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View Full Version : 2x1 4562, the Anima, and Battery Life


rharris
2006.10.16, 04:40 PM
I took a board and put a 2x1 set of 4562's. Just for fun, I started running an Anima (33 turns) to see if I could fry the fets.

It seems to work OK, and I can't manage to fry them (yet). But there seems to be an odd side effect.

The battery life is very, very short. Less then 4 Min.

Is this normal? If I bump up to a 2x2 stack, should battery life increase?d

For you guys running in Open class, how long are your battery's lasting?

shahinjaan19
2006.10.16, 04:55 PM
The first thing I would do is check for a short. Make sure you did a nice clean job on your soldering. A 2X2 stack would cut the resistance by half, but that would mostly translate into a cooler running fet, and may not necessarilty bring a significant increase in run time. I would drop in a motor that you know roughly how much run time you should expect from it to determine if the time is roughly the same or decreased compared to the old fets. Also, we do not know just how often you are pushing the throttle to the max.

rharris
2006.10.16, 05:17 PM
Wide open track. Lot's of wide open time.

The next thing I'm going to do is run a PN FS motor (fet stock, 45 turns) and see what happnes.

The solder looks clean. If the PN has the same issues, then I'll pull the fets off and try a 2x2.

On a stock car with a PN motor, I get around more then 12 min of good run time. (we run 8 min mains and it's got plenty of power up till the end.)

What would you expect out of a 2x2 or 2x3 with a low wind motor?

locwan
2006.10.16, 05:27 PM
fet stacks does make the car more efficient in terms of translating battery power to driving force.. however, don't forget that as you start using hotter motors with less turns, the motor is also drawing much higher current than a stock fet motor would or could with it's lower resistance. This then translates into less run time, as the stored energy is translated into rpm at a much faster rate.

By doing a 2x2 instead of 2x1, and keeping the motor the same, you might see a slight increase in run time; being that the fet stack has lower resistance and is letting more "power" through to the motor instead of disipating it off as heat. But then again, there are many factors in the equation such as battery condition and ambient temperature etc.

rharris
2006.10.16, 05:34 PM
We're running outside (around 75 deg)

It's a 20x20 foot track with wide outside turns, so you can hold the throttle at full if you can make the two outside turns. This gives you a 60' section that's mostly full throttle, Then there is a quick infield section.

I figure something is wrong. When I look at the PN Regional races, they are running 8 min and 12 min mains. There is no way my car would last that long.

I'm running IC3's, Duracell, and others, all with the same short battery life.

But what you are saying is, I should not be able to get the battery life up to 12 min by increasing the stack.

byebye
2006.10.17, 01:02 AM
fet stacks does make the car more efficient in terms of translating battery power to driving force.. however, don't forget that as you start using hotter motors with less turns, the motor is also drawing much higher current than a stock fet motor would or could with it's lower resistance. This then translates into less run time, as the stored energy is translated into rpm at a much faster rate.

By doing a 2x2 instead of 2x1, and keeping the motor the same, you might see a slight increase in run time; being that the fet stack has lower resistance and is letting more "power" through to the motor instead of disipating it off as heat. But then again, there are many factors in the equation such as battery condition and ambient temperature etc.

I agree here with locwan. I too am running the same setup rharris but my track is shorter and this is recent. When I was running it before it did have a short run time. I haven't tested this setup on the larger stafford tracks but I imagine the run time will be short.

My suggestion would be to not drive the car so hard throught the corners. This will reduce the current draw under the heavy side to side load. My cars are setup for understeer and my son has a tendancy to hold the the throttle through the corners. Thats really going to strain the motor and drain the batts quickly.

-Byebye

PaulBoth
2006.10.17, 10:38 AM
My AWD car with a PN AWD motor can easily get more than 20 minutes of run time to a single charge. My 2WD car with AD band running a PN anima ran at least 18 minutes straight on a single charge.

