Separate 12 volt accessory battery

[skuhleman1524]

Hello all, I am new here and did a bunch of searching before i decided to post this question.
So I have a 1990 EZGO Marathon 36V golf cart. This cart will be used at our family lake house for just cruising around. I am adding a radio and lights and a 12v accessory plug as well. Most of what I have read everyone says to add a separate 12v battery. I am going to do this. My question is charging. I know I can add a onboard charger but that just makes for one more thing to plug in. Being that multiple different people will be using it I wanted to simplify it for them. I want to hook up the 12v to 2 series 6v only when the key is off. when the key is on I want it to disconnect it. So I am thinking of running a cheap $25 10A voltage reducer on the key output so I can use the key as a relay trigger wire. then wire my relay between the 12v and series 6v in a normally closed position relay so when the key gets turned on, it powers the cart and the voltage reducer, which then triggers the relay to disconnect. key off and it connects and the 36v charger still sees 36v and charges all batteries.

Sorry for the long post. I know i could easily put a switch instead of using the key switch and reducer. but this will simplify things for the users and less chance of them messing it up.

So what does everyone think of this idea?

[kab69440]

I think a 12v battery and charging receptacle would be a whole lot simpler. It really isn't that much effort to plug in the 12v charger.

[skuhleman1524]

Yea it would be for me. but my grandpa (80 yrs old) and my parents and their friends. and the rest of my family and what not. I know they would forget to plug it in. we have an onboard charger on out pontoon boat and they always forget to plug it in as well. so Im thinking outside the box of a way to dummy proof it for them. I just wanted to make sure my idea will actually work before I did it.

[ddeblance]

I have a 12v reducer in mine. I placed a fuse block and ground block in the dash behind the cup holders. Installed the reducer under the seat drivers side. Ran power and ground from 36v pack to reducer. Ran 12v power and neg from reducer to fuse block in dash.

Ran another 36v lead from pack to the dash and connected to the key switch (where the lights used to be connected, moved lights to fuse block and separate rocker switch on dash). This 36v lead is used to power on the converter if yours has the power-on lead...
So headlights, stereo and underglow lights are all individually controlled by rocker switches (and acc plug) it all has power with the turn of the key to the second position. Also connected battery meter to the back side of the key switch, so it turns on with the key as well.

All this thanks to this site... All my cart would do before this forum was go forward and reverse...

Now, I don't mind my wife jumping on it and taking off and able to use everything and not worry about power or burning the thing down.... lol...

[skuhleman1524]

Thanks for the help everyone. I think im gonna try this out and see how it works out. I will be sure to come back and let ya know. Also going to make custom speaker enclosures and will update that as well.

[chloe]

If you get the right battery, you shouldn't need to charge it all the time. I run a gel cell motorcycle battery for my cart lights and LED's. A full night of cruising and letting the cart set with the LED's on has never required more than about 20 minutes on the 2amp trickle charger to bring it back to full. If you are the one plugging the cart in, plugging the trickle charger in should not be that much more effort. Certainly a lot simpler.

[black&yellow]

I would zip tie the 12v charger plug to your cart charger plug so when they plug the cart in they will know that the other plug must need to be plugged in as well. That is if you decide to do a receptacle. Plus you could label the plugs and receptacles with a label maker if you really wanted to dummy proof it.

[DonBenigno]

The other option is just add a DC to DC converter. Then you will not have to worry about getting a seperate battery and charger

[springr51]

I just tap 12 volts off the 36 volts. never a problem yet. :

[Jerj7907]

Isolating 2 batteries to get 12 volts and in a matter of time you will have issues. Go the easy route buy a voltage reducer to 12 volts and run accessories off of that. Plug cart in with single stock charger and all good. Don't have to haul the weight of a 7th battery either. It is a little work up front but long time this is the way to go. If you isolate 2 batteries you are asking for trouble unless you constintly maintain the 2 and rotate thru batteries. I lived without an inverter for 7 months and have had the inverter for about 4 months. I am convinced this was a wise decision.