RCCrawler Forums

Thump Wallop · 01-11-2010, 01:54 AM

Hey all,

I have done a search in this forum for some answers, and have not turned up anything that I consider 'conclusive' and was hoping you bright people could set me straight....

I saw the LRP 5000Mah batteries that are designated Rx batteries, and specifically, they look designed for the HPI Baja's..

Given that they are Rx only use, I would assume they are not up to the task of powering a crawler..or are they? Nowehere on the LRP site, or in their literature is there any mention of their discharge rate..so I assume this would be the bugbear? Even if they are only 10 or 15C, at 5000mah that would mean a discharge rate of 50 to 75A by normal reckoning. I suppose normal reckoning may not come into effect in this case.

I saw these in my LHS by chance and thought they would be ideal tomount over the front axles based on their size, and 5000mah would give me mega crawl time...this is purely for a basher, no comping. I am using the HW 32T motor and ESC combo that has a burst of 190A but a nominal of 35A....and this system does not even tax my current battery which is a TP 25C 2200mah ...all 7.4V systems.

I have noted that normally Rx Lipo's have thin guage wires and JST plugs which are totally unsuitable for this sort of application, but this particular model has both the thin guage servo wires, the balance tap and a set of heavier guage wires with a Tamiya connector factory-fitted...

http://www.lrp.cc/en/products/vtec-b...0-74v/details/

The link above is the unit ...

I have done some googling as well and cannot get any info....would love to hear others opinions here...

Regards
Andy

Thump Wallop · 01-11-2010, 10:52 PM

Whoa, not one opinion....

I must have stumbled across a winner here. I still dont know if I should stump up the cash or not to try this out.....I guess somebody ought to huh?:-P

Rockcrawler · 01-12-2010, 12:21 AM

It really depends on the C rating (like you said). But one thing about receiver batteries that you have to think about is the wire. A receiver does not pull that much so the wires are usually too small to supply a crawler.

Sharkey · 01-12-2010, 12:49 AM

ive seen receiver batteries rated at 1c or 2c, so thats 5-10 amps. receiver packs are generally a low current draw, and the cells can be similar to whats in a cell phone. myself, i wouldnt use them, too risky.

Thump Wallop · 01-12-2010, 02:22 AM

Thanks for the reply guys. Appreciated.

I guess the C rating is the secret. As mentioned earlier, the wires are not the typical thin wires you get on receiver packs..they are the same thickness as on most std esc's, and they have a Tamiya connector on the end.....so from that perspective, they seem like they would handle a bit more of a load than 5-10 amps....mmmm. Soooo tempted to try a pack out and see what happens....whats the worst...? they burst into flames? ...lol

Rockcrawler · 01-12-2010, 02:47 AM

Quote:

Originally Posted by Thump Wallop

Thanks for the reply guys. Appreciated.

I guess the C rating is the secret. As mentioned earlier, the wires are not the typical thin wires you get on receiver packs..they are the same thickness as on most std esc's, and they have a Tamiya connector on the end.....so from that perspective, they seem like they would handle a bit more of a load than 5-10 amps....mmmm. Soooo tempted to try a pack out and see what happens....whats the worst...? they burst into flames? ...lol

Sorry, I was half asleep.

I see what your talking about on the wires now. I wonder why they are selling them as RX only?

Thump Wallop · 01-12-2010, 07:29 AM

Quote:

Originally Posted by Rockcrawler

Sorry, I was half asleep.

I see what your talking about on the wires now. I wonder why they are selling them as RX only?

iI am not sure, and I have seen one in the flesh so it's definately not a 'generic' pic......I am soooo tempted to go pick one up, they are pricey here in the Middle East, but then so is everything RC....works out at about US$150 for the pack....

