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Old 02-05-2008, 03:02 PM   #1
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Default Lipo RX Packs

I'm thinking of a Lipo RX pack for my 1/8th and 1/10th nitro cars. Some say the packs are overly expensive, difficult to charge, ware out quickly, provide too much over voltage that has wrecked receivers and servos, and some have even exploded.

What is the experience of others? Beside weight, what else is good about lipo RX packs?
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Old 02-05-2008, 03:22 PM   #2
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first off, the advantages are obviously weight savings.
then you have to run a regulator, this supplies a constant voltage throughout the packs charge. you get 6 volts at the start of the usage, and 6 volts near the end of its charge. this makes for a more consistent feel of servos , rather than having around 7 volts at the start (fast servos) and 5.5 volts at the end, (slower servos) be carefull which reg you run, some supply between 6.7 volts and 6 volts, check your servo ratings max power input, or youcan damage a servo. by running a 1500mah lipo pack with the regulator (a must) , in effect its actually increasing the capacity of the battery cause its been regulated at a lower voltage. cheers, plus keep your lipo pack away from engine heat, if its to be placed on the chassis, insulate the chassis, as the chassis gets hot also . cheers
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Old 02-05-2008, 03:25 PM   #3
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oh patto has answered at the same time best of both worlds , just waiting for those lipos you picked out at rcmush there the go! cheers!
lithium polymer (lipo) batteries need a designated charger that can charge lipo not nmhi or nicd or expect to cause damage, you get a good weight drop with these batteries as they offer excellant run times possibly 50% better than nmhi, they can be subject to effects of rough handling so they need to be properly secure and properly wrapped as lipos are lightly wrapped hence the weight difference and the possibility of damage from being banged around especialy offroad.no memory effect and good life expectancy many charges but if looked after lipo is the battery to use.oh and I forgot that you need a regulator to bring your battery voltage down to a voltage the rx and servos can handle.
cheers
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Old 02-05-2008, 06:27 PM   #4
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Originally Posted by Pattojnr View Post
first off, the advantages are obviously weight savings.
then you have to run a regulator, this supplies a constant voltage throughout the packs charge.
Do I have to use the regulator when I charge the pack?
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Old 02-05-2008, 06:33 PM   #5
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Originally Posted by going4#1 View Post
Do I have to use the regulator when I charge the pack?
no, the regulator regulates output from the battery, not input from the charger.
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Old 02-06-2008, 04:46 PM   #6
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Any recommendation for lipo/regulator combo? I saw the VXR 1300mAh and now there is the Xceed 1300 (which looks a lot like the VXR). Does anyone know what the weight of a 1300 pack + regulator would be?
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Old 02-06-2008, 06:29 PM   #7
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premium power have a 1300mah and regulator to match which weighs around 70grams!
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Old 02-06-2008, 10:27 PM   #8
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I use the protek r/c 2300mah pack and novak regulator. This combo has AWESOME runtime!
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Old 02-09-2008, 07:13 PM   #9
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I want to use a 1300mAh 2-cell lipo in a 1/8th on-road car. What size regulator do I need? 3A or 5A?

Thanks.

Rob
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Old 02-09-2008, 07:43 PM   #10
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Quote:
Originally Posted by going4#1 View Post
I want to use a 1300mAh 2-cell lipo in a 1/8th on-road car. What size regulator do I need? 3A or 5A?

Thanks.

Rob
i suggest the 5a i dont know why exactly its just what was reccomended to me by some other lipo users...I have the protek 5a regulator w/out switch...
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Old 02-09-2008, 07:53 PM   #11
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Do you run the lipo in a hard case or not. I'm looking to put one in my touring car(Mtx-4) just not sure which model would fit. What's the average price with regulator looking for about 1300-1500 mah.
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Old 02-10-2008, 06:11 AM   #12
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Do you run the lipo in a hard case or not. I'm looking to put one in my touring car(Mtx-4) just not sure which model would fit. What's the average price with regulator looking for about 1300-1500 mah.
I'm going with the Xceed lipo 1300mAh 2S which looks a lot like the VXR pack. I think I'll go with the Xceed regulator as well. It has VXR printed on the circuit board. Probably a VXR regulator as well.

As for what pack to go with, I found this site informative:

http://www.powerstream.com/BPD.htm

For whatever pack you consider try to compute the pack's average watt-hours which is:

E = C*Vavg

Multiply the average or nominal battery voltage times the battery capacity in amp-hours to estimate of how many watt-hours the battery contains.

So for a 1300mAh 2S lipo pack (1300mA = 1.3Amps, 1 lipo cell = 3.6Volts)

E = 1.3 * 3.6 * 2 cells = 9.36 watt hours

If 2 servos draw an average of 2 watts each (total 4 watts) you'd have over 2 hours of run time with this pack. Keep in mind this is a rough estimate.

Rob
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Old 02-10-2008, 10:43 AM   #13
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Quote:
Originally Posted by lil-bump View Post
Do you run the lipo in a hard case or not. I'm looking to put one in my touring car(Mtx-4) just not sure which model would fit. What's the average price with regulator looking for about 1300-1500 mah.
if the Xceed stuff looks just like the vxr product than you can also go with the the protek product which is also just rebadged vxr product...i think i paid between 25-28 for the regulator and about the same for the battery
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Old 02-12-2008, 02:43 AM   #14
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Do i need to choose the lipo rx batt with balancer jack? I have premium power 2s lipo rx batt pack(without balancer jack) and it only lasted about 3 months, i was using it in my RRR. All my other lipo batteries has got the balancer and i charge them in balance mode, and all of 'em are still good.
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Old 02-12-2008, 05:10 AM   #15
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Do i need to choose the lipo rx batt with balancer jack? I have premium power 2s lipo rx batt pack(without balancer jack) and it only lasted about 3 months, i was using it in my RRR. All my other lipo batteries has got the balancer and i charge them in balance mode, and all of 'em are still good.
I'm still pretty new to Li-po. Could you explain what a balancer jack is? Is it simply a charging jack that is connected to both cells in a two cell pack in parallel? In other words, the plus wire is attached to both plus terminals of a two cell pack and the minus wire is attached to both minus wires of the two cells? This would be different in a typical NiMH pack where the minus wire is attached to the minus terminal of the last cell and the plus wire is attached to the plus terminal of the first cell and all the cells are linked in series.
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