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  1. #1
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    Questions about charging my first 2S (traxxas) batteries with my iCharger 206b

    I've only charged 1S small helicopter batteries with my iCharger 206b this far and just got to 2S traxxas batteries in the mail today for my merv and mini-summit. Here we go:

    1) I usually charge my little heli batteries at 1c, so 0.3 for a 300mah battery say. I know I choose 2 cell and I connect the balance plug, but what charge rate should I pick. I don't have the charger in front of me to try it so I may be skipping something, but I don't want to mess anything up.

    2) it's ok to run the batteries down until I notice it slowing/stopping right? Do I need to use to use the charger to put this in storage mode every time when I'm finished if I use them once a week or so? Pick 2 cell and storage and it does the rest right (just connect both plugs).

    3) coming from NIMH, do i have to change any settings on the car to run lipo, i'll dig up the manual but i think so right?

    What else should I be asking?

    Thanks a bunch!!


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    Last edited by Eddie NYC; 01-28-2013 at 08:15 PM.
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  2. #2
    RC Turnbuckle Jr. JimmyNeutron's Avatar
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    1) 1C is the industry standard for charging batteries...

    To calculate the charge rate of your pack
    mAh x charge C rate / 1000 = charge amps
    For example:
    A 2200mah 20-40C pack that states a 2C charge rate.
    2,200 x 2 / 1000 = 4.4
    This battery pack can be charged at 4.4 amps.
    - Please note that if no charge C rate is stated, 1C is standard.

    2) NO... do not run until the RC slows. USE A LVA!! They are less than $5 and will alarm when the cells reach a certain voltage. Over discharging a LiPo is DANGEROUS... not only to your RC but to YOU and those around you.

    I suggest storage dis-charging if the pack is going to be left for more than 30 hours or so. I suggest storage charging immediately after a run.

    3) If your ESC has LVD or Low Voltage Detection, be sure to activate it. If it does not, I suggest ordering a Low Voltage Alarm and possibly a 2S balance extension.
    Whatever it is I just typed... could be wrong.

  3. #3
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    1. How many mah is the pack you're charging? Divide that by 1000. To charge a 5000 mah pack, you need 5 amps. A 3200 mah battery needs 3.2 amps...and so on.

    2-3. You need to have low voltage detection ENABLED. Turn on the ESC and wait for it to arm as normal. The LED should be green for LiPos. If the light is RED, low voltage detection is DISabled...do not use LiPos until you press and HOLD the ESC button for 10 seconds! After that, the light should turn green, meaning low voltage detection is enabled. Green = "go" for LiPos.

    P.S. -- You don't have to put your LiPos into storage unless they're going to be sitting disused for several months. To be totally honest, I really don't even use storage mode...I just balance my LiPos every time I charge and keep them from extreme temps. They're no worse for the wear...
    Make it idiot-proof and along comes a better idiot

  4. #4
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    Quote Originally Posted by zippogeek View Post
    . I just balance my LiPos every time I charge and keep them from extreme temps. They're no worse for the wear...
    Thanks. With my charger it should automatically balance once I choose 2 cell right? I just plug in the second cable? I need to grab that manual as well....


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  5. #5
    RC Turnbuckle Jr. JimmyNeutron's Avatar
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    No... you have to select balance charge.

    Storage is important... it is proven to be extremely beneficial.
    Whatever it is I just typed... could be wrong.

  6. #6
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    So this looks to be the right charging setup for the traxxas 2s 2200 lipos right (not charging now so not in a lipo bag for the pic)?



    And sorry about this but i have 2 other questions that should wrap this up:

    1). if I use storage mode you don't connect the balancing cable correct?

    2) after i charge the batteries how long can they sit before i use them before they start to lose a charge??

    No one around does RC and I've never used a 2S before. I'm use to quick charges with my blade **** and mcpx's.

    Thanks again!
    Last edited by Eddie NYC; 01-28-2013 at 11:53 PM.
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  7. #7
    RC Turnbuckle Jr. JimmyNeutron's Avatar
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    If the charger needs the balance cable, it will ask for it. That is a nice thing about good chargers... hard to mess it up!

