Minor Cart Radio electrical hookup (help)

[OldManTime]

I pulled my 12v radio console from my old cart 36v, installed in my new cart 48v with 6 - 8v batteries, I need a Voltage Reducer, any one have one?

[villagetinker]

First of all I am not a golf cart expert, however, I am a retired electrical engineer. I have the equipment to test your radio. It may have been damaged by connecting it to 16 VDC. Also, as I recall the electric carts usually have equipment to operate the 12 vdc accessories (lights, horn, turn signals, etc.), and if this converter has sufficient capacity then the radio should be connected to this supply. If it does not have sufficient capacity, and additional converter can be added.
Send me a PM if you want to get together, I am located in the village of Pinellas.

[Uberschaf]

The radio should be able to run fine on 16v. 16v dc is the max on most decks.

[villagetinker]

Uberschaf,
You are probably right, however, that rating allows for the normal voltages seen in an automotive application, 12 VDC at rest, 13.8 VDC charging, and occasionally higher if something goes wrong. Connecting the radio to 16 VDC at rest, with subject the radio to approximately 18 VDC during charging, and since this is part of the motor circuit, it could be subjected to transients from the motor drive electronics.
IMHO I would install a DC-DC converter.

[villagetinker]

UPDATE.
I worked on the cart today, and there was a wiring error causing all of the problems. Once we figured our what was going on we got the radio to work. Aslo, the wiring problem caused the fuse to blow.

As for the basic "12 VDC" connection on the electric carts. WOW did I get an education when I did some serious research on Google last night. It appears that most (if not all) Golf cart manufacturers simply tap the 36 or 48 VDC battery string to get something close to 12 VDC for lights and accessories.

While this does work, it has some disadvantages.
1. The 2 batteries that are tapped for the 12 VDC supply are getting additional load that the other batteries in the string never see.
2. If you drive a lot a night, or use a lot of 12 VDC accessories, this additional load could shorten the life OF THE 2 BATTERIES used to supply the 12 VDC.
3. Because the batteries are NOT being discharged EQUALLY it is probable that they will not be recharged equally.
4. These 2 batteries will also require additional maintenance (water), etc.
5. It is conceivable that these 2 batteries will have a shorted life then the other batteries.

I learned early on in my electrical engineering career that it was very bad design to tap a battery string for lower voltage loads, and utilities go to great lengths to avoid doing this.

I also found that DC - DC converters for 36 (or 48) VDC to 12 VDC tend to be expensive, especially if these are going to supply all of the DC loads, lights, turn signals , horn, radio, etc. However, using a converter spreads the load across all of the batteries and completely eliminates the uneven loading of a tapped string.

Now, I have no idea if I have just made a mountain out of a mole hill, but I thought that I would provide this information for all users of electric golf carts, just in case you are seeing some of the above problems.

Hope this helps.