JerryG
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<font color="blue"> You can show me this and that but I have had it happen in the real world </font>
Oil
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cordless drill battery
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TWINKLE_TOES
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gsxr110, I learned more about your heli than I did about your battery/battery charger.
<font color="blue">it states in my 9-channel Futaba PCM manual about memory effect on its' own battery pack </font>
If I was Futaba or any or any other manufacture of stupid battery chargers and I could shift product liability to some abstract phenomena attributable to technology I would do the same thing. By the same token if I was a manufacture of smart chargers I would profess use of my charger would eliminate the dreaded memory effect.
Memory effect was seen originally in spacecraft batteries subjected to a repeated discharge/charge cycle that was a fixed percentage of total capacity (due to the earth's shadow). After many cycles, when called upon to provide the full capacity, the battery failed to do so. This performance could be corrected by a single deep discharge and proper recharge. Your application is hardly like this.
I have no doubt that the performance you are getting from your batteries is less than it could be. What you are calling "memory effect" is most probably a result of overcharge by a stupid charger or premature charge termination from a stupid charger.
<font color="blue">it states in my 9-channel Futaba PCM manual about memory effect on its' own battery pack </font>
If I was Futaba or any or any other manufacture of stupid battery chargers and I could shift product liability to some abstract phenomena attributable to technology I would do the same thing. By the same token if I was a manufacture of smart chargers I would profess use of my charger would eliminate the dreaded memory effect.
Memory effect was seen originally in spacecraft batteries subjected to a repeated discharge/charge cycle that was a fixed percentage of total capacity (due to the earth's shadow). After many cycles, when called upon to provide the full capacity, the battery failed to do so. This performance could be corrected by a single deep discharge and proper recharge. Your application is hardly like this.
I have no doubt that the performance you are getting from your batteries is less than it could be. What you are calling "memory effect" is most probably a result of overcharge by a stupid charger or premature charge termination from a stupid charger.
</font><font color="blue" class="small">( .....most probably a result of overcharge by a stupid charger or premature charge termination from a stupid charger. ) )</font>
I doubt that since I have tried that pack on a $150 charge/discharger (best non-lipo out there) and one another charger about 3X more in price (a Schulze, top of the line ). Stupid charger, I do not think so.
Again, I know the capaciity of the cells since they get tested (with a fluke meter) once per month before charge, after discharge and after charging. I also know the temp before and after and what it should be around, along with the motor.
So let summarize here, someone on TBN says there is no memory effect while all the r/c flyers say yes along with manuafactures of the products (batteries, charger, heli manufactures, etc).........hmmmmm. Never mind that I have had it happen to one pack and the other started to die by about 40 seconds to 1 minute unless I cycled it when not being used; along with the RX & TX batterie(s). Thanks but I know that I have had it happen, along with other heli owners.
I doubt that since I have tried that pack on a $150 charge/discharger (best non-lipo out there) and one another charger about 3X more in price (a Schulze, top of the line ). Stupid charger, I do not think so.
Again, I know the capaciity of the cells since they get tested (with a fluke meter) once per month before charge, after discharge and after charging. I also know the temp before and after and what it should be around, along with the motor.
So let summarize here, someone on TBN says there is no memory effect while all the r/c flyers say yes along with manuafactures of the products (batteries, charger, heli manufactures, etc).........hmmmmm. Never mind that I have had it happen to one pack and the other started to die by about 40 seconds to 1 minute unless I cycled it when not being used; along with the RX & TX batterie(s). Thanks but I know that I have had it happen, along with other heli owners.
Soundguy
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</font><font color="blue" class="small">( performance could be corrected by a single deep discharge and proper recharge )</font>
I'll agree with you there.. Many rechargeable battery issues come from improper charge/discharge schemes. However.. how many people do you know that completely discharge their batteries before charging? heck.. in some situations you can't. The average consumer is not going to take a piece of equipment apart to get at an installed battery pack in order to attatch a small value, high wattage load resistor and let it set there and discharge, let alone know what or how/why any of this helps.
Some from cheapy handheld devices that simply use switches and motors ( handheld cordless screwdrivers.. etc.) could theoretically discharge by leaving the button held for a while, as the motor windins provided the load. However, many of the newer electric devices are PWM controlled, and the 'logic' shuts down while there is still non-negligible power left in the cells. I have an 18v sawzall. When it gets to the point that the blades no longer 'go', and the PWM wine dies down.. that battery pack is still setting at about 5v unloaded.. perhaps 3v loaded. No way for the average user to discharge that by using the device for the load.
