RCCrawler Forums

xjnation · 11-09-2005, 10:56 AM

General Battery information

by Inverted_Flying, terrys01

This is not necessarily specific to any one battery type. This page is to help explain the different types of batteries used for E-Flight as well as give some general information. This was information that was posted in a thread on the Ikarus BBS and some information was gathered and put here. Thanks to everyone to added to the discussion.

Terminology

C = Capacity or charge current
1C = Charge the pack at 1x it's capacity (3000mAh at 3.0 amps, 2400mAh at 2.4amps)
C/10 = Charge at 1/10th the capacity (3000mAh at 300mAh, 2400 mAh at 240mAhs)
Lio = Lithium based battery cell. Lio-Polymers, Lio-Ion are examples
Out of balance battery - pack is when some of the cells in the pack still had some charge left in them while others have no charge remaining.
IR = Internal Resistance
Trickle Charge = A trickle charge is less than C/10 and is meant for continuous charging for standby devices such as cordless phones
Slow Charge = C/10
Peak charge = Charge at 1C and Slow or Trick after pack peaks.
Fast Charge = Charging above 1C

Out of balance battery

Pack is out of balance is when some of the cells in the pack still had some charge left in them while others have no charge remaining. So when you charged the pack three of the cells peaked before the others did. That would leave the other cells a little under charged. So when you ran the pack out the undercharged cells dumped before the fully charged ones causing the under charged cells to feel warm. Cells begin to really heat up when they reach their "dumped" point.

Fixing an Out of Balance pack - The C/10 charge theory

Just do a C/10 (c = capacity i.e. 2400mAh pack is charge 1c at 1.2A) charge for 14-16 hours, the magic of "slow charge" is that it equalizes the cells. As the cells fill up some will get full before others, but at the C/10 rate there is no danger of over charging because the cells that are full can safely dissipate the "over charge" as heat, without damage, giving the other cells time to fill up. This is also why it's a good idea to occasionally C/10 charge all your packs, in normal use over a number of cycles they will start to become unbalanced and the C/10 charge will rebalance them. Setting a C/10 trickle rate after a pack peaks will also do this, the pack will peak when the first cell or two does, but the others may not be quite full yet, if left at the C/10 trickle for some time after peak the cells will rebalance. Some people say that they see a reduction in power if the trickle charge after the pack has peaked, stating they perform best hot off the charger. This is not as noticed with NiCds but it does seem to be true for NiMHs, but Suspicions are it is temperature related as NiMHs always seem to perform better when warm and the time spent trickle charging will let them cool.

Charging at higher rates

This is to drive up the initial voltage of the pack. "Car jockeys" charge at high amp rates to get that extra edge at the start of a race. But the higher voltage only lasts for about 20-30 seconds and then the pack drops off to its normal 1.2 volts per cell. But in flying you don't need or want that higher short-term voltage. You want the pack to charge at a lower amp rate so it fully deep charges for long run out times.

Zapping Cells-

NiCad cells build up crystalline formations, as they are manufactured and later as they are cycled. These crystals cause tiny bridges to form between the plates inside the cell. The more crystal formations the harder it becomes for the cell to absorb and release energy effectively. This is refereed to as IR or Internal Resistance. A "Zapper" pretty much explains it's self. It's basically a transformer and huge capacitors that store up a very large charge and then releases it through the cell in a couple microseconds. This tends to shatter the crystals breaking down the IR in the cell and making it more efficient. Commercial zappers are very expensive and can pass as much as 30,000kva through a cell. There are less expensive "maintenance" zappers that put up to 90volts at up to 1kva through a cell to help keep crystals from building up.

There is still some debate on whether or not zapping actually does anything for NiMH though. There is also still discussion on whether or not "Zapping" cells will shorten the life. People have shown as much as a 14% improvement in NiCad cell performance with high current draw (above 40amps) applications. But again it may shorten the cell life and number of times the cells can be cycled.

The Biggest Problem With Battery packs

With our batteries is that they eventually go out of balance and depending on your charger's peak sensitivity, some cells will be overcharged while the others catch up, or the slow cells will not get fully charged and will be over discharged or even reverse charged as the pack runs down.

Only Charge batteries Once a day.

