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mnwrr
10-25-2005, 06:09 PM
Guys, I'm new to RC and I'm still having trouble understanding the basics. Batteries for instance. I read that a great pack for the Mini Inferno is the 42s 9.6v 8-Cell 1100mah NiMH Battery Pack by United RC Xtreme. I d/led Kyosho's manual (VERY skimpy :mad: ) and it asks for 6 alkaline or Ni-MH AA batteries.

AA batteries have normally 1.2 v, so does this mean that I can run the car with 7.2 v up to 9.6 v? What will be the difference in run time and engine output with these two setups?

And now about amps. RC's pack uses batteries with 1100 mAh. What will be the difference if I used a pack with the same number of sells but with lower (like 850 mAh) or higher amps (I found a 6 cell saddle pack with 3300 mAh - let's say it's a 8 pack just for comparison)? In these two cases, how much run time would I get? Will there be difference power-wise, I mean, will the car be faster or slower?

pimpsmurf
10-25-2005, 07:02 PM
The mini inferno can take up to 8 cells NMHD.

GP1100 cells offer the high-discharge required for fast motors.
Larger (heavier) cells would offer longer (slower) runtimes, and most likely offer more than enough current for fast motors. It would definately be slower than 1100 cells because of the added weight, and would have longer runtimes.

Get a good matched and zapped NMHD pack and you will be happy. Everyone preaches UnitedRC (they never pick up the phone? lol), so that is what I'm getting.

-JNY

janniz
10-25-2005, 07:20 PM
I'll try to explain with my bad english...:rolleyes:
Basically: the more volts (more cells), the more speed. The more mAh, the longer the runtime. But this also depends on how many Ampere your motor draws while running - faster motors usually draw more Amps. With the GP 1.100 mAh cells and an AON brushless (which draws alot of Amps) you will still get about 10 to 15 minutes of runtime, depending on the surface and the pinion you are using.

But not all cells can deliver high currents - GPs and some LiPos do, most AA-Batteries dont. If they cant deliver high currents, it results in a dropping voltage which means less speed. So, the more Ampere your motor "needs", the better cells you have to use. The 1.100 GPs are very good and they are what most people who run NiMH are using.

The number of cells only increases the voltage, not the mAh, because most battery-packs you can buy are wired serial (what is the right word? in german it is "in Serie") not parallel. If you wire them parallel, it increases the mAh but the voltage stays the same.

And now some native speaker should explain it in a way that can be understood :D



Edit: damn, I allways type to slow - but I have to translate while typing :rolleyes:

DrVonHoSS
10-25-2005, 08:05 PM
I'll try to explain with my bad english...:rolleyes:
Basically: the more volts (more cells), the more speed. The more mAh, the longer the runtime. But this also depends on how many Ampere your motor draws while running - faster motors usually draw more Amps. With the GP 1.100 mAh cells and an AON brushless (which draws alot of Amps) you will still get about 10 to 15 minutes of runtime, depending on the surface and the pinion you are using.

But not all cells can deliver high currents - GPs and some LiPos do, most AA-Batteries dont. If they cant deliver high currents, it results in a dropping voltage which means less speed. So, the more Ampere your motor "needs", the better cells you have to use. The 1.100 GPs are very good and they are what most people who run NiMH are using.

The number of cells only increases the voltage, not the mAh, because most battery-packs you can buy are wired serial (what is the right word? in german it is "in Serie") not parallel. If you wire them parallel, it increases the mAh but the voltage stays the same.

And now some native speaker should explain it in a way that can be understood :D



Edit: damn, I allways type to slow - but I have to translate while typing :rolleyes:

You know English better than I know German! ;)

It goes like this..

More voltage = more power/speed
More Amp/milliamps = more capacity/runtime

Another thing to keep in mind... the more cells you use the shorter your runtime will be. For example a 6 cell 1100mah battery will run longer than an 8 cell 1100mah battery. As voltage increases amp draw increases.But dont let that bother you.. its just useless trivia. Ever wonder how a 4 cell 1/12th scale car can run 8 minutes? Thats why.

Get the 8 cell pack!!

I know the HALF8 stock electronics can handle 8 cells.. but im not sure if it could handle much more.

UNITED_RC
10-25-2005, 08:06 PM
Get a good matched and zapped NMHD pack and you will be happy. Everyone preaches UnitedRC (they never pick up the phone? lol), so that is what I'm getting.

-JNY

Thats because we are busy building packs....and we have caller id! ;)

Just kidding with you JNY!

Email is the BEST way to get ahold of us......

pimpsmurf
10-25-2005, 08:13 PM
Yes, it actually is great as it is.

Apogee or Kokam are the brands of choise for high-discharge lipos.

