yes another battary thread..

[josh7owens]

ok guys i have my charger. I have my truck paid for on order. All i need now are my lipos. What lipos should i get. I want the best of the best. Money isn't the issue. What should i get? I want a high end lipo that will give me crazy power. doesnt have to be huge either. 800ma-2000ma 3s

also please dont say ma because from my understanding they are no better then the cheap *****s

[espresso1967]

Here you go, I use Yeah Racing for my on road lipo needs and the prices you just can't beat. Now I just looked to see if they made something for 1/18 and here it is.

http://www.ultralinehobbies.com/inde...=646&parent=72

[josh7owens]

it needs to be a 3s

[suprafanatic26]

********* has ***** 3s lipos..1600 mah..i got them awhile ago..but they are on backorder now..so i don't know if buying from them right now is the best thing..so try looking around ebay or yahoo auctions or something for them

http://www.*********.com/*********/s...idProduct=6539

[josh7owens]

i was looking for more of a high end racing battary really.

I think with a LVC we could run 2 of these...
http://www.*********.com/*********/s...idProduct=7315
I would be sick!

[Redman65]

www.maxamps.com also check out AE/Reedy I would think with their RC18's they may have something quality that would work. SPC may be worth a look as well. I know I will stick with MA. Cost is in the ball park of the other batteries people who race use. Check out any hobby web site and serch for this scale lipo. Should give you a plenty of options......

Also, google mini rc web sites. Then go on their boards and see what people who race the smaller scales use. Worth a shot....

[pedester 99]

I think with a LVC we could run 2 of these...
http://www.*********.com/*********/s...idProduct=7315
I would be sick!

no you can't, one, i doubt they would fit and 2, a 4 cell lipo will send the esc into over voltage protection so ya, the most cells you can use with the stock esc is 3 or 6 if they are in parallel

[shizzon]

im sorry but maxamps is on something with those prices, selling those for $75 a piece, that is ridiculous. you can get equal or better performance out of zippies and you can get 6 of them for the price your paying for two of the maxamps. As a company maxamps prays on the uninformed masses, those who take what the magazines say for granted, and dont realize that maxamps pays them Alot to recommend their products. You are paying for their advertising budget, not the batteries.

[josh7owens]

no you can't, one, i doubt they would fit and 2, a 4 cell lipo will send the esc into over voltage protection so ya, the most cells you can use with the stock esc is 3 or 6 if they are in parallel

dude a 12 cell nihm fully charged is about 19.2 volts (1.6 per cell). 4s Lipos fully charged are 17.0v (4.25v per cell). The reason traxxas said no to the 4s is b/c not as many people make them, the battary tray has to be drimaled to make it fit, and there is no lvc for a 4s. input guys...

heres a 4s cut off.

http://www.maxamps.com/Novak-4S-SS.htm

[pedester 99]

dude a 12 cell nihm fully charged is about 19.2 volts (1.6 per cell). 4s Lipos fully charged are 17.0v (4.25v per cell). The reason traxxas said no to the 4s is b/c not as many people make them, the battary tray has to be drimaled to make it fit, and there is no lvc for a 4s. input guys...

uh..."dude", how the hey to you get 1.6v per cell for a fully charged nimh pack?... as far as the 4s thing goes, read this thread and let me know what you have to say after....click here dude! ...posts like this make it quite clear...(this is a post from that thread by DIRTDEVIL who is a traxxas employee)

Majestic is correct with his comment. It will not handle 4s power as per the engineering department here at Traxxas. I feel if anyone would know the limitations of the esc it would be them. And at any point you feel like testing this known fact....please have $45 dollars and a box handy to send it back in and we will gladly repair it for you. This is a quote straight from the owners manual "Alternating; Blinks Red then Green: If the motor has no power, the VXL-3m has entered Over Voltage Protection. If a battery with too high voltage is used, the VXL-3m will go into a failsafe mode. Warning: If input voltage exceeds approximately 20 volts, the ESC may be damaged. Maximum peak input voltage limits are 12.6V in LiPo Mode (see page 17) and 18V in NiMH Mode." If you would like to read this for yourself or feel that you have other questions please feel free to check out the owners manual. http://www.traxxas.com/PDF-Library/7008_7108_manual.pdf

edit: and to the comment that the battery tray must be dremelled to fit 4 cell lipo... people were thinking of running 2 2 cell lipos in series, ie: a 4 cell lipo with no dremelling required, also, not that you need a 4s lipo pack to run the equivalent voltage in a revo or slash, 4s lipos aren't hard to find. that didn't factor into why traxxas said it won't support 4s lipos. you were right about the lvc, although that was only part of the reason why traxxas said no 4s

[josh7owens]

uh..."dude", how the hey to you get 1.6v per cell for a fully charged nimh pack?... as far as the 4s thing goes, read this thread and let me know what you have to say after....click here dude! ...posts like this make it quite clear...(this is a post from that thread by DIRTDEVIL who is a traxxas employee)

so what if you ran it in nimh mode and ran a LVC that's what I'm saying. would it know the difference in whether the power was coming from a lipo? isn't a volt a volt?

