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Pumpkin drop event

Understanding Batteries 101

colorex

Rotor Riot!
Mentor
#21
yeah just replacing the whole pack. and yes i agree with you there lol i would'nt think of mixing power types it freaks me out enough removing bad cells from lipo's :)

thx again.. ill let ya know how it turns out.
Where is the Li Ion from? If it's just another plane or car battery then you should be ok... but if it's from a drill or cellphone then it might not be good to use it.
 

lobstermash

Propaganda machine
Mentor
#22
It'd probably work as a power source, but charging it would be dangerous. New LiPo batteries are so cheap on Hobbyking, I wouldn't take the risk (if it was me).
 
#23
Its from a r/c heli i did some looking up on it and i don't think it has the amps. its a BNF 18500 1100mAh 11.1v..

and yeah the batts are cheap before shipping i'v alrdy looked and was gonna get a $15 2200 3cell but it came to $64 with shipping and it would also only be $25 at the hobby shop but thats still alot for me lol this is one reason i love the hobby most items are so cheap :) and my first batt lasted 3 yrs so lucky me :) my friend has gone trough like 5 and he don't fly to much...
 
#25
yeah nice but i just looked again only one option for canada is standard and it's $30 but still if i had $60 i would get 2x 2100 3cell $15 each.. ill do it just takes me awile :) ill never give up on flying.. i can't wait to get new batts and they will be twice as big :) this summer will be so fun.. i got 4 planes waiting and building more... this is the best hobby ever.
 

IamNabil

Senior Member
#26
I really like the concept of LiFE batteries, but either they don't make them for planes, or I haven't figured out how to read their markings yet. Is there a reason that they aren't used more (or at all outside of transmitters?)
 

Carl

Junior Member
#28
Hi, can someone explain how you figure out what amps you use for different batteries? From what I understand you need to know this for charging more then one at a time by multiplying the number of batteries by the amps each battery should be charged at.
For example: a 3s 5000 35c ?

Thank you
battery noob >.<
 

Craftydan

Hostage Taker of Quads
Staff member
Moderator
Mentor
#29
Carl,

(starting from ground zero, just to make sure we're up to speed)


First, the red herring -- the 35C is the discharge rate and usually has little to do with charge rate (higher discharge may mean better built battery, but not always). If they spec a charge rate, then you *can* use that, otherwise, assume 1C charge rate or lower and you're batteries will behave nicely for your charger.


Second, the cell count "S" sets your target voltage. If you've charger wants the setting for cell, it's easy -- just use the S number for a single pack. Otherwise if it wants voltage, set it to cell count x voltage (charger might want nominal voltage -- S x 3.7V -- or full voltage -- S x 4.2).

Finally, the maximum current is set by the "charge rate" x "charge capacity". the capacity is the mAh if it's in the hundreds or thousands. If it's in a small decimal number (0.8 or 4.4), it's in Ah. for the bigger number, it's charge rate x capacity / 1000. if it's the little number, it's charge rate x capacity.

So for your 5000mah battery, at a 1C rate will need 5000mA, or 5A.



that's all for a single pack (but you've gotten this far, right?)



**IF you are charging multiple packs with a parallel wire harness** the max charge current adds but the target voltage remains the same( for example 3 of those 5000mAh packs at 1C will need 5A+5A+5A = 3x 5A = 15A MAX, but voltage stays 3S).

**IF you are charging multiple packs with a series wire harness** the max charge current stays the same, but the target voltage adds (for example 2 of those 5000 mAh packs at 1C still needs 5A max, but the charger needs to be set to 3s+3s = 2 X 3s = 6S voltage)

**** only charge batteries of the same size in parallel/series. otherwise, charging them together is just not a good idea.

** if your charger has multiple screens/controls/plugs** It's really several independent chargers sharing the same power supply. Set up each charger for a single pack, according to what you've plugged in to it's ports. In this case the "same pack" restriction doesn't apply.

Regardless of how many cells and how they're wired up, you can charge at a lower current than the 1C rate -- it will just take longer. Some people choose to charge at 0.5C (or 2.5A for the example) just as insurance that their batteries last longer.
 

