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Old 09-09-2008, 07:12 AM   #1
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Default New to electric...need advice

I've ran nitro for years and just bought an E-Revo to try out the electric world. What is the best battery for the money to run with the stock motors? I'll eventually get a BL setup, but not quite yet. I know it can handle the 7-cell packs, but is it better to buy the packs pre-made or buy individual cells and solder them yourself? Any tips with the soldering would be great too!

Thanks for any "serious" advice. Please don't comment if it doesn't pertain to the question.
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Old 09-09-2008, 07:17 AM   #2
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Do yourself a favor and and buy the good stuff once. This is what you need, you will not need to upgrade when you move to brushless.

http://www.maxamps.com/EMAXXARTRKIT-6000-74.htm
OR this
http://www.maxamps.com/EREVOARTRKIT-8000-74.htm
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Old 09-09-2008, 07:22 AM   #3
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Let me re-phrase that...something that is the best for my money that I can actually afford...not something that is more than the truck costs. I don't race, so there is no point in dumping $500 into a set of batteries and a charger/balancer. I will go there when/if I have the money to do so, but not until then. What I was trying to get at was what brand of battery is the best for the money or which cells to buy and solder my own packs. OR is there an inexpensive lipo set that can run the stock 540 motors with the stock ESC. Like I said, I am fairly new to elecs, so go easy on me.
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Old 09-09-2008, 07:41 AM   #4
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just get a couple matched NiMH lots of companys make good cells . check out Team orion, slingshot. Remember Batterys are where you get your power the better your batterys the more power you can make.
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Old 09-09-2008, 08:35 AM   #5
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Keep in mind that voltage equals speed and amperage equals run time. If you are going with dry cells, 7 cell packs will deliver the most speed and matched cells will maintain that speed longer than unmatched sport cells.

Properly built side by side packs with HD solid copper bars will be the most efficient, and the more powerful your cells the more important this becomes to the overall life of your entire system because of the lower resistance which means less heat generated for the same amount of energy expended.

If you have to use a jumper wire, go with a high strand count 12ga wire with a silicone jacket, like Deans Wet Noodle wire. Use the same wire to build your connector pigtail and only make it as long as it has to be to reach your esc plugs without strain. Don't worry about Deans plugs, the new Traxxas high current connectors are just as good and much easier to solder.

If you build your own packs make sure you only use as much solder as is required to secure the bars to your cells. Excess solder and/or cold joints increase resistance.

It's best to use a hot iron (at least 60W) with a large, flat, properly tinned tip, rosin core solder with a high silver content, paste flux, and make sure to scuff the tops of your cells and the contact points of your battery bars, then clean them with denatured alcohol before you tin them. It's also vital to avoid overheating your cells, so use plenty of flux, then tin and join your cell pairs as quickly as possible. Allow each pair of cells you just soldered to cool before moving to the next pair. Once you have all the pack joints done, make sure you have the pack properly oriented before attaching a pigtail. If you can get away with it, solder your pigtail directly to the pack, if not bend and solder a battery connector bar (or use a purpose built pigtail tab) to the cells on both ends of the pack and attach the pigtail. It's not a bad idea to test fit the pack before attaching the pigtail and it's connectors to make sure everything is going to fit like you want it once it's all soldered up. Once you are done building, clean off all the excess flux with denatured alcohol and an old toothbrush, then put a small bead of shoe goo between each pair of cells and let it fully cure.

Keep in mind that touching most any combination of the attached battery bars with a conductor like a screwdriver, pliers, loose wire, laying them on a metal table top, etc, will result in a dead short so be careful handling your completed packs. It's best to remove them for storage, but if you elect to leave them in the car, please, please, please, unplug them from the esc before you put your truck away. Leaving packs plugged in to an esc is a very good way to start a fire.
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Old 09-11-2008, 05:51 AM   #6
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Thanks for the advice and tips! I have a couple of 3700mah matched race packs that I just soldered the leads and dean's connectors and can't wait to try it out. It was too late last night when I finished. I turned it on in the house just to "blip" the throttle and holy cow what a difference compared to my 3000mah sport packs!!! It needs way more room than I have in my living room!
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Old 09-20-2008, 10:09 PM   #7
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On MaxAmps' web site, they have basically the same NiMH battery pack available in a flat pack version, and a shotgun pack version... is there a difference in performance between the two? Or is it just whatever fits the customers' application?
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Old 09-20-2008, 10:49 PM   #8
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Quote:
Originally Posted by rccrazy_racer View Post
Let me re-phrase that...something that is the best for my money that I can actually afford...not something that is more than the truck costs. I don't race, so there is no point in dumping $500 into a set of batteries and a charger/balancer. I will go there when/if I have the money to do so, but not until then. What I was trying to get at was what brand of battery is the best for the money or which cells to buy and solder my own packs. OR is there an inexpensive lipo set that can run the stock 540 motors with the stock ESC. Like I said, I am fairly new to elecs, so go easy on me.