PDXFNG · 01-12-2010, 09:34 AM

CreepyCrawl · 01-12-2010, 10:21 AM

I found this shop that carries that pack for $114.00 US and they ship world wide, but with shipping it may equate to the same price you'd pay localy...

http://www.the-border.com/product.php?productid=32019

Pricey, but it's LRP and a high mAH so I'm not surprised. I did a little searching on LRP's site and it appears that all of the other Lipo packs that they offer and show specs for are rated at 25c, so the 5000 (part #79935) may have the same discharge rating.

LRP seems to uphold fairly tight quality specs within their line, so I can't imagine that they'd be using different cells just for that one pack, but it's difficult to say for sure without contacting them directly.

y2kgtp · 01-12-2010, 01:46 PM

My guess on the Tamiya connector, is that's it's just a pre-wired connector, so they just use whatever size wire comes with it. I would not use it as a judge on a C rating.

The words "Rx only" would make me not want to run it.....

456heinbach · 01-12-2010, 05:07 PM

Damn if it wasn't so pricey I would def try one. Is there a way to tell what the c rating is using like a voltometer or something? Sorry I'm not to much in the know about lipos, I just know enough to charge and run them. I'm curious I am going to call LRP/Associated, and report back.

y2kgtp · 01-12-2010, 05:24 PM

What about this for 35$ shipped?

http://www.hobbypartz.com/83p-5000ma...4-25c-car.html

Thump Wallop · 01-13-2010, 09:15 AM

Heinbach.....be sure to let us know your findings :-)

Y2kgtp....the reason I am looking at the LRP is simply because of the compact size. The normal sized stick packs would not fit on the forn axle, and because the Junfac Joker has that lovely servo/battery tray, it would be a shame to have to waste it....purpose designed and all....thanks all for the input....

y2kgtp · 01-13-2010, 09:26 AM

Quote:

Originally Posted by Thump Wallop

Heinbach.....be sure to let us know your findings :-)

Y2kgtp....the reason I am looking at the LRP is simply because of the compact size. The normal sized stick packs would not fit on the forn axle, and because the Junfac Joker has that lovely servo/battery tray, it would be a shame to have to waste it....purpose designed and all....thanks all for the input....

Yeah, the size looks good, but I bet it is smaller as a really low C rating. If your ESC\Motor can handle it, perhaps you should look into 3S (11.1v) Lipos. You will get alot more runtime for Mah ratings due to the higher efficiency of running more voltage. This is why guys are reporting around an hour of runtime on a 1300Mah 3S battery.

And you can get these from Hobbyking or hobbypartz for under 10$ a battery. get 3-4 batteries, and you should be good for several hours out playing.

Personally I just bought 4 of these to try out. I also have 3 of the 15C ones I bought for a heli, and thought they might make a good crawler battery.

http://www.hobbypartz.com/83p-1300mah-3s1p-111-20c.html

izeman · 01-13-2010, 09:37 AM

hi

not wanting to hijack the thread, but it's nearly the same question i have.

found those on ebay, and they are really cheap, so i thought to give them a try with my 45t in my ax10.

http://cgi.ebay.de/3x-7-4V-900mAh-20...item3efb670713

15c with 0.9ah would lead to 14a maximum. i don't know how much current a 45t pulls in a crawler. it never got even hand warm with my standard 3200mah 2s lipo.

what do you think?

y2kgtp · 01-13-2010, 10:01 AM

I'm guessing your 2S Lipo has a higher amp rating than these 900mah ones.

If they were both marked 15C, your comparing 48A (3200,ah 2S) vs 14A (900 2S) constant current.

izeman · 01-13-2010, 11:11 AM

Quote:

Originally Posted by y2kgtp

I'm guessing your 2S Lipo has a higher amp rating than these 900mah ones.

If they were both marked 15C, your comparing 48A (3200,ah 2S) vs 14A (900 2S) constant current.

thank you. sure. but this doesn't answer my question

i know that my big lipo is "stronger" (25C and 3200mah) = 80a. so this can deliver much more power than the small one (14a)

maybe i should ask the question more precisely: how little current is enough for 45t and some crawling time?

izeman · 01-14-2010, 07:57 AM

i now ordered a 2s lipo pack 80grams with 1300mah and 20/30c. that should work w/o problems for crawling i guess.

