** LIPO BASICS ** Read me first!

[BrettOssman]

I have a Blade mCX2, mQX and mCPX2, so the batteries are 500mAh and less. I'm using the stock chargers, so nothing fancy. Sounds like I need a charger that also discharges and has a voltage indicator of some sort.

My mCX2 batteries have been sitting for weeks after a full charge, so they are probably toast.

How often should I check on batteries that have been sitting, to confirm they haven't discharged too much?

BTW, great stuff you posted. I never would have known.

Amazing this kind of info isn't in the manuals.

[Slyster]

Little packs aren't so important.. since they cost so little.. and I don't know what the little helis LVC is set to. I have a 130X.. and never have hit LVC, I time my flights to 4 minutes and have gone to 5.

Once you get into the $150+ 6s5000mah lipos it gets real important to take good care. Better chargers will also tell you cell voltages and mah put back in.

[BrettOssman]

True, cost isn't a big deal, but it is very annoying to go out to fly and have 3 of your 5 batteries toasted.

I'll have to see what they have in the way of chargers for these small packs. Based on what I know now, some features could include:

• Voltage readout
• Discharging (setting a voltage cutoff level would even be better)
• Mutilple battery capability

[BrettOssman]

I e-mailed Duratrax on this, but may get a quicker response here.

Just got an Onyx 235 yesterday with an adapter for charging up to 6 batteries simultaneously. For example, I have 5 EFlite, 1 cell, 1S, 200mAh, 3.7V LIPO batteries. Two are 25C and 3 are 30C. I also have 3 500mAh 12Cs.

The Onyx manual easily explains the setup for one battery, but how do I adjust for multiples. Do I just multiply all settings by the battery count, hence treating as one larger battery? Also, I'm assuming I can only parallel charge the exact same batteries with the same voltage level?

By the way, does the S, as in 1S, mean the cell count (e.g., 1S = 1 cell, 2S = 2 cell, etc.)?

Searched this thread, but didn't see anything about this.

Thanks

[Slyster]

First... Is the adapter a series adapter or parallel adapter? It would be helpful if you have a link for the charger/adapter you bought.

and are all your lipos 1 cell? (1s)

What heli are your packs for?

[BrettOssman]

Originally Posted by Slyster

First... Is the adapter a series adapter or parallel adapter? It would be helpful if you have a link for the charger/adapter you bought.

and are all your lipos 1 cell? (1s)

What heli are your packs for?

Charger:
http://www.duratrax.com/chargers/onyx/dtxp4235.html

Adapter:
http://www.progressiverc.com/paralle...-2-charge.html

All batteries are 1-cell (1s)

• The 500 mAh batteries are for a Blade mQX
• The 200 mAh batteries are for a Blade mCPX V2 (again, note that two are 25 and 3 are 30C)

[Slyster]

Yes that is a proper parallel cable. You can safely charge all your 1 cell (1s) packs together regardless of their capacity or C rating.

For every 500mah pack I would add 1A to the charge rate. And for every 200mah pack I would add .4A to the charger rate.

That would give you a 2C charge which is fine for those lipos.

So for example, if you were charging two 500mah packs and three 200mah packs... you would set the charger to 3.2A.

[BrettOssman]

Originally Posted by Slyster

Yes that is a proper parallel cable. You can safely charge all your 1 cell (1s) packs together regardless of their capacity or C rating.

For every 500mah pack I would add 1A to the charge rate. And for every 200mah pack I would add .4A to the charger rate.

That would give you a 2C charge which is fine for those lipos.

So for example, if you were charging two 500mah packs and three 200mah packs... you would set the charger to 3.2A.

Cool

I assume :

• Cell Count = # of batteries, since they are all 1s
• Capacity = Sum of the mAh
• Safety Time = no clue LOL
• Delta Peak (mv/C) = ???, looks like might be irrelevant
• Trickle Current (mA) = ???, looks like might be irrelevant
• Current = you covered that

[Slyster]

cell count stays 1s. (since they are in parallel and not in series)
Capacity.. yes just add them up.
Disable safety timer.. just don't charge unattended.

your charger will only 'see' a single 1s2000mah pack (or whatever the total capacity added up to)

[BrettOssman]

Thanks again for the advice.

The first parallel charge seemed to work. Will get a better idea on my next fly times. Any suggestions on a battery tester that would work for these small batteries? I would like to check voltages before and after parallel charging.

[Slyster]

Most chargers have a monitor mode to tell you the current voltage. Not sure about that one.

[BrettOssman]

Originally Posted by Slyster

cell count stays 1s. (since they are in parallel and not in series)
Capacity.. yes just add them up.
Disable safety timer.. just don't charge unattended.

your charger will only 'see' a single 1s2000mah pack (or whatever the total capacity added up to)

I got a small voltage tester which seems to work great. However they all read a little over 4 V. Am I overcharging?

[Slyster]

A full cell is 4.2v. An empty cell is around 3.7v.

[BrettOssman]

Originally Posted by Slyster

A full cell is 4.2v. An empty cell is around 3.7v.

OK, I'm confused.

The batteries say 3.7V, so I thought that was max. What should I run them down to? Also, what would the storage voltage be?

[Slyster]

3.7v is just the nominal voltage.

What is more important is that you never put back more than 80% capacity into them. But this is difficult to know with micro helis and their blinky chargers. Its more important for larger more expensive packs and most of us use chargers that show mah put back in.

Example.. if you have a 6s5000mah pack... you time your flight so that when you charge lipo, you put no more than 4000mah back in... and the charger tells you that. If you put more than 4000mah back in you must lower your flight timer.. or you will damage the packs.

End voltage is less important than how much you took out of it when flying.

[BrettOssman]

Originally Posted by Slyster

3.7v is just the nominal voltage.

What is more important is that you never put back more than 80% capacity into them. But this is difficult to know with micro helis and their blinky chargers. Its more important for larger more expensive packs and most of us use chargers that show mah put back in.

Example.. if you have a 6s5000mah pack... you time your flight so that when you charge lipo, you put no more than 4000mah back in... and the charger tells you that. If you put more than 4000mah back in you must lower your flight timer.. or you will damage the packs.

End voltage is less important than how much you took out of it when flying.

So, if I'm paralleling 3 500mAh batteries, max back in should be 80% of 1500, or 900 mAh.

[Slyster]

Thats the idea, but it is 1200mah. You did the math wrong is all. 1500 x .8 = 1200.

[BrettOssman]

Originally Posted by Slyster

Thats the idea, but it is 1200mah. You did the math wrong is all. 1500 x .8 = 1200.

Oh yeah, duuuuh.

Too many beers.

[BrettOssman]

I set my charge capacity to 40% of total for storage. However, when I run that charge cycle the completed charge capacity is always higher. Would that completed capacity number be what the batteries are at when done, or the amount sent by the charger during that cycle?

I have an Onyx 235 charger, if that helps.

[BrettOssman]

Originally Posted by BrettOssman

I set my charge capacity to 40% of total for storage. However, when I run that charge cycle the completed charge capacity is always higher. Would that completed capacity number be what the batteries are at when done, or the amount sent by the charger during that cycle?

I have an Onyx 235 charger, if that helps.

Some more info.

I am parallel charging 5 1C 200mAh LIPOs.

My charger settings are:

• 1C
• 2 amps, which the charger reduced to 1.6
• 400 mAh capacity

After the cycle the capacity shows 480 mAh.