QUOTE (crusader4x @ Dec 1 2008, 01:45 PM)
I'm not trying to be argumentative, just trying to understand and I do appreciate your explanations so please educate me!
So, as you've explained it, my 9.6v battery simply cannot supply the current the motor needs THUS making it suck compared to my 7.4v lipo? Did I get that right? Is that why my 9.6v NiMh battery can't even turn my G&P M120 while my 7.4v Lipo not only turns the motor, but does so at a significant ROF?
But you're statement was that the 7.4v lipo was more equivalent to an 8.4v NiMH than a 9.6v. A wonderfully working 7.4v lipo is NOT equivalent to a 9.6v NiMH (much less an 8.4v) that can't even turn the motor.
If it is as you stated that, "voltage level that dictates the ROF," why then do larger cells (same voltage) produce higher ROF? Why does my 7.4v have a ROF higher than my 8.4 or 9.6v batteries (all at their peak charge level) in the same gun under the same load? It would seem to me that factors other than voltage level affect ROF.
crusader...not an issue and I am happy to help. It appears I was correct in my assumption that you were speaking of a modified rifle. Yes, I would tend to believe your 9.6v battery is not rated to supply enough current to make your setup function. However, a 9.6v battery that can supply enough current would have a higher ROF than your 7.1v Lipo. If you read my last paragraph, you would see where I specified ”you need insure that all three are equal in the ability to supply a specific amount of current under the same load.”
That would not be the case in your scenario as you are trying to compare under-rated 8.4v and 9.6v cells with one that has a high enough current output that it can do the job. Equalize the test by using comparably performing NiMH’s, thus making a fair comparison and you will see where it produces the results I noted.
So, it appears you are confusing rate of fire with the "Ability to Fire". "Rate of Fire" is directly associated with the motor turning a specific rpm and these rpm’s are controlled by the voltage supplied by the pack. The higher the voltage, the higher rpm's you will turn on a motor under nominal load. This is a fact, as well as a by-product of Ohms Law that cannot change. What you are experiencing though with the cell packs is a voltage drop, usually caused by overloading the cells, since they cannot produce the higher amount of current required to run your modified system. This voltage drop would once again slow your ROF.
Any time you place a load on any battery, you will experience a voltage drop. As long as your battery is matched to the load, you will see little change in ROF. Adding a battery that cannot supply the current required will cause a slower rate of fire, so in answer you your last question, the ability of a battery to produce the current necessary to run under a give load would be an indirect factor that effects ROF. Notice I said indirect, as it is still the drop in voltage from the overload of such a battery that slows the ROF, as the cells will try to push the required current through to the motor; so once again, the voltage of the source determines ROF. Finally, if you try two batteries of the same voltage that are both more than strong enough to run the motor, the battery with the larger capacity cells will have a slightly higher ROF, as its voltage drops less under load. However, the difference is nominal and where you begin to see a wide variance is when one battery is most likely underrated, such as your 9.6v where another battery was matched for the load, I.e. the Lipo. Even the comparison with a better grade 9.6v pack and you will be surprised at the results.