www.robowars.org

RoboWars Australia Forum Index -> Technical Chat

Battery chat v2
Goto page 1, 2  Next

Post new topic   Reply to topic
  Author    Thread
Glen
Experienced Roboteer


Joined: 16 Jun 2004
Posts: 9481
Location: Where you least expect


 Reply with quote  
Battery chat v2

A long time has passed since we last had a good discussion about batteries. Technology has bounded along and now we have 10c charge lipos and 80c discharge ones on the market, plus the proliferance of cheap lipos from hobbyking has made bot building a lot easier for most now we dont have to cram in kg's of hand made batteries.

But anyway! One point of discussion to get the thread rolling. Lipo quality.

I've sampled a few different brands so far and it seems the quality difference is pretty evident.

The thunderpower 30c lipoly i got off hobbyking years ago, which was the best of its time worked great, and even now goes pretty good in its new life as a stand in dewalt drill battery.

The nanotechs i bought (admittedly the 130-160mah kind) are all completely dead as are the first of Josh's in deepcleaner. Neither, i don't think, were used well outside their specs. Lots of internet talk seems to heap the nanotechs in as performing to specs, but dying early.

The random other packs that killer runs all work just fine too. Ones a turnigy and ones a flightpower i think. The one that predated turnigy. both are 20-30c types. Nothing but good things to say with them.

Haven't got anything to say about my g6 lipo at the moment but hopefully soon Smile

What are your experiences with the different brands?
_________________
www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz

Post Tue Mar 27, 2012 6:01 pm 
 View user's profile Send private message Send e-mail Visit poster's website MSN Messenger
marto
Experienced Roboteer


Joined: 08 Jul 2004
Posts: 5459
Location: Brisbane, QLD


 Reply with quote  

I would have to say that I have not used a nano tech (130/160mah) long enough to get it to the point of dying my main issue with them is that the tabs on the ones with the small connectors are very hard to to get to and if you break off the bit with solder its almost impossible to make a good connection. I have also had several of my 2S packs break in combat.

I got one of the new pre made 2S ones today and it looks ok. But time will tell if it exhibits the short life span of the other ones. However when they are like $3 I don't really care too much if they die after 3/4 rounds.

As for feather batteries I have not had a lot of luck with lipos every time I try to use them I end up leaving them plugged in or pulling too much current out of them and it ends in a puffy useless lump.

I abuse the crap out of my A123s yet all of my packs are still reasonable. I think balancing them when you charge them is a must and one of my crappier packs is slowly dying but considering how old they are they still take 2100mah regularly and I have not really had any issues.

Unfortunately it is becoming quite hard to find legit packs for reasonable prices these days. I would be interested to hear how the "clone" cells miles and jules got are doing.

Steve
_________________
Steven Martin
Twisted Constructions
http://www.botbitz.com

Post Tue Mar 27, 2012 8:51 pm 
 View user's profile Send private message Send e-mail MSN Messenger
miles&Jules
Experienced Roboteer


Joined: 19 May 2010
Posts: 3973
Location: ipswich QLD


 Reply with quote  

Well the green a123's we got from hK seem to act the same as the old white ones we got from you Steve. I used them both in different fights at the Nationals and they both worked well. ......but they were really warm after each fight in Judge mental...I guess that is because the spinner was alwarys drawing alot of power. I would Love to combine both the 6cell packs i have, one for drive and one for weapon....Cause I'm sure i could feel the power drain when driving and spinning at once.
Yep havent had an a123 die since we been Balancing.

Every lipo I touch seems to go puffy....Im to afraid to go for a big one.
_________________
Miles Blow - Julie Pitts
www.mulesfilm.com.au
www.wombokforest.com.au

-Pickasso- Vivid Sportsman champion 2015

Post Tue Mar 27, 2012 11:15 pm 
 View user's profile Send private message Send e-mail Visit poster's website
Nick
Experienced Roboteer


Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW


 Reply with quote  

It's just a hunch, but I think that the problem with the small capacity 1 and 2 cell batteries dying early might be to do with the chargers. I found all my chargers have problems detecting full charge on small packs and may be over-charging them, which is a Very Bad Thing for lipo packs.

I just got some Nanotechs for the ant and will keep an eye on the charging cycles.

Brand-wise, I am totally happy with Thunderpower for power delivery, construction and build quality - all at a price of course!. Hyperion seem to be about the same, but I am only just starting to use them.

Poly RC had lower construction quality but still delivered plenty of power while staying cool.

For me, the important point is to over specify the battery capacity by 30 to 50%; even the cheaper packs will perform well if they are operated under their maximum specs.

Edit: where would I find 80C continuous packs? Shocked

Post Wed Mar 28, 2012 6:35 pm 
 View user's profile Send private message
Jaemus
Experienced Roboteer


Joined: 01 Apr 2009
Posts: 2674
Location: NSW


 Reply with quote  

I've not had any fail yet that were not due to physical damage. That said, i did notice the other day that the turnigy 2S 1AH packs which are still strapped into Venator seem to have gone fairly puffy. I didnt remove them or do any maintenance on them after its last fight (several years ago?) so that's kindof understandable.