1000mah with 15c (and probably 10c constant) was a bit to low for taking the risk.

y2kgtp · 01-14-2010, 08:01 AM

I have some 3S 15C 1300Mah packs from hobbypartz for 10$ that seem to do ok so far. On a 27T, they lift the front tire 4" on hard acceleration

Had to turn down the EPA so the kid does not go off course with that!

(Just using 27T as I had them laying around)

izeman · 01-14-2010, 10:00 AM

i would order @hobbypartz as well, but p&p to europe is 200% of the lipo's price.

01-11-2010, 01:54 AM	#1
Thump Wallop Newbie Join Date: Aug 2008 Location: Dubai Posts: 18	Rx batteries to power a crawler? Hey all, I have done a search in this forum for some answers, and have not turned up anything that I consider 'conclusive' and was hoping you bright people could set me straight.... I saw the LRP 5000Mah batteries that are designated Rx batteries, and specifically, they look designed for the HPI Baja's.. Given that they are Rx only use, I would assume they are not up to the task of powering a crawler..or are they? Nowehere on the LRP site, or in their literature is there any mention of their discharge rate..so I assume this would be the bugbear? Even if they are only 10 or 15C, at 5000mah that would mean a discharge rate of 50 to 75A by normal reckoning. I suppose normal reckoning may not come into effect in this case. I saw these in my LHS by chance and thought they would be ideal tomount over the front axles based on their size, and 5000mah would give me mega crawl time...this is purely for a basher, no comping. I am using the HW 32T motor and ESC combo that has a burst of 190A but a nominal of 35A....and this system does not even tax my current battery which is a TP 25C 2200mah ...all 7.4V systems. I have noted that normally Rx Lipo's have thin guage wires and JST plugs which are totally unsuitable for this sort of application, but this particular model has both the thin guage servo wires, the balance tap and a set of heavier guage wires with a Tamiya connector factory-fitted... http://www.lrp.cc/en/products/vtec-b...0-74v/details/ The link above is the unit ... I have done some googling as well and cannot get any info....would love to hear others opinions here... Regards Andy

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01-11-2010, 10:52 PM	#2
Thump Wallop Newbie Join Date: Aug 2008 Location: Dubai Posts: 18	Whoa, not one opinion.... I must have stumbled across a winner here. I still dont know if I should stump up the cash or not to try this out.....I guess somebody ought to huh?:-P

01-12-2010, 12:21 AM	#3
Rockcrawler I wanna be Dave Join Date: Jan 2005 Location: Hueytown, Alabama Posts: 6,777	It really depends on the C rating (like you said). But one thing about receiver batteries that you have to think about is the wire. A receiver does not pull that much so the wires are usually too small to supply a crawler.

01-12-2010, 12:49 AM	#4
Sharkey Rock Crawler Join Date: Sep 2009 Location: Abbotsford BC Posts: 563	ive seen receiver batteries rated at 1c or 2c, so thats 5-10 amps. receiver packs are generally a low current draw, and the cells can be similar to whats in a cell phone. myself, i wouldnt use them, too risky.

01-12-2010, 02:22 AM	#5
Thump Wallop Newbie Join Date: Aug 2008 Location: Dubai Posts: 18	Thanks for the reply guys. Appreciated. I guess the C rating is the secret. As mentioned earlier, the wires are not the typical thin wires you get on receiver packs..they are the same thickness as on most std esc's, and they have a Tamiya connector on the end.....so from that perspective, they seem like they would handle a bit more of a load than 5-10 amps....mmmm. Soooo tempted to try a pack out and see what happens....whats the worst...? they burst into flames? ...lol

01-12-2010, 09:34 AM	#8
PDXFNG Pebble Pounder Join Date: Apr 2009 Location: Gresham Posts: 185

