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Old 08-28-2010, 10:36 PM
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Default Re: lipo trouble

That battery listed is for sure to small for that Night-Crawler,
Even thought it’s probably just a 55 turn 540 motor , it still draws more when the small 280 size motors from a 1/18 scale vehicle for which these type battery’s are intended.
Probably already just from the steering servo ?
But check your instructions , since I would expect it still should give you a longer run-time as just 2-3 minutes , as long your are easy on the throttle-finger !
There should be something in there how to program the Lipo shut-off .

Because of ( usually ) larger size vehicles , like 1/10 scale , use 540 type motors and full-size steering servos ( a high torque steering servo can pull easily 1- 2 amps alone , and even more if it has to work hard or being blocked in movement ! )
Compared to smaller stuff , like 1/18 or 1/16 scale vehicles with 280/380 type motors and mini or micro-servos , yes , I would say as a rough judgment you can go by scale to figure out needed battery size

Don’t just go by the C-rating !
That only means that battery can dump up to x-amount of the rated capacity !
So if you have a 1000 mA/h 20C battery and compare that to a 2000 mA/h with just 15C battery , that 2000mA/h 15C battery gives you more punch !

I don’t believe this 20C rating on that small 1650mA/h battery anyway !
These small 18 or 20 gauge wires sure as **** don’t take no 33 amp abuse !
That would probably cause a nuclear meltdown on the battery as well on the wires and connectors.

For the other guys “fighting” the Lipo-shut-off problem in general ,
If you just run regular NICD’s or NIMH’s , there is no need to disable the LIPO-shut-off , as long your NICD or NIMH is still in good condition , means under load not to much of a voltage drop .
If your vehicle shut’s off to soon with the LIPO-shut-off enable , with the use of a NICD or NIMH , that means that your NICD or NIMH battery has seen better days .
LIPO shut-off’s usually work in the 6 volt range ,
Means voltage drops below 6 volt , shut-down .
A good battery , no matter if LIPO , NICD or NIMH will maintain , even under heavy load ( high current draw ) a voltage above 6.5 volts .
If it drops below , that means your battery is worn down .

As for the guys with the Tamiya MFU’s in there trucks ,
A LIPO shut-off is not necessarily needed here , since the MFU shuts down anyways when the voltage get’s to low ( even thought not indented as a LIPO-shut-off , but it’s handy side effect of the MFU’s )
The same applies to the Tamiya tank- MFU’s .

As for deep-discharge of a LIPO , yes , as long the LIPO is new , it will probably survive it , but you may run in trouble with some chargers .
Some chargers will NOT recharge a deep discharged LIPO !

And be very careful with these LIPO’s !
They are an extreme fire-hazarded !
There is nothing else more dangerous in the battery-world as a LIPO !
Get a LIPO-charging bag !
LIPO’s do NOT get hot during charging , so they can be charged inside a closed bag / container !
I have not seen one yet going up in flames , but supposedly it is a much bigger mess as if you blow up a NICD or NIMH.

Either it’s at my place or in our TankMuseum , LIPO-charging bags are mandatory if you use LIPO’s !

Much cheaper way for good batteries are Lithium-Ion battery’s .
I use them in my trucks with low RPM motors and gear-reductions .
They do not give you the high C-rating , but they are cheap and available in high capacities .
The ones I use come as a 3.6 volt D-cell size cell with 4000mA/h , I use 2 of them ,
Which even can be installed in the tanks on a truck , like in a short-wheel-base day-cab in which you may don’t have the room for regular size battery’s .
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