Well, cable length should be negligible if we are not talking thousands of amps in too small cables! Don't forget that every battery itself is actually made up of several parallelled lead-plates (although in the same electrolyte, so it is still the same cell) and no cell is equal either. If some cell is bad you have trouble, and with the double amount of cells the probability for that is statistically doubled!well, the reason why parallelling 12v batteries is bad, is that no battery is created equal, and if you have 2 in paralell, one is bound to get more loaded than the other. this can be a mismatch in cable length, or even a slight randomisation in better/worse during the manifacturing, just no battery is equal, and in paralell, they create trouble.
16x 100 AH 6v or 8x 105 AH 12v is pretty much equal, 120+AH 12v starter batts and better are quite commonly availible, probably the best choice in this situation, you can get a new one around the corner if one blows up, 6v are more rare, but would be cheaper to replace in theory. the golden middle road of 8x2 12v is actually not (see above).
http://smarttchallenge.com/ (rules are there)My school converted a 1987 Mazda RX7 last school year and competed in the SMARTT Challenge. We did well in the competition, but this year we would like to make some improvements in the vehicle. We powered our vehicle with 12 8volt batteries, as we could not exceed 96volts. This year we are thinking about switching to 12volt batteries. We would have 16 12 volt batteries in a series parallel configuration. We would parallel each two batteries and then serial the 8 parallel connections. I want to know if that would be more efficient. The SMARTT Challenge has both a range competition and a speed completion. Most people set up for one or the other, but we are going for a middle of the road setup.
no, more like 77 minutes at 150 amp, or 160-170 minutes at 75 amp. look into the peukert effect. (basically, the faster your discharge compared to the battery capacity, the less total capacity you're gonna get, and the other way around, if you double the battery AH on the same draw, it slightly more than doubles the time) combined with air drag, its best to drive 'slow' (40-50 mph?) at the range test..The batteries that I currently are using has a rating of 116 minutes at 75amps, and the ones that I was looking to replace them with have a rating of 77 minutes at 75amps, but with the parallel conection that should increase to 154 minutes at 75amps correct?
ah well.. What is your drive train?Alexander_B what type of batteries do you suggest. Remember that my comp. rules require lead acid batteries. Our current set up is twelve 8V batteries connected in series. We went with 8V over 6V in order to save weight. I know that the 6V batteries have a high Ah rating, but my caculation told me that the added weight would counter act the longer life. The motor that we have is 6.7" in dia. x 12.28" long. I think this motor is part of our speed problems. We are only getting about 40 mph on a flat surface. Would I be better off changing battery configuation, or spending my money on a bigger motor?
You cannot tell the power of the motor?Alexander_B what type of batteries do you suggest. Remember that my comp. rules require lead acid batteries. Our current set up is twelve 8V batteries connected in series. We went with 8V over 6V in order to save weight. I know that the 6V batteries have a high Ah rating, but my caculation told me that the added weight would counter act the longer life. The motor that we have is 6.7" in dia. x 12.28" long. I think this motor is part of our speed problems. We are only getting about 40 mph on a flat surface. Would I be better off changing battery configuation, or spending my money on a bigger motor?
I cannot see why you should not be able to reach much higher speeds... 550 A @ 96 V gives you about 50 kW, more than the motor peak, and should be more than enough to reach higher speeds.We are using a standard transmission.
Interstate Batteries U8VGC.
We are 500lbs below GVW.
We have extra space in both the front and back.
Controller is a Curtis 1231C and it can deliver up to 550A.
40HP peak on the motor.
