Warning to anyone new to RC and Lipo batterys

[kyleservicetech]

Originally Posted by booterspaw

Thanks guys. I'll check all of these out. Like I say, I can use all the help I can get! I've got a dream of some day making my 20 yr. old Goldberg Cub electric. I guess we all have to have a dream. (That is if the wing is still good enough to fly.)

Interesting: What is the wingspan and wing area of your Cub?

What can help in your project is one of those computer spreadsheets such as www.motocalc.com, free for 30 days, then its $39.00.

If you've got a larger model, perhaps 6 or 8 pounds or more, you might want to put in higher quality equipment. Take a look:

Thread on model with 70 size glow engine conversion to electric
http://www.wattflyer.com/forums/showthread.php?t=45222

A Hacker A50-12S motor with a 5 cell Lipo power pack will outperform a 70 size 4 stroke glow engine. Of course the glow engine can have longer flights on a tank of fuel, but the electric version can easily be set up to give 8 minute flights on a charge.

[booterspaw]

It's a 76". Rated for a 40-61.

[kenchiroalpha]

Originally Posted by kyleservicetech

Interesting: What is the wingspan and wing area of your Cub?

What can help in your project is one of those computer spreadsheets such as www.motocalc.com, free for 30 days, then its $39.00.

If you've got a larger model, perhaps 6 or 8 pounds or more, you might want to put in higher quality equipment. Take a look:

Thread on model with 70 size glow engine conversion to electric
http://www.wattflyer.com/forums/showthread.php?t=45222

A Hacker A50-12S motor with a 5 cell Lipo power pack will outperform a 70 size 4 stroke glow engine. Of course the glow engine can have longer flights on a tank of fuel, but the electric version can easily be set up to give 8 minute flights on a charge.

Hi Dennis
Ive had good results with these free programs
Fixed wing
http://www.brantuas.com/ezcalc/dma1.asp
Helicopter
http://dhrc.rchomepage.com/calcAdvanced.htm
Take care dear friend
Yours Hank

[kyleservicetech]

Originally Posted by booterspaw

It's a 76". Rated for a 40-61.

Or, take a look at a Hacker A50-16S with a 16X12 APC-E prop and a 5S Lipo pack.

I've got one, and it works very well with a similar capability 6S2P A123 pack. It turns that prop at about 6000 RPM.

[kyleservicetech]

Originally Posted by kenchiroalpha

Hi Dennis
Ive had good results with these free programs
Fixed wing
http://www.brantuas.com/ezcalc/dma1.asp
Helicopter
http://dhrc.rchomepage.com/calcAdvanced.htm
Take care dear friend
Yours Hank

Hi Hank
Looked at Brantuas, they only list a couple of the Hacker motors I like to use.

But, the price is right.

[booterspaw]

Originally Posted by kyleservicetech

Or, take a look at a Hacker A50-16S with a 16X12 APC-E prop and a 5S Lipo pack.

I've got one, and it works very well with a similar capability 6S2P A123 pack. It turns that prop at about 6000 RPM.

What's the best sight to check that out on?

[kenchiroalpha]

Originally Posted by booterspaw

What's the best sight to check that out on?

Hi
Pleased to meet you
Ive a few Hackers as well
http://www.aero-model.com/Hacker-Brushless-Motors.aspx
http://www.hackerbrushless.com/Motor...tionChart.aspx
Hacker homepage
http://www.hacker-motor.com/en/home/index.html
Take care
Yours Hank

[kyleservicetech]

Originally Posted by kenchiroalpha

Hi
Pleased to meet you
Ive a few Hackers as well
http://www.aero-model.com/Hacker-Brushless-Motors.aspx
http://www.hackerbrushless.com/Motor...tionChart.aspx
Hacker homepage
http://www.hacker-motor.com/en/home/index.html
Take care
Yours Hank

I've purchased a motor from here several years ago, no problems noted:
http://www.rctoys.com/rc-products/HA-A50-16S.html

And you can actually run those Hacker motors at their rated power and not overheat them.

[booterspaw]

Got a problem. I was soldering wires to a deans connector, touched the two wires together and got a spark. Do you think I ruined the battery ?

[zzlentz]

No.Try it and see.

[booterspaw]

Thank ya sir. I hope you're right. It's a BRAND NEW battery. THANKS AGAIN

[Rockin Robbins]

Originally Posted by zzlentz

How do I know the battery is balanced?
Do the chargers that come with the plane shut down auto. after full charge.
Do I need to sit and watch it charge?Or can i go fishing?
I'm new to this you know,and you're scaring the hell out of me.

You know your battery is balanced in only one way. You take a voltage meter and test each individual cell's voltage using the usually white balancing plug of your battery. This plug has a common ground wire and one wire from the positive side of each cell. Testing the voltage between each positive wire and ground should tell you each cell has the same voltage. If they don't your pack isn't balanced.

