Life Battery Discharge Question
 

I'm new to Life batteries and want to check my batteries capacity..... However when i go to discharge a 6.6 pack it only lets me discharge to 4.0 volts... is that ok or too low?


at what mah should i discharge my battery to get a realistic reading 200mah?

RE: Life Battery Discharge Question
 

Wassup tallica?

Im gonna follow this thread cause im running the 3200mah life. There doesnt seem to be a whole lot of info out there on them yet. Im just using the cheap life charger that has no display on it. It has three different charge settings and thats it. Oh, and a flashing light to tell you what its doing. And it beeps. www3.towerhobbies.com/cgi-bin/wti0001p

And there was no real instruction manual with the charger (only the battery). After a few flights, I went to charge my batt for the next flying day and the thing started beeping and flashing, indicating "reverse polarity". So I checked the voltage on it and it was like 6.9 somthing. So it still had a ton of juice left in it. Im assuming that it was showing reverse polarity because it had more juice than the charger was putting in??? I dont know, im new to all this stuff.

I think im gonna get that new futaba br-3000 battery checker/balancer/ voltmeter. Ive only got a multimeter to read the voltage. And i know that it really doesnt tell you much since it can be low on MAH and still give high voltage until it is way low. Right? The voltage curve is not a steady drop from what I understand.

Do you use a battery checker of some sort, or do you get your info from the batt charger??? I shoulda shelled out some more coin for a multi function charger.

Lemme know if Im wrong on this stuff. Im still trying to learn.

The 3200 mah life battery obviously has plenty of power to run my radio system and electronic ignition for a lot longer than my transmitter battery will last. Im wondering how it will do once I add the smoke pump.

Jeremy

RE: Life Battery Discharge Question
 

Metallica, I have done some reading on Lifep04, and A123 cells, 2.0 volts per cell is the minimum cutoff voltage for these batteries.
I have my charger set to 4.2 volt cutoff when discharging 2S. I don't know what the proper discharge load is, my charger doesn't allow
me to set this. I know my charger discharges at less than 500mah.

RE: Life Battery Discharge Question
 

An excerpt from what you should ideally read the whole thing since you're into asking a lot of A123 questions..

http://www.hangtimes.com/a123_batter...iants_faq.html

RE: Life Battery Discharge Question
 

what i did was fully charge my pack.... then i did a 8 minute flight, and topped it off at the field and put in about 300 miliamps....later i did another8 minute flight and put in about the same... this was on a 50cc 3d plane.... so i now feel comfortable using Life batteries

this is the inexpensive charger i use http://www.hobbyking.com/hobbyking/s...dProduct=12104


i use a hobbico voltmeter with a 250 mah load to check my batteries before i fly

RE: Life Battery Discharge Question
 

CG Retired. Where are you?

RE: Life Battery Discharge Question
 

To set the record straight. A123 is a type of battery LiFe PO4 made by a company called A123 systems. it comes as a cylindrical battery,
we in the hobby industry use 2 of their cells either the 18650 1100mah cell, or the 26650 2300mah cell. this is a very high performance
LiFe PO4 cell that can handle loads up to 40c. Other companies make LiFe PO4 cells in the foil wrapped and cylindrical forms, they are not
A123 they are LiFe PO4 batteries also known as LIFE.

Before you start reading the hangtimes website and doing what is recommended there, read any info that comes with your battery, Hangtimes
only sells batteries made by A123 systems, and the capacities, charging and discharging rates may be different for your type of Life battery.
If you can't find any info PLEASE contact the manufacturer or company that you purchased the pack from. If the cells in your battery are not
made by A123 systems they are not A123's.

Barracuda, I have to agree that a first cycle to gauge the battery, and the discharge and recharge monitoring input is the best way to find
the actual flying time on a pack. but I am just recommending people err on the side of caution regarding the voltages and cutoffs on their
particular packs.

RE: Life Battery Discharge Question
 

I think the Hangtimes sight is good reading for anyone looking to move into Life batteries. Althought A123 And other Life batteries have different
characteristics, the chemistry is pretty much the same. Here is a good part of the FAQ's on the hangtime site that relates directly to
Metallicajunkie's original post

Mach2 If your charger does not have the ability to measure MAH, or voltage, the Watts up meter can be plugged between the battery and charger
and has this function in it. and it is a very handy tool.

Q: Can I use a Load Tester to check my A123 packs relative state of charge?

*

Here's an area where A123's are radically different than Nicad or NiMH packs... Load Testing A123's is ineffective for determining state of charge... the beasties just don’t 'react' like we expect.. a 1 amp load for 10 seconds will convince somebody not familiar with them that there’s something wrong with the load tester or the pack.. the needle starts to sag after a few seconds with some meters, (resistor impedance values jump up rapidly under the continuous load) and decreasing voltage displayed on the meter usually indicates approaching doom for the resistors, switch & connectors rather than reflecting any useful info on the state of charge for the pack. Continued loading can melt out connectors, meter resistors, switches, etc. ESV 'loading' just doesn't work with A123's in the tried and true sense as the cells are quite happy delivering enough amperage to melt out your gear, even when nearly discharged. Because of the incredibly flat discharge curve and the ability of the cell to deliver massive amounts of current, using a standing voltage level under load to decide when to recharge can lead to a disaster via damage to switches & connectors... Further, when A123's DO go flat, they do so remarkably fast. So, we go to the next question..

*

Q: How do I know when to recharge?

