FahrtAutoRC

Right. Understood.

How about computer systems? Lighting? Is it indoor and possibly in need of heat in the cold months?

I'd estimate the cost off the top of my head as being a heck of a lot less than the other costs in his overhead, poor guy has alot of checking to do! Take the other guys advice and buy yourself a cost meter, set it up and check it all out. With all that charging you might be stretched pretty thin, it even takes power to flush the toilet, and that's a lot of people!

Henryslash

Foxy: lol, edited by mods. I'll send you a pm later.

FahrtAutoRC

I've never personally checked it to the exact dollar and cents, but I know when outdoor race season is going on and we are doing lots of soldering, charging, etc there is no noticeable spike in our bills or power consumption. Our biggest pack we use, btw, is a 4s 5800 mAh 50c LiPo.


And henry, I'll not even warrant that with a response. You, sir, are above and beyond the call. Unbelievable. If you have a problem with me, report it to the mods in private or take it to our wonderful PM system. Do not sully the boards here with petty insults.

john01374

We did some cost analysis for a small hobby shop that was thinking of opening a a track about 4 yrs ago.We looked at things like lighting costs, charging, soldering, radios etc etc.

What it came down to was the cost was in the pennys per day per person and weren’t enough to affect the admission costs.

I would need to go back to my spreadsheets but the cost was something like 1.2 cents per battery per hr.

Soldering was in the fractions of a penny and running a small radio was the highest cost at something like .02 per hr.

GerKonig

You are right on your statement! W = A x V

So if you increase the A in order to shorten the charge time, you are also increasing the Watts:-) Conclusion: you gain nothing but time charging at higher C's

Of course, saving time can be very important also, as you can process more batteries on one charger...

Gerry

phmaximus

Dont stress thats normall most of the chargers max out at 5 amps, if u use that charger u will have to put up with 1.2-1.5 charging times.

psb667

So it costs about 3.5 cents to charge a 5000 on my charger thats assuming my fluke is accurate.

Henryslash

Hi

phmaximus

ahh sorry, 1.2h is 80min. and 1.5h is 90min. Its physically impossible to get it done any faster if charged at 1c. no battery is that efficient.
if a battery has 1c charging rating, to work that out, u divide the mah rating by 1000 then times by 1

Most lipos are ofically rated at 1c max charge, U can get ones with higher charging rates

U could look into some Reedy LiPo 5500mAh 7.4V 60C discharge 2c charge...but then u would need a charger that can charge up to 11amps
It could be charged in 36-42min

Foxy

It's possible to charge almost any lipo at 2C, the manufacturers are terribly paranoid by the fact that early lipos caught fire when abused (overcharged or discharged), which led to a knee-jerk reaction of almost the entire RC world, to say that charging at more than 1C was a) detrimental to the battery and b) dangerous, both of which are frankly, a load of old bollocks.

You can definitely 100% charge ANY hobby grade 5.2Ah lipo battery at 6A, no question, no doubt, no problem.

Here's what I would do in your shoes. I'd buy a few cheapy battery checkers (they're very cheap and literally you plug in the balance plug and it reads off the voltage of the cells). Check the batteries before you (fast) charge and after you (fast) charge. As long as the voltages stay pretty close (within say .2 to .3 of a volt difference between the cells, MAX), you would be ok to fast charge them at 5 or 6A, even if they say 'charge at 1C only', remember, 1C of a 5.2Ah hour is already 5.2A, it's not like 6A is going to make any difference to the battery. If it was a 4Ah battery, then it would make a difference, as 1C would be only 4A, then 6A is a 50% increase in charge current. Still, with the battery checkers, at least you'll know when a battery absolutely MUST be balance charged the next time (if it has a cell with like half a volt difference from its mate).

SyCo_VeNoM

most mine say charge at 1C but in small print say 2C is ok
Like my turnigys all say 2C max and I'll charge em at 6A(they are all 5000mah+ packs), but my sky lipos don't and honestly they were so cheap($7 shipped) I don't really trust them charging them over 1C.