Now over at RCModelReviews, specific video on this at http://www.youtube.com/user/RCModelR.../0/qX1L77LzQuU, he has found that some balancing chargers are so far out of calibration that they potentially seriously UNbalance your packs. He's promised testing of major and minor brands and instructions on how to fix your charger if it needs it.

Wonder how my Parkzone charger is going to pan out? But the gold standard is a voltage meter. Don't trust your charger! Be from Missouri and make the voltmeter show you! Then if it shows your charger balances the cells properly you should only check infrequently. You're good to go.

[kyleservicetech]

Originally Posted by zzlentz

How do I know the battery is balanced?
Do the chargers that come with the plane shut down auto. after full charge.
Do I need to sit and watch it charge?Or can i go fishing?
I'm new to this you know,and you're scaring the hell out of me.

The Cellpro (Cellpro 4S, 10S, and Powerlab 8) line of chargers balance the cells while charging, and will bring up any low cells before charging the entire pack.

And at least my Powerlab 8 charger allows reading the voltage of any cell while charging the battery pack.

[Rockin Robbins]

Denny, have you found any of your chargers not properly balancing packs? I'm absolutely positive you've checked them carefully. I'm very curious what that review is going to find, because what prompted the review was the finding that one of his supposedly reliable balancing chargers was seriously unbalancing his packs.

Here is one reason you (collective you, not talking just to Denny, who knows more than I do) don't want to run your LiPos down to LVC if your LVC is set down near 3V per cell. Suppose your balancing charger gives you a half-volt difference between most charged and least charged cell, and the two top cells are the same voltage. Sure that would be a lot but bear with me. Now your particular LVC is 3¼ volts per cell or 9¾ volts for a three cell pack. And you do that--run it down to LVC.

If all cells have drained at the same rate, you now have two cells just a tad more than 3¼ volts and one a tad less than 3. It's now damaged and may not recharge properly. Repeated runs to LVC will compound the damage until you're left with junk.

A few ESCs monitor the individual cells of your battery and call LVC when the first one reaches the trigger voltage. But that is no safer than just refusing to depend on low voltage cutoff and using a timer yourself to ensure that you land before LVC.

Do it! Your batteries will thank you for it and live much longer. And check out your charger regularly. Trust but verify. It works every time it's tried.

[kyleservicetech]

Originally Posted by Rockin Robbins

Denny, have you found any of your chargers not properly balancing packs? I'm absolutely positive you've checked them carefully. I'm very curious what that review is going to find, because what prompted the review was the finding that one of his supposedly reliable balancing chargers was seriously unbalancing his packs.

Here is one reason you (collective you, not talking just to Denny, who knows more than I do) don't want to run your LiPos down to LVC if your LVC is set down near 3V per cell. Suppose your balancing charger gives you a half-volt difference between most charged and least charged cell, and the two top cells are the same voltage. Sure that would be a lot but bear with me. Now your particular LVC is 3¼ volts per cell or 9¾ volts for a three cell pack. And you do that--run it down to LVC.

If all cells have drained at the same rate, you now have two cells just a tad more than 3¼ volts and one a tad less than 3. It's now damaged and may not recharge properly. Repeated runs to LVC will compound the damage until you're left with junk.

A few ESCs monitor the individual cells of your battery and call LVC when the first one reaches the trigger voltage. But that is no safer than just refusing to depend on low voltage cutoff and using a timer yourself to ensure that you land before LVC.

Do it! Your batteries will thank you for it and live much longer. And check out your charger regularly. Trust but verify. It works every time it's tried.

You hit the nail on the head for running any battery pack to LVC (Low Voltage Cutoff). Take a look at chapter XIV on my thread below:
http://www.wattflyer.com/forums/showthread.php?t=45222

As for chargers, up until now, I designed and built my own 350 watt chargers for my A123 battery packs. Worked well, but did not include any cell balancing. And in another thread, IMHO, those balancers such as the Astroflight "Little Blinky" configured for the A123 cells simply do not work. The voltage discharge curve on the A123 cells is just to flat.

When Cellpro came out with their Powerlab 8, I bought one. Very nice unit, far better than anything I built.

And, out of curiosity, I took one of my two cell receiver 2300 Mah A123 packs, and discharged just one of the two cells to about 3 volts DC, completely running it down.

Then the two cell A123 pack, with one cell at full charge, and the other cell completely flat, was connected to the Powerlab 8 charger, along with the balance cables. The '8 charger had been previously configured to charge at a one ampere rate.

The Cellpro Powerlab 8 went into its "Safe Mode", and brought up the low cell first to the same voltage as the charged cell, a voltage of 3.4 Volts DC. Apparently zero charge current was applied to the fully charged cell during the first portion of the charge cycle.

The '8 charge rate was downgraded in the safe mode to 0.5 Amps. Bringing up the low cell took several hours. Then after both cells were at 3.4 Volts DC, the '8 charger brought the pair of them up to the proper 3.65 Volts DC.

Nice machine.

