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  1. #1
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    NIMH vs Lipo Battery

    Stock slash goes 40 mph with incl NIMH battery....It seems like running 3S lipo batteries causes heat issues. Running 2S lipo batteries, the truck also goes 40mph. Is there an advantage to running 2S lipos or why not just use the NIMH battery? Also maxx amps has a 8 or 9 cell NIMH battery that will push the truck to 60mph. Will that cause heat issues?

  2. #2
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    A fully charged 2S lipo will give you 8.4v and weigh considerably less then a nimh pack. On top of that they last longer because a Lipo doesn't loose it's power as you run the battery down, it stays consistent until the battery hits a certain level and then drops dramatically. A nimh battery has a consistently less power as you run it down, so a Lipo gives you a longer quality run time. Also Lipos can come off the truck and be put right back on a charger so you can run again sooner, nimhs get hot and need a rest after being run.

    I've never used one of those extra big nimh packs before but I doubt any of them can ompete with a 3S lipo pushing 11.1v. Nimh cells are heavy, more cells more weight for not a lot of power, lipo cells are light and have more power.
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  3. #3
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    Will I have problems on 3S?
    Will I benefit from 45c lipos on this or should I save some money and just get a 25c battery

  4. #4
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    A good quality, matched, 6-cell Nimh pack like the EnerG4600s's, will hold voltage just as well as a 2S LiPo pack of similar capacity. The part about LiPo's not losing power as the pack runs down is not true and is just an internet myth that will not die.

  5. #5
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    Quote Originally Posted by Jakey
    A good quality, matched, 6-cell Nimh pack like the EnerG4600s's, will hold voltage just as well as a 2S LiPo pack of similar capacity. The part about LiPo's not losing power as the pack runs down is not true and is just an internet myth that will not die.
    I have older GP3300 6cell packs getting around 9.6volts fully charged. If the Energ4600 can hold a charge wouldn't the higher voltage gain surpass the weight lost for a normal 2s lipo when it comes to proformance?
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    There is no myth. If you have ever run a lipo pack you would know that there is no drop or loss in performance until the battery is close to the low voltage point. Everyone on this and every rc forum could tell you that. That is one of the great benefits of a lipo. Longer run times and consistent power. I have both types of batteries. If you don't believe this, ask to watch someone run both and you will see for yourself. Lipos are cheaper that the high voltage nimh packs. That is another added benefit.
    Last edited by El Sob; 08-28-2010 at 08:20 AM.

  7. #7
    RC Turnbuckle Jr. Emaxx2.0's Avatar
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    Quote Originally Posted by El Sob
    There is no rumor. If you have ever run a lipo pack you would know that there is no drop or loss in performance until the battery is close to the low voltage point. Everyone on this and every rc forum could tell you that. That is one of the great benefits of a lipo. Longer run times and consistent power.
    . Jakey does more then just run lipos.
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  8. #8
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    Just from my experience, I raced my friend around the track (he has Traxxas 8.4 nimh) and I had 2s with 45c. After the first lap he wasn't getting as much zip for jumps and I still had the same zip lap after lap until my lvc kicked in. I don't have any data just that this is my experience with nimh vs lipo. Hope that helps.

  9. #9
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    Quote Originally Posted by El Sob
    There is no rumor. If you have ever run a lipo pack you would know that there is no drop or loss in performance until the battery is close to the low voltage point. Everyone on this and every rc forum could tell you that. That is one of the great benefits of a lipo. Longer run times and consistent power.
    Uh, OK, sure and the world used to be flat too. Why? Because everyone knew it was, therefore it had to be true.

    It is physically IMPOSSIBLE for a battery pack, any battery pack, to hold constant voltage/power while under load. For anyone to say so, they are just perpetuating that ongoing internet myth, which does nothing to help those who are looking for help with battery questions.

