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Occasionally a battery pack will be returned to me.  The customer will tell me it does not check up to snuff on their cycler.  I always replace the battery under warranty as I want you to be happy.  I always cycle the pack on one of my regularly calibrated ACE Digipace 1 units.  In each case, the battery is in fact good.  Usually the customer is using a Hobbico Accucycle.  Here is one of the letters I have exchanged.  I am happy to warrant your batteries, but please take time to check your cycler before returning a pack.  Even if you don't have a warranty concern, it is a good idea to check your cycler from time to time.  The letter below outlines how to do it.

"Hi Dave,

Yes, I did charge and cycle the pack at least five times before 
 ever using it.  I use an Accucycle and charge at 125mah and discharge at 250mah. 
 Btw, the pack is supposed to be "1800mah", but I could never get past 1400mah. 
 I don't know if that had anything to do with it, though.

I will send it back so you can check it.

 John Doe"


I have warranted about 4 packs in the last month, never from a crash, but from not cycling up to par.  Every one of them was using Hobbico Accucycle.  Every pack tested perfect upon return.  Hobbico cyclers are not very good.  Many of them discharge at significantly higher rate than they say so they give you a false bad pack reading.  Maybe it is because Hobbico (Tower) likes to sell batteries, I don't know, but I presume it is because all Hobbico stuff is built by the lowest eastern bidder they can find.  Not much quality control.  I use and recommend ACE products.  I think their stuff comes from overseas as well, so maybe they are not as good as they used to be.  I don't sell these, but they are commonly available.  Just want you to know this is a genuine opinion and not a sales pitch.

I have a good digital AMP meter that I use to check the calibration on my cyclers.  They do slip adjustment and need recalibrated from time to time.  It is not a sign of inferior quality always.  A cycler has to be kept right up to snuff at all times.  You wouldn't want your doctor using a faulty heart monitor and your battery is a required organ just the same.

It is common wisdom to never us a pack that does not test 80% or better of the factory rating.  Anything below this number has a high risk of doom.   That is my opinion and the opinion of many battery gurus.  You should have contacted me about it only cycling 1400 as we would have been able to go over all the possibilities.

If you don't own a good digital amp and volt meter, then you might want to think about getting one.  This way you can verify what your charger is telling you from time to time.  And I don't mean the $20 - $40 cheapies at Radio Shack, think about getting the best you can for around $100 and you will probably get a good one.  If you have a friend in electronic repair you can check it against his good fluke meter to see if it is accurate.

Your discharge function should kick over to charge when the pack has reached 1 to 1.1 volts per cell.  There is only a few mAh difference in this adjustment as it falls from 1.1 to 1 in seconds.  However, if your charger is cutting off at 1.12 or more (I know it sound picky but it is a big difference), then your cycler is building a memory into the pack.  If it is cutting off below 1 volt per cell, it could ruin a pack.  Make this test by patching into the battery pack or wiring harness and take the measurement while it is being discharged.  You can't pop the pack off when you see it kick over and measure it then.  It is the voltage under the discharge load that we want to know.  If the number is too high, you are getting false bad readings; if it is too low, you can ruin or damage a pack.

Put your amp meter in line with a pack.  Make a harness or set of jumpers so one leg of the charge has to go through the meter to get to the pack.  Be careful to set the meter correctly.  If you have it set at 50mah range, you could blow a resistor and ruin that range.  Set it at the closest range to 300mah or more.  Note the discharge rate when you first start discharge on a full pack and in the middle and at the end of discharge.  It should be exactly the same (within 1%) no mater the pack voltage as it's state of charge declines.  If it is higher than 250 (what the Accucycle is telling you) then you will get lower than reality readings and tend to fault a pack to early.  If it is below 250, then you will get much better than reality readings on your packs and tend to use them too long.  Once you know the number, it is OK if it is 220 or 275 or whatever.  With the true number known you can plug it into your equation and get the true capacity of your pack.  That is what you really want to know.

You need to know the true capacity of the pack if you are going to be accurate on the 80% rule.  For me, I get rid of them long before they are down to 80% and always replace a pack no mater how good it rates if it is 3 years old.  Many do this every year.  I think that is a little excessive but everyone has their own opinion on batteries.

Probably these Hobbico cyclers are just all over the scale, some right on, some high and some low.  Of course, if a customer cycles a 1800 pack and gets 2045 out of it, they just think they got a special good pack and never contact me.  I only hear about the low reading units for that reason.  But, I get just as suspicious of my cyclers if one reads very much too high.

With your cycler in line to test the discharge rate you can also test the charge function.  Use the same principle and note the number at low battery, mid charge and full charge to see it is staying the same.

You have to put at least 140% in a NiCad to fill it up.  I always figure 160% so I have a little safety margin to make up for inaccuracies and packs with slightly different personalities.

Bare minimum: 
140% of 1800 = 2520.   2520 / 125 (your stated charge rate) is 20.16 hours. 
(1.4 X 1800)

Safety margin method: 
160% of 1800 = 2880.   2880 / 125 = 23.04 hours. 
(1.6 X 1800)

Once you know the true charge rate of your charger, you can figure out by the 140% rule how full you were getting your pack.

Many factory radio packs are rated 50 to 100 mAh below the true cell size.  Some will be tricked and think because the factory pack cycles right at rated capacity that the cycler must be OK.  This is no way to test your cycler.  Manufacturers cheat the number down a little to sucker people into using marginal packs and not returning for warranty.  Not saying they all do it, but I have seen it many times.

And last of all, you could just have a bum pack.  I have yet to take one back that did test bad, but I am sure there will be first time.  I don't expect to sell hundreds of packs and every one to be perfect.  Providing warranty service is just part of being in business.

I hope I did not tell you too much of what you already knew.  You could be an expert and I would have no way of knowing.  I just wanted to cover all the basics.  It is important to determine the exact reason for any failure to be sure it does not happen again.  If you don't have the expertise or equipment to check your Accucycle, you can send it to me.  I will check it out and give you the numbers.  I could return it with your new pack.

Dave Thacker 






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