Go Back   oOple.com Forums > General > General Race Chat

Reply
 
Thread Tools Display Modes
  #1  
Old 27-02-2020
adey's Avatar
adey adey is offline
Senior Member
 
Join Date: Mar 2010
Location: west midds
Posts: 838
Default Blinky racing battery help

Hi all. Been racing for many years with buggies and have tons of experience but I am struggling to understand an issue with blinky racing. We are thinking of running a buggy class with 13.5 blinky and some of the drivers have said with today's low profile lipos they would dump in the race. The batteries are ok with a 7.5 with boost but a 13.5 blinky would take up too much power and the battery would dump. Can anybody explain too me how a 7.5 with boost used less power than a 13.5 blinky. Many thanks.
Reply With Quote
  #2  
Old 27-02-2020
mark christopher's Avatar
mark christopher mark christopher is offline
Spends too long on oOple ...
 
Join Date: Jan 2007
Location: haxey, doncaster
Posts: 7,787
Send a message via MSN to mark christopher
Default

Quote:
Originally Posted by adey View Post
Hi all. Been racing for many years with buggies and have tons of experience but I am struggling to understand an issue with blinky racing. We are thinking of running a buggy class with 13.5 blinky and some of the drivers have said with today's low profile lipos they would dump in the race. The batteries are ok with a 7.5 with boost but a 13.5 blinky would take up too much power and the battery would dump. Can anybody explain too me how a 7.5 with boost used less power than a 13.5 blinky. Many thanks.
13.5 would use less power by far, afraid they are talking out there butts, you would not dump.
__________________
MBModels - Schumacher Racing - Vapextech.co.uk - MRT - Savox - SMD

Last edited by mark christopher; 27-02-2020 at 06:48 PM.
Reply With Quote
  #3  
Old 27-02-2020
Danosborne6661's Avatar
Danosborne6661 Danosborne6661 is offline
Mad Member
 
Join Date: Mar 2007
Posts: 1,301
Default

It wouldn't.
__________________
SchumacherPhat Bodies

Mendip R/C Raceway - Offroad Racing in South-West
WORM-Racing - GT12 Racing in the South-West
Reply With Quote
  #4  
Old 27-02-2020
adey's Avatar
adey adey is offline
Senior Member
 
Join Date: Mar 2010
Location: west midds
Posts: 838
Default

Even Trish from Schumacher said on his you tube video that he used a full thickness shorty lipo to win the stock class at Eos daun because of this. I just don't see how it uses more power.
Reply With Quote
  #5  
Old 27-02-2020
coolhands coolhands is offline
Member
 
Join Date: Dec 2012
Location: London, UK
Posts: 40
Default

I think they are using the wrong terminology. I’ve read that with touring cars for example you would suffer because the voltage drops a bit (so does not ‘dump’ like the old days) and that loss of performance means you can’t win etc This is because you don’t have an excess of motor power, like in a mod class, so need every scrap of performance you can eek out of the vehicle. Hence why you might need full size Lipo to keep higher voltage.
__________________
Associated B6.1d
Reply With Quote
  #6  
Old 27-02-2020
charlesk's Avatar
charlesk charlesk is offline
Senior Member
 
Join Date: Apr 2013
Posts: 460
Default

Quote:
Originally Posted by coolhands View Post
I think they are using the wrong terminology. I’ve read that with touring cars for example you would suffer because the voltage drops a bit (so does not ‘dump’ like the old days) and that loss of performance means you can’t win etc This is because you don’t have an excess of motor power, like in a mod class, so need every scrap of performance you can eek out of the vehicle. Hence why you might need full size Lipo to keep higher voltage.
That's exactly it, because you're on full throttle a lot more and even then acceleration isn't stunning you notice the drop. Also they tend to be geared high, which draws a few extra amps, exaggerating the issue of acceleration when a little down on voltage.

Last edited by charlesk; 27-02-2020 at 04:52 PM.
Reply With Quote
  #7  
Old 27-02-2020
adey's Avatar
adey adey is offline
Senior Member
 
Join Date: Mar 2010
Location: west midds
Posts: 838
Default

A racer at our club was using a 13.5 in a cougar laydown with a 23 pinion and kit spur running a little boost. He dumped after 4 and a half mins with a low profile 3200 lipo. I don't see how as I run lipos that are 3200 with a 10.5 with boost and it's fine.
Reply With Quote
  #8  
Old 27-02-2020
MiCk B.'s Avatar
MiCk B. MiCk B. is offline
oOple Advertiser
 
Join Date: Nov 2006
Location: Dublin, Ireland
Posts: 1,425
Default

Hi,


You'd need to check if he had fully charged the lipo.