    Quote Originally Posted by ksoul
    Just from my experience, I raced my friend around the track (he has Traxxas 8.4 nimh) and I had 2s with 45c. After the first lap he wasn't getting as much zip for jumps and I still had the same zip lap after lap until my lvc kicked in. I don't have any data just that this is my experience with nimh vs lipo. Hope that helps.
    Fair enough, however I am talking about a matched Nimh pack, not an unmatched stick pack. And yes, whether or not you perceived it, your LiPo did drop off in potential power as it was being used. I race nearly every weekend and run at least one RC vehicle nearly every day and I can easily tell when a LiPo pack is fully charged or partially charged. There is a significant difference in performance as a LiPo pack drops through its discharge cycle.

    For what is worth, if your friends Nimh pack drops off that much in power and so soon into the discharge cycle, it most likely has one or more damaged cells. These cells were probably damagd from over-discharging, running the vehicle and pack down until it barely moved and/or stopped. Do this just one time and the pack will behave exactly as you described.
    Last edited by cooleocool; 08-28-2010 at 10:57 PM. Reason: merge

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    I would definitely be open to try a 7 cell matched pack, if someone would send me one :-)

  11. #11
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    Quote Originally Posted by Emaxx2.0
    I have older GP3300 6cell packs getting around 9.6volts fully charged. If the Energ4600 can hold a charge wouldn't the higher voltage gain surpass the weight lost for a normal 2s lipo when it comes to proformance?
    To answer you question you first have to define performance. Do you mean straight line acceleration, top speed or all around handling and power on a track?

    Quote Originally Posted by ksoul
    I would definitely be open to try a 7 cell matched pack, if someone would send me one :-)
    I'm sure many would agree with you.

    For the OP, try a 5000mAh/2S pack with a true 20C rating or higher. I run a 5000mAh/20C/2S pack in my Slash 4x4 with very good results. You will really like how the truck handles with the reduced weight of LiPo.
    Last edited by cooleocool; 08-28-2010 at 10:58 PM. Reason: merge

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    ok, I am relatively new to LiPo but this is what I found so far...

    My 4X4 UE did go much faster with a 5200mAh 2S 40C than the stock NiMH and almost double the runtime! I believe it's because of lighter weight and the 40C rating.
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  13. #13
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    yes good nimhs hold their voltage much like a lipo. but what most people dont consider is how many amps the nimh will put out compared to the lipo. so IMO the fights over nimh and lipo are stupid because they are all about how fast the battery drops off. which doesnt really matter. what matters is how many amps that nimh can give. and every nimh i have ever put in my 4x4 has had a hard time giving it what it needs which makes it very slow. it also makes the battery very hot, and that means you are pushing the battery to its limits. which means nimh is out of date and soon will be a thing of the past. just like nicd batteries and brushed motors.

    and im sure thats the same reason jakey always recommends lipo to people who are thinking about it. lipos are just better. and like jakey has said, you can most certainly tell between a freshly charged lipo and a half dead one.
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  14. #14
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    The difference in drop-off between a "normal" Nimh pack and a good one is huge.
    My venom 3300 starts to drop off almost instantly and is only good for bashing.
    My stock traxxas 3000 packs drop off noticably after about 8 minutes of the 20 they run for, and lose power steadily after that.
    My Reedy pack loses very little speed or acceleration until about 12 minutes of the 25 it runs for, and even then it's a slow small drop until at 25 minutes it suddenly doesn't have any oomph.
    When I borrowed a balanced pack it was consistant until about 15 minutes of it's 25 minute run time, and again it was also a slow small drop until it suddenly lacked power.
    With both of the last two batteries I could actually drive another 10 minutes or so, but with such reduced power that the truck is useless on the track.

    What that all means is that for 6 minute qualifiers and 8 minute mains the difference between the LIPO guys and my best batteries is really only the weight and ease of re-charging. Last race I went to I had the fourth fastest lap time of all 1/10 4x4 SC trucks in any class, and three of those four had much hotter motors.

    It's actually at practice that the difference is more obvious, where my run-time is 5-10 minutes less than the guys with good LIPOs (but the same as cheap ones) and they can get by with two batts. By the time they check the truck over and let the motor cool the dead battery is ready to go onto charge, but I need to leave my Nimh batts sit for 45 minutes before they are cool enough to recharge.

