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Questions about going lipo.
Posted: Fri Dec 14, 2012 11:09 am
by Boredome
Hey everyone new here and just took out the old gold pan out of the closet for the first time in 4 years probaly even longer. And of course battery's aren't so greath from sitting that long. I have 2 venom 7.2v 4200mah. But was woundering if I can switch to lipo battery's for the longer run time. I don't have a brushless set up and don't plan on changing to brushless. Unless if I get back into the hobby big again. Just looking to have fun but longer run time and less time letting batteries cool.
So I done some research and I know I need a different charger and a low voltage cut off and the batteries of course. I wanna go with 7.4v so I get a 2 cell lipo right? And wanna stick with the 5000 mah. Already have this picked out on hoppypartz.
http://www.hobbypartz.com/libaprforcar.html
http://www.hobbypartz.com/thac6smbachw.html
http://www.hobbypartz.com/98p-40c-5000-2s1p-hardcase.html
The total for all that was about 25$ more if I just got two 8.4v 5000 mah.
So if these lipos would be a big improvement to my fun time with the car I would go for them but if they are not gonna be a big improvement I may just stay with the nihm batterys.
By the way my esc is an lrp runner with reverse and I also have a lrp icp digital sport. Old school compared to what is out there now but they where both new when I used to race around with the rc10.
Thanks in advance.
Re: Questions about going lipo.
Posted: Fri Dec 14, 2012 12:50 pm
by Charlie don't surf
Lipo won't give you longer run time per se over NiMh. Mah (mili amp hours) is the same either way, 5000mah is 5000mah- NiMh are unstable and difficult to keep good, where lipo is going to be more expensive with new equip and such. Either way you'll have about the same amount of fun!
Re: Questions about going lipo.
Posted: Fri Dec 14, 2012 1:03 pm
by Boredome
ok.
stupid question but i think i read this right or i can be totaly wrong.
is this true like how nihm batterys are great for the first couple minutes then they get slower slower and slower then just stop. and lipos hold the full power of the car till the cut off shuts buzzs/shutdown.?
sorry for stupid questions just alot has changed since i put them in the closet.
and the stuff in the link is it decent stuff for the price or is it garbage?
and how are lipos shelf life?
Re: Questions about going lipo.
Posted: Fri Dec 14, 2012 1:09 pm
by jwscab
everything you have selected will work fine, good choices.
yes, Lipo batteries sustain the operating voltage for a longer duration and then will quickly dump, however, at that point, you need to stop discharging immediately. Your voltage monitor will be yelling at you at that point anyway. NiMh has a more linear discharge cuve, they will keep going slower and slower until depleted. They are finicky with charging and storage voltage. Lipo's are easier in that respect, with the lipo balancing charger you selected, and keep the cells partially discharged when storing, they can be store for quite a long time.
Re: Questions about going lipo.
Posted: Fri Dec 14, 2012 1:22 pm
by Boredome
ok thanks
and what are good battery plugs to connect to the esc?
i had the older ones and i remember them always melting from poor contact from vibrating/bouncing around.
they looked like this
Re: Questions about going lipo.
Posted: Fri Dec 14, 2012 1:46 pm
by jwscab
the old molex/tamiya style connectors are a terrible choice for any high current application. I have used sermos/powerpole/duratrax as well as the newer style deans plug, either is a good choice. There are also others, EC3, EC4? something like that, they are essentially bullet style connectors in a duplex housing.
whatever you chose, you need females for the battery and males for the esc and charger.(just pointing out to not forget about the charger).
I currently use deans 'T' plugs, the newer style or available clones.
Re: Questions about going lipo.
Posted: Fri Dec 14, 2012 2:08 pm
by Boredome
ok are these one similar to what you are using?
and have you had any connecting problems with them?
http://www.ebay.com/itm/120991023870?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
Re: Questions about going lipo.
Posted: Fri Dec 14, 2012 3:20 pm
by jwscab
I have heard of people having issues with the clones, but I have not seen any issues.
Re: Questions about going lipo.
Posted: Fri Dec 14, 2012 4:12 pm
by Charlie don't surf
The only issue I have seen with the knock offs is poor solder connection if the surface isn't prepped- deans seem to be fine unprepared-
Re: Questions about going lipo.
Posted: Fri Dec 14, 2012 5:40 pm
by Boredome
Ok. And what do you mean by not prepared solder surface? Should I scuff them with sand paper to give the scolded something to stick to?
Re: Questions about going lipo.
Posted: Sat Dec 15, 2012 12:44 am
by Charlie don't surf
Yep
Re: Questions about going lipo.
Posted: Sat Dec 15, 2012 1:36 am
by Boredome
Ok simple enough then.
And getting off topic a little bit I know I said I wouldn't go brushless but I didnt know I could get a set up for under $70.
But is this a good set up for my rc10 Goldpan?
http://www.hobbypartz.com/96m10-car-2848-3000.html
http://www.hobbypartz.com/hobbywing-ezrun-35a-brushless-esc.html
Re: Questions about going lipo.
Posted: Sat Dec 15, 2012 10:22 am
by Charlie don't surf
Those are fine, there are better systems that are easier to program, smoother on throttle etc- but those will work just fine and not be overkill on power.
Re: Questions about going lipo.
Posted: Sat Dec 15, 2012 11:16 am
by dldiaz
Charlie don't surf wrote:Lipo won't give you longer run time per se over NiMh. Mah (mili amp hours) is the same either way, 5000mah is 5000mah
I am no expert, but, I thought LiPo would give longer run times from the same "mah" rating by virtue of lower internal resistance... In other words LiPo's don't lose power that turns into heat.
With Nickel based batteries, a lot of your "juice" is wasted making all the heat they produce during a run (heat requires energy, which could otherwise be used for a longer run time, as with LiPo's).
On another note, my favorite thing about LiPo's is that they don't lose their charge while sitting for a couple days - I charge all my batteries during the week, then I don't even bring a charger to the playground on the weekend.

Re: Questions about going lipo.
Posted: Sat Dec 15, 2012 11:42 am
by knucklebuster
You are also not wasting energy to push around additional weight. Lipos weigh less.