Carl

Junior Member
#30
Thanks Dan, that helps
Not to sure where the 1c setting is on my chargers, only ever change amps and volts and amps is pretty much always at 4.
So from what you are saying I should be adjusting my amps to the mah of each battery
ie. 3cell 2200mah is charged at 2.2 amps
 

Craftydan

Hostage Taker of Quads
Staff member
Moderator
Mentor
#31
Pretty much.

Also check the specs on your batteries. You might be able to go higher if they give a charge rate and you're in a hurry.

Otherwise, take the time for 1C or lower and they'll last longer.
 

Balu

Moderator
Staff member
Admin
Moderator
#32
Did I overlook it or is information on how to safely dispose LiPo batteries missing from the sticky post?

For example I keep hearing that you should put LiPos in saltwater to discharge them completely before disposing them. Even Josh mentions it in the latest video.

Having played with electrolysis for a while as a kid* I've learned quite fast that salt water plus electricity corrodes away the electric poles in a jiffy. After that there is no current flow possible anymore and with that no discharging.

I somehow don't think that's a good way to do it. Isn't it better to create a circuit with some kind of old car light for a few days?



* Yes, you can do "funny" stuff with some self made H. =)
 

xuzme720

Dedicated foam bender
Mentor
#34
Did I overlook it or is information on how to safely dispose LiPo batteries missing from the sticky post?

For example I keep hearing that you should put LiPos in saltwater to discharge them completely before disposing them. Even Josh mentions it in the latest video.

Having played with electrolysis for a while as a kid* I've learned quite fast that salt water plus electricity corrodes away the electric poles in a jiffy. After that there is no current flow possible anymore and with that no discharging.

I somehow don't think that's a good way to do it. Isn't it better to create a circuit with some kind of old car light for a few days?



* Yes, you can do "funny" stuff with some self made H. =)
Yes or any kind of low current device that won't be harmed by a low voltage will work...
 

Ron B

Posted a thousand or more times
#35
now I have a voltage checker
I want to make my batteries last a long time and charge at 1 amp and balance charge so what is the lowest voltage I want my batteries to get to so I can not have to worry about puffing them or cause unnessesary wear on them?
 
#36
I have a question about my Li-po battery
2200mha, 25c 11.1v battery

I used it twice learning to fly.

When I use my IMAX b6ac charger it says low voltage when I try to do a balance charge.

Does this mean the battery went bad?

As far as I can see there is no damage to the battery itself or puffed.

If it went bad how should I dispose of it?

Any thoughts how it went bad so quickly?
 
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Ron B

Posted a thousand or more times
#37
Sidney
make sure your cell count is correct like 3 cell batt. and you set it for 4 cell it will give you this reading. also make sure your balance plug is in the right slot. you have to charge with the main wires and the balance plug both hooked up at the same time to get a balance charge.
 
#38
Having played with electrolysis for a while as a kid* I've learned quite fast that salt water plus electricity corrodes away the electric poles in a jiffy. After that there is no current flow possible anymore and with that no discharging.

I somehow don't think that's a good way to do it. Isn't it better to create a circuit with some kind of old car light for a few days?
DINGDINGDINGDING!!! Give the man a cigar!

You're totally right - putting a LiPo in salt water is NOT a good way to discharge it for disposal, for exactly the reasons you give. Electrolysis corrodes the electrodes into uselessness before the battery discharges to a safe level. Now you have the worst of both worlds - a charged battery with no way to discharge it.

The automobile taillight discharger is the best way to do it. One (for up to 3S) or two (for up to 6S) taillight bulbs connected in series, add your favorite connector, plug the battery in, wait a few hours (or overnight), unplug battery, cut off the connector on the battery, strip the wires, twist them together, toss battery in trash.

The last steps (shorting out the battery wires) ensure that any tiny remaining bits of charge are gone. If you've discharged the pack several hours past the point when the light bulb goes out, the remaining charge isn't enough to cause any danger when you short the pack.
 
#40
Can anyone give me the different voltages for a LiFe Battery? What is considered full, low, best storage voltage? Any help is appreciated.