    Quote Originally Posted by SF1688
    ok, I am relatively new to LiPo but this is what I found so far...

    My 4X4 UE did go much faster with a 5200mAh 2S 40C than the stock NiMH and almost double the runtime! I believe it's because of lighter weight and the 40C rating.
    The longer run time is mostly the higher Mah rating. 3000 to 5200 is nearly double the reserve capacity, hence nearly double the run time. The 40C means the motor always has as much power as it wants, which greatly improves acceleration and helps a bit with top-end.
    Last edited by cooleocool; 08-28-2010 at 10:58 PM. Reason: merge

  15. #15
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    There is little in common between LiPo and NiMH other than the fact they both store electricity!

    LiPos start fully charged with 4.2V per cell and most LVCs cut in at about 3.2-3.4 V per cell (certainly all 3 stock ESCs leave the battery at about 6.6V at start of charge). This means that at the start of a run you will be putting 8.4V into your car and at the end 6.7V. As for a given resistance power over a resistive load is proportional to the square of the voltage you would imagine at the end of a run just before the LVC cuts in you will have about 2/3 of the power at the start. However this doesn't tell the full story. With a newly charged LiPo the voltage is 4.2V though this drops rapidly to between 3.6V and 4V (depending on the load being applied, typical high loads applied by RC cars will drop this to around 3.7V) within the first 5% of capacity. With most RC cars a typical load will be in the vicinity of 20-30 Amps or about 4-8C for typically used batteries, and hence this 5% will only be about the first minute of use. for the next 70% of the capacity there is little further voltage drop, probably in part due to higher mobility of charged particles as the battery warms up partly counteracting the voltage drop with decreased ion concentrations. This is Why a LiPo gives similar performance until it hits the last 10-20% of capacity. Because of the very low internal resistance of a LiPo the voltage remains about 3.7V even under very high loads.






    With an NiMH battery you have a similar discharge curve though there is a slower drop at the start of the cycle, taking about 15% of capacity to fall to about 1.2V/cell and also an earlier drop off in voltage near the end, tailing off after about 70% used. Hence the gradual decline in performance is somewhat more noticeable.

    Note that a 6 cell NiMH will have a nominal voltage around 7.2V for most of the discharge cycle and a 2s LiPo about 7.4V - minimal difference - so why does a 2s LiPo perform so much better - about 50%?

    The answer lies in internal resistance of the battery. Even the very worst 2s LiPos have extremely low internal resistance, around 0.01-0.02 ohms - so even supplying 60 amps the voltage drop will only be about 1V - it can supply 60 amps at 6.4V output.

    There is great variation in internal resistance in NiMH batteries though the best NiMH batteries have 2-3 times the internal resistance of LiPo batteries. and hence at 60A (I doubt any NiMH batteries can sustain this rate due to heat issues) draw the voltage drop will be 2V for a very good NiMH pack and about 3V for a mediocre one. Hence the 7.2V pack is supplying 4.2-5.2V compared to the LiPo at 6.2V. A good 7 cell NiMh would be supplying about 6.2V and hence would be competitive with a 2s LiPo though the extra weight vs LiPo would likely make the vehicle slower.

    This is idealised and in practice the voltage drop in the NiMH would limit the current that can be supplied and a more realistic set of figure would be 2s LiPo: 60A 6.4V, very good quality 6-cell NiMH: 45A 5.6V, very good quality 7-cell NiMH 60A 6.6V.

    Poor quality NiMH batteries will not even come close to the 2s LiPo and will get very hot.

    As a note - the lowest internal resistance batteries are the NiCD batteries - with only the best LiPos nearing their internal resistance - and hence NiCD can be safely be charged at very high rates because of this - just a shame the capacity of NiCD is so low.

    Note that this voltage drop times the current is turned into heat in the batteries so it is no wonder that NiMH batteries get so hot during use in RC cars.

