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Old Oct 27, 2011, 08:20 AM
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It's like your psychic! I actually just did exactly that and from the same vendor, too, woah!

I've made several packs and I quite enjoy the soldering challenge with my old eyes but, considering the difference, in this case, was about 2-3 bucks a pack, I just said fuhgedaboudit and bought the pretty one.
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Old Oct 27, 2011, 08:03 PM
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Whilst I'm waiting, I velcroed an old 730 MaH 2S lipo onto the chassis to get a feel for lipo in this application and yeah, despite the added weight, the car accelerates better and has higher top speed. Can't wait for the 240 packs to get the weight back in line and see what it does then....
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Old Oct 31, 2011, 11:50 AM
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Originally Posted by wparsons View Post

I really like the hyperion batteries but I would stay aeay from those packs. No balance leads, at least none in the picture.


I have been making my own packs for some time now using the bare hyperion cells. I just install the balance lead and use that as the main discharge plug as well with no problems at all.

I buy the balance leads from Hobbyking and the wire gauge is the same as the wire gauge that came with the premade packs I purchased before starting to make my own plugs.

I am running my packs in a modified SCT that uses an 8750kv motor on a large open track. Pretty much wide open throttle the entire 4 minute race with no issues.

I even have about 4 packs I made from the Rhino 360 packs from Hobbyking. Those are buy far the cheapest way to make packs and they hold up great.
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Old Nov 02, 2011, 08:45 AM
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The need for balancing on cells this small isn't really an issue. That's more important on bigger packs.

My latest problem is my ancient Electrifly polycharge charger is fubar and won't charge the car's packs so, I'm off the road until I can get another charger.

While I was at it, I ordered an EDF 50 motor. I've already done the magnet mod on the stocker and the car is hilariously uncontrollable on the gym floor I run it on...next step, even more power and gear it for speed, bwahahaha!
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Old Nov 03, 2011, 12:30 PM
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Originally Posted by ho50ca View Post
The need for balancing on cells this small isn't really an issue. That's more important on bigger packs.
Not true. While the potential for fire and property damage is considerably smaller with these small packs, the potential is still there.

For me it is more of a concern for pack longevity. If a lipo cell drops below 2.85 the chemistry begins to change and the life span of the battery is lessened and that cell cannot hold voltage under load as it once did.

Without an occasional balance charge, the packs can become unbalanced. As you continue to discharge and charge the pack the cells can get even more imbalanced as chargers only look at the packs total voltage while charging, not the voltage of each cell as it would when balancing.

For example, if you have a cell that discharges slightly faster than the other the ESC willl cut off the car at 6volts. It could be one cell is 2.9 and the other is 3.1.

While this difference isn't big, the problem arrises when you charge/discharge an unbalanced pack. When you charge the above pack it will stop charging at 8.4 total volts on the pack. That would be approximately 4.5 volts on one cell and 3.9 on the other. As it discharges again they will get even further out of balance.

Now, I am exaggerating the time it would take for a pack to get this far out of balance but the above happens with all packs and unless balanced occassionally, your pack will start a downward spiral and potentially swell/rupture, or just not take a charge and become usless.

For me, why take the chance. I balance every pack I have, everytime I charge it.
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Old Nov 03, 2011, 01:33 PM
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Nothing wrong with balancing. However, you are indeed exaggerating the necessity for balancing and the possibility of damage, in packs of this size.

Plus, packs this size are pennies. I have gotten hundreds of charge cycles out of far larger packs and they're still good to go, years on. I really should be occasionally balance charging those packs but, I didn't have a balancing charger at the time.

The wee packs I have that are without a balance tap, I expect I'll get hundreds of charge cycles out of them and they are super cheap to replace, in the event of eventual failure.
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Old Nov 06, 2011, 11:33 AM
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True, my hyperion packs stay within an acceptable balance longer than my cheap rhino batts. It isn't the battery life that I am as much concerned about but the damage that can result from a damaged pack. My rhino packs don't discharge as evenly as my hyperions and I have to balance them more often.
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Old Nov 07, 2011, 07:15 PM
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it never hurts to balance a lipo regardless of size. If it catch fire or blows smoke out, the smoke is toxic to breathe, I wouldn't want it in my house. and fire takes a $110 model and $40 brushless system to junk. all over a $10 battery.
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Old Nov 07, 2011, 10:07 PM
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Ever had one actually light up? I've beat the sh$t out of lipos and never had the fabled lipo fire ensue. I have a couple puffies (out of dozens of cells) and I stop using them at that point, even though they show ok on the DVOM. Not that it CAN'T happen, it's just pretty unlikely. I charge my batts outside (Car battery based charger) so the risk is pretty slight to the house, anyway.

