Weird ESC Problems - RC-Monster Forums

Major Azzwoopin · **Weird ESC Problems -** 07.13.2005, 10:27 PM

I got a Associated RC18MT a few weeks back. I have the mamba 5400 kit but haven't installed it yet. Well I was running the stock motor and ESC on two different battery configs. One was the stock 1100 mah 7.2 volt pack, the other was a maxamps LI PO pack of 2s2p 900mah cells.

The thing ran alot better on the LIPO packs, but the other day the ESC stopped "recognizing" the 8.4 volt lipo pack. When I connect it to the esc input and turn the switch on it does nothing. No lights nothing at all. I measured the voltage and it was at 8.4 I have let it drop and it is now at 8.2 and still nothing when connected to the LIPO pack. If I hook up a fully chared nimh 7.2 pack to the ESC it works fine. A fully charged venom 7.2 stick pack was reading in at 8.05v and it worked just great also...
Any ideas... Is that extra .15 of a volt beyond the tolerances of the ESC.. The ESc says it will work up to 8.5v??

I am lost..thinkin about just puttin the mamba in.
Only reason I haven't is my 2 and a half year old is having a blast with the rc18 with the stock motor and I wanted him to get a little more comfortable with the stock motor before I overwhelmed him with the mamba power. I'll have to post a vid when I get the chance. You won't beleive it is him running the thing. He runs it and my rottweiler chases it all over the place. I am amazed at his ability to control and get around obstacles and drive it right to where you want or ask him to.

gcurtis2121 · 07.13.2005, 10:58 PM

If I were you, I'd buy a new RC18T and let your son play with it. Meanwhile, slap the mamba in the one you've got and let 'er rip!

Major Azzwoopin · 07.13.2005, 11:08 PM

LOL... He can handle the mamba I know. He adjusted from a mini mauler to the stock RC18 in about an hour.
I'm building a brushless Savage with a 7xl for me to play with. I also have a new Emaxx that I am putting a HV-Maxx into.

I am going to have to start selling some vehicles on on ebay or something. I don't have enough time to run them all. We got a NITRO powered CEN CT4S, CEN Fun Factor stadium truck, Savage25 (soon to be BL), and a CEN Genesis. Electric we got a Mini Mauler, RC18MT mamba 5400, and an Emaxx HV-maxx.

gcurtis2121 · 07.14.2005, 12:14 AM

Man, that is a LOT of vehicles!

The HV is a good system, nice and easy to install, just plug and play. But if you're looking for power, go ahead and list that thing on ebay before you run it and get a 9L/9920 from Mike here at RC-Monster. It'll smoke that HV, you'll be amazed at the difference.

I ran an HV, for a very short time. Not impressed at all with the performance. I guess that's my fault though, because it is advertised as a "mild" brushless system. If you decide to go with the HV, visit the Novak site and check out their revised chart on gearing. There have been lots of problems with people having HV's overheating and thermaling due to improper gearing. They've been getting some bad press on some other forums.

Anyway, have a great time with your son, it's awesome that you and he can have a fun hobby together, especially at that age!

Take care and best wishes!

Serum · 07.14.2005, 01:47 AM

Weird thing with your mamba esc. measure the voltage of the lipoly once it is connected to the esc. Sounds like a dead battery to me.

Major Azzwoopin · 07.14.2005, 11:11 AM

Serum,
It is the stock ESC, I haven't put the mamba in yet. Good idea I will try that and check that voltage this evening when I get home.
Gcurtis,
It is awesome. All he wants to do is go to our LHS and run the "trucks" "which truck we gonna run daddy" which truck we fixin daddy. and man if we get something new I think he may actually get more excited than me...aaaaaaa maybe not. LOL

I might do that put the HV-Maxx on ebay and get a 9920 and 9l from mike for the emaxx.

Major Azzwoopin · 07.14.2005, 10:08 PM

Serum,
You were right it was a bad cell. It was a 2 cell lipo pack and one of the tabs busted off of one pack. 2s2p actually little cheap 900 mah packs. has anyone here had any problems with getting solder to stick to any lithium packs??? I got soem 900mah lipo packs from max amps and the positive leads had a little tag on the end. That tag would take solder but the lead itself wouldn't. Well one of the tags came off and I guess the pack is screwed. These other Lithium cells I bot from batteries america take solder on both leads real nicely.
Oh and I got that 5400 mamba installed in the rc18MT and I put together a 3s 1200mah pack (not sure on the C rating) and man does that thing scream. I don't see how people say the higher 6800 and the 8000kv kits are driveable. The thing was pretty tame on nimh 7.2 packs. maybe that is what they were runnin those bigger mamba kits on.

Serum · 07.15.2005, 01:49 AM

i thought that there was a special kind of tin, that could solder on that other part of the wire..

Dafni · 07.15.2005, 09:27 AM

Hey, good to hear Junior enjoys the hobby and got the hang of it so quickly. Amazing, at 2 and a half! My 5 year old son gets frustrated quite quickly when driving a big RC. He likes my MiniZ Monsters, though. I got one for me and one for him. He also likes to help me fixing my trucks, but he tends to hide screws and stuff in his pockets.
The other hobby I share with him is skateboarding. We're having a good time when we're out skating. Something more physically oriented, not bad either. RCing is more of a bad weather option for us, I mostly drive my BL's when the kids are asleep.

Major Azzwoopin · 07.15.2005, 10:59 AM

Deans solder works well on the batteries america lipo packs. but not at all on the positive lead only on the max amps pack. I tried some other normal (more lead) solder also and nothing to that positive lead on 3 packs now. So it isn't just the one. I even sanded and alcohol'd the leads also.
As for my little boy. It is awesome. He likes helping me work on them by getting me tools or opening parts. Sometimes he gets a vehicle that isn't broke, that I am not working on and turns it over to "fix it" also, while I'm workin on one. The electric vehicles he seems to do real good with. The nitro's he hasn't done as well with yet. Electric is so much easier for getting him involved with. No roto start or pull start, and no glow plugs, no engine stalling, and if it wrecks it won't stall if it flips upside down 100yds away.

On second thought I don't think he can handle the mamba yet. The Mamba rc18mt is most likely a bit too powerful. But he does handle part throttle real well. e doesn't just pull it wide open and go.

Dafni · 07.15.2005, 01:44 PM

Yeah, I know this pretending to "fix it" game. I just have to be carefull when he has those cutting pliers :eek:

My son loves to remove and change tires. And to stack them all.

Sorry for the off-topic hi-jack :o

I would also save the BL mini for the big boys. Stock is fast enough, I've heard.

Major Azzwoopin · 07.15.2005, 01:59 PM

My little guy loves to stack the tires also.
You are right on with the pliers/cutters too. Mine saw me use a pair of really sharp side cutters to cut a wire to length, before I soldered it. Now I have caught him getting ready to cut my antennae wire at least 2 times. It is so hard to keep all of the sharp stuff away. Things that look harmless can be real nasty to those little guys.

Dafni · 07.15.2005, 02:14 PM

My word. They keep you on your toes, eh? My son is allowed to use the side cutters, he loves to "snap" wires. I give him leftover wire and he collects the "Gold" in a zip bag. I explained to him it would be a pain to replace wires in a working truck, and so far had no troubles.
He uses to grab gears and screw sand stuff and puts them in his own boxes. But I know his hiding places ;)

Good to have another RC daddy here.

Yepp, the tire stacking can go out of controll. My daughter enjoys this, too. They make me take off all the tires.

Good luck, mate, and enjoy each and every day of fatherhood. They grow so fast. 2 and a half is a cute and funny age, my daughter is this age, too.