  16. #16
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    Quote Originally Posted by El Sob
    There is no myth. If you have ever run a lipo pack you would know that there is no drop or loss in performance until the battery is close to the low voltage point. Everyone on this and every rc forum could tell you that. That is one of the great benefits of a lipo. Longer run times and consistent power. I have both types of batteries. If you don't believe this, ask to watch someone run both and you will see for yourself. Lipos are cheaper that the high voltage nimh packs. That is another added benefit.

    Hate to bring the bad news but lipo's DO drop off. Just because everybody says so doesn't mean its true. Take a 8.4v fully charged lipo and run it and test it every 5 minutes. It consistantly drops off from 8.4 to the point of wherever your LVC kicks in. Granted it is a very small dropoff unlike nimh, but it is there. And there IS a loss in performance, small, but it is there also.

  17. #17
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    I only wish I would have been advised to run lipo from the start. With our 3 pedes and slash 4x4 I bought 6 extra TRX series 4 4200 mah batts and wasted my $. I don't race because I would not be competitive against everyone since they all run lipo. I'm looking forward to switch to lipo soon...
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  18. #18
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    Quote Originally Posted by Mud Puppy
    The longer run time is mostly the higher Mah rating. 3000 to 5200 is nearly double the reserve capacity, hence nearly double the run time. The 40C means the motor always has as much power as it wants, which greatly improves acceleration and helps a bit with top-end.
    mine came with 4200mAh's...
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  19. #19
    RC Turnbuckle Jr. El Sob's Avatar
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    Quote Originally Posted by wjmiller3
    Hate to bring the bad news but lipo's DO drop off. Just because everybody says so doesn't mean its true. Take a 8.4v fully charged lipo and run it and test it every 5 minutes. It consistantly drops off from 8.4 to the point of wherever your LVC kicks in. Granted it is a very small dropoff unlike nimh, but it is there. And there IS a loss in performance, small, but it is there also.
    Ok I will agree but koolkat put it in the terms that no one can argue. I am sure you can do an internet search and find the same information. Do you run lipo batteries? if you do not borrow one from a friend. I think you will be surprised in their performance. I have both. I prefer the lipo. It is more efficient. But I am done with this argument. Buy the battery you like best.
    Last edited by El Sob; 08-28-2010 at 12:54 PM.

  20. #20
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    Quote Originally Posted by koolkat
    There is little in common between LiPo and NiMH other than the fact they both store electricity!

    LiPos start fully charged with 4.2V per cell and most LVCs cut in at about 3.2-3.4 V per cell (certainly all 3 stock ESCs leave the battery at about 6.6V at start of charge). This means that at the start of a run you will be putting 8.4V into your car and at the end 6.7V. As for a given resistance power over a resistive load is proportional to the square of the voltage you would imagine at the end of a run just before the LVC cuts in you will have about 2/3 of the power at the start. However this doesn't tell the full story. With a newly charged LiPo the voltage is 4.2V though this drops rapidly to between 3.6V and 4V (depending on the load being applied, typical high loads applied by RC cars will drop this to around 3.7V) within the first 5% of capacity. With most RC cars a typical load will be in the vicinity of 20-30 Amps or about 4-8C for typically used batteries, and hence this 5% will only be about the first minute of use. for the next 70% of the capacity there is little further voltage drop, probably in part due to higher mobility of charged particles as the battery warms up partly counteracting the voltage drop with decreased ion concentrations. This is Why a LiPo gives similar performance until it hits the last 10-20% of capacity. Because of the very low internal resistance of a LiPo the voltage remains about 3.7V even under very high loads.






    With an NiMH battery you have a similar discharge curve though there is a slower drop at the start of the cycle, taking about 15% of capacity to fall to about 1.2V/cell and also an earlier drop off in voltage near the end, tailing off after about 70% used. Hence the gradual decline in performance is somewhat more noticeable.

    Note that a 6 cell NiMH will have a nominal voltage around 7.2V for most of the discharge cycle and a 2s LiPo about 7.4V - minimal difference - so why does a 2s LiPo perform so much better - about 50%?

    The answer lies in internal resistance of the battery. Even the very worst 2s LiPos have extremely low internal resistance, around 0.01-0.02 ohms - so even supplying 60 amps the voltage drop will only be about 1V - it can supply 60 amps at 6.4V output.

