Really? Hhhmmm.....
All I know is you shouldn't treat them like Ni-cads or Nimh and should avoid discharging.
So I just balance charge to full and use.
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Really? Hhhmmm.....
All I know is you shouldn't treat them like Ni-cads or Nimh and should avoid discharging.
So I just balance charge to full and use.
Going to try sorting my new lipo tomorrow but i want to check one more thing. Its currently balanced at storage voltages (6s 4800mah, all at around 3.85v) so am i right in thinking that unlike nimh batteries, its not going to charge to full mah as there is some juice already in there? what I'm trying to say is that the charger will say its fully charged once all cells are at 4.2v and around about 2900mah (thats 60% of the full capacity based on the fact that storage voltages leave the battery charged at around 40%)
thanks
dan
how easy is it to seperate out a 6s lipo brick into a 6s saddle pack? im thinking what all i will need to do is cut the shrink wrap, seperate and re-shrink wrap again?
it is that easy. but people will warn you not to incase you cut or damage the packaging to the cells.
might get the local model shop to do it then!
they propably wont do it for you either, and advise you to buy a saddle pack lipo.
Don't bother. Lipo's aren't designed to be taken to bits or rather you'll damage the individual cells trying.
Yep and if you damage the cells with say a stanley knife, the correct course of action is to run!!Quote:
Originally Posted by typhoon_driver
Run like buggery, phone the fire brigade and wait for it to die down, if it's safe use a fire extinguisher to put all the bits out then go out and replace any bits which were sat anywhere near it.
http://www.youtube.com/watch?v=9wAh70CVGNQ
I disagree with the above comments, there's no issue in making your own pack up just be careful when taking of the heat shrink and make sure you give it a good slow balance charge after ...
Also in reply to the above video link you will notice the live and neutral have been extended from the lipo, which has probably been shorted out or set on a massively high charge current to produce the combustion of the cells... In reality when a cell is punctured the most it does is release smoke... As seen here;
http://www.youtube.com/watch?v=V5mwLcFV8PU&sns=em
If you slip that much with a stanly while cutting your heatshrink of While making you saddle bags... Well then you shouldn't be attempting the mod :)
Just do it in a ventilated area... Although the smoke fumes from a lipo aren't as bad for you as that from a nicad...it still don't smell great.
More misconceptions about lipos hopefully put to rest.
i disassembled a nackered pack just to see what was inside. The issue came when trying to part the individual cells as they had been glued along the centre. The cells are very easy to damage trying to take them apart.
@Dave, I've also heard that Li-Pos are contagious if they so much as cough on you(!)
And when you drop them the four horse men of the appocolypse escape and hell freezes over....
in reality lipos seem to be getting bad press of people in the robot circuit from people who in reality know nothing about them...
hmmm! not quite what i was trying to potray. Treated with respect then lipos are perectly safe.Quote:
Originally Posted by mr_turbulence
http://www.youtube.com/watch?v=G1qAml7qBAc (just don't dip em in a bucket of salt water, short them then stick a great big nail in them with a stick :proud: )
There is a risk with lipos (but having had an a123 go up spotaneously in the shed recently this applies to all batteries). If you know what the risks are then fine they are safe.
Be careful, but that applies to everything we do really.
hey peoples, would it be posible to get a decent 4 cell lipo battery and charger for under £100? or would £150 be a better target?
yes.
I have a pro peak quattro (£14) and dualsky pcm pro balancer (another £18) from Al's Hobbies and the quattro can charge at up to 3A (I think) so it should work for feather sized batteries. You need some sort of power supply for it but I just hacked a 1.5A wall wart to it and it was fine.
