have some time before I can race anyway.
active_sport is offline  
Old 06-19-2009, 05:28 PM
  #11  
Tech Master
iTrader: (31)
 
Join Date: Mar 2009
Location: Monmouth Beach, NJ
Posts: 1,455
Trader Rating: 31 (100%+)
Default

Originally Posted by active_sport
I am a newbe to the lipo scene. Given that I know nothing about them. In antipitation of going Lipo I have purchased a Lipo capable charger w/balancing.

I am just having fun with my HPI RS4 Pro w/Mamba Max 5700 setup w/4600 nimh 6 cell packs. This alone has made the RS4 insane. I have already melted 1 diff... I also just purchased A Traxxas Rustler XL-5 that I will be moving the CC Mamba Max system over to. I will be just bashing during the summer around the house, but maybe bring it indoors over the winter to race. (I know it's not a race truck.... I am just getting back into RC so I will hone my skills with it, then step up). I also plan to buy a Slash or SC10and race that in a spec Short Course class.

What I need is a recomendation on Lipo battery that I can bash with, but will be a decent pack at the track as well. I am not interested in a 3 cell at this time. What I would like is to purchase a cheap pack that will give me good bashing and good performance on track (as practice pack) and then once racing season comes around I will purchase a quality "race" pack.

I would be interested in some reading material (posted online) about the differnet ratings of Lipo. What to lool for, etc.

Thanx in advance!

Just bought this SMC 6000 - http://www.spcracing.com/index.php?productID=84

They are very good for the buck. Get them now, because they go quickly!
vstrok is offline  
Old 06-19-2009, 06:14 PM
  #12  
Tech Champion
 
Join Date: Oct 2007
Posts: 7,342
Default

Originally Posted by active_sport
The CC Mamba setup has Lipo cutoff programable. Not sure if my Chargery 1010B has 2C charging or not. But being able to top off between heats will be nice. That means I maybe able to have 1 battery for heats, then use the 2nd battery (really good one) for the main. Ofcourse these numbers are based on one truck, so adding a slash would double the amount of batteries. I have a few good Nimh batteries that I could use for the practice rounds. So I maybe able to get away with 4 Lipos. I will wait for a racer to pop in and leave a comment. I have some time before I can race anyway.
Depends on how big of a race, how much time between rounds, what classes/motors you are running, brushless or brushed, etc. Plenty of guys get by with just one lipo for a car, for everything, practice and all, but it is a little tight, somewhat limited practice time. For 2 classes a couple of chargers and 3 lipos should be enough unless it's a quite small club race. Can't imagine needing more than 2 lipos and 1 charger per car, at least with offroad. Good luck!

Last edited by Dave H; 06-19-2009 at 06:30 PM.
Dave H is offline  
Old 06-20-2009, 07:18 AM
  #13  
Tech Adept
iTrader: (6)
 
Thirtybird's Avatar
 
Join Date: Jan 2009
Location: Metrot Detroit, MI
Posts: 240
Trader Rating: 6 (100%+)
Default

I've been running VTA using a LiPo for a while, and am finding 1 LiPo more than sufficient! I have a 4200 mah pack and when I recharge between rounds, only about 1000 mah is going back in before it is peaked. In theory I could use that for both qualifiers and the main if I really had to... I don't though as it is only taking about 20 minutes to re-peak. Your mileage will vary running a faster class/motor
Thirtybird is offline  
Old 06-20-2009, 09:21 AM
  #14  
Tech Regular
Thread Starter
iTrader: (45)
 
active_sport's Avatar
 
Join Date: May 2009
Posts: 443
Trader Rating: 45 (100%+)
Default

Originally Posted by Thirtybird
I've been running VTA using a LiPo for a while, and am finding 1 LiPo more than sufficient! I have a 4200 mah pack and when I recharge between rounds, only about 1000 mah is going back in before it is peaked. In theory I could use that for both qualifiers and the main if I really had to... I don't though as it is only taking about 20 minutes to re-peak. Your mileage will vary running a faster class/motor
Hey Thirty,

I notice your from Metro Detroit. Where do you race at? I am in Wyandotte (Downriver). Also, because I have been out of the hobby for quite a while, what is "VTA" mean???
active_sport is offline  
Old 06-20-2009, 11:23 AM
  #15  
Tech Lord
iTrader: (21)
 
Join Date: Jul 2008
Location: Houston, TX
Posts: 11,530
Trader Rating: 21 (100%+)
Default

Vintage Trans Am -

http://www.rcuniverse.com/forum/m_8350410/tm.htm
Duster_360 is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.