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  1. #1
    RC Enthusiast
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    High output lipo charger questions and recommendations

    I began researching this subject back in August but some family issues cropped-up that postponed this until now. I want to upgrade from nimh to lipo batteries. I will be running these batteries in two Traxxas trucks—a Summit and an EMBE.

    I’ve spent a good bit of the day using the search function on this forum to learn as much about lipo batteries as I can. However, I still have some questions.

    I want to charge two batteries at a time relatively fast—say 45 minutes or less. Based on what I’ve learned, that takes a lot of amps and watts. Per Hughes500Bob, I’ll need to calculate how many watts I’ll be using during charging. Using the popular iCharger 208B/P350 psu combo as an example:

    2S—8.4v x 20 amps max = 168 watts
    3S—12.6v x 20 amps max = 252 watts

    Does that mean if I charge two 2S batteries at once it will take twice as long to do (versus charging just one battery)? Will the amount of watts needed also double (i.e two 2S batteries at 168 watts each = 252 watts required)?

    Another question is how does one determine how long it takes to charge batteries? I know that it takes longer to charge an 8000 mah battery than it does to charge a 5000 mah one. But I have no clue how to determine charge time based on number of batteries being charged, amps, watts, and mah capacity.

    At this point, I have no idea if the 208B and P350 will do what I want. I’ve also considered the upgraded Hyperion Duo + with 300W/300W capability and the 45 amp psu from Max Amps. Or do I need to step up to something like the iCharger 3010B or FMA Cell Lab 8 and a 24V psu?
    Thanks,

    T-MaxxTom

  2. #2
    RC Racer
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    Dec 2009
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    Middlemount Australia
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    159
    I'm no expert but I think I can answer a couple of your questions.

    If you are wanting to charge two batteries at once (2 x 2s or 2 x 3s) you double the charging watts needed for the single battery.

    The first thing to consider is what sort of current your batteries will safely charge at?
    This should be written on the battery somewhere or on spec sheet from the manufacturer, for example "Max charge at 2C". This is worked out the same way as the discarge C rating (Ah rating x 'C' number).
    To ballance charge a Lipo battery in 45mins I would assume you would have to be charging at 2C or maybe better. This is a guess on my part but I know ballance charging my 9000mAh batteries at 1C takes there abouts 1Hr and 15mins.

    Now you know what each battery can safely charge at you need to decide what method of charging you are going to use. You can charge in series or parallel. Parallel charging is alot safer just for the human error aspect but does require a higher amperage charger to acheive the same result. Both series and parallel charging do require adaptors of one sort or another, different adaptors are used for seiries and parallel.
    Parallel charging - As menctioned this is the safer way to charge multiple batteries, requires double the amps of the single battery at the same voltage (8.4V for 2s, 12.6V for 3s)
    Sieries charging - This is the cheaper way to charge mutiple batteries so long as you dont screw up and kill your batteries, burn down the house or shed etc, requires double the voltage (or cell count) same max amps as the single battery.

    Now that you have decided HOW you are going to charge, and what sort of amperage the batteries can safely handle, now you can work out what sort of charger you are looking for. Just note that whatever wattage you come up with the charger will need a little bit more to account for heat losses and what not, then the power supply will need more than the charger for the same reason.

    I can give you more spesific info just let me know. If you want it post here so every one can use it maybe.

    On a personal note the next charger I buy will be an Icharger 3010B or 306B with a power supply from here.

  3. #3
    RC Turnbuckle Jr.
    Join Date
    Jul 2010
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    England
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    5,778
    Quote Originally Posted by T-MaxxTom View Post
    I began researching this subject back in August but some family issues cropped-up that postponed this until now. I want to upgrade from nimh to lipo batteries. I will be running these batteries in two Traxxas trucks—a Summit and an EMBE.

    I’ve spent a good bit of the day using the search function on this forum to learn as much about lipo batteries as I can. However, I still have some questions.