As for a feather sized 4s lipo supposedly the 25C Gens Ace ones that Giant Cod do are quite good considering that they're £30 for a 3300mah one and have been tested and not exploded.
i have a pro peak quattro plus, will this work? wow, £30 thats good, thanks Jordan
I don't see any difference apart from an extra £15 on the price tag and a plus after it's name :proud:
In case you missed it there was a link in there to the testing of that brand of lipo (I couldn't really see it on my screen)http://www.giantcod.co.uk/forum/view...&t=7579#p23517
Hobbyking LiPo's ?
it was £20 posted and it had a mains plug with it
Anyone know of a half decent lipo cut-off rated up to 6s? Possibly a BEC that cuts it's output causing the failsafes to kick in once the lipo has got down to 3.7v per cell
Last Sunday on the airfield:Quote:
Originally Posted by mr_turbulence
http://www.flyinggiants.com/gallery/...er2011_54_.jpg
http://www.flyinggiants.com/gallery/...er2011_55_.jpg
And nothing bad happened to the lipo.
Yup, seen them smash into the ground in helis too- no damage... I had one mounted to the front of my brushless combat wing... Nose dived into the ground going about 150mph and it didn't do much.
This Funjet was doing about the same speed. The lipo is about 80% buried into the ground.
Oh yeah! I can see just about buried it is now, impressive!
Would a battery like this:
http://www.giantcod.co.uk/3000mah-lipo- ... 06608.html
Be able to run two Argos drill motors and a speed 900 or simulaly powered axe weapon? And would it need charging in-between fights?
Going by the spec's it probably would yeah, but I notice that people in this thread often say that Li-Po's vary vastly by brand and with that being GiantCod the brand may be of the cheaper variety.
Max, check out the 'Gens Ace' range of li-po batteries available on GiantCod. They're still pretty cheap but testing and reports from other users seem to say that their performance is similar to some of the higher-end brands of li-po batteries available. I've got myself a pack for using in Drumroll so will see how they go.
So this one would be better
http://www.giantcod.co.uk/gens-3000-lip ... 06609.html,
Is a 25c discharge rate going to be enough to power the speed 900 for the axe and the drills?
If it was one of our machines.
Scorpion XXL speedo. Means 45 amps per channel current limit =90A, doesn't matter for the voltage.
Speed 900@12V, officialy 54A stall.
144A together.
3000mAh*25= 75A
I guess that's simple enough.
But you very in likely to stall them together, drill motors, generally won't go above 10 amps, so I would have thought that you would be ok... As long as the average draw of the drills is below 10 amps? Or am I barking up the wrong tree?!?
We're talking Murphy's law here.
Normaly, a reasonable 2WD feather drive won't ask more than 500mAh from a 4S A123.
But I messured Lesha Drillmotors drawing 100A+ for a few seconds before becoming magic smoke.
So would I be advised to put a 75A fuse before the battery
It is an option. Will keep your batteries in 1 piece, untill the opponent runs them trough, after the fuze blows.
I believe it's a requirement to have an in-line fuse rated below potential when using Li-Po's. Plus it'll save your investment. I'd advise having them before your motors too to save your ESC's (obviously adjust the rating)
All sorts of nasty-ness can happen to the insides of your robot when fighting and you'll want to protect the expensive bits!
The requirement is to have a low voltage cut-off. A fuze doesn't react on voltage. Only amperes.
The point in the fuse is to stop your pack being over disscharged by pulling to many amps....An inline fuse will stop this.
If your pack can supply 100a contin and 200a burst.... go for a 100a or less fuse.
The fuse is to protect your lipo NOT your motors.
also - why buy cheapo lipos when you can get a 40% sponsorship deal from flightpower that all FRA members are entitled to thanks to robochallenge.
Also... flightpower offer great customer service.. i recently had a pack go down on a dodgy connection... i sent an e-mail to flightpower, had a response within an hour... and a new lipo on its way to me free of charge...they even told me how to fix my old one to keep as a spare.
So I think this battery looks perfect and with the extra 40% discount that is an incredibly good price!
http://global.flightpower.co.uk/index.p ... cts_id=212
What do you think?
What discount do we get?