+ Reply to Thread
Page 1 of 3 1 2 3 LastLast
Results 1 to 10 of 25

Thread: I want to understand batteries

  1. #1
    mnwrr Guest

    Question I want to understand batteries

    Guys, I'm new to RC and I'm still having trouble understanding the basics. Batteries for instance. I read that a great pack for the Mini Inferno is the 42s 9.6v 8-Cell 1100mah NiMH Battery Pack by United RC Xtreme. I d/led Kyosho's manual (VERY skimpy ) and it asks for 6 alkaline or Ni-MH AA batteries.

    AA batteries have normally 1.2 v, so does this mean that I can run the car with 7.2 v up to 9.6 v? What will be the difference in run time and engine output with these two setups?

    And now about amps. RC's pack uses batteries with 1100 mAh. What will be the difference if I used a pack with the same number of sells but with lower (like 850 mAh) or higher amps (I found a 6 cell saddle pack with 3300 mAh - let's say it's a 8 pack just for comparison)? In these two cases, how much run time would I get? Will there be difference power-wise, I mean, will the car be faster or slower?

  2. #2
    pimpsmurf Guest

    Default

    The mini inferno can take up to 8 cells NMHD.

    GP1100 cells offer the high-discharge required for fast motors.
    Larger (heavier) cells would offer longer (slower) runtimes, and most likely offer more than enough current for fast motors. It would definately be slower than 1100 cells because of the added weight, and would have longer runtimes.

    Get a good matched and zapped NMHD pack and you will be happy. Everyone preaches UnitedRC (they never pick up the phone? lol), so that is what I'm getting.

    -JNY

  3. #3
    janniz Guest

    Default

    I'll try to explain with my bad english...
    Basically: the more volts (more cells), the more speed. The more mAh, the longer the runtime. But this also depends on how many Ampere your motor draws while running - faster motors usually draw more Amps. With the GP 1.100 mAh cells and an AON brushless (which draws alot of Amps) you will still get about 10 to 15 minutes of runtime, depending on the surface and the pinion you are using.

    But not all cells can deliver high currents - GPs and some LiPos do, most AA-Batteries dont. If they cant deliver high currents, it results in a dropping voltage which means less speed. So, the more Ampere your motor "needs", the better cells you have to use. The 1.100 GPs are very good and they are what most people who run NiMH are using.

    The number of cells only increases the voltage, not the mAh, because most battery-packs you can buy are wired serial (what is the right word? in german it is "in Serie") not parallel. If you wire them parallel, it increases the mAh but the voltage stays the same.

    And now some native speaker should explain it in a way that can be understood



    Edit: damn, I allways type to slow - but I have to translate while typing
    Last edited by janniz; 10-25-2005 at 08:22 PM. Reason: typing too slow

  4. #4
    DrVonHoSS Guest

    Default

    Quote Originally Posted by janniz
    I'll try to explain with my bad english...
    Basically: the more volts (more cells), the more speed. The more mAh, the longer the runtime. But this also depends on how many Ampere your motor draws while running - faster motors usually draw more Amps. With the GP 1.100 mAh cells and an AON brushless (which draws alot of Amps) you will still get about 10 to 15 minutes of runtime, depending on the surface and the pinion you are using.

    But not all cells can deliver high currents - GPs and some LiPos do, most AA-Batteries dont. If they cant deliver high currents, it results in a dropping voltage which means less speed. So, the more Ampere your motor "needs", the better cells you have to use. The 1.100 GPs are very good and they are what most people who run NiMH are using.

    The number of cells only increases the voltage, not the mAh, because most battery-packs you can buy are wired serial (what is the right word? in german it is "in Serie") not parallel. If you wire them parallel, it increases the mAh but the voltage stays the same.

    And now some native speaker should explain it in a way that can be understood



    Edit: damn, I allways type to slow - but I have to translate while typing
    You know English better than I know German!

    It goes like this..

    More voltage = more power/speed
    More Amp/milliamps = more capacity/runtime

    Another thing to keep in mind... the more cells you use the shorter your runtime will be. For example a 6 cell 1100mah battery will run longer than an 8 cell 1100mah battery. As voltage increases amp draw increases.But dont let that bother you.. its just useless trivia. Ever wonder how a 4 cell 1/12th scale car can run 8 minutes? Thats why.

    Get the 8 cell pack!!

    I know the HALF8 stock electronics can handle 8 cells.. but im not sure if it could handle much more.

  5. #5
    UNITED_RC Guest

    Default

    Quote Originally Posted by pimpsmurf

    Get a good matched and zapped NMHD pack and you will be happy. Everyone preaches UnitedRC (they never pick up the phone? lol), so that is what I'm getting.

    -JNY
    Thats because we are busy building packs....and we have caller id!

    Just kidding with you JNY!

    Email is the BEST way to get ahold of us......

  6. #6
    pimpsmurf Guest

    Default

    Yes, it actually is great as it is.

    Apogee or Kokam are the brands of choise for high-discharge lipos.

    GP1100 cells are pretty much the top dog for 1:18 high-discharge NMHD

    I think you can easilly put 2 Kokam 740 Li-Poly Pack in there, which would have higher constant current discharge (30 amps or so) than the apogee pack, but a lower capacity. 45amp burst! =)

    Capacity is very important however, and the kokam cells would have to be rewired to allow cell matching which is a pain to say the least. I don't believe kokam uses PC boards to wire the packs.

    -JNY

  7. #7
    mnwrr Guest

    Default

    Could I use any battery to make a battery pack? For instance, if I soldered in serial 8 Sony 1.2 v 1200 mAh? I'm having some trouble in finding a saddle 8 pack, so I may have to make my own pack. At least in all the Brazilian Web stores I've been to, it's hard to find 1100 mAh batteries, so I was thinking of using the next closest one, the 1200.
    What do you guys think?

  8. #8
    mnwrr Guest

    Question

    Quote Originally Posted by UNITED_RC
    Thats because we are busy building packs....and we have caller id!

    Just kidding with you JNY!

    Email is the BEST way to get ahold of us......
    Do you ship to Brazil? How much would be S&H for one or two 8 packs?

  9. #9
    DrVonHoSS Guest

    Default

    Ebay is also a great place to look if UnitedRC doesnt ship to Brazil.. but im sure they do.

  10. #10
    Join Date
    Mar 2005
    Location
    Tokyo, Japan
    Posts
    3,049

    Default

    ...UNITED RC ships the whole planet At least they do when they put the soldering iron down

+ Reply to Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts