AGM/Remits

Discuss matters of a general nature
User avatar
Rally Stylz
Posts: 669
Joined: Mon May 19, 2008 7:51 pm
Location: Hamilton

Tue Aug 29, 2017 11:17 pm

B.C.Ninja wrote:
Mon Aug 28, 2017 8:27 pm
If I purchase a 2s stick pack at say 8000mAH and one at 4000mAH for half the price, I can charge the 8000mAH at twice the speed as the 4000, as they would be drained of the same amount of capacity after a run in the same car, also how does it make it safer to charge one at 8 amps and 1 at 4amps just because one has a greater capacity, the internal circuitry is the same, they are both usually 2s2p so all cells will see the same current, its just that one has a higher capacity due to a little more polymer inside of the cells.
Your point here seems to max sense but from experience, You try pull 100amps out of a 500mah battery for 30sec and then do the same to a 8000mah battery and observe that capacity does in fact make a difference.

Charge rates need to be rated in C as a 1300mah 2s micro battery cannot handle the same charge amperage as a 6000mah 4s.
TLR|ORCA|Hitec|Savox|Gens Ace|Dynamite
If you don't crash then you're not trying hard enough

User avatar
B.C.Ninja
Posts: 697
Joined: Thu Nov 05, 2009 8:51 am

Wed Aug 30, 2017 7:49 am

A valid point yet the NZRCA rules , like most people point out, are set for NZRCA sanctioned meetings, and last time I checked Micro was not an Official class in the rule book, so technically wouldn't be covered by the rules anyway, yes there are exceptions to the rules, but like stated previously it is a MAX charge current, just because you can doesn't mean you should, but having the option would improve things in my opinion.

User avatar
B.C.Ninja
Posts: 697
Joined: Thu Nov 05, 2009 8:51 am

Wed Aug 30, 2017 9:17 am

To put it in another perspective, the NZRCA rules state that for Mod racing I can run whatever turn motor I want, my current esc is only rated to an 8.5T, but I want to run a 4.5T, with your example regarding the micro batteries and using the same ideology if I run the 4.5T and everything goes up in smoke then it was the rules fault, the rules are a set of goal posts to work within, they aren't there to fix stupid, with any rule regarding technology of some sorts, manufacturers guidelines are still to be adhered to regardless of the rules stipulated, so if a rule states max 10 amp but your lipo is only rated to a 5 amp charge, then the onus is on you the individual and not the rule. The two most dangerous scenarios regarding lipo charging are wrong chemistry selected and damaged lipos, if we can look towards reducing ones stock and therefore overall cost of replacement lipos, then we are creating a safer environment, we have all seen that one guy that is still persisting on using that ballon in their car, why not move towards a rule that would essentially minimise that risk.

User avatar
Scott 119
Posts: 507
Joined: Fri Nov 19, 2010 8:37 am

Wed Aug 30, 2017 11:39 am

I think so far the 1C charge rate has been great and see no reason to change it I use 4 packs to 3 cars. I often see pictures from overseas events with lipo fires I don't know the exact cause but i know they don't restrict charging.

Many batteries claim they are 5c charge capable but are they really? Most brands can't even quote a truthful discharge current let alone a charge current. A person running micro still follows club rules which are normally NZRCA so a racer could charge a 1800mAh pack at 5C following manufactures guidelines which would be below 10amps but id consider it to be a higher risk then charging at 1C. Even a 3000mAh battery could be charged well above 1C @ 10 amps.

If your concern is safety then perhaps all lipos should be scrutineered for damage before the event including puffing, plenty of guys use puffed packs but they are a higher risk.
Scott Brownhill - HOT Ltd

TLR Racing
Morgan Fuel
Savox
ORCA RC
Spektrum
VS Engines By Rody

Michael Jones
Posts: 395
Joined: Thu May 15, 2008 12:37 pm
Location: Christchurch

Wed Aug 30, 2017 3:01 pm

I think increasing the max charge current may not be the best idea. Most people tend to charge at the max current they can do legally. Alll that will happen is that people will ditch their cheap chargers from Hobbyking etc and buy new chargers which can do 10 amps - added cost. The other thing that will happen, is the people with smaller capacity batteries will gain a power advantage due to the higher charge rating difference if charged at 10a. So some people will feel they should buy smaller capacity packs to gain a bigger advantage - once again added cost.