[pedester 99]

i guess that could work just watch the temps, i'm not sure how the modes on the esc works if it lets you set them or not

edit: just read in the manual and ya it lets you set the modes so i guess technically you can run 4s if you run it in nimh mode with an lvc, i wouldn't trust it tho, i could see running into temp issues fairly fast with lipo

[josh7owens]

i guess that could work just watch the temps, i'm not sure how the modes on the esc works if it lets you set them or not

edit: just read in the manual and ya it lets you set the modes so i guess technically you can run 4s if you run it in nimh mode with an lvc, i wouldn't trust it tho, i could see running into temp issues fairly fast with lipo

temp issues? the voltage would be basicly the same as 2 nimh packs. Also the reason I mentioned 2 4s battarys is because I am planning on building the first dual bl 1/16 scale revo.

also here the battary i was talking about.

http://www.*********.com/*********/s...idProduct=7315

It is 2-3mm to tall. I can drimal that much out to make it fit. Its only a 1550 ma so the run time would be less then 15-20 mins i would think. Its not like I'm going to run it for a hour lol

[filmmaker]

temp issues? the voltage would be basicly the same as 2 nimh packs. Also the reason I mentioned 2 4s battarys is because I am planning on building the first dual bl 1/16 scale revo.

Not if I build it first!

[pedester 99]

temp issues because of the nature of lipos, longer run times, more consistant voltage etc.

[josh7owens]

how would you wire this for 2 4s battarys?

http://www.maxamps.com/Novak-4S-SS.htm

just run the sensor wire to the two battarys in paralell? that way as soon as one shut off it would shut off both motors?

btw the two speed controlers will run to the recever using a y adapter. so that way they will both get throttle at the same time with the same %.

temp issues because of the nature of lipos, longer run times, more consistant voltage etc.

the esc can take a Continuous 52a's

these battarys give out about 32.5-45 amps (25c) Continuous and 39.0-72 amps (30c) burst. so its not maxing out the continous amps at all. I think it will work. Am I going to have to be the genny pig and try it for everyone? I'm already building the first custom dual bl set-up unless someone within the first 2 weeks of being able to get another esc and motor beats me to it.

not 100% sure on that amp output but the lower number is from a 800ma battary and the higher is from a 2200ma battary so it should be somewhere between there. how do you calulate amps?

never mind i found it.

heres a good link to read...
http://monster.traxxas.com/showthrea...lculating+amps

What does the "C" mean in 10C, 20C etc ?

we use the designation 10C etc to mean how much a cell or pack can discharge in amps. C always equals the capacity of a cell or pack. For example. Let use a PQ31003S pack rated for 12C. In this case C=3100mah. the number before the "C" is the multiplier. so 12 x 3100 = 37200mah. to get amps we simply divide by 1000. 37200/1000 = 37.2 amps. 1000mah = 1amp.

Continuous-
25x 1550 = 38750mah
38750/1000= 38.75 amps

burst
30x 1550= 47500mah
47500/1000= 47.50 amps

which is under the 52a continuous.

the vxl motor is 4000kv.
the fully charged voltage is 16.8v

4000kv x 16.8 = 67200 RPM

now that sounds like a lot but by mini t with a mamba kit is a 8700kv and 11.1v lipo

8000kv x 11.1 = 88800 RPM

so if my mamba can hold up to a 30 min run of up to 88800 RPMs i hope to god traxxas's vxl can hold up to 67200 RPM for 15 mins.
power-

V/R = I
V*I = P

V = 16.8 Volts
R = .125 ohms
I = 134.4 Amps

16.8/.125=134.4
16.8 * 134.4 = 2257.92 watts or 2.25792 hp.

the MMM claims to put out between 5 and 6 hp. a dual 1/16th set up would put out 4.51584 hp. Thats almost as much as the MMM and half the wieght.





ps- anyone know the wattage output of the vxl motor?

if my calculations are wrong please tell me how to make them right. also who knows the wattage of the vxl motor. from what i got told the 1/10 scale one is around 600 watts. I'm trying to calculate the battary draw.

another question. If you run 2 battarys in parllel does that double the amps that can be drawn.

for example if my output cont. for 1 battary was 38.75 would running 2 of the same battarys make me able to have a output of 77.5 amps?

the reason i ask is...

