Question about batteries

[d_j_stockton]

ill start out by saying that im not the most electronically minded so please forgive the noob type questions.

i have read in the paperwork for the car that he stock speed controler is good for a 6 or 7 cell nimh battery, and his has got me thinking. i have no plans to upgrade the speedy, so with this in mind im still running stock motors, with 8 tooth pinions ariving very soon, with a view to upgrading to banebot rs390's when i fry a motor in the future. would i benifit more from running and 8.4v nimh hump pack ors running a 2s lipo and an external voltage alarm??

Cheers David

[Docwolf]

Lipo will always be the better performer.

[d_j_stockton]

doc, will i see any reduction in clod stall when useing the lipo because of its better power delivery properties?? also what "c" rating should i use?? found these on ebay 7.4V 5000mAh 30C Li-poly LiPo Li-Po RC Battery Pack | eBay

what do you think??

[smitty808]

I ran a 2S lipo, and an 8.4 hump pack in mine at different times. The performance was actually pretty close, but the weight difference was unbelievable. The lipo is tiny compared to a NiMh of the same size.
I tossed a 3S in mine, and it ran perfect(with MASSIVE performance gains.), until I flipped it into a creek and wet down the esc. They tell me it shouldn't run a 3S, but it was doing fine until then. My son's is on a stock esc, and 3S, with several packs through it, and running fine too.
Your mileage may vary. Your esc may melt the first time you try it. (but it probably won't).

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[Docwolf]

If you are ordering out of China, I would just go with Hobbyking.com and get a good well known battery from a good supplier. that battery you posted is not one i have ever heard of and with Lipo i would not chance an unknown pack. the stock ESC is only rated for 8.4 volt, but i know a lot of guys on here have run 3s for a long time with no issues. My dad recently switched from a 9.6 volt pack to a 2s pack and the performance increase was night and day on the stock the controller. that same rig is right now running a no name Chinese made 4s rated ESC and 3s on the stock motors, it still has clod stall, but it works more as a rear dig now. In other words at low speeds the rear will stall, but it has enough power to over come it when you pull the throttle, works super nice. I am currently running a 30C on my 5000 mah 3s and 25c on my 6000 mah 2s. i think the lower the Mah, the higher the C rating should and the higher the Mah the lower the rating from what have been told . All in all, you should be fine in the 25 to 30 C range, you don;t generally need a done of burst in crawling unless you are comping.

[G's ^]

I run value hobby Gforce 2s 800mah 30c lipos , $5.50ea And ship out of Illinois .They are great for there compact size. There run time is ok for there small size. I would spend 3 more dollars next time and get 1300s , they are just a touch bigger. Im using the stock esc with no problems.
I didn't notice Any power gains switching to 2s lipo over 7.2 nimh. Just more consistent power till it hits the set voltage on alarm. I plan on switching to 3s in the near future. Strictly for the power gains of 11v. I will try 3s with stock esc , although not reccomended ! Many have done it with great results , although some went up in smoke. If it frys , well I'll upgrade the esc.
8.4v nimh may have a lil more juice when fully charged than 7.2 lipo will , but more than Likely the 8.4 nimh will fade where the 7.2 lipo holds consistent till its dead.
Lipos can be a pain to deal with at times. Never let them go below there limit , and be careful with charging and storage. Lipos require a lipo charger , regular nicd/nimh charger will not do.

[LostFedExMan]

I run 3s lipo on stock speed controller and stock motors with a low voltage alarm, and I will NEVER go back.

[G's ^]

Originally Posted by LostFedExMan

I run 3s lipo on stock speed controller and stock motors with a low voltage alarm, and I will NEVER go back.

I will go that route here soon when I order some new batts. What's he worse that happens , I have to buy a better esc haha.

[d_j_stockton]

Thanks guys for the advice, cheers David

[Pat M]

3s lipos, alarm & charger ordered from Hobbyking today. Will report back after the test

[G's ^]

Originally Posted by Pat M

3s lipos, alarm & charger ordered from Hobbyking today. Will report back after the test

Hope you have better luck than a buddie who ordered 2 battery's over a week ago from hobby king , said in stock on there page , still not even a tracking #

[nolan533]

Forgive the stupid question but
Going with lipo's is lighter I thought the weight from the heavier nimh Batts would help with traction or does it not work that way

[G's ^]

Originally Posted by nolan533

Forgive the stupid question but
Going with lipo's is lighter I thought the weight from the heavier nimh Batts would help with traction or does it not work that way

From my experience the heavy stick pack throws the center of gravity off . Even when mounted down low on skid plate. Side hilling and steep up or down with the weight of the heavy pack tends to help it flop.
What works best for me was dropping weight wherever I could , and going with small 2s Lipo lacks and mounting them on to the front axle. That along with taking out my electronics tray and mounting all electronics with Velcro down low to the skidplate made huge center of gravity / stability gains.
Look at most all xr10 / berg / bullys , they drop down in the 4lb range , and all run small lipos on axles where weight is needed and keeps the battery down low as possible.
A scaler rig won't care about weight as much , they want really long run times and won't do most of the lines a good comp rig will do. So larger heavier nimh or hard case LIpo stick pack battery's isn't a big issue.

[nolan533]

Thanks for the info G's^
I have allot to learn about crawlers yet

[nolan533]

I am thinking of going lipo after reading this.
I may have missed it but what is a good c rating?
Do I need to use a hard pack or is a regular lipo ok
I have ordered a low voltage alarm out of China so it should be here oh next year or so
And last but not least to get a 20 to 30 minute run time what mah should I shoot for
I am running pretty much stock and I plan on staying with 2s

[G's ^]

I'd go Atleast a 30c . I use soft packs , hard packs work too but usually are heavy and bigger in size. Screw ordering from china man , volt alarms Are like 3$ from value hobby , batteries not much more and out of Illinois. My 2s 800mah packs running consistant non stop last from 10-15min depending on the terrain. My 1300 mah packs go I'd say 20-30 may be less depending on terrain and how hard I gotta get in it and how often. I run small packs because the battery is mounted on my front axle , so nothing over 1300mah soft packs will fit on my axle. If your running it in the stock tray you could get a 6000mah and run all day on a battery , if you don't care about weight.

[nolan533]

Thanks G's ^
Great info I will checkout. Value hobby
I will see just how mad the wife will get with my next order. (LOL)

[SeTh_Rs10]

Ya I can vow for value hobby I bought there lipo alarms and some batteries fast shipping and cheap


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[G's ^]

Originally Posted by nolan533

Thanks G's ^
Great info I will checkout. Value hobby
I will see just how mad the wife will get with my next order. (LOL)

Ya I hear ya , I just encourage my wife to buy things she wants when out shopping , that way I can justify my spending lol.
You will be surprised on how affordable there battery's are , and so far no compromise for quality.

[nolan533]

I have bought from value hobby before I just had forgotten about them.