    That is the correct setup... 2.2 amps due to it being a 2200mAh.

    I have had a set of speed run only 3S in the fridge for 8 months now... still at 3.85v/cell.
    Whatever it is I just typed... could be wrong.

  8. #8
    RC Turnbuckle Jr. mike-susieq1's Avatar
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    SPC started selling the low voltage alarms maybe traxxas will sometime since they are making lipos, chargers now.
    http://www.specpointbatteries.com/in...?productID=154
    DEU 8:18 ESV

  9. #9
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    Quote Originally Posted by Jimmie Neutron View Post

    I have had a set of speed run only 3S in the fridge for 8 months now... still at 3.85v/cell.
    Thanks! Is 3.85v charged and ready for use or sitting in storage mode? sorry about the dumb questions.


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  10. #10
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    Quote Originally Posted by Jimmie Neutron View Post
    Storage is important... it is proven to be extremely beneficial.
    In that case, +1 what Jimmie says. He knows a lot more than me. I'll have to consider this storage thing a little more...
    Make it idiot-proof and along comes a better idiot

  11. #11
    RC Turnbuckle Jr. JimmyNeutron's Avatar
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    Without getting really technical, storage stresses the cells out less... less stress = longer life span.

    Eddie:
    I am not trying to blow your mind or stop you from asking questions... questions are good!
    I did a LiPo write up a while back and saved it. It is lengthy, so take it a little at a time if you have to... but this will centralize a lot of LiPo information and might answer future questions not only for you, but all of those that read it.

    ___________________________
    I wrote this a while back... but most of it applies here too:

    I apologize in advance for the length of this write up. However, I feel that it is important to have as much factual LiPo information as possible and to have it all in one location.
    That being said...

    LiPo 101
    now in session


    Rules
    1) NEVER discharge below 3v/cell
    2) NEVER charge above 4.2v/cell
    3) NEVER puncture your pack
    4) NEVER short out your pack
    5) NEVER use a pack that has puffed
    6) NEVER charge unattended
    7) NEVER charge at a higher C rate than recommended
    8) NEVER use a pack that has been over charged/discharged
    9) ALWAYS check cell voltage before connecting your pack to anything
    10) ALWAYS keep your LiPo pack well balanced

    To calculate the charge rate of your pack
    mAh x charge C rate / 1000 = charge amps
    For example:
    A 2200mah 20-40C pack that states a 2C charge rate.
    2,200 x 2 / 1000 = 4.4
    This battery pack can be charged at 4.4 amps.
    - Please note that if no charge C rate is stated, 1C is standard.

    To calculate the constant discharge rate of your pack
    mAh x minimum discharge C rate / 1,000 = available amps
    For example:
    The same 2200mah 20-40C pack.
    2,200 x 20 / 1000 = 44
    This battery pack can consistently provide up to 44 amps.

    To calculate the peak/burst discharge rate of your pack
    mAh x maximum discharge C rate / 1,000 = available amps
    For example:
    Again, the same 2200mah 20-40C pack.
    2,200 x 40 / 1000 = 88
    This battery pack can provide a peak discharge rate of up to 88 amps.
    Peak rates are limited in time... unfortunately, this amount of time does not have an industry standard. This is how a lot of inflated discharge ratings can be claimed. In my experience, honest retailers/manufactures of packs will list the constant discharge rating along with the burst discharge rating and not only the burst rating.

    Ratings
    When setting up your power system for your RC, make sure that the lower discharge C rate matches or beats the continuous amperage rating of the ESC. I try to beat it by at least 10%. This practice will provide you the most out of your system and it will also keep your batteries from working too hard. A LiPo should NEVER be warm... during use or charging. If it is, you are abusing the pack. Also, the less your pack has to work the longer it will last.