The other thing to remember is that it doesn't matter whether it really makes a difference in performance, but more the perceived gain, which will make people spend more money.

A better idea would be just make the charge rate 2c if time is an issue. But to me 1c charge rate is good.

Mike

User avatar
B.C.Ninja
Posts: 697
Joined: Thu Nov 05, 2009 8:51 am

Wed Aug 30, 2017 3:27 pm

Good points raised here, its all good as i have some 20000 mAH packs on order so will be charging at 20 amps at the next meet, like i mentioned earlier there is no standard in the world for rating the c rating of a battery, so why base a rule on it, the only thing stopping anyone from charging their packs at a higher current is a thin sticker on that pack, as it is the only way to scrutineer charge rates is to be present when the lipo is initially put on charge, the selected charge rate drops as thd charge sequence progresses, maybd someone from the nzrca could chime in on the method they use to check this at events.

User avatar
Matt Whitmarsh
Posts: 3418
Joined: Tue May 13, 2008 10:28 am
Location: Te Awamutu

Wed Aug 30, 2017 4:54 pm

B.C.Ninja wrote:
Wed Aug 30, 2017 3:27 pm
maybd someone from the nzrca could chime in on the method they use to check this at events.
I've never seen it being checked at any event I've ever been to.
Intech ER-12
Intech ER-14
Losi 8ight 3.0 Tekno V4
Ofna TS4 Pro

User avatar
ed
Posts: 1399
Joined: Mon Apr 07, 2008 11:52 am
Location: Wellington, New Zealand

Thu Aug 31, 2017 4:41 pm

Matt Whitmarsh wrote:
Wed Aug 30, 2017 4:54 pm
B.C.Ninja wrote:
Wed Aug 30, 2017 3:27 pm
maybd someone from the nzrca could chime in on the method they use to check this at events.
I've never seen it being checked at any event I've ever been to.
I do!

be it the first and second years we ran lipos, Scott and then Jason (as the NZRCA preidents) went would to make sure everyone was charging at 1c and had a lipo bag

ed

Mishy
Posts: 12
Joined: Fri Aug 07, 2015 9:56 am

Thu Aug 31, 2017 5:03 pm

Whatever rule comes out of this, it most certainly needs clearer enforcement! Who else has heard about people charging at silly rates to get a performance advantage?

User avatar
Scott 119
Posts: 507
Joined: Fri Nov 19, 2010 8:37 am

Fri Sep 01, 2017 8:22 am

Whatever rule comes out of this, it most certainly needs clearer enforcement! Who else has heard about people charging at silly rates to get a performance advantage?
Some of the chargers like the I Charger allows for a user to discharge really fast generating heat then recharge the lipo at 20amps which also generates heat in the cells. Guys in the USA are charging at 20 amps just before a race to try and get the most from their packs.
Scott Brownhill - HOT Ltd

TLR Racing
Morgan Fuel
Savox
ORCA RC
Spektrum
VS Engines By Rody

User avatar
colin storey
Posts: 1840
Joined: Sun Apr 20, 2008 6:46 pm
Location: maungaturoto

Fri Sep 01, 2017 10:15 am

Scott 119 wrote:
Fri Sep 01, 2017 8:22 am
Whatever rule comes out of this, it most certainly needs clearer enforcement! Who else has heard about people charging at silly rates to get a performance advantage?
Some of the chargers like the I Charger allows for a user to discharge really fast generating heat then recharge the lipo at 20amps which also generates heat in the cells. Guys in the USA are charging at 20 amps just before a race to try and get the most from their packs.
20a is a bit conservative from what I've read. Individual race tracks were putting a maximum charge rate on it for meetings they were holding.
Goodride Tyres
Team Tekin
Tekin RSX
Tekin Rs/Spec
Tekin Redline
GP Tyres
Team Zombie
Team Roche