    There is great variation in internal resistance in NiMH batteries though the best NiMH batteries have 2-3 times the internal resistance of LiPo batteries. and hence at 60A (I doubt any NiMH batteries can sustain this rate due to heat issues) draw the voltage drop will be 2V for a very good NiMH pack and about 3V for a mediocre one. Hence the 7.2V pack is supplying 4.2-5.2V compared to the LiPo at 6.2V. A good 7 cell NiMh would be supplying about 6.2V and hence would be competitive with a 2s LiPo though the extra weight vs LiPo would likely make the vehicle slower.

    This is idealised and in practice the voltage drop in the NiMH would limit the current that can be supplied and a more realistic set of figure would be 2s LiPo: 60A 6.4V, very good quality 6-cell NiMH: 45A 5.6V, very good quality 7-cell NiMH 60A 6.6V.

    Poor quality NiMH batteries will not even come close to the 2s LiPo and will get very hot.

    As a note - the lowest internal resistance batteries are the NiCD batteries - with only the best LiPos nearing their internal resistance - and hence NiCD can be safely be charged at very high rates because of this - just a shame the capacity of NiCD is so low.

    Note that this voltage drop times the current is turned into heat in the batteries so it is no wonder that NiMH batteries get so hot during use in RC cars.
    First I want to say, as I have in numerous previous threads, LiPo is a superior technology for our use, however good Nimh packs are much better than the average RC user gives them credit for. For the record I am talking about good quality matched and zapped cells like the EnerG4600's.

    These cells have measured IR's of 1.0 to 1.3 mO. I have yet to test a LiPo cell with IR this low and I have tested hundreds of LiPo cells.

    When I sold and tested Nimh cells they were graded and matched at 35-Amps continuous. Every assembled pack was then further tested a rate between 35-Amps and 80-Amps continuous. Over the course of the last 2 to 3 years and in every pack I tested, a EnerG4600 pack was approximately 95% discharged when the cells were pulled down to 1.1 volts each. Or in other words, a 6-cell pack was 95% discharged at 6.6 volts total for the pack and this 95% relationship remained fairly consistent at discharge rates up to 80-Amps continuous. This means an equivalent 7-cell pack would operate at 7.7 volts or higher for 95% of the useable discharge capacity. Far better than the 6.6 volts you used as an example of a loaded operating voltage.

    While LiPo is superior to Nimh for several reasons, do not underestimate a good, matched and zapped Nimh pack.
    Last edited by Jakey; 08-28-2010 at 01:02 PM.

  21. #21
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    Quote Originally Posted by El Sob
    Ok I will agree but koolkat put it in the terms that no one can argue. I am sure you can do an internet search and find the same information. Do you run lipo batteries? if you do not borrow one from a friend. I think you will be surprised in their performance. I have both. I prefer the lipo. It is more efficient. But I am done with this argument. Buy the battery you like best.

    All I have are lipo's. I was just saying that lipo voltage DOES drop off throughout the run and even the graph above shows that....

  22. #22
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    Jakey your talking about top of the line very very expensive nimh packs and it still barely beats out the performance of my $20 2S 5000mah ******* pack. Lets compare a $20 nimh pack to my $20 lipo pack and see how they match up!
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  23. #23
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    I was just trying to clarify facts on good Nimh performance.

    For what it is worth, we used to sell Matched Sport Packs that were EnerG4600, 6-cell, matched, zapped and assembled and sold for $39.95. However time and technology waits for no one. Remember, just because you can currently purchase a low cost pack that is provided through government subsidizations and is illegally shipped in blatant disregard for shipping regulations, don't think it will go on forever.

