Lipo - Another Convert

[hibbs]

Like many before me I am considering lipos. I've been reading posts on here for hours and become increasingly confused. I have a few questions if you guys wouldn't mind.

I have 2 trucks - AX10/SCX10 both running FXRs/55t integy- I mostly do trail running and some rock crawling. Waterproofing is a big issue for me. I have packed my axles/trans with grease and my runtimes are poor (~30 mins)with NiMH even at 4200/5000 mah 7 cell/ batteries (cheap duratrax). I think this added friction/strain is killing the runtime. I was hoping to get some runtime back, an hour or more from a 3s with a 35t or 45t would be nice

1. Is the hitec x4 a decent charger? (or the clones);I would like to charge multiple packs at once

2.Is water a concern for lipos or no, the maxamps are awfully expensive for 11.1v with higher mah ($130 for one battery )?

3. Do I need to look at higher C rating since there is likely a strong draw given the friction in the drivetrain from the grease (or maybe I'm wrong)?

[Duuuuuuuude]

1. I don't have an answer on that one...

2. There are a few people here who have waterproofed their own lipos. Just search "waterproof" and read what comes up.

3. The higher the c rating, the better off you are (though there is no real need to get super high c ratings unless you plan to have really heavy loads on the system). Unless you go with a higher mah pack, low c ratings are easy to exceed. Anything less than a 20c should be avoided as far as I'm concerned...even being cautious its easy to over amp them.

If you don't know how to do the amperage math on lipo's, its easy.

Take the mah, move the decimal point over three places, and multiply it by the c rating.

Example: 2000mah 30c lipo = 2.0 x 30 = 60 amps.

[menace]

If lipos are exposed to oxygen they combust--so they are naturally waterproof--if they weren't they would explode right after being manufactured--that said you don't want to expose the balance taps any more than you have to as shorts between cells can also make them go poof.

[chevellian]

1. Looks like a nice charger with all the features you would need. I don't have any experience with this charger.

2. Although lipo's are already waterproof, I seal mine around the shrink wrap with clear rtv silicone and fill the taps with dielectric grease for added security.

3. What the Dude said. There is a lot of good info here: Team3six


I am a bit concerned about your current run times. Axial rigs with 55t motors should be running for hours on a 5000mah battery. I run a 10lb scaler with a 45t motor and the axles and tranny are packed with grease, I get around 1 hour of run time with only a 2000mah battery. You may see increased run time with a lipo battery compared to nimh because they seem to have more energy and you would be using less throttle, but mah is mah no matter what architecture the battery is.

[bob1961]

my 55t holmes hand wound motor in my 7 lb crawler gave me over an hour run time on each of 7 batteries i made from 1500 elites cells....sounds like something is up with your system or batt's.......bob

....

[killswitch]

I'd say a big part of it is the "duratrax" on the batttery labels. I've never seen a duratrash battery ever produce decent numbers or performance before. Another part of that issue is the weight you are lugging around with the huge NiMH cells. I'd probably remove some of the grease you have in your drivetrain too. As long as everything is coated, you should be ok. Plus, if you are going in the water/mud on the regular, you need to step up the maintenance and make sure your drivetrain is in good working order. WD40 can be used before hand to help displace some of the water and bearings can be replaced on the cheap if you go through avidrc or dont mind waiting for bearings from hong kong. As far as runtime goes, I was able to squeak about an hour and 10 minutes when using a 55t and 1350mah 3 cell TP pack in a 2.2 axial based truck. Same packs with a built 35t in the same truck and I get about 35-45 minutes, depending on terrain and how throttle heavy I am.

[racerrandy]

I bought a tranny from a guy that had it packed with grease and the drag was horrible, I took it apart and cleaned it then just lubed the bearings. You don't need it completely packed to protect the bearings and your runtime would have to get much better.





Randy

[hibbs]

Thank you all for your helpful replies! Sounds like the issue is with my trucks more than the battery type. I used to get ~1.5 hours before going to 2.2 tires, lots of wheel weights packing the axles, etc. I have considered taking some of the grease out of the axles/trans but it is nice peace of mind knowing almost no water can get in because of excess grease. I do try to take care of my battery packs, I RTV the ends and don't top off/store drained. 2 are 7C electrifly 3000mah, 2 duratrax 7C 4200mah, 1 venom 8C 5000mah (I know they're cheap-o). It is very difficult to spin the pinion on an assembled axle so I'm going to have to do something different with the waterproofing before jumping into lipo. Thanks guys you've saved me lots of $

@ chevellian- I just use general purpose grease so maybe its too thick? What type are you using/where do you buy it from?

[losikid]

i don't suggest max amps when you do go lipo, their over priced and over rated in my opinion, my 4 cheap Chinese batts preform lots better than the two max amps i have, i also contacted maxamps about this and they told me their battery wasn't designed for a lcc so that is my problem and they weren't going to do nothing, so their over priced packs are to pay for advertising not customer service or quality packs.

If you want to go super cheap, hobbypartz.com is the cheapest (but they don't last long, i've been through 3 batts out of the 4 i bought there), next place is hobbyking.com, and get the turnigy packs, they also now have turnigy nano-tech but i've never used them, so i can't comment on them but the regular turnigies seem like a decent lipo i've had a few from day one and they are still going strong, quite puffy though. and if you are feeling to pay the extra $ for a quality lipo get the elite packs from cheapbatterypacks.com, i haven't used them but all the reviews i have read say they are top notch, better than any other battery they have used. I haven't bought them yet because i have 5 lipos right now and i don't need anymore...

[chevellian]

I use marine grease I got from Ace.

[M1tch]

i have just gone from 7.2v nimh to 3s lipo on my clod stick and am impressed. i use tipple 1300Mah packs which are giving me at least twice the run time of my old 6xAA 2600 packs, plus more power (30C-enough to break stuff today!!). i bought them locally with a charger. i would not go back to nimh.

get a good charger, dont skimp on quality as you will regret it

i use marine grease, or if there is a cycle shop around try asking if they have something suitable. its not worth packing everything full of grease as water can still get in. a regular strip and regrease is best policy. i ride mountain bikes all year and regularly check all bearings, sealed get just as bad as any other eventually