lipo compared to nimh?
08-03-2008, 06:18 PM
#16
Man.. I don't know what kind of racing or bashing you're doing.... but in 17 years I have never had anything damage my car or batteries resembling driving a nail through my battery! lol.. and that was a Lithium Ion and not a Lithium Polymer.... Hey.. check the cell phone in your pocket... it probably has a LiPo in it!
As for the voltage dropping off.. if you buy good NiMh packs and take care of them, they don't drop off like you say.. actually they maintain a better level voltage over a LiPo... the NiMh actually get better with care and a little use over their race life. It does however take some work.. discharging, equalizing and charging..
It's a personal choice... both are good..
Jerome
As for the voltage dropping off.. if you buy good NiMh packs and take care of them, they don't drop off like you say.. actually they maintain a better level voltage over a LiPo... the NiMh actually get better with care and a little use over their race life. It does however take some work.. discharging, equalizing and charging..
It's a personal choice... both are good..
Jerome
08-03-2008, 06:18 PM
#17
Another feature with using Lipo packs are you dont need to bring a charger w you to the track....If you have 3 or 4 lipos charged you are set.....
You dont need to repeak packs discharge packs...you can travel to and from racing much lighter now....no chargers, PS, discharge trays....
You dont need to repeak packs discharge packs...you can travel to and from racing much lighter now....no chargers, PS, discharge trays....
08-03-2008, 06:46 PM
#18
Tech Regular
Yes, a nail is extreme but if a battery can take a nail, it will be fine on the track.
My first time at OCRC (a month or so ago) in Huntington Beach, I saw a car take a landing bad and poof...Up in smoke and flames!! It wasn't a NiMH powered car, it wasn't an A123 powered car. You guessed right, it was a LiPo powered car.
IF you are experienced and careful, LiPos provide a great value. They are not for your average high school kid basher.
If you want the ultimate in high output current capabilities, it's hard to beat the value of a 30C continuous / 60C burst current of A123s cells.
If a better and safer power source than the A123 hits the market I'll be all for it.
My first time at OCRC (a month or so ago) in Huntington Beach, I saw a car take a landing bad and poof...Up in smoke and flames!! It wasn't a NiMH powered car, it wasn't an A123 powered car. You guessed right, it was a LiPo powered car.
IF you are experienced and careful, LiPos provide a great value. They are not for your average high school kid basher.
If you want the ultimate in high output current capabilities, it's hard to beat the value of a 30C continuous / 60C burst current of A123s cells.
If a better and safer power source than the A123 hits the market I'll be all for it.
08-03-2008, 06:53 PM
#19
Tech Regular
08-03-2008, 09:35 PM
#20
Haulin - was it the LiPo or a speed control.. like a GTB? Those have been popping right and left at our track..
I agree that most of this hobby including LiPo use takes some care..
The a123 packs are rated at a lover voltage though.. seems like it would be slow for stock racing..
And again and again I keep hearing all this stuff about how LiPos are better for higher current draw... um.. we've been racing mod for decades... who's having problems? NiCad and NiMh have been doing fine.. just dont use cheapy stick packs and you'll be fine.. lol
Jerome
I agree that most of this hobby including LiPo use takes some care..
The a123 packs are rated at a lover voltage though.. seems like it would be slow for stock racing..
And again and again I keep hearing all this stuff about how LiPos are better for higher current draw... um.. we've been racing mod for decades... who's having problems? NiCad and NiMh have been doing fine.. just dont use cheapy stick packs and you'll be fine.. lol
Jerome
08-03-2008, 10:30 PM
#21
Tech Apprentice
Yes, a nail is extreme but if a battery can take a nail, it will be fine on the track.
My first time at OCRC (a month or so ago) in Huntington Beach, I saw a car take a landing bad and poof...Up in smoke and flames!! It wasn't a NiMH powered car, it wasn't an A123 powered car. You guessed right, it was a LiPo powered car.
IF you are experienced and careful, LiPos provide a great value. They are not for your average high school kid basher.
If you want the ultimate in high output current capabilities, it's hard to beat the value of a 30C continuous / 60C burst current of A123s cells.
If a better and safer power source than the A123 hits the market I'll be all for it.
My first time at OCRC (a month or so ago) in Huntington Beach, I saw a car take a landing bad and poof...Up in smoke and flames!! It wasn't a NiMH powered car, it wasn't an A123 powered car. You guessed right, it was a LiPo powered car.
IF you are experienced and careful, LiPos provide a great value. They are not for your average high school kid basher.
If you want the ultimate in high output current capabilities, it's hard to beat the value of a 30C continuous / 60C burst current of A123s cells.
If a better and safer power source than the A123 hits the market I'll be all for it.
so basicly... to sum up what you said...
Dont be retarded with your expensive batteries?
A123 cells have lower voltage so def not for me... not to mention there size....
and there are plenty of lipos out there rated at 30c
08-04-2008, 01:04 AM
#24
Tech Regular
Voltage is only a consideration for stock motors...but then again A123 cells are not ROAR legal in the first place.