GP1100 cells are pretty much the top dog for 1:18 high-discharge NMHD

I think you can easilly put 2 Kokam 740 Li-Poly Pack in there, which would have higher constant current discharge (30 amps or so) than the apogee pack, but a lower capacity. 45amp burst! =)

Capacity is very important however, and the kokam cells would have to be rewired to allow cell matching which is a pain to say the least. I don't believe kokam uses PC boards to wire the packs.

-JNY

mnwrr
10-26-2005, 01:18 AM
Could I use any battery to make a battery pack? For instance, if I soldered in serial 8 Sony 1.2 v 1200 mAh? I'm having some trouble in finding a saddle 8 pack, so I may have to make my own pack. At least in all the Brazilian Web stores I've been to, it's hard to find 1100 mAh batteries, so I was thinking of using the next closest one, the 1200.
What do you guys think?

mnwrr
10-26-2005, 01:31 AM
Thats because we are busy building packs....and we have caller id! ;)

Just kidding with you JNY!

Email is the BEST way to get ahold of us......
Do you ship to Brazil? How much would be S&H for one or two 8 packs?

DrVonHoSS
10-26-2005, 01:33 AM
Ebay is also a great place to look if UnitedRC doesnt ship to Brazil.. but im sure they do.

BitHed
10-26-2005, 01:45 AM
...UNITED RC ships the whole planet ;) At least they do when they put the soldering iron down ;)

UNITED_RC
10-26-2005, 02:06 AM
Do you ship to Brazil? How much would be S&H for one or two 8 packs?

Per Bitheads comments.....WE SHIP WORLDWIDE!!!

:)

Shipping for the two packs (x42s) would only be $5.00!!! :)

If you have a paypal account, you can order directly from the website!

Email us if you have any questions about placing an order: sales@unitedrc.com

URC

Ronny
10-26-2005, 08:11 AM
Guys, I'm new to RC and I'm still having trouble understanding the basics. Batteries for instance. I read that a great pack for the Mini Inferno is the 42s 9.6v 8-Cell 1100mah NiMH Battery Pack by United RC Xtreme. I d/led Kyosho's manual (VERY skimpy :mad: ) and it asks for 6 alkaline or Ni-MH AA batteries.

AA batteries have normally 1.2 v, so does this mean that I can run the car with 7.2 v up to 9.6 v? What will be the difference in run time and engine output with these two setups?

And now about amps. RC's pack uses batteries with 1100 mAh. What will be the difference if I used a pack with the same number of sells but with lower (like 850 mAh) or higher amps (I found a 6 cell saddle pack with 3300 mAh - let's say it's a 8 pack just for comparison)? In these two cases, how much run time would I get? Will there be difference power-wise, I mean, will the car be faster or slower?

Hey LUW :)

Another thing that should be mentioned - which is very important , is that if you get a pack that doesen' have "high output" in form of delivering amps - like the Red 8 cells pack from Kyosho for example, your motor (if using a brushless) will COGG! This means that every time you pull the trigger hard, your car/motor will "stutter" for the first feet or two.. By using high quality cells like the GP1100's for example, this is no problem at all - and you'll have power to light up your wheels from stand still :eek:

From what I know, URC can safely hook you up with some serious power!

mnwrr
10-26-2005, 02:38 PM
Thanks URC, I'll get in touch with your sales department! :) Now I just have to find a decent charger.

But back to the "physics" of these things. Could I make my own battery pack just by soldering the cells in serial?

Smoothound
10-26-2005, 05:54 PM
Capacity is very important however, and the kokam cells would have to be rewired to allow cell matching which is a pain to say the least. I don't believe kokam uses PC boards to wire the packs.

-JNY



This can be a good thing ;)

There are a fair few Lipo packs available these days that suffer really poor discharge rates not so much because the cells are crap(There are also a lot of rubbish cells available as well) but because the pack is poorly put together.

Highest discharge packs currently available are FlightPower and PolyQuest(these 2 use the same cell manufacturer but different assembly plants), Kokam and Thunder Power Prolites.

Biggest problem with Liths for the H8 is getting packs that fit, which as far as I'm aware non of the above do currently :mad:

This is where UnitedRC appear to have the market sewn up with their APL cells, reasonable discharge, balancers and better capacity than NiMh :D

pimpsmurf
10-26-2005, 06:35 PM
Smoothound:

Absolutely, and Apogee makes great stuff. Oh yeah. I'm definately going with the unitedrc 11.1v lipo pack, because I won't have to screw with it, it already has the connector for balancing, wired 2s2p, and the longer runtime. Plus, the price is the best you can find on apogee packs.

b-p-p.com has a big (polyquest or kokam) pack that they use, but they use 1 single pack going "through the middle" (quote Troy@b-p-p.com). I'm not sure where through the middle they went, as I don't have my Mini-Inferno here yet, but he did say it was a 1000mah or so pack I believe, so it would be pretty small.

