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Post by GTS on May 4, 2019 10:47:11 GMT -7
This will be a documentation thread of sorts. I finally took the plunge and ordered 2 - 30v/10a variable power supplies off ebay. They have fine & coarse adjustment, the vendor is in the US and I also purchased a "Square Trade" warranty on each of them. I have never done the Square Trade thing before and am hoping I won't have to document anything on that  . The vendor I picked had a reasonable price plus over 12 positive feed backs on the exact same item in the past year. I am supposed to receive them by or before May 13th, so will update this thread at that time. The price wasn't the lowest but definitely on the low end. The total price including "Square Trade" and state sales tax was $129.19 for the two of them. This is a picture of what I ordered, from the vendors ebay ad. I will share the vendor with y'all once I receive them.
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Post by Deleted on May 4, 2019 11:49:03 GMT -7
you should get good use out of that. I have used one myself. clean source so pickup shoes won't get real dirty too soon. hope yours works as well as mine did.
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Post by GTS on May 4, 2019 12:30:56 GMT -7
you should get good use out of that. I have used one myself. clean source so pickup shoes won't get real dirty too soon. hope yours works as well as mine did. Thanks alpink, I appreciate your feed back. That's a confidence booster  . At this time I just couldn't budget two of the the popular Voltec/Mastech power supplies and figured I'd give these a try. Hopefully my journey will help someone else make a choice one way or the other. With my electronics knowledge some what limited, appreciate the comment on the clean power source and shoes getting dirty. The linear power supply I am currently using possibly has been the cause of fast shoe grime build up. I didn't realize dirty power could contribute to that. Thanks for the tip!
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Post by AJR on May 4, 2019 17:15:39 GMT -7
It looks good to me. I think they are all pretty much the same, just with different names on them. Two of those should suit your needs perfectly.
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Post by dave632 on May 8, 2019 16:19:30 GMT -7
Yes Gale that looks like the ones I started with, just a different name on them. I still have one that I use on my test bench, should serve you well. Price has
actually come down since I bought mine some years ago, think I paid 80-90 each for mine.
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Post by GTS on May 9, 2019 17:45:36 GMT -7
The power supply's arrived today, 4 days early . So far, so good! Very pleased!
I ran a car that I had records of from previous runs and it performed the very same with the new power supply.
In case anyone is interested, the vendor I used is this one . This Vendor, no longer is on Ebay, as of 11-11-20. Sorry.
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Post by dave632 on May 9, 2019 20:11:57 GMT -7
Looks good. I would suggest a relay in the future as it takes the load off the switch. You can use a low current switch that way.
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Post by GTS on May 13, 2019 18:18:07 GMT -7
Was able to get the new control center fabricated and wired this weekend, except for a fuse block that will be here tomorrow, hopefully. Will be running 5 amp blade fuses for each lane. The fuse block will attach just to the right of the control center. The momentary switch for a simultaneous start is working good so far, it's rated at 15 amps per pole. More research to do on a relay before acquiring that. Will be doing a lot of testing when I get my cars back from Knoxville as I have a lot of times written down for those cars using the old power supply and 90% of those were recorded using both lanes simultaneously. My goal is to have equality between the two lanes whether running 1 or 2 lanes. It's seemingly been pretty equal but noticed a few things when running 2 - 2.5 ohm cars at the same time. The biggest noticeable improvement has been that I can listen to the stereo at a tolerable volume while racing . No hum from these new power supplies at all  . I also like the idea of being able to use the old power supply being hooked up to my dyno, because of the adjustable voltage . All in all, still very pleased with these new power supplies!
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Post by GTS on May 14, 2019 6:56:39 GMT -7
And a schematic, of sorts, how I wired things up (chose 10 ga wire thru out). Hope it helps someone.
EDIT: There is an updated schematic using a relay here . |
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Post by dave632 on May 14, 2019 9:10:51 GMT -7
Looks good Gale. You will find that the faster cars 2.5 etc will benefit from the dual power supplies more than the
6+ ohm cars but I saw improvement in ET in all classes when I switched to dual power supplies. Not much change in MPH
however. What this also will do is not take power away from one car and give it to another, path of least resistance rule
etc. The 30A supplies I went to only seemed to help the unlimited, they picked up in ET and MPH with some slight ET difference
in 2.5s.
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Post by AJR on May 14, 2019 14:45:44 GMT -7
Gale you have put together one beautiful track! Great attention to detail! Top shelf set up man.....impressive . A very good point that Dave brought up......no more power robbing. Both cars/lanes are independently powered and one car will not rob power from the other. I saw a definite improvement when I went to the dual supplies. Dave and Eagle both run 30amp supplies versus our 10amp. There is definitely a difference there too, but I've found that the ET's are still consistent and relative to each other. My track will run 2 to maybe 4 hundredths off of Daves track consistently depending on the build. When we had races in Colorado, they ran 2 deep cycle batteries that fully charged were at 27v with unlimited amps. Talk about fly......these cars flew up there. That is some gear stripping amperage and plenty gears suffered. But it woke them up. |
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Post by GTS on May 14, 2019 15:20:27 GMT -7
Thanks Dave! Thanks Jeff! You have been my inspiration and I appreciate that!
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Post by GTS on May 22, 2019 12:20:57 GMT -7
Yesterday I wrote down some times for comparison. The times above the line are with the old power supply (15 amps for both lanes) and below the line is the new power supplies with 10 amps available for each lane. Some were very similar and some were an improvement. I opted to not show the Habitual/Eagle times as they are, IMO, irrelevant to the type of power but have more to do with setup & other factors, let's just say it liked Dave's Smoky Mtn. track a whole bunch better than it's home track  . All runs were at 20 vdc and were all run 2 cars at once. Dates and lanes are on the left side. All in all, I think it's better and was worth the transformation.
On another note; I have a relay on order and will be switching to that form of starting around the end of June. I don't really care for the momentary start toggle switch. It works and all, just don't care for it. The relay will be 30 amp DPDT with a 12vdc coil. The coil will be activated using a 2 ohm Parma with a separate 12 volt supply. The relay will replace both toggle switches in the schematic shown above. I'll document that when it happens in my track thread.
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Post by AJR on May 22, 2019 14:00:45 GMT -7
Very cool breakdown Gale. Looks like pretty significant improvements! I like to see the comparative numbers that you and various other racers put up with tuning and track setups. Dave632 does that quite often and it can be very beneficial to tuning and other things. I do however want to bring attention to something. We all have different power and feed setups and although some, like Smoky Mountain are superior, the numbers are relative to one another. My track typically runs .02 -.04 slower than Dave's depending on the build, but it is consistent. I can pretty much count on my cars running faster there but so will everyone else. I'm ok with that because when the cars are here, they will run slightly slower, but so will everyone else's. Every now and then I will have a car that really likes the added amps and will wake up. Some racers may not realize that and that is why I wanted to bring that up. Hope that makes sense.
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Post by GTS on May 22, 2019 16:39:06 GMT -7
Makes perfect sense to me |
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. The vendor I picked had a reasonable price plus over 12 positive feed backs on the exact same item in the past year. I am supposed to receive them by or before May 13th, so will update this thread at that time. The price wasn't the lowest but definitely on the low end. The total price including "Square Trade" and state sales tax was $129.19 for the two of them.
. At this time I just couldn't budget two of the the popular Voltec/Mastech power supplies and figured I'd give these a try. Hopefully my journey will help someone else make a choice one way or the other.
. I also like the idea of being able to use the old power supply being hooked up to my dyno, because of the adjustable voltage 
.