On another hopefully less controversial point...I just decided that there's nothing that can be done for the stock motor in this car, even with the magnet mod, so, I stuck an EDF 50 in there and the smallest pinion in the package...I'm hoping for a big speed increase when matched with the 2S Hyperions. We'll see tomorrow
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Old Nov 08, 2011, 05:42 AM
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not only have i had them light up, alot of people have had there houe burn down because of thinking that such a little cell cold not hurt much . on the micro heli forum from a single 500 mah cell burnt him badly another lost his house lipos are not to be underestimated . although they have open new possabilities in the hobby due to weight reduction and voltage they have also opened a new level of danger for the new hobbiest .
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Old Nov 08, 2011, 10:50 AM
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Alot of people? Really dude? Don't assume because you've heard 1 or 2 reports here that this is common. That's called an attributional error. There's thousands of people charging lipos on this site and who's reporting their repeated successes?

Besides, what's wrong with charging your lipos in an ammo box, coffee can or a lipo safe? Or not leaving them unattended? That's just fine and has nothing to do with whether balancing would have prevented those fires, which I doubt.
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Old Nov 08, 2011, 05:24 PM
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Originally Posted by ho50ca View Post
Alot of people? Really dude? Don't assume because you've heard 1 or 2 reports here that this is common. That's called an attributional error. There's thousands of people charging lipos on this site and who's reporting their repeated successes?

Besides, what's wrong with charging your lipos in an ammo box, coffee can or a lipo safe? Or not leaving them unattended? That's just fine and has nothing to do with whether balancing would have prevented those fires, which I doubt.
ok first ive been in rc for over 25 years so i dont iassume anything it's know it all people who are the one's who get bit . i was pointing out a few that have had major problems from a single thread on rc groups if i wanted to do some home work i bet i could find thousands if not more . and nothing is wrong with charging in an ammo box i never said there was . lipos when balance charging or not can and will catch fire its the nature of the beast there is no paper stating that in so many uses it will fail . and you seem to for get that they are mass produced and most anything mass produced will have bad batches and thouse are the ones that give the most danger when they go bad some puff and give warning and some dont just puff they ruin the rc they are in or catch fire . i was simply pointing out to use caution and was not pointing the finger at you but seems you have a guilty mind pointing me out .
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Old Nov 13, 2011, 07:10 PM
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New Micro SCT owner

Hi, all...

Just picked up a white/red/black truck today. I converted it to LiPo right away. I used the same connector as what's used on Eflite's UMX Beast/Sbach/Stryker 180, so I can use my homebrew Hyperion 240 mAh 2s packs. Had fun doing laps around the driveway & playing around with shock settings. I've run a few packs, and the motor seems to be breaking-in OK. I am impressed with how controllable it is at speed & how well the stock suspension handles the bumps - considering the scale. Thinking about getting the Spektrum 2.4 GHz brushless kit.

Joel
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Old Nov 14, 2011, 09:46 AM
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I stuck a $10 EDF 50 brushed motor in it and am about to go 3S lipo, using 180 single cells. I'm well into the mid 20 mph range as it is, hoping to bust 30 on 3S. All's well so far. I might toss a voltage regulator in line with the ESC, to make sure it lives happy on 5v.
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Old Nov 14, 2011, 01:35 PM
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SCT on-board video

Decided to mount my trusty #3 keychain cam to the roof & take her for a spin outdoors. The video is rough, but it's smoother than I expected it to be. Watch for the flip @ 4:20 - while I was jumping the bump at the entrance to my driveway.

Anyone running taller gearing with the stock motor on a 2s pack? I'm still running the stock 12/58 gears. It only took 100-110 mAh to recharge my Hyp 240 2s pack after the 7:20 min run, which included lots of WOT driving. Was thinking about gearing-up a bit.

Losi Micro SCT - on-board video (7 min 20 sec)


Joel
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