Blinky racing battery help

[adey]

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.

[mark christopher]

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.

[Danosborne6661]

It wouldn't.

[adey]

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.

[coolhands]

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.

[charlesk]

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.

[adey]

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.

[MiCk B.]

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. :-)

[adey]

I'll find out.

[Ritchie T]

Malkin is massively under geared ;)

[mark christopher]

oh the joys of blinky racing, battery and motor wars!

[Danosborne6661]

oh the joys of blinky racing, battery and motor wars!

Less applicable in offroad IMO

[neallewis]

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.

[adey]

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

[neallewis]

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... :thumbsup:

[daz75]

If those packs were LiHV (and not Lipo), then they wont be charged to 3200mAh anyway, .
:

Why would that be?

[KRob]

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.

[Danosborne6661]

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!

[daz75]

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?

[Wig]

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.

[NeilRalph77]

Which begs the question why make them if we can't run them?

[daz75]

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.

Oh ok thanks for the info. I just stick them on charge and wait for it to finish charging. Should I be doing something different?

[neallewis]

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!

Yeah I was really good fun actually. We had a heat of 6 who would normally be quite close running modified, so it it was just good close fun racing, easier on tyres and still competitive. We also had a lower heat of 6 drivers running 13.5.
I do think a lot of club racers who start out with the fastest motor the can buy would all be doing themselves a favour running 13.5T stock until they need to progress. I found it so much more easier to drive, you can actually think about racing lines and being precise on the track, and just getting faster due to not needing to be marshalled.
Next indoor season at Batley Buggy Club we'll be promoting the 13.5T to beginners and those wanting a less crazy pace of racing.

York club have a good competitive 17.5 class which has proven successful for their beginner racers.

[neallewis]

Which begs the question why make them if we can't run them?

LiHV packs? They have a natural built in safety margin when charged to BRCA requirement of 8.4V instead of 8.6-7V. And you'll never get to the full quoted capacity as you are charging to a point under its peak voltage and capacity. LiHV (High Voltage) are 4.35V per cell vs the 4.20V of the standard Lipo, and typically have a higher energy density than the equivalent Lipo pack.
Cell production factories have mostly switched now to producing the LiHV formulation cells, and so the RC battery assemblers will just use the stocks that are readily available, and mark them up as LiHV.

I imagine it wont be too long before the 8.4V charge limit it re-addressed by the sanctioning bodies once Lipo packs are no longer common, and everyone has switched to LiHV. I've been running LiHV now for two seasons, charging of course to 8.4V, and have found them to be excellent.

[Danosborne6661]

Yeah I was really good fun actually. We had a heat of 6 who would normally be quite close running modified, so it it was just good close fun racing, easier on tyres and still competitive. We also had a lower heat of 6 drivers running 13.5.
I do think a lot of club racers who start out with the fastest motor the can buy would all be doing themselves a favour running 13.5T stock until they need to progress. I found it so much more easier to drive, you can actually think about racing lines and being precise on the track, and just getting faster due to not needing to be marshalled.
Next indoor season at Batley Buggy Club we'll be promoting the 13.5T to beginners and those wanting a less crazy pace of racing.

York club have a good competitive 17.5 class which has proven successful for their beginner racers.

Love this! Makes buggies appealing again for me

[mark christopher]

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.
or if reported to brca loose your licence.

[mark christopher]

Love this! Makes buggies appealing again for me

already tought thectop guys are discussing lipos and having the "wrong motor" or car.....


the Joy's of stock I'm afraid fun but soon gets silly

[neallewis]

already tought thectop guys are discussing lipos and having the "wrong motor" or car.....


the Joy's of stock I'm afraid fun but soon gets silly

Yes, he'd swapped in a newer muchmore with titanium rotor from his TC, and it was revs biased, not torque, so used it as the excuse as to why I was faster. I just stuck in an old 13.5t I used to use in LMP12.

Someone else was also running a new hot trinity motor, which looked fast between mistakes.

Everyone was broadly the same on the straight though, but I could certainly pull away on the infield. Was it the motor, battery, gearing, the car/chassis or was it driving? :thumbsup:

[stormyyyy]

already tought thectop guys are discussing lipos and having the "wrong motor" or car.....


the Joy's of stock I'm afraid fun but soon gets silly


Really don't know why your bashing just stock class with this argument. It is the same in any class, on road or off road.
If people have the finances/sponsorship to put in a new battery/motor/tyres/esc/servo in every heat because it may be faster they will. In any motorsport from RC to F1 financial advantages has always been there and is a factor in equipment performance, just ask ferrari and mercedes.

It's all part of racing.

[mark christopher]

Really don't know why your bashing just stock class with this argument. It is the same in any class, on road or off road.
If people have the finances/sponsorship to put in a new battery/motor/tyres/esc/servo in every heat because it may be faster they will. In any motorsport from RC to F1 financial advantages has always been there and is a factor in equipment performance, just ask ferrari and mercedes.

It's all part of racing.

Beg to differ I'm not bashing it, I'm pointing out what happens in blinkey, been racing 35 odd years now and seen many things and raced many classes. Inc competative blinky.
I'll be happy if I'm proved wrong this time next year, but over the pond the evidence is there.
I'll build my spare ld into a spec class car and warm my icarger up :thumbsup:

oh and as for Ferrari etc and f1, they spend a fortune, not just because they can, they are looking for every last bit from their package...

