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Old 03-15-2007, 10:57 PM   #1
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Default NOOB battery questions

Well I'm new to this whole electric thing. Been running 1/10 & 1/8 scale nitro for years, & after seeing these 4wd buggies run I just had to have one. I've searched through many, many posts & it's getting old so I'm starting a new one....
I just bought a Kyosho Lazer ZX-5 with KMC conversion to use saddle packs (picture below)
Now for my battery options. I will be racing 1 or 2 times a week, usually 2-4 5 min heats, & 10 minute mains. Trying to figure out my best options...I know a little about Nimh batteries (discharging & equalizing) but know very little about LiPo
This is what I'm trying to decide on...2 or 3, 3800-4200 nimh top quality 6 cell saddle packs or 1 LiPo saddle pack.
Questions on LiPo....
-I would either be getting the maxamps 4400 or 5500 2S LiPo. http://maxamps.com/products.php?cat=54 Which leads to my next question...are both of these packs the same size? Will they work in my buggy? Will I need to mod anything?
-Will one LiPo fit my racing needs?
-Is there any maintenance involved with LiPo (discharging, equalizing)?
-After a 5 min heat, can I just plug it in to the charger & top it off for the next race? How long should it take to peak between races?
-What kind of runtimes am I looking at compared to nimh? If I win the 5 min "B" main & move on to a 10 min "A" main will the LiPo make it through the "A" main without recharging?
-How will my performance differ between the 2 different types of packs?
-It seems like in the long run, if I only have to buy one pack & a charger, that LiPo is the best bang for my buck...correct me if I'm wrong.
BTW I'll be running a Mamba Max 7700...which I have already purchased.
Sorry for the long post, your advice is much appreciated
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Old 03-15-2007, 11:18 PM   #2
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You can't go wrong with either nimh or lipo, but I like nimh IB or EP4200s. From experience, I actually like the weight on my 4wd buggy. With the hot motors everybody uses now, you will end up using a really light setup or adding weight with lipos to get traction. Ofcourse the difference is minor really, but then again it comes down to preference. Just my .02
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Old 03-15-2007, 11:29 PM   #3
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But you have used Lipos...correct? Could you maybe answer a couple of the other questions...thanks. Anyone else? I guess my most important question is; Will one LiPo pack get me through a race day?
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Old 03-15-2007, 11:46 PM   #4
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I have run the maxamps 4400 pack in my xx4. The 5500 is bigger yes... it has one more cell stacked up (5 in each side vs 4 in the 4400 pack)

You can put them on the charger right away after the race... mine took maybe 30 minutes to top it off to the 95-98% charged point and a few more minutes in 'trickle' mode to top it off. That depends on how much of the capacity you use.

If you use about 50% of the capacity (2200mah of a 4400 pack) which I was doing, it takes about a half hour recharge.

The 5500 would recharge slightly faster because you can charge it at a little higher amps (5.5 amps vs. 4.4 amps on the 4400), and the amount you used up will be the same.

The 5500 is a bit tall but I think you can raise the batt bar to fit in in there.
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Old 03-15-2007, 11:57 PM   #5
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So for a 5min heat..how much of the capacity of the battery would be used? Approximately how much, I know there are variables.
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Old 03-16-2007, 08:23 AM   #6
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I was using no more than about 2500mah in my car for a 5 min heat will warm up laps etc... but I could see using quite a bit more on a different type track etc.
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Old 03-16-2007, 09:29 AM   #7
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The nice thing from what I have been understanding about lipo is that you can recharge right away, not have to wait like with a NIMH.

Also, with the bigger mah, you can charger at a higher rate. So what you took out, can be put back in faster.

Bigger mah packs also have more weight so you need to add in less. And thinking more about it, doesn't sound too bad an issue as you can just add weight in where you want.

I am thinking of doing basically the same as you, using 1 lipo pack (right now thinking of a 6000mah from maxamps) for my 4wd buggy (SB V2 Pro) and tie it to a brushless setup (mamba max as well, excep 5700 model).

For those bump ups they do, do you know if they do them right away or is there a delay?

Maybe picking up two lipos would work better? I am thinking right now that to 2 - 3 high quality 4200s still may be pushing it since you can't up and recharge right away, unless of couse you have some other packs you are running instead of those quality ones right away, you could always do that with the lipos too.

Lipos from what I am gathering have specific charging methods and require a specific lipo charger (I am going to be using a MRC 989). Also, a balancer may be something to pick up but I haven't really heard if they are required to have. still trying to figure that out.

But, considering with Nimhs you usually have a top charger anyway and a top discharger board, I think its a wash.
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Old 03-16-2007, 10:13 AM   #8
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Yep... you can put it on the charger immediately after the run. I ran atwo day trophy race and never took the pack out of the car. One pack should do it, but having a back-up pack would not be a bad thing.

Most electric races they do the Bmain early on and the Amains last so there is plenty of time in between to recharge.

Even if you didn't get it fully topped off... or had to run back-to-back, a 5000-6000mah pack would do two heats on a charge anyway.
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Old 03-16-2007, 10:30 AM   #9
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Thats kind of what I was thinking. We really don't burn through a full nimh pack now as it is for most classes.

Also, if I recall correctly, lipos are consistent voltage wise through the discharge?
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Old 03-16-2007, 07:53 PM   #10
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They have a pretty flat voltage curve.... but as all batteries, they do start out high and fall off at the end.

But after the initial drop.... the voltage stays pretty flat or only drops slightly through about 80% of the cycle.
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