Where do you put your battery?

zouz10

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1,493
Location
Florida
Hey guys,
As the title implies where do you put your battery on the MCD Race Runner? The left of the buggy next to the radio box is where I have seen they most of the time, however, I decided I am gonna get a Samba Pipe which will take up that space. I was hoping to run a standard size battery pack. What are you guys using (Li-Po, Ni-MH, etc..)

Thanks,
Chris
 

dgav407

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Messages
125
Location
England
Hi Chris

The standard MCD battery (5 sub-c cells) is meant to fit in the radio box, although it is rather a tight fit once you add the receiver, failsafe and if like me you race the cars a personal transponder. The best solution is to use a flat 5 cell AA battery pack. I am currently using 2400mah Vapex cells and 2700mah Sanyo cells and they both last for at least 90 minutes before needing to be recharged. You will need to remove the divider in the middle of the lower part of the radio box for the cells to fit - a sharp craft knife will do the job.

The other advantage of using AA cells is the cost - the Vapex cells were only £11 ($22) compared to £37 ($74) for the standard MCD battery pack. The better quality Sanyo AA cells were £19 ($38).

Clive
 

zouz10

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1,493
Location
Florida
Thanks dgav,
Does the MCD battery pack come with the car or do you buy it separately? Fitting issues are not as bad since I will not be using a transceiver and I have a micro receiver from spektrum. I am tempted on using some li-po's that I currently have from my RC helicopters which are pretty small and just sitting there doing nothing.
Thanks again,
Chris
 

dgav407

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125
Location
England

zouz10

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1,493
Location
Florida
dgav thanks for all the helpful info. My friend did the li-po thing on his FG on-road and it works well. He needed to put a chip or something to reduce the current. I will probably go with the pack that you mentioned in the link. The reason I want the battery in the box BTW is because I am gonna probably get a Samba pipe, and since it comes on the side mud guard, that leaves little room for the battery.
Thanks,
Z
 

whizzy

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Messages
283
Location
paisley
contact rodger at fg and baja spares as he has bigger capacity batteries that fit in the actual box and possibly cheaper than the mcd one frpm rossendales
 

MONAROMAN

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491
Location
Sydney Australia
one of the guys on this forum from oz (monotheist) is running lipos in his mcd im pretty sure, if he sees this he'll prob give you the low down.
 

monotheist

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Messages
174
Location
Melbourne, Australia
I will also have to find another possie for my lipo pack when my Samba pipe arrives. I was thinking of replacing the top plastic section of the radio box with a flat piece of alloy (or something like that) and mounting the battery on top of it.

I have also seen some people mount the battery to the front by strapping it to the roll catg just behind the shock tower.

IMG_1169.jpg
 

zouz10

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1,493
Location
Florida
Wow Mono, that battery pack is tiny. What is the voltage or current on that thing (I am bad with the electronics). What kind of time do you get on it?
 

monotheist

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174
Location
Melbourne, Australia
It's a 2c (7.4v) lipo rated at 1300mah. Although I have not really been taking much notice of run time the pack will easily provide enough power for 2-3 tanks which is longer that I ever run at a given time anyway.

The pack is currently regulated down to 6v using a single 3A (5A max) regulator. Although this works ok I am concerned the regulator doesn't have the current capacity to feed all 3 digital servo's so am going to add another 2 regs to each of the 2 front steering servos so there will be 3 in total or 9 amps of capacity (15 amps max)

The trick is to buy 2 or more packs and keep them all charged. That way if it goes flat on you you can just swap it out for a fresh one in a matter of seconds. Good thing about lipo batteries as opposed to other battery types is that they keep there charge when being stored so you can charge them weeks/months in advance if you wish.

The most important part about running lipos is to make sure they don't drop below approx 3v per cell otherwise you might damage the pack. A 2c lipo means it has 2 cells in series or a nominal 7.4voltage so with this pack I have to be careful I don't drop it below 6v. You can buy all kinds of warning devices to prevent this but im am using the battery monitor on my Nomadio Sensor to alert me when its time to charge.

You may think all this messing and additional setup around is way to much hassle but I believe it is well worth it. The packs are much smaller, lighter, they don't loose they power when stored and perhaps most importantly your servos are always fed with the same voltage (6v) through out the packs discharge. This means that the servo speed and power remains constant unlike other batteries where they might start at 8v and drops down to 5v before the failsafe kicks in so you would feel the steering and brake power slowly fade during a long race/bash.

Check out unitedhobbies for some really good lipo and regulator prices. I have bought stuff off them many time and the service is really good. I currently have 4 of there lipo packs for use in my MCD and rock crawler and they have been great so far.
 

zouz10

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1,493
Location
Florida
Thanks for the help Mono,
I am gonna get the li-po packs and regulators at my LHS since they have some experience with it. I will try to get something to fit in the receiver box, if not then I will do like you and fit it on top of the receiver box. I will begin that project Monday
 

zouz10

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1,493
Location
Florida
I just got a Thunder Power 910MAH 7.4V li-po battery and a Novak Servo regulator. That battery will fit in the box perfectly (when I cut out the tab inside) and I will mount my micro spektrum receiver beneath the lid of the battery box.
I was told I should get at least 1 to 1.5 hours out of the pack, which is plenty for me!
 

monotheist

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174
Location
Melbourne, Australia
Just be careful zouz as if its the regulator im thinking of its only rated at 3 amps. Not sure what servos your running but my digital Hitec 5745's each have a stall current draw of 4.8 amps each (or 840MA with no load) that means if my front servos were under full load then they would be trying to pull 9.6 amps from the 3 amp regulator and that’s not even including the throttle/brake servo.

Not trying to panic you but just be mindful of it. I was initially running a single 3 amp regulator for a while and to be honest never had any issues but there might be a risk in overloading it at some point. I would say if your front servos are not working too hard they might consume an 1.2 amps each plus the throttle which might chew up 0.6 amps so thats a typical average of around 3 amps. The regulators 3 amp rating should be the continuous current it can supply with a peak rating of 5 amps short term so you should be ok as long as you don't lock the brakes and load up the steering for more than a few secs.

Good news about your lipo hey. Will be a lot neater than mine which is now velcro'd to the shock tower.
 

zouz10

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Messages
1,493
Location
Florida
Mono,
you are right on the money. Do think I should keep this regulator or get something else? If so what should I get?
 

monotheist

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Messages
174
Location
Melbourne, Australia
I would keep it. You will probably be ok its just that with 2 giant scale servos and one normal one you will be right on the edge of its operating parameters.

I rewired my electronics last night to incorporate another 2, 3amp regulators (one for each steering servo) just to be safe. You could either see how you go "as is" or perhaps buy another 1 or 2 regulators for steering use only. Not sure what you paid but mine were under $9US each from here.

https://www.unitedhobbies.com/UNITEDHOBBIES/store/uh_viewItem.asp?idProduct=4319
 

zouz10

Well-Known Member
Messages
1,493
Location
Florida
Man that is cheap, I paid $30 USD for mine. Thanks of the link mono. Any special ways to wire the thing or just put it straight in?
 
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