[neallewis]

Really don't know why your bashing just stock class with this argument. It is the same in any class, on road or off road.
If people have the finances/sponsorship to put in a new battery/motor/tyres/esc/servo in every heat because it may be faster they will. In any motorsport from RC to F1 financial advantages has always been there and is a factor in equipment performance, just ask ferrari and mercedes.

It's all part of racing.

I think you've taken Marks comments the wrong way.
Mark races at our club, and follows the race talk banter on our facebook group. Out of that context he was referring to a conversation I was involved with, and having a poke at it. :thumbsup:

I agree with Mark on the comments about stock racing. It can get very silly (see what happened to GT12 class or stateside stock racing), but the guys racing at our club wont let it get silly. We'll just go back and race modified and let anyone who wants to run the stock motor pace get on with it.
most people have just stuck in a basic 13.5t motor, or pulled an old one out of a TC or LMP/GT12 car. for the last few meetings of our indoor season its just a bit of fun. Next year we'll also offer it for whoever wants to race it, but suggest it for beginners and old timers, or anyone who wants a bit slower pace to learn to get round without crashing.

[claymoreman]

a stock spec car like those raced in the US will cost you 3 times the cost of a modified car as everything is geared to make the car as light as it legally can be which costs a lot of money. We state that all new drivers run 13.5t motors at our club in our rookie class this is to do with teaching them how to drive the car not the car drive them and have them bouncing all over the track and into other cars and breaking not just there own but others. When we first switched to eos carpet we did introduce a motor limit of 10.5t the racing was close and fun but to bring in a true stock class you would have to have specific rules and regulations i.e cars have to be out the box no lightweight parts set motors only x motors from a list to be used same with batteries so it would be down to pure driving. the one problem for a club any club to do this is to actually scrutineer the cars to make sure no one is cheating most club racing only have time to book in and race with track setting up(for many clubs that's because there is not many who have a permanent indoor track) and time limiting with the venues they race in most have set times to be in and out

[stormyyyy]

Beg to differ I'm not bashing it, I'm pointing out what happens in blinkey, been racing 35 odd years now and seen many things and raced many classes. Inc competative blinky.
I'll be happy if I'm proved wrong this time next year, but over the pond the evidence is there.
I'll build my spare ld into a spec class car and warm my icarger up :thumbsup:

oh and as for Ferrari etc and f1, they spend a fortune, not just because they can, they are looking for every last bit from their package...

The thing is I don't think your wrong about how it will go, my point was that I only see this argument about motors and batteries when stock is mentioned and the reality is it happens in all of rc but hardly anyone ever mentions it.

As for the ferrari/mercedes bit at the end does that not prove my point. People who can afford will do everything to get the best out of there package.

[mark christopher]

I think you've taken Marks comments the wrong way.
Mark races at our club, and follows the race talk banter on our facebook group. Out of that context he was referring to a conversation I was involved with, and having a poke at it. :thumbsup:

I agree with Mark on the comments about stock racing. It can get very silly (see what happened to GT12 class or stateside stock racing), but the guys racing at our club wont let it get silly. We'll just go back and race modified and let anyone who wants to run the stock motor pace get on with it.
most people have just stuck in a basic 13.5t motor, or pulled an old one out of a TC or LMP/GT12 car. for the last few meetings of our indoor season its just a bit of fun. Next year we'll also offer it for whoever wants to race it, but suggest it for beginners and old timers, or anyone who wants a bit slower pace to learn to get round without crashing.
thank you neal, that exactly :thumbsup::thumbsup:

[mark christopher]

The thing is I don't think your wrong about how it will go, my point was that I only see this argument about motors and batteries when stock is mentioned and the reality is it happens in all of rc but hardly anyone ever mentions it.

As for the ferrari/mercedes bit at the end does that not prove my point. People who can afford will do everything to get the best out of there package.


I'm not sure you get it.
open if you want more speed, fit a faster motor, you dont need the best lipo motor or speedo, and many run older gear.
run stock and the only way to go faster is fresh motors lipo and better speedo.

[Kev B]

In modified power outweighs grip so it's more about tyres. In Stock every last drop of power counts. So new batteries, latest motor, charging at silly amps all make the difference and to some, not all they will do this too win. Others will not and not be able to keep up so will stick a £20 2nd hand motor in and go back to mod.

[mark christopher]

In modified power outweighs grip so it's more about tyres. In Stock every last drop of power counts. So new batteries, latest motor, charging at silly amps all make the difference and to some, not all they will do this too win. Others will not and not be able to keep up so will stick a £20 2nd hand motor in and go back to mod.
:thumbsup::thumbsup:

[andys]

For what it's worth...

I will race 'Blinky' next winter at MB as I enjoyed it.
You DO need the right gear - and the right setup - which I proved by turning up with an incorrect motor / rotor and having no pace.

Following week - with the correct rotor in the same old 13.5 Much More - I was flying and much, much quicker then the previous week. Also geared the car a lot higher and it liked it. In fact my times we so close to Mod it was silly - and faster than most there that night :)

Re Blinky issues - people will 'cheat' and do silly things regardless of class - be that using more sets of tyres than permitted / abusing lipo's and overcharging as well as cutting the track. Some people are idiots - that's just life.

If you have a decent bunch of people racing blinky - it just allows some close racing and less tyre wear - what's not to like :)

Re original post - I put back around 2000mah into a pack - so no chance of 'dumping' !