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◆ Battery Packs
How is the voltage of a GWS battery pack determined?
A GWS battery pack consists of a number of cells, wired in series. Therefore, the voltage for the pack is equal to the number of cells times 1.2 volts (NiCad cells provide 1.2 volts of electricity). However, because of a cell's internal resistance, the actual voltage you are getting is slightly lower; more like 1.1 volts per cell or even down to 1 volt per cell in the higher current installations.
How fast can I charge my batteries with GWS charger?
Different cells can withstand different charging rates. Checks with the instructions to make certain you don’t damage your pack.
For fast charging, most packs can be safely charged in 15 minutes, which requires a charging current of 4 times the capacity of the pack.
Slow charging is usually done at a rate of 1/10th the capacity, or C/10. GWS lists this as the charge rate in which the cells will not vent (release gases that build up from overcharging). However, even this charge rate can reduce the life expectancy of a cell if left on after the cell is fully charged.
How can I make certain my packs are fully charged?
A GWS peak charger automatically does this. If you don't have a GWS peak charger, we'll provide the way to monitor the charge yourself. You'll simply stop charging when one of the following two things occur: 1. The pack starts to get warm. 2. The charging voltage starts to drop. SECURITY WARNING: if you are doing a manual fast charge (I.e. by watching the temperature and/or voltage yourself: PAY ATTENTION! If the batteries get too much charge they will overheat and that could damage or even destroy your batteries!
How and how long to charge 3000mAh Ni-MH batteries?
Suggest to adjust the knob of the charger to make charging current at 6A (the maximum) and charge for 30 mins.
How to make certain battery packs are fully charged?
A GWS peak charger automatically does this. If you don't have a GWS peak charger, we’ll provide the way to monitor the charge yourself. You’ll simply stop charging when one of the following two things occur: 1. The pack starts to get warm. 2. The charging voltage starts to drop. SECURITY WARNING: Doing a manual fast charge (i.e. by watching the temperature and/or voltage yourself: PAY ATTENTION!), if the batteries get too much charge, they will overheat and that could damage or even destroy your batteries!
How long it will take to charge the battery by using a slow charger?
We didn't have the figure for that. However, our R/D suggests to unplug the battery when you can feel the battery's outside case started to warm. When charging the battery with the slow charger, be sure to watch over the time, or the battery will be damaged probably.
What are milli-amp hours meaning?
The milli-amp hour is the standard unit of storage capacity for a cell.
It is similar to "gallons of fuel" for an internal combustion engine. The milli-amp hour rating of a cell tells how many constant milli-amps of current can be supplied by the pack for one hour. This rating can be used to find the duration that a battery pack can provide given a certain draw.
Because cells are wired in series, the milli-amp hour rating of a pack is the same as the milli-amp hour rating of a single cell.
What are NiMH batteries like?
NiMH (Nickel Metal Hydride) cells are similar to the more familiar NiCad’s in many ways. A cell has a voltage of 1.2V and they are made in the same range of sizes. As compared with NiCad, NiMH cells of the same size and weight generally have a higher capacity (mAh) but cannot be charged or discharged quite so fast. They have a higher internal resistance so they will not deliver as much current as NiCad’s. They can be very useful for sport flying where good duration is preferred to the ultimate in power and they are particularly useful for indoor and slow flight when their relatively light weight for capacity is prized.
Like all battery technologies NiMH cells are improving all the time. At the time of writing the best of the bunch are the new 3000mAH cells in Sub-C size, capable of currents over 30A.
What does it mean "8N750mAh"?
It means 8 cells 9.6V 750mAh batteries.
What is "mAh" meaning?
The "mAh" is the standard unit of storage capacity for a cell. It is similar to "gallons of fuel" for an internal combustion engine. The "mAh" rating of a cell tells how many constant milli-amps of current can be supplied by the pack for one hour. This rating can be used to find the duration that a battery pack can provide given a certain draw. Because cells are wired in series, the "mAh" rating of a pack is the same as the "mAh" rating of a single cell.
What are the maximum charging and discharging rates for 1050mAh and 1300mAh LiPo batteries?
For 1050mAh : Max. charging rate : 1C ; Max.
discharging rate : 6C
What should pay attention to when using new batteries?
Please be noted that most batteries that are new have to be cycled several times in order to gain their higher voltage and best efficiency.
What's the maximum current draw for GWS 9.6V 1000mAh Ni-Cd batteries?
The maximum current draw for GWS 9.6V 1000mAh Ni-Cd batteries is 10C (10 amp).
What's the max. discharging current for 8.4V 750mAh Ni-MH batteries?
The max. discharging rate is 10C.
Should I cycle my packs?
Weigh the dangers of cell reversal versus the dangers of NiCad memory and you may decide for yourself.
Some people discharge their packs to 0 volts per cell and say they have never had a problem. Others say that cycling below 1.0 volt is damaging. Use your best judgment.
Which propeller should I use with these Li-Pol batteries? (9070?, 1080?, 1060HD?)
GW/EP9070 is recommended.
Which is the average fly duration with the 8.4V 750mAh battery fully charged ?
The average fly duration of 8.4V 750 mAh battery is 5~7 mins .
Can I deep discharge an individual cell safely?
It can be discharged to 0 volts per cell safely. Cell reversal can't occur with individual cells. As a matter of fact, cycling an individual cell is a good way to determine its exact capacity.
Can I use Lithium batteries for electric flight?
No, we’ll give you a warning first. Base on many factors, we do recommend that not using this method for your electric flight.
According to GWS security instructions of Ni-Cad and Ni-MH cells, there is a very definite instruction that you should never solder directly to the cells. The reason for this is that the cell has a number of components which are made of plastics and which can be damaged by excessive heat. In particular there is a vent designed to allow excess hydrogen to be safely removed from the cell. If you damage the vent, oxygen from the air can enter the cell and the internal chemistry will be severely degraded, dramatically reducing the life of the cell.
If power with a geared GWS 400 2.14 A drive 8x6 prop and need 3 cell 1500 lipo. It's like a rocket about 47 mph.
3 cell 1500 lipo is not yet finished at this moment. GWS will procced on 1300 lipo & 2200 lipi production soon.
My charger works great but i didnt know how long or what setting to charge 3000 Ni-mh batteries
For charging 3000 Ni-mh batteries,e suggest to adjust the knob to make charging current at 6A (the maxima) to charge 30 mins.
8N750mAH battery means ? wat is the voltage ? or how many cells ?
8n750mAH means 8 cells 9.6V 750mAH.
Regarding the 8.4v 730mAh battery, what are the charging?amps and minuets that I should be charging this battery at ? I'm also using a PRO-TECH model 700 adjustable amp and 15 min timer charger?
Since you are using a PRO-TECH model we are not able to provide you with the exact information.If you use GWS charger,all charging information on the instruction manual you can get.However,our engineer advised,it is 2 time capacityo charge battery pack,according to your statement.
have the speed controller and its only for Ni-cad or Ni-MH ,What batteries are you using that are NOT Lithium or Lipo ?
You can use LiPo's with an ordinary speed controller, just so long as you don't go below 3v per cell, off load, both with Himax brushless motors., using CC Phoenix 25 speed controllers which are set up for LiPo to cut off a 7.4v with 3 cell packs have flown for over 10 minutes and then topped up the battery and only got 425mAh back into a 1500mAh pack. LiPo's really are the future and you'll save a fair bit of weight. We have been using them with ESC's not LiPo compatible and its easy enough to land and check battery voltage, having said that you'd notice the degredation in performance well before the packs are over discharged.