Old School Tech Help.

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SoloGraphix
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Old School Tech Help.

Post by SoloGraphix »

At our local track we decided to start running legends again, but with an easy to grasp amended set of rules that differ from the Legend Spec rules from years past. Our constraints are 27T stock motor, 4 cell NIMH batteries and Spec tires (any spec tire, as long as they are sold as spec).

I am in need of some advice and tricks of the trade on 27T motors and NIMH Battery care. My brother and I have acquired a comm lathe and we run the X-Stock motors with the ball bearings, I am looking for any useful information to get the most out of these motors and keep them running in tip top shape.

I bought used 4 cell 4600 packs (all using EnerG cells) that I am sure we have abuse by just running and charging, rinse and repeat. I am in the market to get a couple new packs to finish the season and I am looking for advice on keeping them running strong for as long as we can without buying new every week. Advice on charging them to get the most out of them would be helpful as well, I know our batteries are dropping off quicker than fellow racers, and the pack I most recently ran for the A main at the last race was just flat from the time i set it on the track.

I know that buying a bunch of motors and a bunch of batteries to cycle through each race with would be ideal, but its not really in the cards. I just need to get the most out of what we have and plan to get. In all honesty most people are just doing the run and charge method, and the class is pretty fun, we have had speed and seen it slowly go away as the batteries are getting abused and the motors are due for some maintenance.

Thanks for any help.

Jay Dub
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Re: Old School Tech Help.

Post by Jay Dub »

Well, in general your stock motors will get a little faster as they get older as long as they aren't overheated (this will kill the magnets and defiately make it slow). This is because as the com is reduced in size it effectivelly increases your timing. You just need to make sure they are trued on a regular basis. A com diameter of .275-.280 is optimum for power vs. efficiencly. Also keep up on your brushes and springs, make sure they don't get too old, or discolored. Also, as the comms get smaller, the gearing will have to go down to compensate (slightly). I used to find that over the life of the motor I might loose a tooth (or two) on a 48p pinion gear.

Batteries. This is where the real power is made. if your car has gotten noticeably slower, this is where to look first. Nimh batteries are shit, and there is nothing you can do about it. They are bleaders when you buy them, and all you can do is slow the bleading while you own them. The single worst thing you can do to them is OVER DISCHARGE them! You can kill a brand new pack on its very first run if you over discarge it. The individual cells should NEVER get below .9v (certain types can go .85v). This is why cell balancing and proper storage is so important. Firstly, the cells hould be discharged on a high quallity tray (I like the Rayspeed trays) so that each cell is brought down to .9v (the cutoff is in the tray). Then the pack should be charged to peak with a delta setting appropriate for your cell and pack type. Run the pack. As soon as the pack begins to show signs of dumping, pull it off the track, and throw it on the tray to equalize the cells. When you are done using the packs for the day, equalize them, and charge them for storage. A good rule of thumb is a 1000ma of charge per week of storage. This is important because NiMh cells naturally discharge while stored (about 2% per day). So, if you aren't going to run them for 3 weeks, put in 3000ma of charge etc. The reason you don't want to put more charge in then necessary is that you will have to discarge them and re-charge them before your first race (If you want to get the most out of your battery, and this is racing right?). Generally speaking, these packs perform their best on their first discharge (or heat cycle) every 3-4 days. If you have a fully charged pack, and you have to discharge it completely before you charge it again, then you just used its best cycle :roll: . This gets to be a pain, because if you are planning on using the same pack several times in a day, then you can count on diminishing returns from that pack.

So, the basics of proper care are: Buy enough packs so you don't have to run them more than once a week, never over dishcarge your cells, always tray the packs, properly charge your packs, and always store them with the proper amount of charge.

There is one more thing you can try to do, and that is cell conditioning. Many cells respond well to aftermarket style conditioning systems. I used for several years a Spintec discharging/conditioning system on my packs (trinity ripped them off, and made copies as well). It will condition the batteries, and give you info like runtime, voltage, capacity, internal resistance, and overall "energy". I found that these worked well on several of the packs I had, and had mixed results with others. The only issue I have with this type of conditioner is that it works on the pack, not individual cells. So you need to be carefull when getting near the end of a discharge to monitor the individual cells so they aren't over discarged.

All in all, you can only count on 20 to 25 great cycles from a new pack, propably more in a 4 cell application. Keep track of how many cycles each pack has so you know when its getting old. As the pack starts to get old, you will notice it becoming finicky. One run will be great, and another will be shit -even with the same care regiment. That's just the way they are when they get old. The Rayspeed tray will run you $75 to $100 new, and a Spintec will run you the same. If you are interested, I have both (and haven't used in years -since I switched to LiPo) you can have them for $50 shipped. BTW I didn't post all this just to sell you my old stuff :lol: :lol: :lol: . -Jeff

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SoloGraphix
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Re: Old School Tech Help.

Post by SoloGraphix »

I appreciate all the info, and thanks for taking the time out to do so.

I can already tell that we are probably doing most of the right things with the motor, but are KILLING the batteries we have. I will talk to my brother and see about what expenses we want to make for this class. I can already tell that new packs are a must because of the explanation you gave about packs becoming inconsistent and ours definitely have. I can honestly say that our care/conditioning of the packs is non existent and we probably ruined them much quicker than should of happened. I did buy them used as well which I am sure didn't help things much.

I will get back to you on the sale via PM once I chat with my brother.

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SoloGraphix
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Re: Old School Tech Help.

Post by SoloGraphix »

Can I use an original turbo thirty for NIMH batteries?

Jay Dub
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Re: Old School Tech Help.

Post by Jay Dub »

I am not sure if the original turbo 30 has a NiMh function, however I had some upgrading done on mine and it will do them now. I sent it to Competition Electronics, and had a BL screen installed, software upgraded, and some new leads put on. didnt cost that much. -Jeff

BTW your stuff is packaged up, and should go out tomorrow. -Jeff

Shadow
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Re: Old School Tech Help.

Post by Shadow »

Here's a little help on your motors. Make sure the bushings/bearings are fully seated in the can and endbell. A wood dowel works great for this. For brushes use Trinity's 4505 brush with a red / green spring combo. Red on the positive. When you put the motor together center the arm in the magnetic field using the shims in the motor. And if you can find Trinity's brush hood alignment tool, follow the directions and use that to align the brush hoods. This really makes motors go fast. Some of this you may already know. If you have any questions just ask.

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