Both of those times were at the PN world cup qualifier here in toronto... That track had a 37 foot straight - lap times in the 11 - 12 second range.

I'm almost inclined to think there is something wrong with the batteries... or at least the charging of them. What charger do you use? What kind of gearing ... maybe it's over/under geared for the track causing undue drain?

PB

rharris
2006.10.17, 02:18 PM
This is what I'm saying!!! I would expect to get more then 12 min of good run time. I could be the cells.

I am leary of the board becouse this is the first set of fets I've solderd myself. But I have a pro teaching me and he says everything checks out.

I've got an IC3 charger, two Duracel 15min chargers, one energizer 15min charger, a handfull of Radioshack Xmods chargers and one MAHA 8 cell charger. (as the local club leader for kids... haveing a ton of battaries is a must!)

I've only run the car 5 times over the past few weeks. I didn't really notice the problem till this Sunday. That was the first time I put the car down and tried to race it against the other pan cars in the club. It could be the IC3 cells I was using. I tried two sets of cells with the same results, but I've had issues with the IC3's before.

I think before I do anything else, I'll pick up some new cells and see if that helps.

AD band eh? I've been thinking of running an AD for Modified. I have an EX-10. Did you have to upgrade the fets to run the Anima? Philip of PN say's I'll need to. But I'd be pretty stoked if I didn't need to touch the factory board.

PaulBoth
2006.10.17, 02:38 PM
This is what I'm saying!!! I would expect to get more then 12 min of good run time. I could be the cells.

I am leary of the board becouse this is the first set of fets I've solderd myself. But I have a pro teaching me and he says everything checks out.

I've got an IC3 charger, two Duracel 15min chargers, one energizer 15min charger, a handfull of Radioshack Xmods chargers and one MAHA 8 cell charger. (as the local club leader for kids... haveing a ton of battaries is a must!)

I've only run the car 5 times over the past few weeks. I didn't really notice the problem till this Sunday. That was the first time I put the car down and tried to race it against the other pan cars in the club. It could be the IC3 cells I was using. I tried two sets of cells with the same results, but I've had issues with the IC3's before.

I think before I do anything else, I'll pick up some new cells and see if that helps.

AD band eh? I've been thinking of running an AD for Modified. I have an EX-10. Did you have to upgrade the fets to run the Anima? Philip of PN say's I'll need to. But I'd be pretty stoked if I didn't need to touch the factory board.

Those times are based on charging IB750 cells on my ICE charger at 1.2 amps with a Delta peak of 3mv/C. Average discharge for these same cells assuming a 4 amp load with a .8V cutoff are around 660 - 680 mah.

It was either the Anima or the Macho that was the handout motor. Regardless, there was at least 5 or 6 cars that were running AD band and nobody from memory had any problems.. I've had no issues with mine since... I would say as long as your not stuck against a wall, holding the throttle, you should be fine.

PB

P.s. Let me add that my above times are only how long I drove the car for. The punch from the cells obviously wasn't as great at the 15 minute mark for example as it was when freshly peaked. However, the car's were still plenty fast at the end of those times.

rharris
2006.10.17, 03:28 PM
Let me add that my above times are only how long I drove the car for. The punch from the cells obviously wasn't as great at the 15 minute mark for example as it was when freshly peaked. However, the car's were still plenty fast at the end of those times.

I totaly understand. I don't expect the car to have as much punch in the last few min as it did in the first.

I'll try a new set of cells first and keep you posted. The more I think about it, the more I think that's the issue.

shahinjaan19
2006.10.18, 02:01 AM
I have a set of IC3s, and I've discovered that the charger does not fully charge them after the 15 minute cycle. I think that's about 70-80% of max charge. Try placing them on your xmods charger after the 15 minutes, and it will continue to charge for up to 30 minutes. I'm sure if you do this you will add a couple extra minutes to the track and notice a bigger punch from the beginning.