01-12-2010, 10:21 AM	#9
CreepyCrawl I wanna be Dave Join Date: Oct 2006 Location: Centered Posts: 2,082	I found this shop that carries that pack for $114.00 US and they ship world wide, but with shipping it may equate to the same price you'd pay localy... http://www.the-border.com/product.php?productid=32019 Pricey, but it's LRP and a high mAH so I'm not surprised. I did a little searching on LRP's site and it appears that all of the other Lipo packs that they offer and show specs for are rated at 25c, so the 5000 (part #79935) may have the same discharge rating. LRP seems to uphold fairly tight quality specs within their line, so I can't imagine that they'd be using different cells just for that one pack, but it's difficult to say for sure without contacting them directly.

01-12-2010, 01:46 PM	#10
y2kgtp Quarry Creeper Join Date: Dec 2008 Location: Deltona, FL Posts: 402	My guess on the Tamiya connector, is that's it's just a pre-wired connector, so they just use whatever size wire comes with it. I would not use it as a judge on a C rating. The words "Rx only" would make me not want to run it.....

01-12-2010, 05:07 PM	#11
456heinbach Quarry Creeper Join Date: Feb 2009 Location: ewetah Posts: 315	Damn if it wasn't so pricey I would def try one. Is there a way to tell what the c rating is using like a voltometer or something? Sorry I'm not to much in the know about lipos, I just know enough to charge and run them. I'm curious I am going to call LRP/Associated, and report back.

01-12-2010, 05:24 PM	#12
y2kgtp Quarry Creeper Join Date: Dec 2008 Location: Deltona, FL Posts: 402	What about this for 35$ shipped? http://www.hobbypartz.com/83p-5000ma...4-25c-car.html

01-13-2010, 09:15 AM	#13
Thump Wallop Newbie Join Date: Aug 2008 Location: Dubai Posts: 18	Heinbach.....be sure to let us know your findings :-) Y2kgtp....the reason I am looking at the LRP is simply because of the compact size. The normal sized stick packs would not fit on the forn axle, and because the Junfac Joker has that lovely servo/battery tray, it would be a shame to have to waste it....purpose designed and all....thanks all for the input....

Sponsored Links

01-13-2010, 09:37 AM	#15
izeman Rock Stacker Join Date: Oct 2009 Location: Vienna, Austria Posts: 85	hi not wanting to hijack the thread, but it's nearly the same question i have. found those on ebay, and they are really cheap, so i thought to give them a try with my 45t in my ax10. http://cgi.ebay.de/3x-7-4V-900mAh-20...item3efb670713 15c with 0.9ah would lead to 14a maximum. i don't know how much current a 45t pulls in a crawler. it never got even hand warm with my standard 3200mah 2s lipo. what do you think?

01-13-2010, 10:01 AM	#16
y2kgtp Quarry Creeper Join Date: Dec 2008 Location: Deltona, FL Posts: 402	I'm guessing your 2S Lipo has a higher amp rating than these 900mah ones. If they were both marked 15C, your comparing 48A (3200,ah 2S) vs 14A (900 2S) constant current.

01-14-2010, 07:57 AM	#18
izeman Rock Stacker Join Date: Oct 2009 Location: Vienna, Austria Posts: 85	i now ordered a 2s lipo pack 80grams with 1300mah and 20/30c. that should work w/o problems for crawling i guess. 1000mah with 15c (and probably 10c constant) was a bit to low for taking the risk.

01-14-2010, 08:01 AM	#19
y2kgtp Quarry Creeper Join Date: Dec 2008 Location: Deltona, FL Posts: 402	I have some 3S 15C 1300Mah packs from hobbypartz for 10$ that seem to do ok so far. On a 27T, they lift the front tire 4" on hard acceleration Had to turn down the EPA so the kid does not go off course with that! (Just using 27T as I had them laying around)

01-14-2010, 10:00 AM	#20
izeman Rock Stacker Join Date: Oct 2009 Location: Vienna, Austria Posts: 85	i would order @hobbypartz as well, but p&p to europe is 200% of the lipo's price.

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