    Parallel
    Running two LiPo's in parallel will double run time and also your available amperage... which is handy for high demand systems. Some misinformation I have read about the discharge C rating of packs in parallel is that the rating of the pack doubles. This is not the case. The C-rating of a battery pack is a fixed parameter of that pack; well actually it is the cells within the pack that have the C rating. Connecting two packs in parallel does not change either pack as they still have the same specifications, however it does create a battery "system" with twice the effective C rating. The packs are the same, but the parallel system is now theoretically capable of discharging at twice the Amp rate. This is much like the cumulative capacity available when connecting two packs in parallel.
    The packs ran in parallel MUST be of the same cell count and should be the same age, capacity, and brand.

    Series
    Running two LiPo's in series will double voltage, therefore nearly doubling the speed of your RC. Capacity remains the same. The two packs ran in series MUST have the same capacity and discharge rate. Also, they should be of the same age and brand.
    Be prepared to gear down when increasing voltage on your power system.

    Charging
    There are many charging options out there... it can get really confusing really fast. The best advise I can give is to get the absolute best charger you can afford and to ask before you purchase. Your charge system is the backbone of your electric RC hobby, treat it as such. RC's will come and go, but your charge system will remain.

    The following features are what I consider to be the absolute bare minimum for a charger... balance charging and a storage charge/discharge feature. If the charger cannot perform these tasks, look for another charger. If you are going to be charging multiple LiPo's at the same time or 10th scale or larger packs, I recommend getting a charger that is capable of at least 10 amps or more. Also, ANY half-decent charger can charge multiple LiPo's at a time. It does not require a dual or multi-charger to perform such a task. It only requires the right support equipment... such as a ParaBoard, which I use.

    Storage
    Storage voltage is 3.85v/cell. This voltage is the only voltage that is not super critical for LiPo. Anywhere between 3.5-4v/cell is considered to be acceptable for storage.
    I suggest putting a full pack to storage voltage if it is not going to be used within 30 hours or so. The longer a pack is at full capacity, the shorter its lifespan will be.
    I also suggest bringing a pack up to storage voltage after a run. When a LiPo's voltage lowers to a certain point, they begin to loose their voltage quickly. I would hate to see you loose a pack (or more) due to not charging up within a few hours after a run.
    For long term storage; I bring my packs to storage voltage, seal them in an airtight container, and stick them in the refrigerator. As I type this, I have had my "speed" set of 3S packs in the fridge for over 8 months at storage voltage... I check them monthly and they are still at 3.85v/cell. Almost makes me regret buying them. lol



    Here is what I have done...
    this information might help with your decision

    I use inexpensive batteries.
    I have found them to be very reliable, extremely cost effective, and they have been proven to be under-rated; usually providing more mAh and a higher discharge C rate than stated on the pack. SPC is a great brand that under promises and over delivers. There are others that claim extreme discharge ratings that are simply impossible with the technology that is available.

    I use an iCharger 206B.
    When I purchased the charger, I thought I would never use all 20 amps of its capability. Well, now I rarely charge at anything less than 20 amps lol. I have even considered selling it to get more amperage! I have performed hundreds of charge cycles with this charger and it handles the task without a single issue.
    I highly recommend any charger in the iCharger line.

    I built my own power supply.
    I have ~$30 into my 24v 75a 1800watt power supply.
    Sounds complicated, but it really is not that difficult. If you go this route, you are going to want a server power supply as they do not drop voltage when you are pulling amperage like a standard ATX PC power supply.
    You can also purchase these pre-built at a very reasonable price.

    I hope this information helps!!

    Here are some links to some more:
    http://traxxas.com/forums/showthread...rger-vs-cooker
    http://traxxas.com/forums/showthread...charging-setup
    http://traxxas.com/forums/showthread...ply-Conversion

    EDIT:
    I added the storage section
    Last edited by JimmyNeutron; 01-29-2013 at 10:36 AM.
    Whatever it is I just typed... could be wrong.

  12. #12
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    EXCELLENT RESOURCE! Thanks.
    Make it idiot-proof and along comes a better idiot

  13. #13
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    Thank you!!
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