Can you use 3 12v batteries with 2 12v motors?

[RH JOINERY]

Hi guys and girls. I am just in the process of buying the motors for my T2 before i make my chassis and i am just wondering if you can use 3 12volt batteries with 2 12volt motors.  I am just wondering if the extra battery will help when going up inclines, am i wrong in saying this?  And what is the best wattage for these motors? I am a joiner by trade and im a complete novice with electrics but i am willing to listen and learn from any advice you have to give.  
   Many thanx Rory.

[Tufty]

Hi Rory,

The simple answer is yes but what are you trying to achieve by using 3 batteries?
RLT supplied motors are 12v 200w.
Tufty

[RH JOINERY]

I read somewhere on this from that someone had used something called a tacho meter, this, when the motors came under strain pulled ore power to the motors so i just thought that having the extra battery would help with this matter. so is the extra battery just a waste of money and time? Thanx tufty

     Rory.

[brian]

Hello Rory.

In answer to your first query, the answer is yes, you can use as many twelve volt batteries as you can fit in if you want to.  All the batteries would be connected positive to positive, negative to negative which is known as being connected in parallel and the motors would be connected with a positive (Red) wire to the first motor and then onto the second motor. The negative (Black) wire would go the first motor and onto the second motor.  This again would have the two motors connected in parallel

If the motors turn in opposite directions when you have connected them in this way, just reverse the connections to one motor.

Brian.

[RH JOINERY]

Thanx Brian but is it the batteries that help it climb inclines/give it more power or is it the wattage of the motors? Many thanx Rory

[brian]

Rory, you could get one battery that equalls the out put of the three, the only advantage of multiple batteries is to be able to distribute the load around the the area available, there is realy no other.

Batteries are rated in ampere hours. the larger the capacity,(Ampere hours), the bigger the battery size, but of course some times, the available space is unable to physically accomodate the large battery, so, the problem can be overcome by using two batteries at half the capacity, (Ampere hours) which would make the batteries smaller in size, then connected in parallel, brings the capacity back upto the larger batteries size.


Brian.

[brian]

Hello Rory.

The ability to do work, (Climb an incline) can be achieved in two ways. gear the motor down which would increase the power but be achieved at a lower speed which might then be unacceptable, or, you could increase the motor size and leave the gearing as it was with the speed that you required.

But of course, the increase in motor size would have a greater amperage consumption, and therefore use up the batteries capacity quicker, which would require a larger battery for the given required useage time.

I would use two of the motors supplied by Richard at Toylander, connect them in series along with two 12v batteries connected in series to give 24  volts.

I use a single 12v motor with a single large 12v battery, but I wish I had gone the route I am reccomending.

It's all a balancing act.

Hope this is of some help.

Brian.

[Tufty]

I read somewhere on this from that someone had used something called a tacho meter, this, when the motors came under strain pulled ore power to the motors so i just thought that having the extra battery would help with this matter. so is the extra battery just a waste of money and time?

The tacho acts as feedback for the speed controller (if the speed controller has the ability to do this), if the motors slow (ie. hit a hill) the speed controller applies more power (like cruise controll on a car). As Brian says having extra batteries would not give you more power as it's the motors wattage which determines the power (providing the batteries are 'big' enough to supply the amount of current required). If you want to use a 24v speed controller (you will need 2x 12v motors or a 24v motor) you will need 2x batteries wired in series to achieve the 24v supply.

In it's simplest form you can look at it in terms of
Battery = Car Fuel Tank (the bigger it is the more range you have)
Motor  = Car engine (the bigger it is the more power you have). 

Until you get into the realms of 12v/24v
Tufty

[RH JOINERY]

Thanx tufty, is there some kind of chart i can work off? Or is it just trial and error.

[RH JOINERY]

Thanks Brian, your input has put my mind at rest.
   Many thanks Rory.

[Tufty]

Thanx tufty, is there some kind of chart i can work off? Or is it just trial and error.

Chart showing what?

[RH JOINERY]

Like what size ampheres you need in a battey for what watt motor i am using? 
 thanx tufty  sorry for been a pain.
 
    Rory.

[markh15]

Hi Rory,
It's the Amp Hours that give the vehicle longer to run,

If a motor is 12v, and the battery is 12 v - 35 ah, that means that the battery will deliver 12 volts for 1 hour at 35 amps OK?

If the motor draws less than this, then you get more running time from the battery, I think it's the motors amps divided into the batteries amps = the running time in hours.
I might be wrong though, but someone will put me right (usually Brian, the Electrical Engineering Genius).

I'm not well up on electricals, but I remember this from my appentice days as a mechanic.

If you get hold of larger a/h batteries, then the car will run for longer on one charge, but larger A/hours = more money! Most Mobility Scooters have 35 a/h batteries, and will go (none stop) for about 25 miles, depending on terrain and weight carried. As you children (and mine) will stop - start constantly during play, and weigh considerably less than an adult, then you should get at least a weekend out of the batteries before charging.
I can take Harvey out in his car for about 2 hours, about 1/2 a dozen times before they need charging up again.

Don't forget, that scooter and other 'Leasure' batteries, are 'Deep Cycle', and need to be run down to about 20% capacity before re-charging. Otherwise it shortens their lifespan.

Hope this has helped,
Regards,
Mark.

[Tufty]

Like what size ampheres you need in a battey for what watt motor i am using? 
 thanx tufty  sorry for been a pain.

Hi
No worries.
You'll be very hard pushed to find a motor which needs more current that a battery can supply, basically as said elsewhere on the thread a 35A/hr battery will deliver 35A for 1 hour this isn't the max current the battery can supply (it will supply 140A for 1/4hr, 70A for 1/2 hr or 17.5A for 2hr etc.) If you think of the amount of current a car starter motor takes it's alot more than a TL will pull. We run 12V winches on 35mm sq cable which is capable of carrying over 250A (although we've never measured the current they pull, the larger the cable the less voltage drop there is over the cable length) on a 4x4.

Motor power (W) = Volts (V) x Current (A) therefore a 200w motor will pull 17 A at 12V with a nominal load.

200 = 16.66     
12


However a motor does not pull constant current due to loading going on/off load (going uphill/downhill, starting/stopping etc.) but it's all you have to work from.

So in theory a 35A/hr battery will power a 200W 12V motor for roughly 2 hours at nominal load. In practice as Mark says it will be longer than this as the motor won't pull full load all the time.

Hope this doesn't confuse the life out of you.
Tufty

[gavinbailey]

Hi - sorry for hijacking this thread however I'm interested in extending the useful range/play time of my Toylander between charges.  My car runs 2 x 12v standard motors from Richard with 2 of Richards standard 12 v batteries in series to give 24v.  We tend to use it for faily long runs and on one earlier today we only just got back home.  Pulling up hills on the way back the car was really struggling as the batteries were pretty drained. 

I presume if I want to extend the range by increasing the total amp/hours of the batteries I could add a third 12v battery (provided I have the space), connected in parallel with one of the existing batteries to increase the total capacity?  That I presume would be the same as having one of the 12v batteries with a larger ah/hr capacity? 

Any comments/advice would be appreciated.

Regards,

Gavin.