lispro

I have a 4.8V 1400 mAh NiCd receiver battery in a 40 size plane. The battery has been working fine (is 3 years old), but I thought since we are coming into a new season I would cycle it with the Hobbico Accucyle elite. This charger discharges then charges the battery with standard settings as follows:

NiCd/NiMh, 4 cells, peak charge 0.55A, trickle 30mA, peak sensitivity 8mV/cell, discharge 0.3A, discharge cutoff 1.1V/cell

After a cycle of discharge and then charge it says the capacity is 498mA, and 5.708V. I am confused. Is this a bad battery?
I also have a Voltwatch2 on this plan (perhaps a controversial topic) and is is full green. (Yes, I am to lazy to use an ESV before each flight).

I tried cycling another battery (1600mAh Nicad, same settings except charge of 0.8A) and it said the capacity was 1478 mAh.

Any help is appreciated.

Thanks

Mk23socom

My Feedback: (7)

Sounds to me like the battery is on its way out.. I would strongly consider a replacement were it me.

RCVFR

My Feedback: (7)

When your battery capacity is below 80% of rated, it's time to replace it. Yours is well past that point.

Scirocco14

Try cycling it again and see what it reads. If I understand my Accu-cycle correctly, it shows how much capacity was LEFT when you discharged it. If it was partially discharged to begin with, it would read low.

I've had this happen with batteries that came with planes I've bought, but after a couple of cycles they were right back up to full capacity.

Let us know what happens!

Mark

lispro

Thanks for the replies. I don't think it is worth it to fly with a questionable battery, and will plan to replace. I cycled it twice and got similar results (about 500mAh capacity on a 1400mAh battery). I thought that cycling would discharge to a pretty low but safe level and then charge, and that the reported capacity by my charger would be near the rated capacity of the battery (1400mAh). Since I am only getting about 30% of rated capacity I will ditch the battery, unless I am doing something wrong with the charge cycle.

Stick 40

I agree, the battery is bad.

But the printed rate on the battery is not what we generally go by. I am cycling my new battery's and getting the actual amount to start with, as most do not give the amount printed on the battery when we get them.

They may be close, but most will not give what is printed on the pack. I am testing new battery's and putting the date and amount I can get out on them right on the pack so that in 3 or 4 years I know ,what is what.

sticks

jester_s1

I'll offer my NiCd care routine for whoever is interested. A new pack gets 5 cycles before going into the plane, and I check the capacity on each one. I slow charge the pack on a C/10 rate with the peak detection sensitivity turned all the way up. Every pack I've had started off a little low on capacity, then improved to a little better than its rated capacity by the 5th cycle. The 5 cycle routine has two purposes: to break in the pack so that it delivers full capacity, and (mostly) to test the pack to make sure there are no faults that will cause an early failure. I've caught one new pack this way that was bad from the factory. It was a name brand pack that was toward the upper end cost wise and would have cost me a model if I had used it without testing. I write the capacity of the last test on the battery for future reference. Then every 6 months I do a single cycle test by discharging and doing a C/10 charge then discharging again. I write that capacity and the date on the battery so I can see the history of the pack later. When I notice a 10% drop in capacity I'll do the test again, then toss the pack when it's down to 80%. Some packs will deteriorate to that point in a couple of years, while others can last 5-6 years and still be good packs. The point is I know the true condition of my packs always and can catch problems before they cost me a plane. I am currently switching over to LiFe packs and will do the same testing on them that I do on NiCd's to ensure that I am always flying with good packs.

