Re: Battery questions [TANKS]

["Milenko" <milenko-at-king-nerd.com>]

Excellent info as always.  Thanks Steve!!!


----- Original Message ----- 
From: "Steve Tyng" <STyng-at-acptrust.com>
To: <tanks-at-rctankcombat.com>
Sent: Wednesday, April 12, 2006 10:37 AM
Subject: RE: Battery questions [TANKS]


> Jeremy wrote:
> 
>> Just wondering how changing/charging batteries work on the 
>> battlefield.  I know that batteries can be moved around on 
>> the battlefield by supply vehicles, but is there enough time 
>> to charge batteries during the day or do I need enough 
>> batteries to make it through the entire day?
> 
> It takes longer than the couple of hours between battles to charge a
> battery.  My 24V 6amp charger takes overnight to charge one set of 18AH
> batteries.  Most battlers bring enough batteries for two one hour
> battles.  In the Cromwell's case, I will usually use two sets 18AH
> batteries for a days battling (four batteries total).  I bring an extra
> third set as a backup.  The T34 ran at 12V and carried only one 18AH
> battery and could go through three batteries in one hour of battling.
> 
>> It would seem to me that I'd need quite a stack of batteries
>> if there isn't a chance to charge any up.
> 
> The number of batteries your tank will need depends on many factors
> (motors, voltage, space, driving style).  Also, It appears that PWM
> motor controllers are more battery efficient than on/off controllers and
> will give longer running times.
> 
>> Also, is there normally AC power available near the 
>> battlefield?  Should I get a charger that can run on DC and 
>> use my car to charge the tanks batteries?
> 
> Usually AC is not available at the battle sites.  Get a smart charger
> that will charge and then maintain your batteries.  Avoid cheap
> automotive battery chargers because it is easy to leave these on for to
> long and you will end up overcharging your batteries and damaging them.
> 
>> One last question:  I was cruising ebay looking at gell cells 
>> and there are some people selling giant (~100AH) batteries 
>> made to go in UPS's.  Is it better to get two of these (I'm 
>> going to run 24v) and try to charge them in the tank between 
>> battles and run the whole day that way, or get several sets 
>> of smaller batteries and have to change them out?
> 
> Most battlers get by with 26 to 36 amp hour capacity for a one hour
> battle.  100AH of battery in your vehicle (if it could fit) would
> probably be overkill.
> 
>> Has anyone 
>> had problems with the gell cells dieing from continually 
>> charging them up and then draining them down to almost 
>> nothing?
> 
> Don't drain them too nothing.  I added an easily visible voltage meter
> to the Cromwell to avoid such a situation.
> 
>> I thought that doing that was very bad for gell 
>> cells/lead acid batteries and that deep cycle batteries would 
>> work better for such an application.
> 
> Yes, draining lead acid batteries below a certain voltage level (11.6
> volts I think) will begin to damage them.  Deep cycle batteries are what
> you want.  Avoid automotive and motorcycle starter batteries.  Batteries
> marketed for alarm and UPS systems are deep cycle.
> 
> 
> Steve Tyng