12 replies to this topic

[Michael Jr.]

I have heard everything from add additional power supplies, to use capacitors (which I do) to put one on each lane and finally, Just use one because the one power supply with the most amps will be the one working while the other just sits idle anyway (Bulldog manufacturer had a long discussion with me about the futility of hooking multiple power supplies up to a single track). 

 

So now I'm looking at my "new to me" King and I'm sitting on two 75A and two 90A power supplies and three capacitors and thinking.... gotta be a way to use these to make an awesome power supply resource.  

 

Thoughts?

[Steve Ogilvie]

The trick to make power supplies share the load is to have a central positive and negative post or bus bar to feed the track and feed your power supplies in to the bus with wire that is exactly the same length. The fact that one supply will carry most if not all of the load will not change but the extra supplies will send in additional power when needed, like when 8 G7's hit the glue zones at the same time.12 volt batteries in parallel behave the same way- no matter how hard you try, the constant draw will always get fed from the same battery with the others playing backup. In industrial settings, multiple batteries are always in series. A 250V battery at the nuc plant I worked at had approximately 100 low voltage batteries in series.

 

   The best way to have smooth power is to have a deep cycle battery in parallel with a 90 amp PS. But most fire codes require you to have the battery in a box vented to the outside and that is why everyone uses multiple  PS's and sometime capacitors. An AGM battery does not require outside venting as far as I know. They are very expensive and might still run afoul of the fire code.

[Michael Jr.]

So a combination of 75A and 90A would be fine? The 75A would be automatically relegated to the back up fill when needed role.

[Steve Ogilvie]

Since you already have them, try it and see. Just make sure they are all putting out the same voltage (doesn't have to be exactly the same, but within .2 v should be close enough).

[Michael Jr.]

Since you already have them, try it and see. Just make sure they are all putting out the same voltage (doesn't have to be exactly the same, but within .2 v should be close enough).

 

I might try a 90 and 74 combo for 4 lanes since I have two of each.  That along with the capacitors should keep an uninterrupted flow of power to the entire track in theory.

[Racer36]

Put the 2 90 amp power supplies on it with a few caps and forget about it. Why overthink it?

[Michael Jr.]

Put the 2 90 amp power supplies on it with a few caps and forget about it. Why overthink it?

Because making it complicated seems so much more fun. lol

[zipper]

On our King with eight Group 7 cars during racing with 14.2V the highest peak I saw on the precision ammeter was 280 A.

[MSwiss]

Pekka,

Intersting, but FWIW, chances he'll ever have 8 G7 cars on the track at once is about nil.

[zipper]

I mean his two 75A and two 90A power supplies is overkill...

[MSwiss]

Agreed.

 

I'm not sure if I would split the the lanes, 4 and 4.

 

I did that originally on my King, because I had 2 distinct different brand, big $$, hi tech power supplies, and I was warned that co-mingling them might confuse the circuitry on one, and shut it off.

 

I also had 2 -8D truck batteries on each 4 lane "side".

 

The point is, in Michael's case, if one failed, it would require a race stoppage to replace it with a spare, vs. everybody just running on half amperage.

[mreibman]

Been there, done that.

 

here's the postcards.

 

2 power supplies, 2 marine bus bars (don't have to be marine, these fit the bill with volt/amp ratings), 1 1 farad capacitor to each track.

King track is 2x 75A power, Hillclimb I think is 1 75A + 1 30A.

 

Both tracks run a smooth 13.4V now.

 

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[Bill Seitz]

Really depends on what type motors you expect to be running. One 90 amp supply might be adequate so long as nothing over a 12 motor or Phoenix / Hawk 9 / Mockingbird, but two 90 amp should handle a full track of anything short of open class. As long as a short run of large wire is used between the supplies, no fancy wiring scheme with buss bars should be necessary. Depending on the regulator circuitry in the power supplies, they may not share a part load identically, but will provide the total current output if the demand arises. I am not convinced capacitors really improve the performance of a good regulated power supply. They could cause more harm than good, but they seem to be the latest trend. If you wish to use ones you have already, simply wire them together in parallel between the power supplies and track. I concur with Mike in not dividing the power source between sets of lanes unless you are seeking to achieve some enormous power capacity and the power source chosen will not play well with more than two power supplies in parallel.

 

I am still of the opinion that the most awesome power source for a slot track is a regulated power supply coupled to a large, low resistance battery array. But that awesome power supply also should be coupled to the track with super wiring and many taps, and the whole project begins to be impractical. My home track is an example. I have 8 taps for 108' with a tap at every other section with the longest run being 17' of 10 gauge and double 10 gauge between the power supply and drivers stations. I occasionally run a 27lite, but most of the time it's 12 arms or less. I have to be really careful because the track can smoke an arm quickly if things are not right.