Batteries don't keep track of time, they don't know if it's today, tomorrow or yesterday. As long as you allow them to cool down before putting them back on charge, you can charge them as many times as you like. Of-course the more you use them the less time they'll last in terms of years, but not in terms of cycles.

Memory Effect

Nicads in every application suffer "memory effect" to varying degrees, the newer sintered cells are affected less but NiMh do not suffer this phenomenon at all. The problem with NiMh is that for a given current the output voltage is less than NiCd, because of the voltage drop across the higher internal resistance of NiMh cells. That's why one or two extra cells are added to increase the voltage when using NiMh. Note that some NiMh cells are becoming available whose internal resistance is approaching that of NiCd cells.

Cell types

Nickel Cadmium (NiCd)

NiCd cells can be charged at a pretty high rate. Many time NiCad packs are charged with a rating of up to 2.5 times their capacity. A 2400 mAh cell is thus charged at 6 Amps in 24 minutes. Chargers exist of up to 12A per hour (Robbe's latest). With non sorted packs you shouldn't go above 6A though. The differences between the cells will make the charger false peak and the pack will never be full.

Get a good charger that can handle both NiCd and NiMh cells. Make sure you can charge at least 16 cell packs and set your budget decide on the maximum charge rate. You are bound to charge larger packs sooner or later and a high charge rate will get the time to charge the pack down.

Nickel Metal Hydride (NiMh)

This type of cell has a much larger capacity than NiCd cells. A NiMh cell of 3300 mAh capacity is the same size as a NiCd cell of 2400 mAh. The disadvantage of these cells is that they can't handle bigger currents. For our applications of up to 25 Amps they are very usable. Nevertheless they tend to drop their voltage a bit more than NiCd cells. The latest generation of High Voltage NiMh cells have this a lot less.

Charging NiMh cells must be done a lot more careful than NiCd cells. Most manufacturers say that you shouldn't charge over 1C (1 time the capacity per hour), although many people report charging NiMh cells at 2C without a problem. Whether this over charging will shorten the life of the cells remains to be seen. To be safe it is recommended to stick with the 1C rule.

A few examples:
Panasonic 3300 mAh packs can be charged at up to 3.3 A
Sanyo 3000 mAh packs can be charged at up to 3 A
Sanyo TwiCell 1800 mAh AA cells can be charged at up to 1.8 A

I found this trying to help someone else. It has some good info, hope it might answer some newbie questions.

SVEN · 11-09-2005, 11:05 AM

Good stuff.

badger · 11-09-2005, 11:13 AM

Stickiefied. Great info!

BultacoJim · 11-09-2005, 11:14 AM

Good info
Make it a Sticky?

badger · 11-09-2005, 11:20 AM

Quote:

Originally Posted by BultacoJim

Good info
Make it a Sticky?

Naw, we've all seen this before.

EeePee · 11-09-2005, 02:36 PM

:beer:

JohnRobHolmes · 11-09-2005, 02:49 PM

Nimh has come a long way, and the IB 3800's have such a low IR that after zapping each cell can take 80 amp continuous discharge. That means an unmatched zapped pack can dump in a tad under three minutes. They do have to be warm though.

another way to put it, is that they can discharge at 21C continuous.

Frakk · 11-12-2005, 07:36 AM

"Just do a C/10 (c = capacity i.e. 2400mAh pack is charge 1c at 1.2A)"

wouldnt 2400mah 1c be 2.4A?

DISTURBIN' tha PEACE · 11-18-2005, 01:49 AM

Quote:

Originally Posted by Frakk

"Just do a C/10 (c = capacity i.e. 2400mAh pack is charge 1c at 1.2A)"

wouldnt 2400mah 1c be 2.4A?

But it says "C/10" which is 1/10 capacity

So 2400mah should be .24A

Frakk · 11-19-2005, 05:23 PM

yeah thats what i said, 1c is 2.4 and not 1.2. from this it is obvious that c/10 is .24.

badger · 05-25-2006, 08:14 PM

I unstuck this thread and added a link to it in the new sticky thread that will be the definitive battery thread.

http://www.rccrawler.com/forum/showt...016#post316016

Dickie691986 · 10-27-2007, 03:29 PM

what would give me the most run time? Intellect 1400's or Elite 1500's

Dickie691986 · 10-27-2007, 03:36 PM

what would be the capacity of 8 NiMH 1500 ELITE's?

