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Thread: 200 amp flier ,caps get hot,

  1. #1
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    Default 200 amp flier ,caps get hot,

    I installed a 200 amp flier ESC in a 48” zelos,runs on 8s ,1100 kv motor,452 prop,not super fast but fun,my problem is the caps that are molded into the end of the ESC get super hot after a 5 minute run.the ESC is cool ,motor is cool,yesterday was my shake down run,the caps were so hot,but water tight,that I soaked paper towels in cold water and put them over the caps to cool them down .i have some castle cap banks ,by adding one of those would that help with the load these?or did I buy too small of an ESC for what I’m doing with this big of a boat?
    The only thing I know about caps is what I read here ,thank you,

  2. #2
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    What batteries? How old and ‘C’ rating? How much wire and how many connectors are in line?
    Old batteries may give voltage issues that cause heat in caps. As will too much wire length.
    Also possibly driving style, a lot of ‘off/on’ throttle?

  3. #3
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    SMC 5000 mah,150 c,4 s,bought them 8 months ago for this boat,I started with just 2 in series for 8 s,but one puffed on the first run so I started running 2 on each side in series for 8 s on each side then connected each side in parallel,so the batteries don’t get worked so hard ,but I’m guitly of pretty much all you listed,lots of connectors,wire,on off driving,on the 2 nd run I did some medium laps then some fast laps and the caps did better ,of the 4 lipos , 3 will re charge in 35 minutes at 5 amps but the 4 th will take over 100 minutes to charge and balance ,I’m thinking this one got damaged ,my run time is only 5 minutes with all 4 lipos in the boat ,not running full out all the time ,,,,thanks for the tips ,

  4. #4
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    Yup that one lipo would not be helping the cause. I hate it when that happens. The varying voltages and loads from off/ on driving does heat them up. I am also guilty of this at times. It’s really no biggie until you get to max’img a system and then you’ll notice it. If you are at that point try to eliminate some of the wire/connectors. A more efficient power delivery always helps.

  5. #5
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    I’ll work on that,thanks for the help,

  6. #6
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    Make your own cap bank 9 63v 1000uf caps will help. Positive to positive in a line than tie that to the Plus side of your battery Same on the negative side of the caps too.

  7. #7
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    I checked the store here and didn’t see those caps,I think that might be a bit ambitious for me,how about using a castle cap bank?I have some of those extra,thanks for the advice tho ,I appreciate it ,

  8. #8
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    I think the Castle bank has 4 1000uf caps that would work too. Make sure the voltage rating of the caps is higher then battery voltage...

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    You can always go to ebay and find caps any size you want... Caps are pretty cheap.....

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    I need the board and the end post ,I looked at a couple that are pre built and it seems the boards have a way of connecting the caps ,there are no visable leads ,but the castle ones will work on 8 s so I’ll try those ,plus it’s 112* down here,way to hot to work in my shop,but I’d like to learn how to make a cap bank ,thanks ,

  11. #11
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    Quote Originally Posted by Gofast12s View Post
    Make your own cap bank 9 63v 1000uf caps will help. Positive to positive in a line than tie that to the Plus side of your battery Same on the negative side of the caps too.
    Are you saying parallel or series?

    Screenshot_20180417-192845.jpg like this or

    Screenshot_20180417-191457.jpg like this

  12. #12
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    You wire caps in parallel, not series.

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    You then solder them to the esc wires as close to the esc as possible.

  14. #14
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    So like this [ATTACH=CONFIG]
    Attached Images Attached Images

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    Yes

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    Quote Originally Posted by Prodrvr View Post
    Yes

    ok just for argument sake why not parallel?

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    Quote Originally Posted by Speedfreek View Post

    ok just for argument sake why not parallel?
    Did I give the wrong answer? It's supposed to be wired in parallel.

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    Quote Originally Posted by Prodrvr View Post
    Did I give the wrong answer? It's supposed to be wired in parallel.
    ok

  19. #19
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    I would make up a cap bank of a lot of smaller caps over a few large caps.

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    Quote Originally Posted by Prodrvr View Post
    I would make up a cap bank of a lot of smaller caps over a few large caps.
    Ok, what would you recommend for a 8S set up 2x/4S per side 2x ESC about 360 Amp draw motor TP 5850 1400kv ?
    I have 16x ZLH 63V 1200UF and 20x ZLH 50V 820UF caps.
    Sorry for the hijack

  21. #21
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    The ZLH 820 caps...10 of them to make a pack. I happened to just get in the ZLH 820 63v caps that I gotta get soldering on.

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    Quote Originally Posted by Speedfreek View Post
    Are you saying parallel or series?

    Screenshot_20180417-192845.jpg like this or

    Screenshot_20180417-191457.jpg like this
    Both of these schematics are series-parallel combination. It’s used on high volt, 10s and higher. Most usually just wire all caps in parallel.

  24. #24
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    Quote Originally Posted by CraigP View Post
    Both of these schematics are series-parallel combination. It’s used on high volt, 10s and higher. Most usually just wire all caps in parallel.
    Thanks Craig so like this for up to 8S
    20180118_152648.jpg

  25. #25
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    That looks like a good cap Bank! Make sure you use a good quality cap. If you search for cap banks on the site, I have given part numbers and vendor to get good ones. The one I listed is for 8s... if I recall correctly, it’s 3600uF at 50V with the highest rated ripple current and temp I could find. Spent some time on this... Hang on, I think I got a bag of them, yes, found it! Here’s the info:

    Vendor: Mouser.com
    P/N: EGPD500ELL362MM40H

    Mouser has a spec sheet if you want to learn about that... I use 3 in parallel for 8s to 150A average current. Use 5 for 200A.

  26. #26
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    I thought having more of a smaller uF cap is better than just a few very large uF caps?

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    It depends on the quality and the ripple current rating. A bunch of lower quality caps is not as good as fewer high quality caps. Three of the caps I listed will decouple 50A of ripple current. Don’t confuse ripple current magnitude with motor current. What you are decoupling is the wire power feeds (inductance) and the resistance of wire, solder joints and connectors.

    If your getting ‘just any cap’ at your local surplus shop, then you really don’t know what you’re putting in there. Also, keep in mind, electrolytic caps dry out over time, so I would never buy a surplus cap for any of these boats! This is an extremely harsh electrical demand on the caps! You need to respect that highly...

  28. #28
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    I just got 10 Rubycon ZLH 820uF 63v caps that I was just gonna solder up. Are the ones you listed better? If so, I'll order a bunch.

  29. #29
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    But are 50v caps good for 12s?

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    Quote Originally Posted by Prodrvr View Post
    I just got 10 Rubycon ZLH 820uF 63v caps that I was just gonna solder up. Are the ones you listed better? If so, I'll order a bunch.
    The Rubycon cap has 5 times higher impedance! Just looked it up on Digi-Key site. It would take 5 of those caps to equal just one of the caps I referenced... BTW, Rubycon has a low quality reputation, made for high volume, general purpose input rectifier circuits...

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