    I want to charge two batteries at a time relatively fast—say 45 minutes or less. Based on what I’ve learned, that takes a lot of amps and watts. Per Hughes500Bob, I’ll need to calculate how many watts I’ll be using during charging. Using the popular iCharger 208B/P350 psu combo as an example:

    2S—8.4v x 20 amps max = 168 watts
    3S—12.6v x 20 amps max = 252 watts

    Does that mean if I charge two 2S batteries at once it will take twice as long to do (versus charging just one battery)? Will the amount of watts needed also double (i.e two 2S batteries at 168 watts each = 252 watts required)?
    Length of time is limited only by how powerful the charger is & how high you can set the charge current ( many are limited to 5amps, so for a 5000mah lipo you will never achieve faster than a 1C / 1 hour charge ). A faster charge than 1C will result in charge time less than one hour, but generally speaking you wont see any improvement in charge time past about 3C as charger will still need to slow down as it enters the 2nd half/ phase of the charge ( constant voltage, where the charge current reduces down to nearly nothing but voltage stays the same ).
    Another question is how does one determine how long it takes to charge batteries? I know that it takes longer to charge an 8000 mah battery than it does to charge a 5000 mah one. But I have no clue how to determine charge time based on number of batteries being charged, amps, watts, and mah capacity.
    Easy formula:

    lipo wattage divided by charger wattage ( assuming a 1C charge rate is set ). For example:

    2s 5000mah lipo = 42watts / 50watt charger = 0.84 hours for a full charge- about 50 minutes.

    4s 5000mah lipo = 84watts/ 50watt charger = 1.68 hours- about an hour & a half for a full charge.

    Formula works for any lipo & charger power rating so long as you stick to a 1c charge rate ( 1c meaning charge current in amps matches the lipo's mah rating / 1000 ( 1amp = 1000mah ). Number of cells & mah capacity wont matter so long as the charger can handle that many cells and has a charge current that atleast equals the lipos capacity- being able to set a higher charge current is where the faster charge time comes into play.
    At this point, I have no idea if the 208B and P350 will do what I want. I’ve also considered the upgraded Hyperion Duo + with 300W/300W capability and the 45 amp psu from Max Amps. Or do I need to step up to something like the iCharger 3010B or FMA Cell Lab 8 and a 24V psu?
    See above, hopefully you will see what spec charger you will need to do a one hour charge; anything with a higher spec ( charge current & wattage specifically ) will result in a faster charge
    Last edited by ArmyofDarkness; 11-21-2010 at 10:33 AM.
    Keeping the Mods busy is my specialty...

  4. #4
    RC Racer
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    Feb 2005
    Location
    Rhode Island
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    148
    I'm no LiPo expert but I use my fair share of LiPo's. About 2 years ago I up-graded to the Hyperion DUO and havent had a single battery it wouldn't charge. This year I invested in the G3 LiPo's from Hyperion and after the cycle's Hyperion wants to be done on the batteries you can up the "c" rate on the charge without damage to the battery. Doesnt matter if I charge 1 or 2 batteries it takes the same amount of time. However the power supply will have to handle twice the amps (charging 2 seperate batts) due to the fact you'll have 2 seperate charge circuts going at the same time. My G3 packs will charge in aprox 25-30 minutes (2-3 & 4s packs all 5000cap) where as my older packs were taking over an hour at the lesser rate. The packs come at a cost but let me tell you they hit really hard , hold a long charge & havent heated up yet after many cycles and they charge up quick. I bought the EX series packs with the 45/90 rating. Just thought I would add this as you were asking about charge times. Another nice thing about it the newer DUO charger is it has a discharger & storage function for Lipo cells. Just hit the storage option instead of charge and it will charge or discharge depending on the current state of the pack to be able to store it at the proper voltage level.
    Running on Visa

  5. #5
    RC Qualifier
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    Mar 2011
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    Toronto, Canada
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    Great article. I couldn't find something in one thread like this in the MERV forums.

  6. #6
    RC Champion
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    May 2009
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    Southeast PA
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    1C charge rate = 1 x capacity of the pack = 60 minutes approx.

    A single 2S 5000 mAh pack at 1C is 8.4 volts x 5 amps = 42 watts

    2C charge rate = 2 x capacity of the pack = 30 minutes approx.

    A single 2S 5000 mAh pack at 2C is 8.4 volts x 10 amps = 84 watts

    "2S—8.4v x 20 amps max = 168 watts"
    ^^^^ Setting for four 2S 5000 mAh packs (in Parallel) at 1C = 60 minutes
    ^^^^ Setting for two 2S 5000 mAh packs (in Parallel) at 2C = 30 minutes

    3S—12.6v x 20 amps max = 252 watts"
    ^^^^ Setting for four 3S 5000 mAh packs (in Parallel) at 1C = 60 minutes
    ^^^^ Setting for two 3S 5000 mAh packs (in Parallel) at 2C = 30 minutes

    http://www.tjinguytech.com/charging-how-tos is an excellent lipo information source!
    I make tap adapters and power harnesses.