I know I'm sure not strapping one to the top. :)

-JNY

DrVonHoSS
10-26-2005, 07:53 PM
Thanks URC, I'll get in touch with your sales department! :) Now I just have to find a decent charger.

But back to the "physics" of these things. Could I make my own battery pack just by soldering the cells in serial?

You could.. but only if you know what your doing!! Even KAN type NiMH cells get pretty scary when you dead short them. I was soldering a pack together while enjoying a few beers and shorted the pack.. what a mess! I watched the shrink wrap and solder melt before my eyes.

Also.. one of our local 1/8th scale racers had a receiver pack (KAN cells) blow up in his face.. he had to goto the hospital and all that. He's lucky he didnt lose an eye.

If you decide to make your own pack just make sure you have a good soldering iron and try not to get the cells too hot. It would probably be better to just buy an assembled pack.

mnwrr
10-26-2005, 08:48 PM
You could.. but only if you know what your doing!! Even KAN type NiMH cells get pretty scary when you dead short them. I was soldering a pack together while enjoying a few beers and shorted the pack.. what a mess! I watched the shrink wrap and solder melt before my eyes.

Also.. one of our local 1/8th scale racers had a receiver pack (KAN cells) blow up in his face.. he had to goto the hospital and all that. He's lucky he didnt lose an eye.

If you decide to make your own pack just make sure you have a good soldering iron and try not to get the cells too hot. It would probably be better to just buy an assembled pack.
:eek: Caspita! I didn't imagine them to be potentially harmful. URC is the way, for sure! ;)

mat3833
10-26-2005, 08:48 PM
i had a gp 3300 pack vent in my pocket. it shorted along w/ my screwdriver. the driver was melted!! the pack melted my pants(those board shortish fabric ones) and fell to the ground. it was cool to watch with it on the ground and not in my pocket.

Matt

Hawk
10-26-2005, 10:11 PM
i had a gp 3300 pack vent in my pocket. it shorted along w/ my screwdriver. the driver was melted!! the pack melted my pants(those board shortish fabric ones) and fell to the ground. it was cool to watch with it on the ground and not in my pocket.

Matt

So it that a battery in your pants or are you just on fire? :eek:

mnwrr
10-26-2005, 10:15 PM
:D I knew it wouldn't take long...

pimpsmurf
10-26-2005, 10:24 PM
That's just wrong! :D

NM cells are alright as long as your treat them with respect. Just make sure you have more respect when doing a lipo pack. :)

I use a heatsink clamp to solder the flags, and once it twisted the flag and shorted the pack for a few seconds. I knocked the clamp off, and the cell looked like it wasn't damaged. I put it to the side to dispose of later. "Forget using that thing. It probably has all sorts of internal damage.", I thought.

Unfortunately, sometimes it can take them 5-10 minutes after you short it, before it balloons and catches on fire. I'm glad it was in sight and I was able to throw it out the window near my workdesk. :)

You can actually hurt a NM cell without blowing it up. most people like to use a welder or something to get perfect connection. My local Batteries Plus store has a sweet (sonic?) welder setup and they make packs for me really cheap. They aren't allowed to touch lithium cells though. :(

-JNY

mat3833
10-27-2005, 12:11 AM
So it that a battery in your pants or are you just on fire? :eek:

no it fell out of my pocket, i did get burned tho... it realy hurt :( . the batt shorted through my screwdriver and heated up. it melted through my pants and continued shorting(i said venting before i kno im not realy shure what it was doing all i kno is it was getting hot)at my feet. the cells balooned and popped open. they spewed prety gases and that was it. this whole incident was my fault. just remember to keep metal objects away from your packs!!
LUW, what is that supposed to mean!! :D i am not stupid.... i just make huge mistakes very often! LOL
oh and pimpsmurf it realy was wrong to see a zaped and matched to pro level specs pack go poof right in front of me! it hurt, it realy did :( . oh and not just the burn, my wallet had to go on meds and ended up in the psych ward for a few weeks.

Matt

mnwrr
10-27-2005, 12:18 AM
LUW, what is that supposed to mean!! :D i am not stupid.... i just make huge mistakes very often! LOL
Matt, I was commenting on Hawk's post: I was sure that it wouldn't take long for that joke to come up. :p

And you were LUCKY! You could have had 3rd degree burns very easily!! Chemical fires like that are extremely dangerous!!! :eek:

mat3833
10-27-2005, 12:22 AM
yea i kno, thank god for the gangsta phase i went through!! it probobly saved my thigh. i did however get a mild 2nd degree burn.

Matt

mat3833
10-27-2005, 12:28 AM
oh and one of my old racing buddies vented a pack in his mini t and didnt kno. he picked the car/truck/watever it is up and got hot battery acid all over his hand, i ran and got some soap and off we went to the hospitle(that cant be how you spell that...). his hand has some scarw from where it happened.

Matt