Henryslash

Very good

FahrtAutoRC

I usually match what I charge mine to what they are rated, that's how I was taught and have always done it. For example, I charge my 5800 @ 5.8, and our 5000's at 5.0. Been doing it for a couple years now too, ever since we got back into the hobby

Henryslash

Ok so i am just in from running my slash 1/10 2wd vxl using 5200 mah zippy 30c lipos.

Foxy

Yes and no. A serious driver may even put more strain on it at a track, with very aggressive acceleration and braking, reducing runtime further. Amateurs however, will stop and start, they will crash, so the cars will spend some time on their roof, and runtimes will be greatly increased simply due to driving style and the fact they won't (be able to) go as fast.

The only way to be sure would be to run an actual dress rehearsal at your planned venue, using the same type of person you expect to be catering to, I'm surprised you are getting such short runtimes, are the cars fully ballraced? (ball bearings throughout?) A traxxas guy will have to answer that for you, I'm not sure, but anyway if in critical places, bushings are employed instead of bearings, simply swapping them for good quality bearings will make a huge difference to runtimes.

The other thing you can do is reduce motor kv to extend runtimes, but of course that will make the cars slower in a linear way (for example, going from 3000kv to 2000kv will reduce top speed (but not acceleration which will still be instant) 33% as you would expect, and runtimes too will be considerably longer if not the full 33% also).

When I said (in your other thread) that I would expect half an hour from those batteries, I did mean in real life situations, not constant full throttle running.

Henryslash

Hi Foxy 

FahrtAutoRC

I would advise caution using anything more than a 3s, as the VXL I believe is still rated for nothing more than that.

Honestly to me, something seems off. My Slash 4X4 is powered by a Castle MMP SCTE ESC, and a NueCastle 3800Kv 4-Pole, and the battery is a 2s Turnigy 30-40c 5000mAh. I get about 20 min of solid speed runs, and about 15-17 when I race on our local 1/8 outdoor track. Unless I have missed something, and you are running the mini Slash, but I still don't see where or why you would be getting such low run times. It just ain't normal, at least in my experience.

Henryslash

Hi Friend :-)

FahrtAutoRC

I would look into Turnigy instead, also available from HobbyKing.

I say this because The Summit I seem to constantly have in my posession for repairs gets powered by Flightmax's. The owner got the truck, and then ordered 8 2s Zippys just like those ones. It is now three months later, and out of those 8, 3 of them have puffed, and one has gotten so far out of whack it won't even balance out for nothing now. I double checked when I heard about the issues he'd been having, he runs the same chargers as I do, and I watched him use them, he knows what to do and how to care for his batteries.

On the other hand, I have 2 Turnigy 2s that are 100% original, one is 2 years old with LOTS of cycles, and I also have 3 hand-done 4s LiPos using Turnigy cells, and have never had an issue with any of them as far as I can recall.

The more I think about it, your choice in batteries might be part of the problem. some companies just simply put out junk, As far as cheapo LiPos go, I trust my Turnigys above all the others.

Foxy

The flightmax packs are decent for the price, but the Turnigy Nanotechs are better (as they should be, they are more expensive).

Henry, the next size of battery that will fit (in terms of duration) would be 6000mAh, there may be bigger batteries that fit (you can find up to 8000mAh from various brands). If you measure the internal dimensions of the battery bays, you can then search around on hobbyking for the biggest battery that will fit. Of course 6000mAh will not give you more than a couple more munites compared to 5200, but its a common and easy to find capacity.

Henryslash

Mad question i know but is it possible to connect more than 2 batteries in parallel?

phmaximus

Sure can, u can buy adapters to do that

Traxxas 3064

Henryslash

Hi Ph

phmaximus

U can run as many as u have room for. But there are better whys of doing it, like bigger batteries

phmaximus

U mean connected to the car right? (esc)

U cant charge like that with out a speical ballance plug adapter