Rodney

When cycling a NIxx battery, the cut off voltage should be 0.8 volts if comparing to factory specifications, not 1 volt. Note that I am not saying that it is save to fly until your batteries drop to that point. However, there is still quite a bit of energy still stored in the battery if you cut it off just as it reaches the 1 volt/cell point. Naturally, the manufacturer wants the mah number to be as high as possible so that is why the specifications are usually based on a cut off voltage of 0.8 volts/cell. Not only that, the rate of discharge needs to be controlled too if comparing to factory specs, do not exceed a discharge rate of 0.33C; any higher and you get lower numbers for total mah. IMHO it is safe to fly down to 1.1 volts/cell.

lispro

Thanks again for all the replies. Cycling batteries seems to be a confusing topic for me, but I thought the discharge cutoff of 1.1V was conservative, and in the future I will drop this to 1.0 or 0.9, and see how that impacts the total battery capacity.

Luckily I have a replacement battery on hand, 1600mAh 4.8V NiCd, and am doing an initial slow charging at 150mAh for 16 hours. After one slow charge with this new battery, should I cycle with these settings, or a lower peak charge rate?

NiCd, 4 cells, peak charge 0.8A, trickle 80mA, peak sensitivity 8mV/cell, discharge 0.3A, discharge cutoff 0.9V/cell?

Thanks

jester_s1

Those settings should be fine. Rodney has added some good info there, but I'll also mention that as long as you're consistent in the cutoff voltage you go to, you can do battery testing just fine cycling to 1.1v per cell. The important thing is to notice the change from the new battery. So if the higher cutoff gives you 1500 mah on a 1600 mah battery when new, you'd want to replace the battery when it gets below 1200 mah with the same settings.

Steve Steinbring

I too cycle my new NI-Cd batteries to break them in.

When finishing the initial cycling I record the mah and the date on the individual battery using a permanent marker. In doing this I can see how the battery progresses through its usage. I consider a battery bad when it reaches 70% of its rated potential. Batteries need maintenance meaning that they need to be kept charged and cycled on a regular schedule. Allowing a battery to sit and pretty much totally discharge for extended periods of time diminishes the life of the battery.

KitBuilder

3 yrs is long overdue... go with NIMH or lipos for the airborne unit.. lipos are way cheaper for more capacity but you will need a regulator unless your rcvr and servos can handle it 7.4. I use 3 cell in case I lose one i'm still good.

jester_s1

I know some guys are using Lipos with a regulator these days, but LiFe's, IMO, are the more practical choice. They are a nominal 6.6v but in actual practice put out around 7.2v fully charged. A 6v NiCd puts out 7v fully charged, so they plane doesn't know the difference. You get all the advantages of a Lipo with no regulator and no fire hazard.

Stick 40

I am going with the A123's for my flight packs, much better than NIMH and Lipos. Longer life and none of the fire problems of Lipo's. they do not lose charge !!!

But you need a LiFe/ A123 chargers for them.

sticks

oldtyme

I agree with KitBuilder............I only use Nicds in the shop to check something.........I went to NiMh a long time ago and quit worrying about cycling.

Gray Beard

My Feedback: (-1)

I don't cycle them often but next time you buy a new pack cycle it about 4 times and see what happens. At the moment I'm charging three Lipo packs I just bought just in case I may get to go flying this week. I only use the Lipos in my electric planes and I have been giving the A-123s some thought. A lot of the guys I fly with have been using them for a few years and swear by them.
My problem is I have been doing this a very long time and I have about 5 really good chargers for nicad and nimh and only one crappy charger for the new batteries. I have the older triton that doesn't have a a blancer on it. It's also only DC. I'm using the new Triton I borrowed from a friend and really like it, works on everything but only one pack at a time. It's also a very high dollar charger!! It does cost a bit of money to change over.

oldtyme

Gray Beard............first off, so glad to see you back and going flying!!! I only have one charger, the Accucycle Elite and I use a product from Electrifly called the Equinox. You can use this with most chargers for balancing and it only costs $35 from Tower. I don't like Lipos so I'm sticking to NiMh but I have to ask.........I've seen the term A123 and don't know what they are........can you expand. I don't want to mess around with stuff that is iffy or I don't have the charger/cycler for..........tried electircs and hated it!

Thanks,
Andy