In the 80's I have a small battery discharger I mocked up on a plank of wood using a small automotive lamp. I made it for cam corder batteries. Worked great, and I got another couple years out of cells if i used it correctly.
Speaking of the RC world. I think I still have an old fastcharger that actually had a loading resistor built in. You pulle dthe old cell.. set a timer and let it 'cook' for 15 minutes.. then you threw it on the car battery for 15 minutes. it worked decently.. and kept you from needing a ac power source there.. however my guess is that the discharge cycle was insuficient.. and the charge cycle was way insuficient.. not to mention the battery was way hot during both cycles.
I think most of the problem lies simply in consumer (dumb user) grade equipment....
Soundguy
I'll agree with you there.. Many rechargeable battery issues come from improper charge/discharge schemes. However.. how many people do you know that completely discharge their batteries before charging? heck.. in some situations you can't. The average consumer is not going to take a piece of equipment apart to get at an installed battery pack in order to attatch a small value, high wattage load resistor and let it set there and discharge, let alone know what or how/why any of this helps.
Some from cheapy handheld devices that simply use switches and motors ( handheld cordless screwdrivers.. etc.) could theoretically discharge by leaving the button held for a while, as the motor windins provided the load. However, many of the newer electric devices are PWM controlled, and the 'logic' shuts down while there is still non-negligible power left in the cells. I have an 18v sawzall. When it gets to the point that the blades no longer 'go', and the PWM wine dies down.. that battery pack is still setting at about 5v unloaded.. perhaps 3v loaded. No way for the average user to discharge that by using the device for the load.
In the 80's I have a small battery discharger I mocked up on a plank of wood using a small automotive lamp. I made it for cam corder batteries. Worked great, and I got another couple years out of cells if i used it correctly.
Speaking of the RC world. I think I still have an old fastcharger that actually had a loading resistor built in. You pulle dthe old cell.. set a timer and let it 'cook' for 15 minutes.. then you threw it on the car battery for 15 minutes. it worked decently.. and kept you from needing a ac power source there.. however my guess is that the discharge cycle was insuficient.. and the charge cycle was way insuficient.. not to mention the battery was way hot during both cycles.
I think most of the problem lies simply in consumer (dumb user) grade equipment....
Soundguy
Soundguy- I still have one myself for my old r/c cars. The old ones worked but killed the cells at the same time. At think at one time I melted the outer pack! I never did discharged at that time. Never knew about it…The 15minutes was a long time when waiting.....
The chargers/dischargers today go from $100 to over $1,000K and are very complex and smart. I agree in the past or on drills the discharge is not 100%; but, on my r/c heli packs it is. Mine are 100% discharged going by my dischargers/chargers LCD screen and my Fluke meter. In a drill package costing over $250 I would not care too much, but when I have over $1,000 in batteries packs alone, I care a great deal and amps are my friends! I need to know for flight times. Every electron is needed when turning over 1,800 head rpm with a 5.5 foot diameter main rotor blades! /forums/images/graemlins/grin.gif
The chargers/dischargers today go from $100 to over $1,000K and are very complex and smart. I agree in the past or on drills the discharge is not 100%; but, on my r/c heli packs it is. Mine are 100% discharged going by my dischargers/chargers LCD screen and my Fluke meter. In a drill package costing over $250 I would not care too much, but when I have over $1,000 in batteries packs alone, I care a great deal and amps are my friends! I need to know for flight times. Every electron is needed when turning over 1,800 head rpm with a 5.5 foot diameter main rotor blades! /forums/images/graemlins/grin.gif
Soundguy
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I know what you mean about 15 minutes being a long time to wait while at the track. Even with a couple packs going, you could drain one befor ethe other was done. We'd keep a cooler on hand, cause some of the batteries would come out of the car too hot to touch.
At least using 'black flag' frequencies we never had transmitter cross talk problems.
Yep.. a 9.99 kmart e-screwdriver doesn't worry me much.. however my 18v sawzall wasn't a cheap toy.. I need that battery to last..
Soundguy
At least using 'black flag' frequencies we never had transmitter cross talk problems.
Yep.. a 9.99 kmart e-screwdriver doesn't worry me much.. however my 18v sawzall wasn't a cheap toy.. I need that battery to last..