JohnRobHolmes · 10-27-2007, 07:12 PM

Quote:

Originally Posted by Dickie691986

what would give me the most run time? Intellect 1400's or Elite 1500's

Elite 1500's, they have 1500mah of runtime.

Quote:

Originally Posted by Dickie691986

what would be the capacity of 8 NiMH 1500 ELITE's?

1500mah

Dickie691986 · 11-04-2007, 03:09 PM

what does that mean? how can i convert the 1500mah into mins?

JohnRobHolmes · 11-05-2007, 09:04 AM

1500mah means that the battery will run for an hour if it has a 1500 milli amp load, or 1.5 amp load. Your runtime will depend on many other variables like vehicle weight, geardown, motor, and your throttle finger.

Dickie691986 · 11-06-2007, 07:29 AM

what if im charging at 1.00 amps?

halfcab · 11-07-2007, 02:27 PM

Quote:

Originally Posted by Dickie691986

what does that mean? how can i convert the 1500mah into mins?

Quote:

Originally Posted by JohnRobHolmes

1500mah means that the battery will run for an hour if it has a 1500 milli amp load, or 1.5 amp load. Your runtime will depend on many other variables like vehicle weight, geardown, motor, and your throttle finger.

Quote:

Originally Posted by Dickie691986

what if im charging at 1.00 amps?

charge rate won't effect it, it's how hard you discharge it......how you use it

the higher the load on them the faster they go dead
I would guess about 30-40 min, thats how long the 8cell 1500's lasted in my comp rig when I was using them.....that is not constant driving

life_livin · 05-15-2009, 11:44 PM

i have kind of a dumb question,
i just made the lipo jump and was wondering if you charge lipos like nimh
1500 = 1.5 amp
so a lipo at 3000 mah would be charged at 3 amps?
sorry just need clarification

Crunch · 07-21-2020, 05:55 PM

I'm a complete newbie to LI-PO batteries. There seems to be enough talk about internal resistance that it would seem a good topic of discussion here. I've got a few new packs and individual cells range from 5 ohms up to 10 ohms. When you have a well used pack that is nearing the end of its life, what kind of resistance do you see?

