1981 CC DS 36V to 48v Conversion

[gsmart]

Hellos, I am a BGW new-B in need of some direction. I have a 1981 Club Car DS 36V golf cart. It was not running when I purchased it and discovered one of the main wires was severed just inside the motor. My assumption is the previous owner allowed the batteries to get to low and when he tried to run it the motor arc’d. It was a quick fix and with a new set of batteries along with a little cosmetic TLC the cart looks and runs great. (pics soon).

I am trying to determine if it makes sense to upgrade the guts of the cart versus purchasing a newer version. More speed would be great, but initially I am only looking for more torque, run-time, with a possible addition of 12v for power and or accessories (lighting, radio, etc.).

The cart has a 5 solenoid resistor coil setup, no v-glide. After exhausting all search engines and reading numerous threads on the subject I am still a little short of my answer. The majority of the threads I have read that take you from 36V to 48V have starting points further down than mine, but what I am searching for is what is the minimum that I can do while noticing improvements. Can I change to a non-programmable controller without adding the PB-6 box? Does it make more sense to switch to an MCOR setup to save money?

So far I noticed the shopping list for a full conversion to be:
1. Controller 400+ amp (programmable/non-programmable)
2. HD 48V solenoid
3. 4 gauge battery cables
4. PB-6 Pot Box or MCOR
5. F/R switch
6. 2 6v or 6 (8v) batteries
7. 48V Charger (when required)

What steps can be done to improve performance without necessarily doing it all at once? Thanks and I appreciate any help.

Gordon

[gsmart]

Added pictures of subject cart.

[dougmcp]

If you are just using the cart around the neighborhood and not loading it to excess or trying to turn it into a hunting buggy you can probably go to 48v without all the rest of the electronics.
That conversion would give you about 30% more speed and torque but will be a little rough on the components. The motor will be fine with 48v. Make sure all your connections are clean and tight. If you have too many issues, you can always do the controller and pot box later.
If it runs under heavy load, inclines or hunting you will need to do the full conversion. Cost estimate for that is in the $1200-$1500 range.
BTW, nice updated silver and black look!

[gsmart]

Thank you Doug, I wanted to get rid of the Florida Gator blue paint scheme from the previous owner given that I reside in Alabama, not a good color around here. The silver is actually the BMW titanium silver to match my car so now my car has a mini-me!

Just to clarify, are you suggesting I can add 2 6v batteries in series to make 48v without any other alterations to the current electronics? So no controller, HD solenoid, etc... at this point in time?

My cart use is strictly flat asphalt to the pool and back. I only need increased torque to handle the rear seat along with the additional weight from passengers. I plan to upgrade the wheels to 10" as well, so I figured that would add more strain to the powerplant.

[dougmcp]

Originally Posted by gsmart

Just to clarify, are you suggesting I can add 2 6v batteries in series to make 48v without any other alterations to the current electronics? So no controller, HD solenoid, etc... at this point in time?

Yes, 48v, a way to charge it and you're done.
You will hear lots of comments about it won't last but I think that is only when you start abusing the rig trying to climb a 35% grade with 4 people and a moose on the roof.
I bet if you watch what your doing, clean and tight connections, you'll get years out of this configuration. Lots of others have done it with success.
10" wheels with 205/50-10 low pro tires are the same diameter as the stock tires now so there is no disadvantage to them.
What the heck, even if it crapped out, you only would have to add a controller and peddle box and you're done.

[scottyb]

This cart has 5 36v solenoid speed switches. They are all designed and rated for 36v Not 48v..... I don't think it is safe to run these old solenoids on 48v? What is going to happen IF a solenoid melts in the closed position and letting your foot off the gas no longer slows the cart? If this happens as it can, the driver cannot shut the cart off or slow it down ........ Maybe I'm too cautious? But it could happen

[bdmonist]

The way it has been explained to me is that more voltage gets you top speed but not necessarily more torque. If you are looking for torque, you could just leave it a 36 volt system and upgrade your motor and be happy I think. Some with more experience may correct me here, but I'd like some facts to go along with their opinion. Voltage gets you Rpms which gives your speed, but your torque will come at lower rpms. Theoretically maxed out at 0 RPMs I believe.

IF you do go to 48 volts, I would recommend keeping your batt's and getting two more 6 volts and running 8-6 volt batteries. Run time numbers are very nice... Also recommend upgrading the system to handle the increase.

Brian

[dougmcp]

Originally Posted by scottyb

This cart has 5 36v solenoid speed switches. They are all designed and rated for 36v Not 48v..... I don't think it is safe to run these old solenoids on 48v? What is going to happen IF a solenoid melts in the closed position and letting your foot off the gas no longer slows the cart? If this happens as it can, the driver cannot shut the cart off or slow it down ........ Maybe I'm too cautious? But it could happen

You are quite correct about these not being rated for 48v and could fail. Reports that I have read is that no one has had any real problems with this.
There is actually less chance of a solenoid sticking in the on position at 48v than 36v.
You are not creating any more amperage per se in the solenoid, for a given wattage, the voltage is up by 33% and the amperage actually drops by 33%. If a solenoid were to fail, it would be the actuating coil that would burn out and the solenoid would drop out of the circuit and the cart would stop.

[scottyb]

Are you sure about that? I mean we do see solenoids weld shut (which is the open or on position for newbies )

[dougmcp]

Yes I'm sure. The solenoids that you see welded shut, and there are many, are from years of making and breaking of the contacts under a high current load which causes them to arc, get rough and then stick closed (on position). The reason for this is that the spring is not strong enough to release the contact or it is fact welded closed.

Operating at a higher voltage, given the same power requirement in wattage will require less amperage and therefore less wear on the contacts with an end result in less sticking. 48v applied to a 36v coil is a little tough on it but in actuality the contacts close faster and have less arcing than it would have at 36v. The spring solenoid release is set so there is no difference between 36v and 48v.

Regarding the actuation portion of the solenoid, the disadvantage to running a 36v coil on 48v is that you are overdriving it by 20% and the coil could fail leaving you with a solenoid stuck in the off/open position.

This is just the theory portion of it.
Usually people who upgrade to a higher voltage also run them harder and demand more amperage from them which can create the sticking problem.

You have tons of experience with these and we all know sh*t happens all the time to these carts for reasons no one can seem to explain.

Just for clarification, a solenoid (actually a contactor) has 2 parts, the actuation coil and the contacts.
When a solenoid is welded, it is the contacts stuck together, considered "closed" or "on".
When the coil is burned out it is considered "open" because it cannot actuate and close the contacts.