If that's your contention, and point of question, then it really doesn't matter what you run or get. Get the cheapest stuff available at your local hobby shop.

badassrevo was only trying to be helpful. But if you're worried about being able to "actually afford" stuff you either need to buy cheap stuff or consider that this hobby is too expensive for you.
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Old 09-21-2008, 05:10 AM   #9
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If that's your contention, and point of question, then it really doesn't matter what you run or get. Get the cheapest stuff available at your local hobby shop.

badassrevo was only trying to be helpful. But if you're worried about being able to "actually afford" stuff you either need to buy cheap stuff or consider that this hobby is too expensive for you.
I don't agree.

IMO that $500+ package is just killer... First of all, you can get an awesome charger for $120 that can charge up to 6S Lipo, so even if you need to charge two identical Lipos at once, just wire them up in series and hook up to balance board in a way the charger will see them as one 4S pack.

Next you can get two 5000+ 2S Lipos for under $150. They won't be the best, at least not until you consider their bang for price. A lot of people in this hobby (somewhat including myself) have the tendency to think anything but "the very best" is crap, and limit themselves to only the most expensive stuff out there. No offense. Sometimes it is better not to cheap out, but other times even the cheaper stuff can work just great for your needs... And unless you're competing for 1st place in your A-mains, perhaps you don't need the best?

Anyway, given what this guy has mentioned, some decent matched NiMH packs would run him pretty cheap (assuming he's already got a NiMH-only charger, I guess?) and let him try out his truck. The peak performance will be comparable to Lipo, although not as long lasting. Once he's done with that, he can always upgrade to Brushless and Lipo later on like he said.

OP, feel free to send me a pm if you want some more details on a cheaper way to go BL/Lipo without breaking the bank... as much, lol.
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Old 09-21-2008, 05:44 AM   #10
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Check out www.specpointbatteries.com
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Old 09-21-2008, 09:24 AM   #11
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Do you have a charger that can charge lipo's yet?

If you want to go with nimh batteries at a good price I recommend the Team Brood or Integy cells. I have ran them both and they have treated me well before I switched to lipo.

You can get the Integy batteries from Tower Hobbies.
www.teambrood.com
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Old 09-21-2008, 10:13 AM   #12
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I don't agree.

IMO that $500+ package is just killer... .
I think that's the point, he doesn't want to spend that kind of money.
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Old 09-21-2008, 01:10 PM   #13
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Quote:
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On MaxAmps' web site, they have basically the same NiMH battery pack available in a flat pack version, and a shotgun pack version... is there a difference in performance between the two? Or is it just whatever fits the customers' application?
I didn't feel I needed to start a new thread, so I bumped this thread to ask the above question. ^
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Old 09-21-2008, 06:32 PM   #14
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Quote:
Originally Posted by gfx View Post
On MaxAmps' web site, they have basically the same NiMH battery pack available in a flat pack version, and a shotgun pack version... is there a difference in performance between the two? Or is it just whatever fits the customers' application?
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I didn't feel I needed to start a new thread, so I bumped this thread to ask the above question. ^
No, if both built using same batts, no diff in performance. The big diff is side-by-side construction lets you use a discharge tray to bring down each cell to teh same voltage before recharging. This gains you a more even charge and a little better batt performance and maybe a little more life too. You can replace a bad cell easier in a s-b-s pack than in a shotgun stype pack.

Stick pac is a little smaller than same cell count s-b-s so there are some application considerations. I've converted most of mine from stick to s-b-s so I can better maintain them.
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Old 09-21-2008, 06:57 PM   #15
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I appreciate all of the info...and for those thinking I "can't afford it"...that's just untrue. I'm just not spending the money on something I know nothing about...that's why I started this thread. I'm planning on upgrading to some much better brushed motors like the Trinity Wilds that are a direct fit to the eRevo and should give it much more punch for not much cost. I also intend on getting some lipos strictly for the longer run times. I don't have a charger that will charge them yet...but that is soon to come.

I'll post my findings once I get those motors and batts. If you have ideas on better motors, please feel free to post the info. I can get two Wild's for under $80, so that's pretty reasonable for a boost in performance. Plus, I can sell the originals on eBay to re-gain some of the cost (not that they are worth much LOL).

I just found someone that has this for sale...would this work for my eRevo if I bought another to pair with it? It's brand new...just didn't fit his application.

RC Lipo Battery 7.4 V 4000 mahr
*7.4 volt Lipo Battery 4 Amp Hour
*5 1/2" X 1 7/8" X 1/2"

Thanks again!
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