11-09-2005, 10:56 AM	#1
xjnation Rock Stacker Join Date: Oct 2005 Location: Springfield Posts: 50	Battery info. (kinda long) General Battery information by Inverted_Flying, terrys01 This is not necessarily specific to any one battery type. This page is to help explain the different types of batteries used for E-Flight as well as give some general information. This was information that was posted in a thread on the Ikarus BBS and some information was gathered and put here. Thanks to everyone to added to the discussion. Terminology C = Capacity or charge current 1C = Charge the pack at 1x it's capacity (3000mAh at 3.0 amps, 2400mAh at 2.4amps) C/10 = Charge at 1/10th the capacity (3000mAh at 300mAh, 2400 mAh at 240mAhs) Lio = Lithium based battery cell. Lio-Polymers, Lio-Ion are examples Out of balance battery - pack is when some of the cells in the pack still had some charge left in them while others have no charge remaining. IR = Internal Resistance Trickle Charge = A trickle charge is less than C/10 and is meant for continuous charging for standby devices such as cordless phones Slow Charge = C/10 Peak charge = Charge at 1C and Slow or Trick after pack peaks. Fast Charge = Charging above 1C Out of balance battery Pack is out of balance is when some of the cells in the pack still had some charge left in them while others have no charge remaining. So when you charged the pack three of the cells peaked before the others did. That would leave the other cells a little under charged. So when you ran the pack out the undercharged cells dumped before the fully charged ones causing the under charged cells to feel warm. Cells begin to really heat up when they reach their "dumped" point. Fixing an Out of Balance pack - The C/10 charge theory Just do a C/10 (c = capacity i.e. 2400mAh pack is charge 1c at 1.2A) charge for 14-16 hours, the magic of "slow charge" is that it equalizes the cells. As the cells fill up some will get full before others, but at the C/10 rate there is no danger of over charging because the cells that are full can safely dissipate the "over charge" as heat, without damage, giving the other cells time to fill up. This is also why it's a good idea to occasionally C/10 charge all your packs, in normal use over a number of cycles they will start to become unbalanced and the C/10 charge will rebalance them. Setting a C/10 trickle rate after a pack peaks will also do this, the pack will peak when the first cell or two does, but the others may not be quite full yet, if left at the C/10 trickle for some time after peak the cells will rebalance. Some people say that they see a reduction in power if the trickle charge after the pack has peaked, stating they perform best hot off the charger. This is not as noticed with NiCds but it does seem to be true for NiMHs, but Suspicions are it is temperature related as NiMHs always seem to perform better when warm and the time spent trickle charging will let them cool. Charging at higher rates This is to drive up the initial voltage of the pack. "Car jockeys" charge at high amp rates to get that extra edge at the start of a race. But the higher voltage only lasts for about 20-30 seconds and then the pack drops off to its normal 1.2 volts per cell. But in flying you don't need or want that higher short-term voltage. You want the pack to charge at a lower amp rate so it fully deep charges for long run out times. Zapping Cells- NiCad cells build up crystalline formations, as they are manufactured and later as they are cycled. These crystals cause tiny bridges to form between the plates inside the cell. The more crystal formations the harder it becomes for the cell to absorb and release energy effectively. This is refereed to as IR or Internal Resistance. A "Zapper" pretty much explains it's self. It's basically a transformer and huge capacitors that store up a very large charge and then releases it through the cell in a couple microseconds. This tends to shatter the crystals breaking down the IR in the cell and making it more efficient. Commercial zappers are very expensive and can pass as much as 30,000kva through a cell. There are less expensive "maintenance" zappers that put up to 90volts at up to 1kva through a cell to help keep crystals from building up. There is still some debate on whether or not zapping actually does anything for NiMH though. There is also still discussion on whether or not "Zapping" cells will shorten the life. People have shown as much as a 14% improvement in NiCad cell performance with high current draw (above 40amps) applications. But again it may shorten the cell life and number of times the cells can be cycled. The Biggest Problem With Battery packs With our batteries is that they eventually go out of balance and depending on your charger's peak sensitivity, some cells will be overcharged while the others catch up, or the slow cells will not get fully charged and will be over discharged or even reverse charged as the pack runs down. Only Charge batteries Once a day. Batteries don't keep track of time, they don't know if it's today, tomorrow or yesterday. As long as you allow them to cool down before putting them back on charge, you can charge them as many times as you like. Of-course the more you use them the less time they'll last in terms of years, but not in terms of cycles. Memory Effect Nicads in every application suffer "memory effect" to varying degrees, the newer sintered cells are affected less but NiMh do not suffer this phenomenon at all. The problem with NiMh is that for a given current the output voltage is less than NiCd, because of the voltage drop across the higher internal resistance of NiMh cells. That's why one or two extra cells are added to increase the voltage when using NiMh. Note that some NiMh cells are becoming available whose internal resistance is approaching that of NiCd cells. Cell types Nickel Cadmium (NiCd) NiCd cells can be charged at a pretty high rate. Many time NiCad packs are charged with a rating of up to 2.5 times their capacity. A 2400 mAh cell is thus charged at 6 Amps in 24 minutes. Chargers exist of up to 12A per hour (Robbe's latest). With non sorted packs you shouldn't go above 6A though. The differences between the cells will make the charger false peak and the pack will never be full. Get a good charger that can handle both NiCd and NiMh cells. Make sure you can charge at least 16 cell packs and set your budget decide on the maximum charge rate. You are bound to charge larger packs sooner or later and a high charge rate will get the time to charge the pack down. Nickel Metal Hydride (NiMh) This type of cell has a much larger capacity than NiCd cells. A NiMh cell of 3300 mAh capacity is the same size as a NiCd cell of 2400 mAh. The disadvantage of these cells is that they can't handle bigger currents. For our applications of up to 25 Amps they are very usable. Nevertheless they tend to drop their voltage a bit more than NiCd cells. The latest generation of High Voltage NiMh cells have this a lot less. Charging NiMh cells must be done a lot more careful than NiCd cells. Most manufacturers say that you shouldn't charge over 1C (1 time the capacity per hour), although many people report charging NiMh cells at 2C without a problem. Whether this over charging will shorten the life of the cells remains to be seen. To be safe it is recommended to stick with the 1C rule. A few examples: Panasonic 3300 mAh packs can be charged at up to 3.3 A Sanyo 3000 mAh packs can be charged at up to 3 A Sanyo TwiCell 1800 mAh AA cells can be charged at up to 1.8 A I found this trying to help someone else. It has some good info, hope it might answer some newbie questions.

