Need some electrical help...

Hello all,
I'm trying to figure out how to make a certain water pump run without over amping it to death.
I have a 12v pump that wants no more than 1200milliamps. I would very much like to run it off of my lawn tractors battery. I can solder and am reasonably intelligent, I just don't know much about electrical engineering. It's going to pump a watering hose from a 30 gallon tank on my landscaping cart for watering the gardens and flowers in the yard. It will be mounted to the water tank and outside, exposed to the elements. Anyone who can help?
Thanks

a reply to: Natas0114

What's the amp rating of your battery?

a reply to: Natas0114

The electric motor in the pump will draw the amps it needs to operate. What is the rating on the label on the side of the motor or pump housing?

It will read something like 12v , __ Amp. Fill in the blank... (1200 mA is 1.2 amps per hour of operation). If the tractor is self charging the battery you should be fine to water every day if need be.

a reply to: swanne

The new one will be 235cca 280ca 12v. I have a scooter battery that's a ub1213 12v I was thinking of using. I have a leaf rake that I added an actuator to, with leads ran for it already. That's why I would like to run off that. I have plenty of room for another battery on my cart. I would just like to plug and play, so to speak.

a reply to: intrptr

It's a 1200mlamp. I'm pretty sure that's 1.2 amps @ 12v. It has tiny(20) gauge leads on it, that's why I worry. It's a JT-800B solar water pump for fountains. It's rated at 450-1000 lph. Dc 6-12v

a reply to: Natas0114

You pump isn't something like sensitive LEDs or something - it's a load. In theory your main worry would actually to no get enough amp, but sounds to me you've got enough. The amp going through the load is determined by the load itself, it's basically a resistor.

a reply to: swanne

Awesome. Thankyou, I was worried about killing the little guy. Much appreciated.

originally posted by: Natas0114
a reply to: intrptr

It's a 1200mlamp. I'm pretty sure that's 1.2 amps @ 12v. It has tiny(20) gauge leads on it, that's why I worry. It's a JT-800B solar water pump for fountains. It's rated at 450-1000 lph. Dc 6-12v

Do you plan to operate the pump and water while the tractor motor is running and charging the battery? The operating voltage off the battery will be about 15 v, a tad high for your 6-12 v rated pump.

And those 20 gauge leads are a bit thin under that kind of load. I would use 12 or 16 gauge httn stranded insulated wire, the kind in your house wiring system is 12 gauge. How long does it take you to water the garden all at once?

a reply to: Natas0114

Anytime mate

I think you`re confusing amps with voltage, if you connect a 12 volt pump to 120 volts it will fry the pump.
The pump will only draw as many amps as it needs to operate no matter how many amps are available.

Here`s an example,
your table lamp with a 60 watt bulb in it is plugged into an outlet that is connected to a 120 volt 30 amp circuit , the bulb doesn`t need 30 amps to operate but it works just fine.

It should be also said that fatter cables reduce resistance and can increase power time.

a reply to: intrptr

No, I will not be running the motor. I am very familiar with mechanical (automotive) systems and I know the generator/alternator Will over volt it. And the leads are out of the.pump itself that I'm worried about, it's a submerged style fountain pump for solar applications. I'm just very cheap, And found it for 15$.
I forgot to add- I won't be watering both of my gardens primarily. I have hoses that reach, however I'm planting a bunch of hazelnut trees and a living flower fence this year. So it's more for my initial planting watering needs that are remote from the front gatden.
But I am lazy at times, and will probably water the pumpkins, gourds, and other melon patches. I will try not to run it too hard.

a reply to: Tardacus

Cool, I'm not very good with dc stuff. I have had a couple interesting experiences that I wouldn't wish on anyone..

a reply to: Natas0114

Easy answer, get a LM7812 or ua7812 voltage regulator plus heat sink in a t220 or t03 case style. Grab the data sheet from National Semiconductor or Texas Instruments. On the data sheet there will be some app schematics, chose the one that says "Variable Voltage Regulator." Build it. It will give you about 3vdc to 12vdc, if your battery is at 13vdc or better.

Cheers - Dave

a reply to: Natas0114

In that case, it should be fine. You can always check the leads wth your fingers to see how hot they are running...

...as long as leads aren't open (showing copper) to the elements you should be fine against corrosion, too.

a reply to: bobs_uruncle

Sweet, thanks. I have some heat sinks laying around from other projects. Will look into the regulator for sure.

a reply to: intrptr

Exactly Correct!

A big thanks to everyone for the help. It's much appreciated, and if anyone heads to northwest wisconsin, let me know.
Cold beer, fresh veggies, smoked salmon always ready....

a reply to: Natas0114

I'll be the one bringing the beer. Trust me, you wouldn't regret it.

a reply to: swanne

Sounds good to me.