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    if i had to choose between a $20 lipo pack or a decent nimh i would take the nimh. im not risking my truck and home to a bottom of the barrel pack. they have done tests and there is a big difference between a high quality lipo and a cheap china pack.

    the review said you could buy a $100 pack or you could buy 5 cheap packs. but in the end you would have $100 worth of junk. so i think ill stick to my HQ packs.

    or you can compare those cheap packs to nimhs. would you buy a $60 high quality nimh or would you buy 3 $20 venom nimhs. i know i wouldnt take the venoms.
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  25. #25
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    I have 7 Cheap Lipo packs. The five 2S packs cost around $20 each and the 2 3S packs cost about $30.. That's about $160 total for enough packs to run for Hours. One "good" pack would be at least $100 dollars. I have the factory NiMh 8.4v 3000mAh pack and I get about 12 minutes on that. the last 6 minutes are pretty sad. The Lipos all last over 20 minutes, my 5200 mAh last about 26 minutes and they are all powerful right to the LVC. I won't lie and say at 20 minutes in its just a powerful as a fresh pack, but at 20 minutes in, I can still wheelie on 2S with my MMP and Kershaw 9L.

    I never owned "Good" Nimh packs so I cant comment on those. I'm just sharing my Lipo experience.
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    Would you rather have your product made by someone who gets paid 47cents an hour or someone who gets 12 cents a day?
    Just throwing it out there.
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    It looks like there are only a couple/few people that really know their batteries so far on this thread. I've raced with good quality lipos and good quality nimh packs and the only real difference is weight.But in 1/10th scale offroad racing we usually have to add weight to the vehicle to pass tech inspection.So the advantage of lipo is slim to none for what I race.

    Sure your $20 lipo is gonna out-perform a $20 nimh pack for several reason.Probably the biggest reason is because that $20 nimh pack is gonna have 6 unmatched cells.Also,most cheapo nimh packs are stick configuration,which also hurts pack performance.But if you were to run a matched Ener-G 6 cell pack against any decent lipo,you're not gonna notice much difference at all.You may have to add some more spacers to the springs to compensate for the weight difference,but that's about it.

    The Ener-G pack will have very similar drops too.Anyone who tells you that a lipo runs the same from beginning to end is mistaken.I notice a drop in all my lipos.Happens around the 3-minute mark.Actually I'm happy when it happens because it makes the vehicle easier to keep under control. The voltage will slowly continue to drop,but I don't notice that anywhere near as much as the initial drop.

    I'm not in any way trying to convince anyone to choose nimh over lipo.That's just plain silly. Just gotta agree with the guys on here that have run the really good nimh packs.Heck,there is a guy at my local track who still runs some 2-year old nimh packs that he hard wires before every heat and he is still a top contender even after the rest of us went to lipo.And now that lipo has pretty much taken over,you can get a top shelf nimh pack for a really honest price.

  28. #28
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    Well hears my 2 cents LYPO'S ROCK FTW!!!!

  29. #29
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    Quote Originally Posted by Jakey
    To answer you question you first have to define performance. Do you mean straight line acceleration, top speed or all around handling and power on a track?


    I'm sure many would agree with you.

    For the OP, try a 5000mAh/2S pack with a true 20C rating or higher. I run a 5000mAh/20C/2S pack in my Slash 4x4 with very good results. You will really like how the truck handles with the reduced weight of LiPo.
    Just all around proformance. Which will hold the power better throughtout a race. It's now weight vs power. I seen my unmatched radioshack bought gp3300 get around 9.6volts fully charged. I can imagine a EnerG being a much better pack lol. But I agree with the cheap Lipo statement you make. But I have a question. How do you know if the C-rating manufactures provide are true? Are my Venom(from what I'm reading are using Intellect cells) really producing 40c?
    Last edited by Emaxx2.0; 08-29-2010 at 08:30 AM.
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  30. #30
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    Quote Originally Posted by Emaxx2.0
    Just all around proformance. Which will hold the power better throughtout a race. It's now weight vs power. I seen my unmatched radioshack bought gp3300 get around 9.6volts fully charged. I can imagine a EnerG being a much better pack lol. But I agree with the cheap Lipo statement you make. But I have a question. How do you know if the C-rating manufactures provide are true? Are my Venom(from what I'm reading are using Intellect cells) really producing 40c?
    Once again, I am not debating whether Nimh is better than LiPo for RC use, as it is not in most applications. LiPo is better, but and this is a big BUT ... a good Nimh pack is a lot better than most people give it credit for.