Also was it a one off. Bad pack / uncharged pack.


Did he try a larger capacity lipo eg 5000mah.
If he did what did he take out of it in a run?


Are you sure he dumped the pack and not thermaled the motor?


A lower capacity lipo should not have the same puch as a larger lipo.
(C-rating / max amps the lipo can provide.)


But a 3200 should have more than enough for a 5 minute run.



MiCk B. :-)
__________________
http://www.dublinmodelracing.com/
(Off-road racing in Dublin)

http://www.p-dubracing.co.uk
(Stocking: 8Racing / AVID / GHEA / Xpert Racing / Factory R/C / Alton Design Innovations)

http://www.msdmodels.ie/
(Trackside and on-line RC supplies.)

Reply With Quote
  #9  
Old 27-02-2020
adey's Avatar
adey adey is offline
Senior Member
 
Join Date: Mar 2010
Location: west midds
Posts: 838
Default

I'll find out.
Reply With Quote
  #10  
Old 27-02-2020
Ritchie T's Avatar
Ritchie T Ritchie T is offline
Senior Member
 
Join Date: Apr 2009
Location: Birmingham
Posts: 403
Arrow

Malkin is massively under geared
Reply With Quote
  #11  
Old 03-03-2020
mark christopher's Avatar
mark christopher mark christopher is offline
Spends too long on oOple ...
 
Join Date: Jan 2007
Location: haxey, doncaster
Posts: 7,787
Send a message via MSN to mark christopher
Default

oh the joys of blinky racing, battery and motor wars!
__________________
MBModels - Schumacher Racing - Vapextech.co.uk - MRT - Savox - SMD
Reply With Quote
  #12  
Old 05-03-2020
Danosborne6661's Avatar
Danosborne6661 Danosborne6661 is offline
Mad Member
 
Join Date: Mar 2007
Posts: 1,301
Default

Quote:
Originally Posted by mark christopher View Post
oh the joys of blinky racing, battery and motor wars!
Less applicable in offroad IMO
__________________
SchumacherPhat Bodies

Mendip R/C Raceway - Offroad Racing in South-West
WORM-Racing - GT12 Racing in the South-West
Reply With Quote
  #13  
Old 05-03-2020
neallewis's Avatar
neallewis neallewis is offline
*SuPeRsTaR mEmBeR*
 
Join Date: Feb 2012
Location: UK
Posts: 3,368
Default

I ran 13.5T stock Blinky last night at MB raceway on EOS carpet.

I used my Intellect 4200mAh, a new 4400mAh, and 5000mAh packs, 4200 in practice, and 4400 and 5000 in Qual and Finals. I normally use 4200 and the new 4400 in mod racing, 5000 in my 4wd.

I didn't feel a difference between the 4400 and 5000 in speed, punch or have any fade at the end. They each took about 1665-1700mAh in recharge after the runs, so used about the same for the run. I was playing with gearing. I didn't race with the 4200 as they are a bit older than the 4400. I'll back to back the 4400 and 4200 at some point to see if i can feel the difference. All my packs are less than 1 year old at most. I replace mine every year.

I think I preferred the 5000mAh as I made less mistakes with this. I rolled the car landing a few jumps with the 4400, and didn't with the 5000. I think the added weight helped settle the car, so I went faster overall in the 5 min run due to less mistakes, but the added weight didn't slow the car down.

I normally take more out of each pack in Mod (6.5T) on same track. Blinky certainly used less in a 5min run than running mod.
__________________
-------------------------------------------------------------------------------------------------------------------
Team Yokomo - YZ-2CAL3 | YZ-2DTM3 | YZ-4SF2 | YZ-2T | YZ-2DTM Worlds | YZ-2DTM x2 | YRX-12 x2
-------------------------------------------------------------------------------------------------------------------
10electric | Batley Buggy Club | YORCC | RHR | MB Models
---------------------------------------------------------------------------------------------------------------

Last edited by neallewis; 05-03-2020 at 04:47 PM. Reason: spelling
Reply With Quote
  #14  
Old 05-03-2020
adey's Avatar
adey adey is offline
Senior Member
 
Join Date: Mar 2010
Location: west midds
Posts: 838
Default

That's a very insightful evaluation. I am going to pass this on to my mate who had the dumping issue in response to the argument that a 3200 mah low profile lipo cannot sustain a 13.5t motor in blinky for a 5 min run. Thanks
Reply With Quote
  #15  
Old 05-03-2020
neallewis's Avatar
neallewis neallewis is offline
*SuPeRsTaR mEmBeR*
 
Join Date: Feb 2012
Location: UK
Posts: 3,368
Default

Quote:
Originally Posted by adey View Post
That's a very insightful evaluation. I am going to pass this on to my mate who had the dumping issue in response to the argument that a 3200 mah low profile lipo cannot sustain a 13.5t motor in blinky for a 5 min run. Thanks
Cheers.