[Rockin Robbins]

Originally Posted by kyleservicetech

The '8 charge rate was downgraded in the safe mode to 0.5 Amps. Bringing up the low cell took several hours. Then after both cells were at 3.4 Volts DC, the '8 charger brought the pair of them up to the proper 3.65 Volts DC.

Nice machine.

Well that one sure passes the test! Now lets see which ones aren't working properly. Could take a week or two but results will be interesting.

Holy cow! I just checked RCModelReviews.com and he has the best charging tutorial I've seen so far, which he uses as a teaser for his upcoming expose on which chargers don't balance properly. And he reiterated that he's not out to trash reputations, he's going to show how to recalibrate the charger so it works properly and balances your cells. This is just an outstanding video and even experienced fliers will learn something. I did. But then I don't consider myself an experienced flier yet.

[Gamerjoe]

Is the Lipo Sack product a recommended choice for helping to contain lipo fires when charging? Are there better bags than this one?

[Rockin Robbins]

Sure there are! I use a concrete block on top of a 1.5" thick paver stone. Much better insulation than a lipo bag. No worries, mate!

[Softfx]

Good info...

[AugieDog]

Appreciate the info

[AEAJR]

I like to jump in here from time to time to level set this stuff.

Lipos are not particularly dangerous, as long as you follow instructions.

Charge them in a fireproof container. Just like putting on your seat belt. Doesn't mean you expect to have an accident but the small effort can save you big time if that one in a million event happens. It is easy so why not do it. I use a coffee can.

Charge them using the right kind of charger. Duhhh! In the early times people were using NimH charger for lipos and turning them into bombs. (RTFM - read the friendly manual)

Balance them from time to time. Every time is best but one in 10 is probably adequate. They will last longer and run better. Once they get out of balance their performance goes down, their life goes down and the chance of a bad thing happening goes up.


Charge them at the right rate. Unless your charger or battery maker tell you otherwise, you charge at 1C or less.


Run them below their maximum C discharge level. If the pack is rated for 20C, then don't run those batteries more than 16C for continuous use. Running them at 20C, or whatever their max rate is, puts a real heavy load on the pack especially if you run them at that level for a long time, like the full capacity of the pack. Life will be shortened.

If there is a burst rating, that means burst, like 10 seconds, not 10 minutes.


Any battery can fail and any battery can start a fire. The only pack I ever had catch fire was a NiMh pack. Never had a Lipo pack catch fire, puff up or otherwise do anything bad. I have worn a couple out. And I have damaged a couple by shorting out the leads. No explosions, I just ruined the pack.

RTFM, use common sense, take reasonable precautions with ALL of your battery packs and you will have few problems.

Plan for the worst and you will always be safe.

Like life insurance. You are betting you are going to die. They are betting you are going to live. You hope they win!

You expect the lipo to explode. The lipo doesn't explode. Your expectations are not met. You win!

Have a nice day!

[C-47]

Hello all,

So lets say hypothetically, that you take your plane out one day on its maiden flight and you crash into a tree. Now lets say it stays in that tree for a week with the battery in the plane on till it died. And after a ... ton of work with a skilled archer, fishing line, and a few cops thinking this is the funniest thing they have ever seen. What repercussions should one take if they did get that plane down? Hypothetically speaking of course....

1. Will the battery be OK to use?

2. When you charge a lipo battery, do balance chargers always make a hi pitch noise?

3. are lipos kind of puffy? what are they supposed to feel like?

[zzlentz]

My god!!! Just throw it away!!!!!!!

[Flywhat2]

Originally Posted by C-47

Hello all,

So lets say hypothetically, that you take your plane out one day on its maiden flight and you crash into a tree. Now lets say it stays in that tree for a week with the battery in the plane on till it died. And after ... ton of work with a skilled archer, fishing line, and a few cops thinking this is the funniest thing they have ever seen. What repercussions should one take if they did get that plane down? Hypothetically speaking of course....

1. Will the battery be OK to use?

2. When you charge a lipo battery, do balance chargers always make a hi pitch noise?

3. are lipos kind of puffy? what are they supposed to feel like?

When I say same exp. I mean literally. Had mine up about 40 feet , near end of branch. Made a simple bow, 3/8 x 36" dowel as arrow weightd w/3/8 nut. Light line tied to strong nylon cord. Public park. Shot at least 5 times, finally got cord over, jiggled furiously, plane came down, pulled out of dive and landed gracefuly.

1. Battery is DEAD, useless!!
2. No, chargers are NOT supposed to emit hi-pitched sound.
3. Puffy is DANGEROUS!

4. SCRAP IT!! CAREFULLY!!

5. Don't fly near the edges of space!!

Condolences, Fly

[FLOYD V. ULRICH]

A few years back, I put my plane in the top of a 50 foot tree. No way to get it down. Went to the local fire company and they put their big ladder up . one of the fireman climbed up and brought it down. They asked nothing but a thanks. A donation is well worth getting the plane back.