    To answer your question or part of it, the average consumer does not know if the LiPo pack they purchased is accurately rated. The test equipment to verify C rating is far too expensive for most to purchase and the testing itself can become very dangerous at times. While the C method of rating pack capabilities is a good one, it is frequently exaggerated and exploited in an attempt to increase overall sales. While this is a sad situation, keep in mind that not all RC battery companies are guilty of this deception.

  31. #31
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    I can't remember where I saw some tests on this - one of the popular review/forum sites put a bunch of cheap and good LiPo packs to the test about a year or two ago which I can't find again with a google search.

    They bought a few good brands, a few intermediate brands (Venom was one) and a few cheap brands and tested true vs claimed capacity, internal resistance, run-times at various loads. They couldn't test how fast the batteries deteriorate for obvious reasons (ie how many runs before they are worn out).

    From what I recall all the good brands (single pack price around $60-$120) provided good C ratings and were close to or better than the rated value (I think one greatly exceeded the rating) and capacities were reasonably accurate.

    The medium range packs (about $30-$50) were a very mixed bag - one was very good (better than some expensive ones) and I think at least one was very dodgy.

    The cheap packs showed you generally get what you pay for. None handled stated discharge rates with some below 2/3 of stated. Stated capacities were obviously dreamt up rather than measured by the manufacturer. One nuked during testing.

    If someone can find this article can they post a link.

    If you must buy the really cheap batteries take a few precautions:

    1. Make sure they are posted appropriately - they should not be sent by air - catching fire in the back of a truck is one thing but catching fire on a flight with 200 people on board is quite another.

    2. Do not store them in your house unless you have a means of storing them where they definitely won't burn your house down if they nuke. This is risking more than just your $200K house - it is also risking the lives of your family and perhaps many more if you live in a unit complex. I suggest testing your storage container by nuking another cheap LiPo in the container outside to see how well it contains it. You should do this anyway (storing them safely that is) but it is especially important with cheapies.

    3. Get a battery with a "C" rating at least twice what you need and they just might be adequate.

    4. Only use a cheap truck that you don't mind seeing erupt in flames when the cheap LiPo explodes.
    Last edited by koolkat; 08-29-2010 at 09:57 AM.

  32. #32
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    Quote Originally Posted by koolkat
    I can't remember where I saw some tests on this - one of the popular review/forum sites put a bunch of cheap and good LiPo packs to the test about a year or two ago which I can't find again with a google search.

    They bought a few good brands, a few intermediate brands (Venom was one) and a few cheap brands and tested true vs claimed capacity, internal resistance, run-times at various loads. They couldn't test how fast the batteries deteriorate for obvious reasons (ie how many runs before they are worn out).

    From what I recall all the good brands (single pack price around $60-$120) provided good C ratings and were close to or better than the rated value (I think one greatly exceeded the rating) and capacities were reasonably accurate.

    The medium range packs (about $30-$50) were a very mixed bag - one was very good (better than some expensive ones) and I think at least one was very dodgy.

    The cheap packs showed you generally get what you pay for. None handled stated discharge rates with some below 2/3 of stated. Stated capacities were obviously dreamt up rather than measured by the manufacturer. One nuked during testing.

    If someone can find this article can they post a link.

    If you must buy the really cheap batteries take a few precautions:

    1. Make sure they are posted appropriately - they should not be sent by air - catching fire in the back of a truck is one thing but catching fire on a flight with 200 people on board is quite another.

    2. Do not store them in your house unless you have a means of storing them where they definitely won't burn your house down if they nuke. This is risking more than just your $200K house - it is also risking the lives of your family and perhaps many more if you live in a unit complex. I suggest testing your storage container by nuking another cheap LiPo in the container outside to see how well it contains it. You should do this anyway (storing them safely that is) but it is especially important with cheapies.

