Pretty much stock Geico puffing lipo's.

[yhammack]

First off, I'd just like to say hello. I've searched the site quite a bit but haven't posted anything yet. Now I'm messing around with setups a little so I could use some advice.

My Geico boat is basically out of the box, I added an offset rudder and an Octura M445 prop that I cleaned up and balanced. Other than that, just programmed it for Lipo and set the throttle to 100%, low timing, no brake, high voltage cutoff and slow down cutoff type. I run 2x 2s 5400mah 50C SPC batteries with Traxxas connectors. The boat is setup pretty good, no bouncing, turns great, doesn't flip over. I'm pretty happy with it.... but the batteries swell up like crazy. They go back down after they cool off, but now one of them swelled up enough to split the hardcase open. Even after some short runs, just a few minutes, I can see them slightly puff. If I let it sit for a few minutes at this point, they come back down pretty quick.

So quesion is, what is my solution? Do I need to upgrade the motor/esc? Change the prop to something smaller? I would think I should be able to make more than a few passes without worrying about my batteries swelling up like a busted lip. lol.

[JimClark]

what is the voltage in the batteries after a run? How are the Temps of the motor esc and batteries? Any idea as to how long you ran it?

[lenny]

Hi,
What are SPC batteries ?
Is the prop sharpen and balanced good ?
What is the longest run that you got out of those cells ?
And how many mah go back in to the pack at a full charge ?

[yhammack]

I didn't check the motor/esc temps, I didn't think to bring a temp gun. It didn't feel too hot to the touch though, batteries were warm but not smoking hot. I didn't time the run, but I'm sure it was less than 10 minutes. Not all high speed runs either, some just crusing around and making sure the steering was good. I didn't run the batteries down to the cutoff, but I haven't checked how much is left in them. I'm sure it's in the mid 3's still though. I'll double check when I get home from work.

SPC batteries are Spec Point Concepts

http://www.specpointbatteries.com/

I used them when I raced stadium trucks, always had good luck so I bought more to run in the boat.
I haven't run them all the way to cutoff yet in the boat so I'm not sure, but runtimes in the truck were great. They are good quality batteries.

Prop is sharpened enough to cut your finger and balanced yes.

[martin]

Around 10mins is way to long a run time, keep to 3-4mins max.

[yhammack]

Even cruising like half throttle with an occasional full pass? Man, thought you would get more runtime than that. I see these videos of guys on 6s with big motors running back to back passes without swelling the lipo's.

Just checked the voltages.
Battery 1 (One that swelled the worst)
Cell 1: 3.83
Cell 2: 3.83

Battery 2 (Didn't swell as much)
Cell 1: 3.82
Cell 2: 3.81

They are both 2s2p, if that makes any difference.

[Fluid]

You did not run your packs down too much as the remaining voltage indicates, you are just a bit below half empty after averaging under 20 amps on your run. That would be very slow, I suspect you did not actually run for 10 minutes. Run time limits are usually either low pack voltage or high temperature one/all of the packs, motor, ESC. Running a long time can build up temperatures in the packs, and if they swell up but do back shrink down then high temps are probably the cause. If one cell stays puffed, then it probably overheated since the standing voltage is fine. Boats put a lot more stress on everything than cars do, based on their performance I doubt that those packs are really 50C. There is a lot of mislabeling on the cheaper "value" LiPo packs, but I know nothing about the SPC brand.

How to avoid this in the future? Limit the run time - but who wants to do that? Better quality packs would help - some "value brands" will just give up early.




.

[martin]

The 3-4mins isn't run time you will get from them packs its 3-4mins max then bring boat in to cool off before going out again.

[iop65]

don't use hardcase packs in high cont.amp draw things like FE boats
they are for cars: much lower cont. amp draw and therefore lower heat build-up
cruising along with half throttle is bad for your 60a esc, will get hot

a FE boat : 90% of your driving full throttle !

[ray schrauwen]

...also being 2S2P packs one cell may be dragging the other down. I would change batts to Dinogy or similar. You will love the difference. Stick with packs that are 1P too.

[MORIDE]

It is not the hardcase, I run Gens Ace 40c HC with no issues. Make sure your strut is set even with the bottom hull/pads. Check and grease your cable and make sure the motor mount is aligned. If this doesn't work try a X642, the 445 is great but will produce more heat. Most prefer softcase batteries but I use the Gens Ace hardcase 40c with no issues as I also use them in my trucks/cars. I do not know about those batteries but try something else, Gens, Zippy maybe.

[Megabiker98]

SPC batteries are a pretty well known/used name in the car/truck community, have heard OUTSTANDING reviews on their customer service and nothing but good things about their batteries. If someone has a problem with one they r always happy with the service. But I use hard case batteries in my boat, same 40c as moride and have not had a swelling occurs once. With a 4074, sealing 180 setup! Lol, how old r your batteries? Have they had a lot of cycles on them?!

[MORIDE]

Are the connectors hot?

[yhammack]

Thanks for the replies guys, I know these SPC batteries are much better than gens ace, zippy, etc. (I have some of these for my crawler and other rigs) On the track they have the same punch and life of the $100+ dollar trackpower batteries I had. I don't think quality is the issue.... maybe the 2s2p thing and the connectors could be part of it. Also the battery that is swelling is probably a year or two old, and probably cycled a good amount of times. It's been on the track and through my drift car more than anything.

Anybody else running the 445 prop with stock motor/esc without any issues? I see a lot of people upgrading their esc, so I was thinking that could be a next step. Or just change the prop I guess. But I'd like to work towards more stable speed, not less. :)

Connectors were warm yeah, I wouldn't say there were hot though.

[MORIDE]

Sounds like maybe the batteries internal resistance is high from use, boats draw much more current than cars/trucks. If you are running 4S with 445 you probably don't really need an ESC upgrade. If you want more speed you can upgrade ESC and run 5S with stock motor and get mid 40's, the stock motor is pretty nice actually, just depends on your goals. Upgrading your ESC 1st gives you lots of options. Good luck.