  7. #7
    RC Racer
    Join Date
    Mar 2011
    Posts
    213
    I have the iCharger 3010b with two Pb batteries run either in series for parallel depending on what I'm charging while out wherever I'm bashing. At home I have both a Dell laptop power supply for light charging, and two converted 500 watt power supplies for the high amp needs. I'm ready for 10s10p (not that I'll need that anytime soon, but it nice to know I have room to grow). :-)

  8. #8
    RC Racer
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    Jan 2009
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    Montgomery County, MD.
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    I vote for the Hyperion duo! I ebayed one for cheap, and it's amazing! I'm running a homemade power supply which I highly recommend if you have any type of DIY electrical skill. Very cheap and easy! I can charge two 8000mah 2c lipos from used to full in just under an hour.

    On how to build a ps, here is a guide, there are much better out there, I just can't find them. http://www.wikihow.com/Convert-a-Com...b-Power-Supply

    Basically cut the computer connectors off, run the 12v+ to a bind post, and the black grounds to a bind post, done. You can also do and 5 and 3 volt if you so choose.

    The great thing about the Hyperion is it has variable input power, so don't have to be right at 12v, or worry about resistors. mine puts out between 12-13v resting, and 11-12v under load.
    I gots trucks and no idea what I'm doing!

  9. #9
    RC Champion
    Join Date
    Mar 2016
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    1,053
    Quote Originally Posted by BiikeMike View Post
    I vote for the Hyperion duo! I ebayed one for cheap, and it's amazing! I'm running a homemade power supply which I highly recommend if you have any type of DIY electrical skill. Very cheap and easy! I can charge two 8000mah 2c lipos from used to full in just under an hour.

    On how to build a ps, here is a guide, there are much better out there, I just can't find them. http://www.wikihow.com/Convert-a-Com...b-Power-Supply

    Basically cut the computer connectors off, run the 12v+ to a bind post, and the black grounds to a bind post, done. You can also do and 5 and 3 volt if you so choose.

    The great thing about the Hyperion is it has variable input power, so don't have to be right at 12v, or worry about resistors. mine puts out between 12-13v resting, and 11-12v under load.

    If I were to make the PS how do I charge the batteries to it?and how is it going to balance the batteries?

  10. #10
    RC Qualifier
    Join Date
    Feb 2016
    Posts
    569
    Talk about necro. The power supply that he made is to supply the power to the charger. A charger like the Powerlab 6 will need a separate power supply or a car battery. So instead of buying one from a company, you can put together one using old server power supplies.

    I bought my power supply but you get the idea. The one at the bottom is the power supply and the one at the top is the charger.

    https://traxxas.com/forums/showthrea...arging-station
    Last edited by Blkdrgn808; 04-13-2016 at 06:36 PM.

  11. #11
    RC Racer
    Join Date
    Oct 2012
    Posts
    140
    I have the 206b and 350 power supply. I could not be happier with it. Best rc purchase I've very made never had trouble. Able to buy connectors and balance boards for whatever I need.

  12. #12
    RC Racer
    Join Date
    May 2015
    Location
    Sweden
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    117
    I bought the iCharger 406 Duo at the same time I bought my Slash (then later on a Summit) To power the 406 Duo, I got a 2 x 12v 50A powersupply, bought it on eBay. 24v 50A (or 12v 100A) is enough for the most things I toss at my 406 Duo.

    The 406 Duo is a 2 channel 2x40A charger.
    It can without any problem charge my two 7600mAh 2S lipos (for my Summit) in parallel on one channel with 2C = 30 amps, and at the same time it can charge my two 3S 5000mAh lipos (for my Slash) in parallel on the other channel with 2C = 20A. Thats 50A in total = finish charging after only aprox 30 minutes.

    Normally I charge at 1C, but sometimes itīs good to be able to charge faster or put even more batteries in parallel
    I have a small RC helicopter with 9 small 1S 520mAh lipos. I charge them all together in parallel at 2C = 30min. Thats better then going with the stock charger that takes 1,5 hours to charge one or two of these lipos = 7,5 hours in total chargetime for those nine lipos...

    Last edited by Nisse977; 05-02-2016 at 03:46 AM.
    Slash 4x4 MMX +2400kv
    Summit MMX + Xerun Sensored

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