    3. Get a battery with a "C" rating at least twice what you need and they just might be adequate.

    4. Only use a cheap truck that you don't mind seeing erupt in flames when the cheap LiPo explodes.
    bigsquidrc.com Lipo shootout 1&2, 3 is coming this september. Also have the reviews on alot of popular chargers. The only update is the Hyperion 720i no longer requires a power supply, you can plug it straight into the wall or go DC. Its IMO one of the best right now, just my 2 cents

  33. #33
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    Quote Originally Posted by Jakey
    Once again, I am not debating whether Nimh is better than LiPo for RC use, as it is not in most applications. LiPo is better, but and this is a big BUT ... a good Nimh pack is a lot better than most people give it credit for.

    To answer your question or part of it, the average consumer does not know if the LiPo pack they purchased is accurately rated. The test equipment to verify C rating is far too expensive for most to purchase and the testing itself can become very dangerous at times. While the C method of rating pack capabilities is a good one, it is frequently exaggerated and exploited in an attempt to increase overall sales. While this is a sad situation, keep in mind that not all RC battery companies are guilty of this deception.
    I do agree with some of your qoutes, it really comes down to the consumer doing their homework and deciding whats best for them. I personally like Thunder Power but I did my homework and decided on them for my own reasons. Maxxamps are great packs but for what I was looking for was in the 150 to 180$ range per pack and is way to steep for my checkbook. I agree Lypo's are spendy, but a new 7cell traxxas pack 8.4v nimh pack is between 45 and 50$, I can pickup a Thunder Power TP4300-2SSR for around 74.99 and is ROAR approved. That is comparable in mah to a stock 7-cell Traxxas NIMH which is 4200mah, the thunder power will smoke that pack and is a much better fit and is not to spendy and is only 25 to 30$ more. Just my 2 cents

  34. #34
    RC Turnbuckle Jr.
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    3,650
    Quote Originally Posted by brasco426
    ... I agree Lypo's are spendy, but a new 7cell traxxas pack 8.4v nimh pack is between 45 and 50$, I can pickup a Thunder Power TP4300-2SSR for around 74.99 and is ROAR approved. That is comparable in mah to a stock 7-cell Traxxas NIMH which is 4200mah, the thunder power will smoke that pack and is a much better fit and is not to spendy and is only 25 to 30$ more. Just my 2 cents
    Even though they are good, we can't expect the Traxxas pack to be on the same page as the matched packs I noted above. For what it is worth, a 7-cell, matched and zapped EnerG4600 pack will smoke your TP 4300/2S for sheer power, however the 7-cell pack will weigh twice as much and be much more difficult to maintain as the TP; making the TP a better choice for overall and long term usefulness.
    Last edited by Jakey; 08-29-2010 at 12:35 PM.

  35. #35
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    Quote Originally Posted by koolkat
    2. Do not store them in your house unless you have a means of storing them where they definitely won't burn your house down if they nuke. ......
    Best charging/storage setup I have seen was one of the hollow square concrete cinderblocks sitting on its side (open side up) on a concrete pad with a plastic bag full of sand over the top. If the lipo catches fire the bag melts and fills the cinderblock with sand, snuffing the fire.

  36. #36
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    Quote Originally Posted by Jakey
    Even though they are good, we can't expect the Traxxas pack to be on the same page as the matched packs I noted above. For what it is worth, a 7-cell, matched and zapped EnerG4600 pack will smoke your TP 4300/2S for sheer power, however the 7-cell pack will weigh twice as much and be much more difficult to maintain as the TP; making the TP a better choice for overall and long term usefulness.
    You should sell batteries for SMC seeing how your pretty passionate for them

  37. #37
    RC Turnbuckle Jr. Emaxx2.0's Avatar
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    Quote Originally Posted by brasco426
    You should sell batteries for SMC seeing how your pretty passionate for them
    If only you knew Jakey.
    Simply the best. The beautiful Traxxas SRT and TCP

  38. #38
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    Quote Originally Posted by Mud Puppy
    Best charging/storage setup I have seen was one of the hollow square concrete cinder blocks sitting on its side (open side up) on a concrete pad with a plastic bag full of sand over the top. If the lipo catches fire the bag melts and fills the cinder block with sand, snuffing the fire.

    I think I'll be using this slick trick

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