Now, when it comes to how fast a motor spins (which determines how fast your car goes!) - then the volts comes into play. kV ratings on a motor tell you how many RPMs per volt you will get at full power. at 7.4V, as 3500kv motor will rotate at 25900 RPMs, and 11.V will rotate it at 38850 RPMS - hence a 3S 5000 will definitely go faster than a 2S 8000 battery.

Motors are rated for a certain wattage - let's say the VXL is rated for about 600 watts (it might be higher or lower - let's just estimate here!)
So, at 7.4V - it will pull 600/7.4 = 81 amps
and at 11.1V-it will pull 600/11.1 = 54 amps (yes, lower amps!)

When a battery is placed under load, the voltage drops. The closer the load approaches it's max, the lower the voltage dips, and the hotter the battery will get. So, since a 20C 5000mah battery will be approaching it theoretical max of 100amps (81 amps out of 100 available), the voltage will dip more than it would with the 20C 8000mah battery (81 amps out of 160 available). So, even though the 2S batteries are both rated at 7.4V, the 8000mah will be faster than the 5000mah.

I was looking at the neu motors and they are 700 watts cont. and 1400 watts burst and was trying to figure out if these battarys would even support that of ran in parllel. If not does it double it running it in series? that would be like 29.6 volts but they have a motor that will handle that. although you would have to run a airplane esc.

I'm going to do a dual bl set up on the revo but on the slash i think I'm going to go with a neu motor. SO i was trying to figure out if the battarys will support both.

[filmmaker]

how would you wire this for 2 4s battarys?

http://www.maxamps.com/Novak-4S-SS.htm



4000kv x 16.8 = 67200 RPM

now that sounds like a lot but by mini t with a mamba kit is a 8700kv and 11.1v lipo

8000kv x 11.1 = 88800 RPM

so if my mamba can hold up to a 30 min run of up to 88800 RPMs i hope to god traxxas's vxl can hold up to 67200 RPM for 15 mins.
power-

V/R = I
V*I = P

V = 16.8 Volts
R = .125 ohms
I = 134.4 Amps

16.8/.125=134.4
16.8 * 134.4 = 2257.92 watts or 2.25792 hp.

the MMM claims to put out between 5 and 6 hp. a dual 1/16th set up would put out 4.51584 hp. Thats almost as much as the MMM and half the wieght.





ps- anyone know the wattage output of the vxl motor?

if my calculations are wrong please tell me how to make them right. also who knows the wattage of the vxl motor. from what i got told the 1/10 scale one is around 600 watts. I'm trying to calculate the battary draw.

another question. If you run 2 battarys in parllel does that double the amps that can be drawn.

for example if my output cont. for 1 battary was 38.75 would running 2 of the same battarys make me able to have a output of 77.5 amps?

the reason i ask is...

I'm going to do a dual bl set up on the revo but on the slash i think I'm going to go with a neu motor. SO i was trying to figure out if the battarys will support both.

Where do you come up with 2.25hp for a 1/16th brushless motor?
on 4s that motor would be pulling over 120 amps!
120amps on a little motor could cook it!

The MMM is rated for about 2200watts or about 2.9hp at 100% not 5 to 6 hp...

[josh7owens]

idk, i did the calculations that i got off the link i posted. maybe i was wrong

[filmmaker]

idk, i did the calculations that i got off the link i posted. maybe i was wrong

come up with any new numbers josh?

[josh7owens]

no i haven't done anymore research.

[filmmaker]

Oh ok,
I'm thinking of putting my brushless motor thats from a 3D plane into me Slash!

[Redman65]

im sorry but maxamps is on something with those prices, selling those for $75 a piece, that is ridiculous. you can get equal or better performance out of zippies and you can get 6 of them for the price your paying for two of the maxamps. As a company maxamps prays on the uninformed masses, those who take what the magazines say for granted, and dont realize that maxamps pays them Alot to recommend their products. You are paying for their advertising budget, not the batteries.

I understand this is a free country and you can think what ever you want but what you are saying simply is not true. *****s do not out perform MA. As for what the magazines say they have no reason to lie. Also, there is a reason MA was run in these kits at the RCX show. By the way, MA isn't the only batteries the magazines cover. I also would like to add the MA is #1 because we rc folks voted them there. And by the way you ***** fans are more than welcome to send any magazine one of your batteries and have them put *****s under a microscope any time you wish. I will warn you though, that has been done and ***** is NOT what you claim it is. But if that's what you want to purchase that's fine. And no MA does not pay me to do anything. Your statment is a flat out lie on that point as well as many others. I guess you have a problem with ALL that money Traxxas spends on advertisement not to mention all the money they pay everyone in here for posting how much they like what Traxxas puts out. Again, people can use what ever battery they want who cares but to completely lie about a product that is on of the buest in the business is pathetic on your part. Oh by the way, how much is ***** paying you?