07-21-2020, 05:55 PM	#20
Crunch Newbie Join Date: Jul 2020 Location: USA Posts: 33	Re: Battery info. (kinda long) I'm a complete newbie to LI-PO batteries. There seems to be enough talk about internal resistance that it would seem a good topic of discussion here. I've got a few new packs and individual cells range from 5 ohms up to 10 ohms. When you have a well used pack that is nearing the end of its life, what kind of resistance do you see?

11-09-2005, 11:05 AM	#2
SVEN I wanna be Dave Join Date: Feb 2005 Location: Burnsville Posts: 3,096	Good stuff.

11-09-2005, 11:13 AM	#3
badger Diggin' the new SCX10 II! Join Date: Mar 2004 Location: Norcal Posts: 11,402	Stickiefied. Great info!

11-09-2005, 11:14 AM	#4
BultacoJim Pebble Pounder Join Date: Oct 2004 Location: Colorado Posts: 165	Good info Make it a Sticky?

11-09-2005, 02:36 PM	#6
EeePee MODERATOR™ Join Date: Jul 2004 Location: Ohio Posts: 18,928	:beer:

11-09-2005, 02:49 PM	#7
JohnRobHolmes owner, Holmes Hobbies LLC Join Date: Nov 2004 Location: Volt up! Gear down! Posts: 20,290	Nimh has come a long way, and the IB 3800's have such a low IR that after zapping each cell can take 80 amp continuous discharge. That means an unmatched zapped pack can dump in a tad under three minutes. They do have to be warm though. another way to put it, is that they can discharge at 21C continuous.

11-12-2005, 07:36 AM	#8
Frakk Pebble Pounder Join Date: Sep 2005 Location: Canada Posts: 171	"Just do a C/10 (c = capacity i.e. 2400mAh pack is charge 1c at 1.2A)" wouldnt 2400mah 1c be 2.4A?

11-19-2005, 05:23 PM	#10
Frakk Pebble Pounder Join Date: Sep 2005 Location: Canada Posts: 171	yeah thats what i said, 1c is 2.4 and not 1.2. from this it is obvious that c/10 is .24.

05-25-2006, 08:14 PM	#11
badger Diggin' the new SCX10 II! Join Date: Mar 2004 Location: Norcal Posts: 11,402	I unstuck this thread and added a link to it in the new sticky thread that will be the definitive battery thread. http://www.rccrawler.com/forum/showt...016#post316016

10-27-2007, 03:29 PM	#12
Dickie691986 Quarry Creeper Join Date: Sep 2007 Location: Carlisle Posts: 435	what would give me the most run time? Intellect 1400's or Elite 1500's

10-27-2007, 03:36 PM	#13
Dickie691986 Quarry Creeper Join Date: Sep 2007 Location: Carlisle Posts: 435	what would be the capacity of 8 NiMH 1500 ELITE's?

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11-04-2007, 03:09 PM	#15
Dickie691986 Quarry Creeper Join Date: Sep 2007 Location: Carlisle Posts: 435	what does that mean? how can i convert the 1500mah into mins?

11-05-2007, 09:04 AM	#16
JohnRobHolmes owner, Holmes Hobbies LLC Join Date: Nov 2004 Location: Volt up! Gear down! Posts: 20,290	1500mah means that the battery will run for an hour if it has a 1500 milli amp load, or 1.5 amp load. Your runtime will depend on many other variables like vehicle weight, geardown, motor, and your throttle finger.

11-06-2007, 07:29 AM	#17
Dickie691986 Quarry Creeper Join Date: Sep 2007 Location: Carlisle Posts: 435	what if im charging at 1.00 amps?

05-15-2009, 11:44 PM	#19
life_livin Quarry Creeper Join Date: May 2008 Location: looking for sponsors Posts: 462	i have kind of a dumb question, i just made the lipo jump and was wondering if you charge lipos like nimh 1500 = 1.5 amp so a lipo at 3000 mah would be charged at 3 amps? sorry just need clarification

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