*

This one still gets me smiling.. old codgers like me already know the answer.. the same way we did it before some bright boy came up with the hobby ESV. We fully charge the pack, cycle it to determine capacity. We recharge, fly three or 4 flights, keeping track of the time and the voltage on the pack under the 1 amp load after each flight. At the end of the sessions, we'd discharge the pack to determine capacity remaining and do a bit of math.. we divide the time by the total capacity used and determine how much air time we can safely expect to get out of the pack.. and then cut that in half. Thankfully, most quality A123 capable chargers have a MAH charge counter.. it records the amount of energy it puts in the pack so we don't have to resort to the 'antique' methods of yesteryear.. just charge before you fly and charge again after you fly... the amount of energy used in the flight will be right there on the charger's screen.

-

Some specifics.. the M1 cell rates average 22-2300ma. Voltage drop cliff starts at about 2,000ma. I don’t like to get lower than about 50% remaining before recharging. (I’m a very conservative old codger) My bird used 800ma from the pack in four 10 minute flights (big warbird). I figure I got 5 flights to 50%.. so I field charge on the end of the 4thflight. Yes, I still use the load tester.. and yes, old habits die hard, and checking the voltage between flights is still how I recommend you stay outta surprise territory… but a Load Tester alone is not enough to keep you out of trouble. There are however ways of improving your odds... and this one's important: These are NOT NiMH or Nicad packs. The act of balance charging them at 1C just does not stress the cells a bit. So, if in doubt, CHARGE! Use a quality balancing charger, and get in the habit of checking individual cell voltages. Since virtually all of the quality A123 capable chargers have a MAH counter that records the amount of charge transferred to the pack, before very long, you'll get a good feel for what's 'going on' with your new technology packs in your bird and your confidence in yourself, your power system and your charger will benefit greatly.

-

RE: Life Battery Discharge Question
 

Excellent point Chris, thanks!

RE: Life Battery Discharge Question
 

I just bought this little guys today. Now I can do things right....www.commonsenserc.com/product_info.php


Thanks to all the guys in here giving that info. And thanks to MJ for starting this thread. It motivated me to get a real charger.

RE: Life Battery Discharge Question
 

do you charge via the Dean's connector?

RE: Life Battery Discharge Question
 

Very nice Mach2, it is amazing how important being able to see capacity during charge and discharge is.

RE: Life Battery Discharge Question
 

Mach2, you will plug the deans connector into the 2 wire output of the charger, and the balance plug (white tap) into the side of the charger
this way you can balance the cells while charging. The downside is that if the battery is hard to get to charging may be a pain, in all my
planes I have set them up so the battery can be removed easily for charging.

If you read the Hangtimes website it will show you how to convert your balance plugs to servo plugs and use a charge switch for balancing.

RE: Life Battery Discharge Question
 

Thanks. I use the deans. It is charging and balancing right now.

;)

RE: Life Battery Discharge Question
 

Another good tool to have is a Futaba BR-3000

RE: Life Battery Discharge Question
 

no, on some planes (3d gassers) i have switches that have dean plugs , so i charge through the switch and balance through the plug...... on my glow planes i cut off the deans plug and solder a std servo connector since my glow planes generally dont use high current servos and charge via switch as well

*edit i also forgot to mention you can charge 1c with life batteries....if you have a 2500mah battery you can charge at2.5 amps.....i charge at 1.5 amps to play it safe..

RE: Life Battery Discharge Question
 

Ive been watching them. They aren't out yet are they?

RE: Life Battery Discharge Question
 

There's a couple at our field so I'm assuming they are out

RE: Life Battery Discharge Question
 

Yes they are

RE: Life Battery Discharge Question
 

MJ that fromeco switch is a great one. I use it on any plane over .60 size.

I will add some to over bored said.

You must take a new pack no matter the use and type and run it thru a cycle atleast once. This is to make sure that the pack is in good working order, is very close to its stated MAH rating. Now that you know that pack is good and is at its rated out put. Do as OVERBORED does. I do close to the same as i fly it for a flight or two depending on the size of the pack then recharge to see where its at. do this for a couple flights while extending the recharge time from the 2 flight to maybe 4 and so on.

I run a single 2000 LiFe from Hobbico (tower) on my little mustang with a DLE 30 on it. the pack runs the engine and airplane. It uses about 200-250 MAh a flight i will fly for 6-7 flights before a recharge.

RE: Life Battery Discharge Question
 

where do you get them?

Tower doesnt have them yet. And both of the other places I found them says they are coming soon. Ill have to look around some more....www.espritmodel.com/futaba-br-3000-battery-checker-balancer-voltmeter.aspx

To Airraptor - My LHS owner told me that he doesnt run them below 80% of their capacity. So I should only take my 3200mah down to 2560? I think I should get about 5 flights on that. Before Ive installed my smoke system.

What is everybody elses discharge amount before a recharge?

thanks,
Jeremy

RE: Life Battery Discharge Question
 

I have a rule that My lipos, and now Lifes never go below 40%. Now if they go below 40% without my knowledge then i punish them

Mach2, you have a 3200mah pack, but that is the overall capacity, not the usable capacity. Usable capacity is the amount of mah
measured from cutoff voltage to full charge. I don't go below 40% of that number

RE: Life Battery Discharge Question
 

I kind of confused myself on that one, I was trying to say I use 60%of my battery and try to keep 40% in reserve.

RE: Life Battery Discharge Question
 

Here you go: www.singahobby.com www.tjdmodels.com and PowerHobby on ebay has 7 left...has the best deal at $49.99 shipped free

RE: Life Battery Discharge Question
 

He told be to charge the battery less than the rating. So I made the charge cutoff at 3100 mah. Is that good?

I made three flights today, so Ill see what it puts back in it right now.....

Thanks,
Jeremy