I've got a fair few of the small nanotech cells, will have to round them all up and do some testing to see how they have faired. At the price, im almost happy to consider them single use, or perhaps single event use anyway Razz haha
_________________
<Patrician|Away> what does your robot do, sam
<bovril> it collects data about the surrounding environment, then discards it and drives into walls

Post Fri Mar 30, 2012 9:29 am 
 View user's profile Send private message Send e-mail MSN Messenger
Philip
Experienced Roboteer


Joined: 18 Jun 2004
Posts: 3842
Location: Queensland near Brisbane


 Reply with quote  

I have also found the nanotechs to have a shorter life. I have just thrown out the last of my standard 160mAh batteries. They were bought just before the second antweight event. They all died by physical damage. The 130mAh nanotechs have a much shorter life in my experience.
_________________
So even the rain that falls isn't actually going to fill our dams and our river systems

Post Tue Apr 24, 2012 8:46 pm 
 View user's profile Send private message
Glen
Experienced Roboteer


Joined: 16 Jun 2004
Posts: 9481
Location: Where you least expect


 Reply with quote  

So to cut but a long story short, doing plenty of reading on A123s for a planned bike battery replacement (i have tons of left overs so why not Smile ) and these days it seems as though its almost universally accepted that there are A and B grade cells from enerland, and that most online ebay sellers are hawking the B graders.

That would certainly explain a lot as the later packs i made never lived up to the performance of the original dewalt harvested ones.

Interesting!
_________________
www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz

Post Wed Oct 10, 2012 3:44 pm 
 View user's profile Send private message Send e-mail Visit poster's website MSN Messenger
Jaemus
Experienced Roboteer


Joined: 01 Apr 2009
Posts: 2674
Location: NSW


 Reply with quote  

But say you had A grade cells, would they still compare well to your G6 lipos?
_________________
<Patrician|Away> what does your robot do, sam
<bovril> it collects data about the surrounding environment, then discards it and drives into walls

Post Wed Oct 10, 2012 4:37 pm 
 View user's profile Send private message Send e-mail MSN Messenger
Glen
Experienced Roboteer


Joined: 16 Jun 2004
Posts: 9481
Location: Where you least expect


 Reply with quote  

Not even close lol, the voltage sag under heavy load has always been huge + the problem of them going out of balance as a result, just much less so than the "b" cells. Price wise though the G6's are still prohibitively expensive.
_________________
www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz

Post Wed Oct 10, 2012 4:40 pm 
 View user's profile Send private message Send e-mail Visit poster's website MSN Messenger
Jaemus
Experienced Roboteer


Joined: 01 Apr 2009
Posts: 2674
Location: NSW


 Reply with quote  

So the real sweet spot is actually the Hobbyking Lipos Razz
_________________
<Patrician|Away> what does your robot do, sam
<bovril> it collects data about the surrounding environment, then discards it and drives into walls

Post Wed Oct 10, 2012 5:53 pm 
 View user's profile Send private message Send e-mail MSN Messenger
Knightrous
Site Admin


Joined: 15 Jun 2004
Posts: 8511
Location: NSW


 Reply with quote  

I've actually been considering on using 6 of these Turnigy nano-tech A-SPEC 6000mah 1S 65~130C Hardcase Lipo 's to make a compact racing battery for my AW11 (one that can mount behind the passenger seat).
Setup in 3S2P would make a great lead acid battery replacement for around $150 and 1.5KG, not to mention the 12AH capacity and 1200+ cranking amps Smile
_________________
https://www.halfdonethings.com/

Post Tue Oct 16, 2012 9:06 am 
 View user's profile Send private message
Jaemus
Experienced Roboteer


Joined: 01 Apr 2009
Posts: 2674
Location: NSW


 Reply with quote  

yeah but how do you charge it? alternator would fry em wouldn't it?
_________________
<Patrician|Away> what does your robot do, sam
<bovril> it collects data about the surrounding environment, then discards it and drives into walls

Post Tue Oct 16, 2012 1:48 pm 
 View user's profile Send private message Send e-mail MSN Messenger
Nick
Experienced Roboteer


Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW


 Reply with quote  

Good point - you probably can't charge them with a LIPO charger while the car is running. For just racing, you'd make the pack larger than the expected run time and ditch the alternator?

Post Tue Oct 16, 2012 2:22 pm 
 View user's profile Send private message
Knightrous
Site Admin


Joined: 15 Jun 2004
Posts: 8511
Location: NSW


 Reply with quote  

For charging I was actually looking at a BMS product a colleague has made for his EV conversions, or look at hassling Steve to hack a cheap HK charger to do the job. The car is still heavily street driven, so ditching the alternator is not an option Smile
_________________
https://www.halfdonethings.com/

Post Tue Oct 16, 2012 2:52 pm 
 View user's profile Send private message
marto
Experienced Roboteer


Joined: 08 Jul 2004
Posts: 5459
Location: Brisbane, QLD


 Reply with quote  

On another note.
http://spectrum.ieee.org/tech-talk/green-tech/advanced-cars/a123-bites-the-dust

Sad
_________________
Steven Martin
Twisted Constructions
http://www.botbitz.com

Post Thu Oct 18, 2012 1:15 am 
 View user's profile Send private message Send e-mail MSN Messenger
  Display posts from previous:      

Forum Jump:
Jump to:  

Post new topic   Reply to topic
Page 1 of 2

Goto page 1, 2  Next

Forum Rules:
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum

 

Last Thread | Next Thread  >
Powered by phpBB: © 2001 phpBB Group
millenniumFalcon Template By Vereor.