Question 36 to 48 Volt change

georgia088

Hey guys. Got a couple of questions about upgrading my cart.

I have a ez go pds cart with a DCX400PDS controller, stock 2.25 HP 36V motor (P/N 73445G02). Stock tires (which I would eventually like to change) 4 guage wire. Stock Solenoid (Assuming I should probably upgrade this)
2 year old batteries.

Now, my questions:
1. Will my setup handle 48 volts?
2. Can I add a 12 Volt Golf cart battery to my series in order to obtain 48v?
3. Will any 48 volt golf cart charger charge this setup?
4. Should I change any settings in the controller?
5. What speed would increasing to 48 volts give me on flat ground with one passenger and stock tires?

Thanks in advance!

BGW

__________________
This advertising will not be shown in this way to registered members.
Register your free account today and become a member on Buggies Gone Wild Golf Cart Forum

JohnnieB

1. Controller and motor: Yes Solenoid: No
In fact, I'm surprised your stock solenoid (85A contacts) is still alive feeding a 400A controller.
Get the Super-Duty 48V solenoid (400A continuous/1000A peak) from Carts Unlimited. It works at 36V, 42V and 48V.

2. Bad idea. It might work, but not for very long.
The batteries are connected in series, so they should all have the have same AH rating or they more or less kill each other.
The highest AH 12V deep-cycle battery you can get is only about 1/2 the AH rating of your existing 6V batteries.

3. Probably yes, but if you are buying a 48V charger, get the DPI Accusense.
It is one of the best on the market and the best bang for the buck.

4. That depends on what the current settings are.
The High and Low voltage cutoffs will probably have to be changed.
The throttle up rate may have to be backed off a bit since going from 36V to 48V ups the torque by 1/3.
If you are running regen braking and the slider is set to less than 100%, you want to up it also, since it isn't as strong at 48V.

5. Probably in the high 20's to low 30's.
When I was running a DCX400 and a stock PDS motor, my speed went from 24 MPH to 28 MPH when I went from 36V to 42V, so you'd probably get about twice the increase going from 36V to 48V.

FWIW: With stock height tires, you'll be spinning the motor about 7,000 RPM at 30 MPH, so don't drive downhill at full throttle to see how fast it will go.
I did and found out a new motors and controllers are expensive.

georgia088

Thanks! So, if I would like to go to a 48 volt system now and don't want to wait until my 2 year old batteries need replacing. My best bet would be to buy 2 6 volt batteries? Thanks!

scottyb

Adding 2 6v batteries will get you to 48v. Remember each battery weighs over 60 pounds. This equals almost a 20% increase in overall weight. So while you will have more power you will also have more load. The power to weight ratio is pretty sensitive in an electric vehicle.

georgia088

So would adding a 12v battery to the set up harm the electrical components or just the batteries?

scottyb

We already answered this question in the other thread. My answer was


If you are asking if you can put 48v to your 36v cart without changing the stock control and solenoid the answer is no. It will damage the 36v components and charging a 12v battery with a 36v golf cart charger could lead to personal injury.

georgia088

Scotty: My cart does not have a stock controller. It has a 400 amp alltrax. I do not want to charge a 12v battery with 36 volt charger. I want to add a 12v battery to my 36v system (making it 48v). And I would charge this system with a 48v charger. I don't really care if it shortens the life of the batteries some, but my concern is that it would damage the electronics in the cart. I don't see why it would damage the electronics in the cart because it is 48v, but I don't know a whole lot.

JohnnieB: I just got a chance to really read your entire post. Thanks for the info! So, you are saying increasing tire size with my setup would be better for the motor and controller because it wouldn't allow the motor to turn as many RPMS as it would with stock tires?

chriskent85

2 6 volts are what you need. not one 12v. a 12v will work but it will ruin your other batteries because they dont charge or discharge at the same rate. Listen to scotty B & Jonnie B. they know what they are talking about

JohnnieB

Adding a 12V battery to your existing 6 x 6V pack and charging the resultant 48V pack with a 48V charger will work, but the gross mismatch will rapidly ruin all of the batteries. How long that takes, I don't know, maybe a week, maybe a month, maybe three or four months, but I doubt if your 2 year old 6V batteries will see their third year if connected that way.

In a nutshell, the smaller AH cells of the 12V battery will charge faster the larger cells of the 6V batteries and the charger is looking at the average voltage of all the cells in series, so the net result is the 12V battery will chronically be overcharged while the 6V batteries will be chronically undercharged.

While driving the cart, the smaller 12V cells discharge faster and if discharged far enough, the current continuing to flow through the depleted cells due to the 6V cells still having energy in them, will reverse the polarity of the cells in the 12V battery, destroying them.

My advice is to set up for 48V, but run at 36V until you are ready to entirely replace the existing 36V pack with a proper 48V pack.

If you insist on going to 48V immediately, but will not replace the existing 6V batteries, buy two economy grade 6V batteries and add them to the pack.

The thing to remember if you chose to do this, is the the two economy grade batteries are sacrificial batteries that will have to be replaced when existing batteries are replaced, regardless how long they have been used.