71 replies to this topic

[TSR]

Maybe they didn't do it in the 70's, but they sure as hell started it on the road course King tracks in the mid 80's and this was before slot drag racing got started up again.

Ron, we totally agree, that is when it happened. Mark is way off base here.
OK, I have cleaned up this thread from anything irrelevant. Gentlemen, please continue. Mark Wampler and Nesta, please stay away from this thread.

Roman, no semantics please, when we are talking "12-volt", we are talking battery power that of course can charge to 13.6. Did you ever hear cars fitted with "13.6-volt" systems? Everyone calls it "12-volt". The issue here is when MORE than a "12-volt" battery is being used, suddenly we have 14 to16 volts. And THAT kills slot car motors.
As far as "rubber band", maybe you should try driving non-wing cars sometimes and see where a rubber band around the trigger will lead you on the first lap of a Retro Pro race as we ran last week with only 12.5 volts on dying batteries, with cars that race with no added air control.
I bet that your car would fly all the way from the dead-man through the front door of your raceway in a gracious curve...

[Ron Hershman]

Ron,
Your history of slots is impeccable.

I remember one of the long timer guys. When you would approach him and ask why he was timing his 3 minute
heats 20 seconds long, his answer was because he checked his dark room timer and found out it was 2 seconds fast every 3 minutes so he set his timer long to compensate.
When I said "OK, then set your timer 2 seconds long, not 20", he looked at me
like I was speaking Martian.

I remember the variable power deal in Michigan. I didn't think he could vary it from lane to lane.
I was later told I was an intended target. Despite an all-star field, I don't think Watson, Pfeiffer or Laster made the main because of the goofy conditions.
I spent a whole lot of time spinning my choke dial but I'm pretty sure I won by at least 70 laps over
some handsome young racer running for Parma.

LOL...... ahhhh the good old days. I remember them trying to burn you down in Jackson Mi....not Mississippi..... I remember you pouring Coca Cola on your motor to cool it down so you could continue on your winning way.

I chugged along that entire main on one motor. Richard Akard was pitting for me and I remember him telling Joel..."I don't understand how Ron can run a entire race on one motor".

[Phil Hackett]

Just to add another vote for bringing power down to reasonable levels, I'll add this little story: in preparation for the '93 Reseda Nats I had "X" manufacturer wind me several special Group 7 armatures. They were double winds (6-7's and 7-8's). During practice, with the charger off and the track voltage between 12.9-13.5v, these motors ran fast and hard and for a half-hour at a time. One night, they had the track up to "race" power and those arms barely made it to the "finger" before they died. They went faster on the higher voltage but not **that** much faster.

I had my high voltage jollys burnt out of me at Crash & Burn Raceway in the '70s. (the first USRA race at C&B had 52 motors burn up in **qualifying**!!!)

[GearBear]

Here is an interesting thought... I just came back from the race at Wade Raceway in Idaho. When we used to run on the Canadian White at SHS the voltage was held at 12.4V on computer power supplies. At the time our track record for Eurosports was at just about 2.7 (I don't remember the exact number but it was slightly faster than that). And my best time with a Euro was 2.72. At the race last weekend the track was run on both Batteries and Rivergate power supplies and was set at about 14v. Beuf qualified with a 2.889. Now, it isn't quite a 1:1 comparison as the bodies we used to run are worth about a tenth. But to me, it is interesting that the higher voltage resulted in SLOWER racing on that track.

The reason the higher power resulted in slower racing is that you had to drive quite a bit differently to get around the track. It used to be that you could run full punch on several lanes through the sweeper, finger, and lead on turns. But with the higher power you had to finesse these corners making your overall lap times slower. Also, there was far more crashing IMHO than we used to have due to the higher power.

I tell ya, I sure missed the clean power from our power supplies! They don't fluctuate at all where as each time someone came off you could feel the power surge on the batteries.

[TSR]

So the general solution would be to do away with batteries and use a decent but possibly expensive, DC power supply delivering 13-volt max and let say, 100 amps, plus fat wiring under the track?

