How to pick what size LiPo you need?

[Wilson]

I have my eye on a truck I may be thinking about buying here sometime but I am a total noob to electric rc's so I really don't know much about anything to do with them.

Is there a easy way to find out what size of a LiPo you need to power the rc? I know any LiPo will power it but what I'm wanting to know if there is some kind of way to get a average for run time.

I am getting mixed findings on what size that would work best, I'm seeing that some people say a 5000mah is fine and others say you need a bigger one.

Since I really don't have much of an idea I would just kind of like to know how to figure out what I am going to need. I would rather understand what I need rather go off what I read in forums lol.

 

[Rooky]

I'm not sure how yiu go about figuring it. I usually go with the biggest I can afford.
That being said, its difficult to figure, because there's no standard for labeling them. Its almost as bad as car audio was 15 years ago. Some rate this way, some rate that way. It's especially bad with the C rating. I would recommend a minimum 5000 mah with a minimum 35C discharge rate.
SPC sells good stuff. Venom has a terrific warranty. I also hear good things about SMC and MaxAmps. MaxAmps is more expensive than the rest, but are highly regarded. I've never had SMC or MaxAmps so I can't personally recommend them. I have a couple Duratrax lipos I'm happy with. I use them on a Mamba Monster system and they keep up in a 12 pound rig geared for 70 mph. (In fact they kept up way better than the rig itself)

Hope that didn't further confuse the issue.

 

[Wilson]

Thsts kind of what I was thinking also, Basically just get what I can afford. SMC sells a 9000 that isn't really that aweful expensive but I didn't want to get something so big unless it was actually needed.

With that being said, how about chargers? Do you need the chargers that charge two at once to get them ballanced or would one at a time be sufficient? Any good recommendations on chargers? Again they go from $30 to several hundred dollars, what is needed?

 

[X]

The most important thing is the "s" , the amount of cells. Usually people run between a total of 4s to 6s on savages. The "mAh" is basically your run time, so the larger you can get the longer you can run. The "c" in this case is your charge/ discharge rate. How much power your battery can send to your esc/ motor. You multiply the "c" rating by the mAh rating. So if you have a 5000mAh 35c battery it's peak output is 175 amps.

As far as chargers, the only real need is for it to be able to balance charge. People usually charge lipos at 1c ( in this case capacity). So a 5000mAh battery can be charged at 5A.

 

[Wilson]

Thanks for all the info guys. I'm thinking of buying a x-maxx that's why I'm wanting to use bigger LiPo packs. I'm just trying to get everything in order so I can lay everything out and make sure everything is going to work out as well as don't break the bank lol.

These are the lipos I am considering for right now.
http://www.smc-racing.net/index.php?route=product/product&path=67_99&product_id=348

And here is the charger I may go with.
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXFGRS&P=ML

It is only a 8 amp charger so if I charge two packs at time I'll be down to 4 amps, which may take a while to get them fully charged.

Being new to this I think these are some good choices but what do you all think? I am open to any other ideas, if I'm going to spend this much money I want it to be right.

I have heard good things about the batteries but the charger is just a regular run of the mill charger. Are there cheaper/better ones that I should go with?

 

[hpicelery]

The charger seems really convenient because it has a built-in power supply. That would probably work well for you, but you don't have to have a dual charger to charge two batteries at once. I use an iCharger 106B+
http://www.progressiverc.com/icharger-106b.html
with a paraboard so that I can charge up to 6 batteries at once, assuming they are all starting at about the same charge level.
Downside is that it doesn't have an internal power supply, so you'd have to buy one.

That battery looks interesting, but something worth noting is that it is a soft-case battery. Most folks I know use hard-case batteries because they're harder to damage through impacts. Perhaps more importantly, that thing is going to be HEAVY, though with a truck the size of the X-MAXX that might not be too big of an issue.

Bottom line: Both of those things would probably work fine for you.

 

[Rooky]

Not sure where you could get a good price, but I plan on getting a Hitec X4 charger. Used a buddy's and it is bad! Love it

 

[NightFlier X4.6]

I've been looking long and hard at smc's batteries and think I've found the battery type I want.just want to make sure it'll work OK. They are smc 2s 7.4 5200mah 50c. Any input would be appreciated thanks

 

[Wilson]

Those should work fine for you. I am running 2s in my savage and I think it has plenty of power.

 

[NightFlier X4.6]

Kool yea I plane on running two 2s lipos

 

[olds97_lss]

Well, like what was said earlier in the thread, the larger capacity gives you more run time.

I have 2 of the SMC 9000mah 2S packs for my brushless revo. I've only run it 3 times. Yesterday was the first time I ran it like I run a nitro. Lots of WOT runs through a park and lots of general running/jumping. I got about 40 minutes of run time.

Beings that I'm totally new to larger than micro brushless/LiPo world, I went with the traxxas dual ezpeak id charger. It takes over 3 hours to charge the 9000mah packs and I have to manually reset the charge at about 2 hours because the charger times out at 5000mah.

The packs seem to work well with my rig and they just fit in the battery bays. I don't think I could run anything larger as the hieght/width of these packs fills the bay with a little room to spare with length. I don't know the size of the HPI battery bays.

I'm now looking at the dynamite dync2050 charger because it will charge up to 10A/100W per output for 4 outputs. Which means my 3+ hours charge time will be 1 hour or less. I'm also going to order at least 1 more set of packs because 40 minutes just isn't that long.

 

[Wilson]

Yea wot really sucks the juice out of the lipos. Eventually I want to get a better charger, mines only a 5A so my charge times suffer a little bit.

I have some 5000mah zippy batteries and smc and I don't really have anything bad to say about them. I do think I favor the hard case batteries just because they are a little easier to wipe the dust off of after running.

 

[olds97_lss]

I pulled the pin and bought the 4x100watt dynamite. After charging my 9000mah packs 5 times on the traxxas dual (3+ hours each time), I'm kind of tired of that wait. Might try some of those floureon 8000mah packs off ebay for $65 for 2...