User avatar
B.C.Ninja
Posts: 697
Joined: Thu Nov 05, 2009 8:51 am

Fri Sep 01, 2017 12:27 pm

If anyone wants too they can just buy the turnigy lipo warmer to heat their packs to around the 35ish degree mark, 10Amp on a normal stick pack doesn't do diddly to add any performance to a pack, the remit I put forward was aimed at faster charging but still in a relatively safe range for standard packs at NZRCA events, thus hopefully leading to reduced numbers of lipos held by each competitor, leading to cheaper replacement costs across the board, leading to more frequent replacement. If you want to go and buy dumbass small capacity lipos and think you'll be getting an advantage, well away you go then, and micro batts are they hardcased??? if not then they wouldn't be legal to the rules anyway. The numbers printed on packs are just that, numbers printed on packs, C ratings and discharge ratings I laugh at, I redently saw pacs advertised at 8000mAH with "true" 90c discharge, really........... thats 720 amp dischage rate multiply that by an 8.4V and you have a discharge of over 5.5 KW of energy.........pfft numbers on stickers, we're powering toy cars not factories people.

User avatar
Matt Whitmarsh
Posts: 3418
Joined: Tue May 13, 2008 10:28 am
Location: Te Awamutu

Fri Sep 01, 2017 1:53 pm

The micro packs that people run at Hamilton are hard case and are usually 1800mAh. As you say, they have to be hard case to meet the rules.

I run the Turnigy 2600 or 2400 super-shorties in all of my 1/10th off-road vehicles - they are the same size as one half of a saddle, but are 2s - gives a weight advantage and chassis tuning options for handling purposes, plus they are cheap. I wouldn't charge them at 10A, but perhaps at 5A - as you say, the 10A is a maximum. Smaller capacity batteries are a pain to charge at 1c because you use just as much in a race as a large pack, but they charge at half the rate, so any increase in allowable charging would be good as far as I'm concerned.
Intech ER-12
Intech ER-14
Losi 8ight 3.0 Tekno V4
Ofna TS4 Pro

User avatar
lunchie
Posts: 153
Joined: Tue Feb 21, 2012 7:15 pm

Sun Sep 03, 2017 6:35 pm

as i said above MOST race packs people are using are rated to be charged safely at 10A or more. ive charged my 1800 gens ace micro batts at 10A many times and the batteries did not get hot.

the 1c charge rate makes people have to buy expensive dual/quad chargers when they aren't needed just so they can have packs hooked up. a 10A charge rate is both safe and more cost effective as it will mean many will only need a single channel battery.

faster charge times also means that racers are not getting flustered waiting for packs and pulling a pack off and into a car under pressure and potentailly reverse connecting it. (ive seen this more than once)

we're not talking about what the yanks do charging at 30-40 amps to get the most outta thier 17.5 cars. its only 10A MAX nobody said YOU have to charge at 10A if YOU dont want to. as we generally only use about a third of battery capacity in a race more often than not even setting it to 10a will result in a real world charge of say 6A as it tops off tha batt anyway.
RC10B6
LCracing truggy, LCracing SCT, Tamiya M05 MX5, Blackfoot3 and Lunchbox
TIRCCC

tonymcmahon
Posts: 75
Joined: Wed Jan 28, 2015 1:45 am
Location: Melbourne

Tue Sep 05, 2017 2:30 pm

Some guys here in melb were charging their lipos at 60amps for a club day! Absolutly mad bastards

Post Reply
  • Information
  • Who is online

    Users browsing this forum: Google [Bot] and 9 guests