Soundguy
TWINKLE_TOES
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Chris, <font color="blue"> However.. how many people do you know that completely discharge their batteries before charging? </font>
"Completely" hopfully none. I can't think of a better way to kill a NiCd battery than a high current load to zero volts. The deep discharge I'm talking about is ~ 1 volt/cell I'm guessing the vast majorityof user do this. I use my drill until it slows down (discharged) I use my flashlight until it goes dim(discharged)
A NiCad cell voltage is nearly flat during discharge @ 1.2 volts, this drops off very rapidly when discharged. One thing that should not be done is to try to get the last ounce of performance from your NiCd powered equipment. For example if you rest a drill for a few minutes after it's performance has degraded it will recover and drive "one more screw". NiCd batteries discharged below 1 volt per cell will cell reverse. This doesn't mean a cell at +0.8 volts will become -0.8 volts, it will be a few millivolts negative. Contrary to what some of Rat's references contend this is a recoverably situation upon recharge if the charger is smart enough to go into ~ 120% overcharge. This doesn't have to be a brilliant charger just one that terminates charge when the battery temperature is ~ 5-7 degrees C above ambient or on ~ 100mv of negative DV/DT. The rational for the overcharge is to equalize the charge in each cell. The larger the mismatch in cell charge the more likely cell reversal on discharge. However if you continue to run high currents thru a cell in cell reversal the cell potential will increase negatively and eventually destroy the cell. This high current scenario is exactly what happens when you try to get "one more screw)
"Completely" hopfully none. I can't think of a better way to kill a NiCd battery than a high current load to zero volts. The deep discharge I'm talking about is ~ 1 volt/cell I'm guessing the vast majorityof user do this. I use my drill until it slows down (discharged) I use my flashlight until it goes dim(discharged)
A NiCad cell voltage is nearly flat during discharge @ 1.2 volts, this drops off very rapidly when discharged. One thing that should not be done is to try to get the last ounce of performance from your NiCd powered equipment. For example if you rest a drill for a few minutes after it's performance has degraded it will recover and drive "one more screw". NiCd batteries discharged below 1 volt per cell will cell reverse. This doesn't mean a cell at +0.8 volts will become -0.8 volts, it will be a few millivolts negative. Contrary to what some of Rat's references contend this is a recoverably situation upon recharge if the charger is smart enough to go into ~ 120% overcharge. This doesn't have to be a brilliant charger just one that terminates charge when the battery temperature is ~ 5-7 degrees C above ambient or on ~ 100mv of negative DV/DT. The rational for the overcharge is to equalize the charge in each cell. The larger the mismatch in cell charge the more likely cell reversal on discharge. However if you continue to run high currents thru a cell in cell reversal the cell potential will increase negatively and eventually destroy the cell. This high current scenario is exactly what happens when you try to get "one more screw)
TWINKLE_TOES
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Mike, perhaps we are not talking apples to apples. are your NiCd's sealed or flooded cell technology. If they are sealed and you are discharging them to zero you are your own worst enemy.
The Futaba RX and TX packs are a cheap Nicad which states to completely discharge once per month& when not being used (for memory effect) Again this is from Fubota's manual and support team and about 99% of other r/c flyers. The TX packs will have a shorter life span when not following the rules for r/c.
The same rules apply for NiMH cells also, not lipo's. The cells MUST be discharged after EVERY use. That is from every flyer out there along with manufactures/dealers.
Own worst enemy???I will take the manufacture of the product over anyone that does not fly. Again, thanks but you are not the one paying over $500 for a controller. Buy this controller then prove it to me. Or buy a cheap $250 battery pack and let me know. Worst enemy, LOL.
The same rules apply for NiMH cells also, not lipo's. The cells MUST be discharged after EVERY use. That is from every flyer out there along with manufactures/dealers.
Own worst enemy???I will take the manufacture of the product over anyone that does not fly. Again, thanks but you are not the one paying over $500 for a controller. Buy this controller then prove it to me. Or buy a cheap $250 battery pack and let me know. Worst enemy, LOL.
Soundguy
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</font><font color="blue" class="small">( I can't think of a better way to kill a NiCd battery than a high current load to zero volts )</font>
I never mentioned any shunt loading for discharge.. rather something along the lines of a linear discharge.. either resistive.. or incandescant.
Like arguing with chineese about rice... I'd find it a hard roe to hoe to believe otherwise about not sufficiently discharging a nicad before recharging it. Just seen too many instances where that gives reduced performance.. over a good slow clean discharge and full recharge. And just for clarification.. we are not talking about a high current discharge.
Soundguy
I never mentioned any shunt loading for discharge.. rather something along the lines of a linear discharge.. either resistive.. or incandescant.
Like arguing with chineese about rice... I'd find it a hard roe to hoe to believe otherwise about not sufficiently discharging a nicad before recharging it. Just seen too many instances where that gives reduced performance.. over a good slow clean discharge and full recharge. And just for clarification.. we are not talking about a high current discharge.
Soundguy