[GearBear]

Dokk,

In the PNW we have been running computer power supplies for years. They offer the smoothest power I have ever run on. And as long as you have enough amps available, the power doesn't fluctuate from start to finish. Running battery power, you will often notice power going away at the end of a race. I think we are running 400 or 500 amps worth of power supplies on the Twister. We started with less, but it wasn't enough for the times when the power was first brought online with Eurosports. IE: 8 Euros sucked more than 300 amps of power causing a brown out type of feeling when the power first came on!

Power Supplies are definitely the way to go IMHO. Sure they are expensive to get set up, but once you do, you don't have to mess with batteries ever again!

[TSR]

Sounds cool.
Who's the maker of the supply?

[Rick]

IMO power supplies will be mandatory soon anyway. Also IMO 13.2 is pretty correct for track voltage, the same as a lead acid battery provides. Just have to make sure there is enough amps available to keep it at 13.2. Trying to sell this figure or concept across the whole country, ain't gonna happen, but would be nice.

I read Garys post about 8 eurosports pulling over 300 amps?! I have clamped my track( when in bidness) and the only time we ever saw anything close to that was when a Pro dropped his aluminum choke scross the posts, LOL. Not even 8 Group 7 cars running in thick glue came any where near 300 amps, not even on a spike. But power supplies I don't belive deliver their rated amps RMS that is also a top figure.

Cap Henry just bought my old operation and the last power set up I made. It was 240 amps, but I also ran two batteries on each lane too. And it was set at 2004 voltage of 14.3v.

[zipper]

On Kouvola King with our special heavy duty DC power supply our indicators never went over 270 amps (13.5V I think) when 8 opens were driving in the last Worlds we had on 2005.

[Ron Hershman]

IE: 8 Euros sucked more than 300 amps of power causing a brown out type of feeling when the power first came on!

Considering most open type motors 16T 24's amp surge around 125 amps at "take-off" this would explain the "soft" start.... 8 Euros' are probably pulling about 800 amps at a start and just for a few milliseconds.

I would say for open and euro type racing 300 amps is the minimum and 300 amps Max would more than cover any other type of motors/classes out there.

But then again, it all comes down to how the track is wired also.

[Mr. BB]

Considering most open type motors 16T 24's amp surge around 125 amps at "take-off" this would explain the "soft" start.... 8 Euros' are probably pulling about 800 amps at a start and just for a few milliseconds.

I would say for open and euro type racing 300 amps is the minimum and 300 amps Max would more than cover any other type of motors/classes out there.

But then again, it all comes down to how the track is wired also.

What would be the idea wiring for a King track be?

[RomanK]

In the past the solution was batteries to help overcome the large need for current on start-up and cars hitting glue zones, this was a reasonable yet not the greatest approach as batteries release their current rather slowly causing some voltage drop thus increases in current drawn by cars and ultimately more heat generated. in came large, reasonably priced capacitors and without question a much better solution covering your need for massive current for a few milli seconds.

Last week we ran the Mason Dixon retro race at tne "TRACK" on power supplies and caps (180 Amps and 2ea 1 Farad caps)....results were very good.

Good power supplies don't have to cost alot of money, they can be found in the surplus market keeping in mind that unlike AC power, DC can be paralleled quite easily so multiples of a smaller voltage can be put together to come up with the voltage you need so long as the current meets you needs. Large caps are also available via surplus dealers.

Of course none of this will help much if your track is poorly wired.

[Big E]

Marty,

Well said.

If it was my raceway, i would find a technical way to limit the power on the track to 12 volts by any means, period, end of sentence.

At 12 volts of pure, regulated DC power, motors run cool, last a very long time and provide clean racing at maybe a couple tenths per lap slower.

So what?

Yes, and thank you, 12 volts is really all that's needed here to have a competitive and entertaining hobby. -- Ernie

[dalek]

Just like you say the race car is a complete package, so are track systems. I have had them all. The wiring harness is as important as the power source and many times, more so.

I hated the charging between heats and turning the charger off when the heat started, you would have a surface charge for 20 seconds and then back to the battery reserve the rest of the heat, unless you have multiple battery sets to suck the surface charge into the passive set for the heat it will be very up and down. When batteries are new even with a charger on the ripple is negligible, I have had an oscilloscope on the track to check this. As the battery wears out, the ripple will go up.

Many times when the car runs hot the return is just not of sufficient size although the math says it is.

