48 VDC to 12 VDC for a golf cart stereo

[lbarnaby]

I have a 48 volt golf cart and need 12 volts for a stereo. I understand that just bridging two of the eight batteries (each is 6 volts) will cause these two batteries to never totally charge and eventually fail with a short life. To get all of the batteries involved, can I jumper three pairs of batteries and gang them together for 12 volts? See Sketch

 

[Externet]

DigiKey part number 811-2198 and many, many others could be used. Check specifications.

 

[colin55]

There is NO WAY that you can join any more than two 6v batteries, in a "series-parallel" arrangement, to get 12v. Any parallel-series arrangement will not provide 48v and 12v at the same time. Any arrangement like this will short-circuit some of the batteries.
The only way to do it is have a plug that firstly connects to the first two battereis, then is removed and connects to the second two batteres and then is removed and connects to the third set of two batteries, etc. This way you will use each pair equally.

 

[lbarnaby]

Thanks colin55 - The diagram I drew did not look like it would function; however, I thought that I would ask. It seems that the easiest thing to do is spend the $$ to get a 48 VDC to 12 VDC converter.

 

[colin55]

You can use a change-over switch to get energy from the first two 6v batteries and then click the switch for the next two 6v batteries.

 

[Externet]

Another way:
Install a small 12V motorcycle or lead gel battery to feed the stereo. Trickle charge it with a 13V regulator fed by the 48V.

 

[danchalf14]

radio across two batteries

It has been my experience that the draw from the radio is so small,unless you have a master blaster, you don't have to worry about shortening the life of the two batteries,if it does it is so small as not to be noticed. The batteries will all equalize with another overnight charge anyway. it is important to charge your batteries every time you use the golf cart more than twenty min. of travel time. I worked as an Electrical Troubleshooter in a large GM Truck plant in Ft.Wayne IND. and we charged our carts (with on board chargers) every time we were near an outlet an not using the cart. Since the Electrolyte rises during the charge cycle only water the batteries after charging unless the plates are showing then put in just enough distilled water to cover the plates and then fill the batteries after charging. Do not fill them up into the fill well,but leave about one eighth of an inch below the fill well and not up into the slot or the water will bubble out onto your garage floor. Keep the battery tops clean and spray the posts with a terminal protectant or smear grease on them, I hope this helps people.

 

[MikeMl]

Solution to both the battery imbalance and motor noise problem is here.

 

[Diver300]

I agree with danchalf. VW beetles used to be 6V and they changed to 12 V but some kept 6V radios. So a lot of 12V replacement batteries had an extra connection half way down for the radio feed.

Noise could be a problem even if, as Mike suggests, you have totally separate systems. The golf cart might not have correct suppression.

You could also use a converter, which is a form of buck regulator, to convert from 48 to 12.

 

[ronv]

Dan Has it right. You will notice they run the lights off of 1 or 2 of your 6 volt batteries. You might want to pick 2 different ones for the radio to minimize the ballance problem. The noise may be another problem depending on the cart. I live in a retirement community where everyone that golfs has a cart. When I listen to the radio in the garage some of them will be nasty and others cool. I would check out the noise before I spent any $ on a 48 to 12 converter.

 

[danchalf14]

48 to 12 volt converters

I have a couple of customers of my repair shop that have hooked two 8volt batteries in series for their lights on my suggestion and the headlights are a little brighter,but have been working fine for the last 3 years. Automotive type lights have to take a 16v + or - a little due to surges of the alternator kicking in and out in an automobile or even a Semi Tractor Trailer,which uses a lot of the same lights I use for Headlights and tail lights.

As for the Radio noise I was specifically looking for resistor / capacitor type filter to put across the wires to the radio. I'm not sure where to find one, I know it would be cheaper to build one with radio shak parts. Does anyone out there know what to build.?

Dan

 

[ronv]

Something like this?
**broken link removed**

Otherwise just an inductor (toroid may be best) followed by a good quality cap. Say 220 uhy and 220 ufd. plus a .1 ceramic.

 

[danchalf14]

noise in radio on Golf Cart

Thanks, I am also going to try the .1mfd Tantalum cap across the pwr into the radio. I also found a ferrite core to snap on around either one of the pwr. leads. Your supposed to try both leads to see if noise goes away. I am getting a lot of ideas. I will let everyone know how this plays out, but off to the dentise with a broken tooth , which if crowned will cost $890 they tell me. This will put a dent in my golf cart toy budget.

Thanks, Dan

 

[ronv]

Just got a new EZ GO with the brushless motor, high speed gears and big tires. Passed the speed check station at 33 MPH, but hasn't done a thing for my golf game.