As I have been following a lot of threads concerning charge and discharge rates, I still have not found anything on the accuracy of cycling with a charge rate other than c/10. From what I understand, a peak charger like the triton cannot find peak at c/10 so if you were to cycle with it,you would need a rate high enough to peak but low enough for accuracy. So can I rely on a peaked cycle, or do I need to charge on a different charger then discharge on the triton. On some trial tries it seems to work fine on c/2. I am looking for #s as close to the manufacture spec as possible. It would be great to hear from someone who knows more about this than me. Thanx and happy new year.

This subject has as many opinions as there are people.

Go to;

srbatteries.com

rcbatteryclinic.com

radicalrc.com

When you're cycling, the interesting number is the capacity on DISCHARGE. You should discharge at C/5 to about 0.9V per cell if you want to see the same numbers the manufacturers get.

The charging rate has some effect on the amount stored but not very much (at least in my experience). IMO it makes a lot of sense to charge at the rate you usually use.

Steve

I understand c/5 is manufacture spec on discharge, what concerns me is the 95% or so charge you get with a peak. And I don't think the triton goes in top off mode between charge /discharge mode.The way I see it, if the battery is not charged to 100% it won't discharge to its full potential. This is were I question the accuracy. Thanx for the reply

I've never seen any repeatable difference in discharge capacity between cells slow charged at C/10 and those peak charged at higher rates. Where does your 95% comes from and what is it 95% of ?

Measuring the amount of charge that goes in is pointless. If you leave a battery on C/10 charge for long enough you can appear to put in 500%, 1000% or any other number you like. You won't get any more back OUT though.

Steve

Unless I misunderstand what Al is looking for, C/5 will tell him nothing . C/5 will verify the Mfgrs, mah rating -- nothing more .(and this will be true only if the ambient temperature is controlled at the spec. # generally 80 degrees F)

The only discharge rate that is meaningful in flight applications is the current you are drawing "in flight" ---- then you have a realistic measure of the limits of your pack. This number is probably no lower than 250ma with 500ma very possible --- even higher in some cases of binding surfaces servo ganging etc.

Al is also correct in pointing out that peak detection will give you less than a "full" charge --- it depends where on the curve the "peak" cut off is chosen --- and after it is chosen from a design perspective where in fact it occurs on production types . These can be two widely different numbers . You may object to his 5% differential statement but that is both reasonable and close. My repeatable test number comes out at 2.5% .

In order for any test number to be valid, --- pro or con --- it must be repeatable, by definition, or you have meaningless numbers being influenced by some undefined variables which now must be identified and controlled.

Frankly, if Al has flown with his current set-up long enough to have confidence and success then he should stay with it. At that point we are in a Brand and design preference discussion and there is NO test to end that discussion.

Not trying to be argumentative, just informative.

Al

Thinking a little further on your question, if the difference between "full charge" on a peak detection charger (assuming a reasonable design and Mfg. execution of the design) and C/10 charging is worrying you then you are flying way too close to the limit.

Trying to put it into perspective, the last 20 to 25% of throttle opening on your engine gives an almost indiscernible difference.in RPM.

That is where we are in your battery/charging/capacity discussion from a practical standpoint.

What I am trying to find out is if my numbers when cycling are measured close enough to the same way the manufacture measured when they come up with say 3000 mah's This way if I go to cycle a pack that has not been used for some time,I can compare my #s to that of the rated capacity of the pack. In the past I would charge with C/10 and then discharge with an ace abacus. Now that have a triton I would like convenence of one step cycling at a quicker overall time but somewhat question its results relative to manufature spec (rated capacity). 97.5% of full charge does sound close enough for a reasonable comparison. That was partly what I was asking. Onewasp, what rate of charge did you use to get that close to a full charge? I read somewhere around here it was a little closer to 95% (wasn't really sure of that # either).

550 ma was used on peak detection. 500 ma was my discharge rate.

I ran my tests multiple times, to get a handle on the number.

Then, I could repeat the results at will.

I wouldn't be concerned with a 5% differential if I were you. The actual flight loads, time and temperature will cause a wider variance than that and we generally don't even consider them at the field.

The Mfgr's mah rating is generally set at C/5 with temperature controlled etc. The mfgr. then decides on a % of "meet" they are willing to accept. and then uses the test numbers to rate the design.

You can reasonably duplicate their numbers by doing the same.

BUT, as indicated in my earlier posts we are really interested in flight performance. These discharge rates are different than the Mfgrs. mah test. That is why I use the discharge rate of 500ma.

By establishing capacities and discharge rates that really work in our application we can now reference check them along the life of our packs and reasonably approximate the time we should replace them.

Running a test cycle or two every 30 days (during the flying season) should be more than enough to furnish the graphical prediction as to when our packs are headed into the danger zone.

Thanx for the help If I'm not being to much of a pain, can you tell me the charge rate (*xC) I know you used 550 mah but for what size battery pack? Thanks again.

And to reply to your last post, yes the method you mentioned is the best way to determine the condition of a battery. I was concerned with some packs that have been laying around a while and needed somewhere to start. I have sevral heli's as well as a few giant scale planes with multipal packs in each plane. needless to say some models get more flights then others.

The test packs I used were 4 cell 1400mah and 4 cell 1700mah.

My rule on pack age is 3 years and they are out I don't care what they read. I wont use them in an airborne application.

I follow more or less the same 3yr rule ( most of my models,get sold or meet their end sometime before that) but in that 3yr window several months can pass and here is were my concerns applied. Thank you for your time and informative info