I have used every kind of battery on the planet, 8Ds probably being the worst to use because it's just not correct for the application but they are reasonable and when new really pump out the voltage. Many can tell you the stories of the Nuc power plant batteries I had in the '90s. No charger at all, one day, 120 entries and they lost one-tenth of 1 volt at the end of the day, from Group 12 to opens. They were individual cells 2.2 volts each and weighed in at 80 pounds apiece. There were 48 of them under the pit tables and six 8Ds inside the infield. LOL. No charger required.

 

"I have used every kind of battery on the planet, 8Ds probably being the worst to use because it's just not correct for the application but they are reasonable and when new really pump out the voltage."

 

The owner of P-1 Raceway is thinking that it's about time to replace the 8D battery due to its age.

 

The track is 132 foot 8 lane Hillclimb.

 

Is there something better for slot car tracks than 8D these days?

 

And if not, is there an 8D that is better than other 8D's.

[MSwiss]

Get rid of the batteries and go with 1 or 2 of the below.

http://www.mastechpo...ction-p106.html

[Ramcatlarry]

Many communities code departments frown on lead/acid batteries in a retail store.  When they are being overcharged, they give off hydrogen gas which technically can be explosive.  Has anyone ever heard of one explode?  not me either, but code inspectors never care when their minds are made up.

 

What load is the track using?  Most 110VAC input, 12-15 VDC output power supplies run on the same circuit breaker that the 8D battery charger runs on.  Homeset cars need about five amps per lane. I like the Pyramid brand CB radio power supplies for these.  Easy to find for $85 - 150 .

 

 Low power commercial rental cars use not more than ten amps per lane.  Most new tracks sold in the past ten years run OK on the 70 amp IOTA/Bulldog power supplies designed for the RV (recreation vehicle) industry.  They make many different output models and they can be wired together to make very sturdy power with a very stabile output voltage.  Most dragstrips use a 90 amp unit tuned to 16 volt DC output.  I had four of these on my flat track for the 2006 ISRA/USA Nats for eurosport.  Eagle Dist sells them and many RV dealers stock some as well.

 

Slapshot from the great NW taught me the advantages of the used computer server power supply system over ten years ago.  These units are only 5 VDC output and usually 220 VAC input.  Buying the used ones makes an expensive NEW source much cheaper.  You need to get three identical units, wire them in series and hook them up to a GOOD 220 circuit.  They can be tuned so that the high is over 16 VDC and low is down to about 10 or 12 VDC.  These are NOT the plug and play of a simple power supply and do require an electrician in some cases to get some of the details to work for you.

[dalek]

Get rid of the batteries and go with 1 or 2 of the below.

http://www.mastechpo...ction-p106.html

 

Mike,

 

If we used two of these units, would you wire 4 lanes to each unit or use the two units in parallel?

[MSwiss]

You can do it either way.

The advantage of splitting it would be if you have to run rentals and serious guys on the same track. You can turn the power down on half the track.

The disadvantage is in a race where there is not a full field, you'll have situations where 1 or 2 racers will be drawing from 50 amps on one side, and 4 racers drawing from 50 amps on the other.
(although it should even out somewhat during the course if the race)

The main reason I really like the Mastech's is that they are infinitely variable, and thus you can turn them down as low as you want.

I'd say 40-50% of my rentals, are 4-5 year olds, running full speed, and declaring "I'm winning....I'm winning".

[Half Fast]

If you hook them up in parallel, you can turn one off when the full amperage is not needed (or if one fails)

 

Cheers

[kvanpelt]

I'd say 40-50% of my rentals, are 4-5 year olds, running full speed, and declaring "I'm winning....I'm winning".

 

Mike, I've heard some of the older guys around there declaring the same thing! 

[MSwiss]

I'm telling Bernie you said that about him. Lol

[Ramcatlarry]

There are many ways to wire the power supplies 'in parallel'.  If you use a common buss bar to hook the different power sources to, then only the general amperage is increased.  If you separate the power supplies to only power specific lanes, then voltage can vary for those lanes. 

 

For equal RACING purposes, the buss bar system ensures equal power for everyone,  You can have a battery, capacitor and power supply all hooked to a common buss bar for the white line.