In terms of battery technology, there are 3 main consideration when selecting a power source:
1. Total Energy (i.e. capacity multiplied by average voltage @ chosen C)
2. Safety
3. Weight
In terms of battery packs in general, the Total Energy can be adjusted by putting cells in parallel and/or series.
So it leaves only Safety vs Weight as the considerations of how to pick between 30C power sources...A123 or LiPo.
So your choice of 30C technologies comes down to:
A123 for Safety or
LiPo for Weight (or lack thereof)
In terms of battery technology, there are 3 main consideration when selecting a power source:
1. Total Energy (i.e. capacity multiplied by average voltage @ chosen C)
2. Safety
3. Weight
In terms of battery packs in general, the Total Energy can be adjusted by putting cells in parallel and/or series.
So it leaves only Safety vs Weight as the considerations of how to pick between 30C power sources...A123 or LiPo.
So your choice of 30C technologies comes down to:
A123 for Safety or
LiPo for Weight (or lack thereof)
08-04-2008, 04:40 AM
#26
Wow, thats a lot of info! I didn't even know about hard pak lipos, are the more resistant. Cuz I like jumping and I don't always land right.
And from what I understand from all the reply's is Lipo runs longer with the same power band then nimh but if you have a decent nimh pack then it won't be as noticable. Except the power you would feel is mainly because of the weight difference?
So then next question. Hard case lipo vs soft case lipo?
And then what do I all need to get these batteries running? And what set up is the most user friendly?
And from what I understand from all the reply's is Lipo runs longer with the same power band then nimh but if you have a decent nimh pack then it won't be as noticable. Except the power you would feel is mainly because of the weight difference?
So then next question. Hard case lipo vs soft case lipo?
And then what do I all need to get these batteries running? And what set up is the most user friendly?
08-04-2008, 01:28 PM
#27
Well definitely go with a hardcased lipo... I really love my Orion packs. They have new packs out now 3400, 3800 & 5000... I race off-road modified with hot motors in a XXX-4... no probs.. Get a charger that has the correct CC/CV lipo profile (most LiPo chargers have this now). Maybe get one with a balancing feature or consider an external balancer ($25-$50).
If you go NiMh.. you'll need a way to discharge them with at least 20amps. most chargers that have a discharge feature don't go this high. Consider getting an equalizer tray.
If you are really worried about durability and crashing then maybe just stick with NiMh... they won't blow-up...
Biggest thing is make sure you pay attention when you are charging. Make sure the charger is on the correct cell profile and all the settings are correct for the pack.
Are you racing or bashing?
Jerome
If you go NiMh.. you'll need a way to discharge them with at least 20amps. most chargers that have a discharge feature don't go this high. Consider getting an equalizer tray.
If you are really worried about durability and crashing then maybe just stick with NiMh... they won't blow-up...
Biggest thing is make sure you pay attention when you are charging. Make sure the charger is on the correct cell profile and all the settings are correct for the pack.
Are you racing or bashing?
Jerome
08-04-2008, 02:28 PM
#28
Tech Regular
I don't work for A123...I wish I was smart enough! Those MIT geeks are pretty nuts.
Perhaps it is my current job as a bioengineer for a class III medical device company that patient safety is my number 1 concern when designing products.
I asked here what happened to that car that blew up at OCRC, maybe someone will chime in that knows:
http://www.ocrcraceway.com/forum/viewtopic.php?t=102
Perhaps it is my current job as a bioengineer for a class III medical device company that patient safety is my number 1 concern when designing products.
I asked here what happened to that car that blew up at OCRC, maybe someone will chime in that knows:
http://www.ocrcraceway.com/forum/viewtopic.php?t=102
08-04-2008, 05:08 PM
#29
I race and bash. Has anyone ever heard of thunder power lipo's?
08-05-2008, 06:57 AM
#30
I run Lipos in stock and mod classes. A really good NIMH may have more punch for about 30 to 45 seconds then they start to drop off. Lipo doesn't drop off. I run classes that have weight limits and must add weight to offset for the lighter Lipo. The Lipos still out perform NIMH. In addition, you can run the same batt and don't need a box full that you must charge, discharge, cycle, tray and then find they have dropped performance in a short time. Remember that a matched pack is matched for a very short time of use and then no longer are closely matched.
I have run an Orion 3200 in stock and Orion 4800 in mod for over a year and each is still balanced within .0001 volt without the use of a balancing charger, but I checked them at least every two weeks. Each performs like they did the first time I used them.
I have run an Orion 3200 in stock and Orion 4800 in mod for over a year and each is still balanced within .0001 volt without the use of a balancing charger, but I checked them at least every two weeks. Each performs like they did the first time I used them.
When i ran nimh, they were EP4600 that were excellent matched cells with great numbers. The punch i got out of those batteries was ridiculous but it only lasted for a minute. Having that initial punch threw off my driving style. With Lipo it is constant power throughout which is very nice. its smooth sailing all the way through the race. I personally prefer lipo but i must admit that weight adjustments will need to be made. Run what you brought and make sure you get atleast the required time for the race.