To comment on your racing buddy's situation with 3200mAh packs, I'd suggest the packs may just be experiencing a voltage drop under load. This may be triggering the low voltage cut off on the speedo, and so if looks like the packs dumped. Has he disabled low voltage cut off on the sppedo? If not, do this.

At this point we don't know the age or condition or numbers of charge/discharge cycles of those packs. I suspect they aren't new.

If you assume 1665-1700mAh (that I was pulling in 5 mins) from a 3200 pack, you are using over half the capacity. If those packs were LiHV (and not Lipo), then they wont be charged to 3200mAh anyway, so indeed he would be puling far more more than half of the capacity out of the pack. A pack under load will experience voltage drop.

I think the current draw (and therefore voltage drop) profile from a modified motor will be significantly different to that of a stock motor. Mod will likely be lots more spikes as you are on and off the throttle more, whereas stock will be more constant. Modified motors will potentially draw higher current for less time, with stock motors pulling a more constant load. The output capability of the pack will therefore be felt more in stock racing, where as its may not be as noticeable in mod.

Take home message is: buy a new battery...
__________________
-------------------------------------------------------------------------------------------------------------------
Team Yokomo - YZ-2CAL3 | YZ-2DTM3 | YZ-4SF2 | YZ-2T | YZ-2DTM Worlds | YZ-2DTM x2 | YRX-12 x2
-------------------------------------------------------------------------------------------------------------------
10electric | Batley Buggy Club | YORCC | RHR | MB Models
---------------------------------------------------------------------------------------------------------------
Reply With Quote
  #16  
Old 06-03-2020
daz75 daz75 is offline
Mad Member
 
Join Date: Jul 2012
Posts: 1,846
Default

Quote:
Originally Posted by neallewis View Post
If those packs were LiHV (and not Lipo), then they wont be charged to 3200mAh anyway, .
:
Why would that be?
Reply With Quote
  #17  
Old 06-03-2020
KRob's Avatar
KRob KRob is offline
Senior Member
 
Join Date: Dec 2005
Location: Swingrove
Posts: 608
Default

For the HV 7.6v packs, the mah rating will be if the pack is charged to capacity.
But as for racing we can't charge to the maximum voltage the pack will go to, only to the maximum voltage allowed for racing then the pack will not have the full capacity in it.
Hopefully that makes sense.
Reply With Quote
  #18  
Old 06-03-2020
Danosborne6661's Avatar
Danosborne6661 Danosborne6661 is offline
Mad Member
 
Join Date: Mar 2007
Posts: 1,301
Default

What's it like running the 13.5t blinky Neal? Is it good fun and do you have a few of you running them?

I have just bought a 17.5t to try out for a bit of fun!
__________________
SchumacherPhat Bodies

Mendip R/C Raceway - Offroad Racing in South-West
WORM-Racing - GT12 Racing in the South-West
Reply With Quote
  #19  
Old 06-03-2020
daz75 daz75 is offline
Mad Member
 
Join Date: Jul 2012
Posts: 1,846
Default

Quote:
Originally Posted by KRob View Post
For the HV 7.6v packs, the mah rating will be if the pack is charged to capacity.
But as for racing we can't charge to the maximum voltage the pack will go to, only to the maximum voltage allowed for racing then the pack will not have the full capacity in it.
Hopefully that makes sense.
Nope lol. What's the maximum allowed for racing? How is that checked?
Reply With Quote
  #20  
Old 06-03-2020
Wig Wig is offline
Member
 
Join Date: Oct 2014
Location: Worcestershire
Posts: 193
Default

Quote:
Originally Posted by daz75 View Post
Nope lol. What's the maximum allowed for racing? How is that checked?

In the BRCA rules it states lipos cannot be charged over 4.2v per cell i.e. 8.4v for a 2s. This is a hard and fast rule. If caught charging over this you could be removed from club/meeting etc.


At BRCA sanctioned events voltage is measured before each run.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 08:15 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
oOple.com