Hello all, I am fairly new to the electric hobby scene. I just bought a traxxas summit monster truck and would like some advice on batteries and charger. and as well of course...... my new summit!
I understand the basics of batteries;
mah = power/running time of rc
nicad vs nimh batteries = nimh is newer technology and don't have memory yaddy yadda
amps = charging rate - higher the rate, the quicker it charges but also kills the batteries lifetime.
Okay, now for some questions;
1) whats a good charger? something not too complicated, but easy to operate and understand.
2) what do most people use for amp rate to charge batteries and how long does it take to charge them? (say like a 3000 mah battery) is there a chart comparison somewhere?
3) I need 2 batteries to operate my summit, is there any decent charger out there that is capable of charging both at the same time?
4) I have been reading that timer chargers are no good and overcharge batteries. So if no timer, would do you know when its peak charged?
5) what is the first upgrades I should do to my summit when I get it? I used to own a tmaxx and quickly found out how fast it ripped through those crappy plastic drive shafts. So I want to be pro active and know the weaknesses of it.
anything else I should know about batteries/chargers/summit in general?
I wouldn't even bother with ni-cd's but as far mah go's it will only tell you how long it will run for not really a incraese in any power but i wouldn't get any thing less than 3000 mah packs because the run times at any less aren't worth it! [trust me] but an increase in voltage will give you more power guaranteed! and only use peak chargers for ni-mh/ni-cd that way you get a full charge every time with out going over, plus a lcd srceen on it is always a good thing! so you can see how much your batterys take in, also rule of thum is charge at no more than the rate of mah like if it's a 3600, then charge it no more then at 3.6A or if it's 4000 then no more then 4.0A that way your batterys last there full life!
I would look at the Duratraxx brand chargers::::: ONYX there are several models 1 of witch charges two batterys at one time but NOT lipos.. There is a model that does charger lipos but not 2 at a time. You want a Peak charger not a timer deal...
I would go with lipos and I wouldn;t get anything less than 5000 mah so you can get the longest run times possible.
I am not up on the Summit but I have looked at one and they look to be a nice model. I would look into one if I was more in to bashing.
Those would work fine for starting out. Should give you decent power and plenty of runtime.
If you can afford it you should look into Lipo batteries. They offer more power, more runtime, less maintenance, and more life cycles than Nimh. Read thru some of the several threads where people ask about them and you can pick up alot of knowledge. But what you were looking at would be great to get you out there and running.
So I went ahead and bought the charger and 2 batteries.
couple of questions now;
1) the charger shut (peaked) the batteries off at around 4600 mah (the battery states on it 5000 mah) is that normal? kinda like a computer hard drive stating its a 100 gig but is actually only a 94 gig?
2) the batteries were pretty hot when I took them off the charger. Normal? if so how hot should they get? also, do I have to wait until the batteries cool before using them?
Note - I know that I have to wait until the batteries are cool before recharging them again.....
A little short on capacity is normal. They should only take in the full amount if you're deep-cycling them.
120-130 degrees is as hot as you want to see your nimh batteries get. I have a temp sensor on my Ice and set it to 120 degree cutoff. It rarely cuts before the delta peak does.
In stock racing we time the battery charging or re-peak the packs to make them hot right before running for extra punch. On a mod motor I would start with them cool as they'll heat up on their own with the added current draw.
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I race electrics, why am I always pitting for nitro's?
The reason they wind up 'short' is they never get completely empty. When you start charging they have something left. You would have to discharge them and then zero them with some kind of equalizer and this is potentially damaging to anything but the better quality race cells.
This will clear up the biz about "100 gig but is actually only a 94 gig?"
I would take a look at some Venom 6 cell or 7 cell batteries. a 2500 MAH will last you about 15 minutes. a 7 cell is a little more power then a 6 cell but increases the chances of ruioning someting, been there. take a look at the Prophet Plus LCD. i have one and its great had adjustable amps so you control how long it charges. you can charge any nimh or nicad battery.
So I went ahead and bought the charger and 2 batteries.
couple of questions now;
1) the charger shut (peaked) the batteries off at around 4600 mah (the battery states on it 5000 mah) is that normal? kinda like a computer hard drive stating its a 100 gig but is actually only a 94 gig?
2) the batteries were pretty hot when I took them off the charger. Normal? if so how hot should they get? also, do I have to wait until the batteries cool before using them?
Note - I know that I have to wait until the batteries are cool before recharging them again.....
thanx again
Now something else has been happening. The last 3 or 4 charges one of the packs is only reaching around 3800-3900 mah and is stopping at about 65 minutes. The other pack reaches normal mah of about 4800 and the charge time is about 75-80 minutes...... Why is one stopping so early? Did I buy a bad/defective pack?
Now something else has been happening. The last 3 or 4 charges one of the packs is only reaching around 3800-3900 mah and is stopping at about 65 minutes. The other pack reaches normal mah of about 4800 and the charge time is about 75-80 minutes...... Why is one stopping so early? Did I buy a bad/defective pack?
What you're seeing is the amount of charge you're putting in the pack. The batteries are not at zero capacity to begin with, there is still some juice in them, this is typical (Critical in lipos!). When you start a charge, the charger starts at zero and charges by watching the rate the batteries take current. As the battery gets close to it's capacity less and less current is drawn. When this gets low enough and there is little change the charger "knows" the battery is full. It's a little more complicated that my description but you get the idea.
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It's all fun & games til the flying monkeys show up!
What you're seeing is the amount of charge you're putting in the pack. The batteries are not at zero capacity to begin with, there is still some juice in them, this is typical (Critical in lipos!). When you start a charge, the charger starts at zero and charges by watching the rate the batteries take current. As the battery gets close to it's capacity less and less current is drawn. When this gets low enough and there is little change the charger "knows" the battery is full. It's a little more complicated that my description but you get the idea.
ok heres what i would do..and done. i love hobbyking.com. i have been using zippy lipos for awhile and just got 4 turnigy lipos 5000mah 20c, for 20$ a pop, and there acucell charger is awsome. i have had 0 problems out of them. just my 2 cents
newb needs advice
Battery / charger
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