Dash / Accessories Customization

[RobotObsession17]

I need help with design considerations to customize the dash of my 2008 EZGO Electric TXT. The cart has had a stereo for 15+ years. Oddly, I am converting the golf cart to an autonomous robot, but don't let that cloud your response.

Near term, I need to add lights and turn signals (so I know what the robot is about to do, and can abort if something goes awry). So any lessons learned on lighting is appreciated.

I welcome ideas on the key switch. For example, I think the switch (by default) is Off / On / On&Lights. I do not like that, because it's the opposite of what people that drive a car are accustomed to (which is OFF / Accessories / On). I like the idea of the key switch turning off everything....to prevent the battery from being run down by something inadvertently left on. I welcome brands you recommend, etc. I have created a plethora of robots, but know little about the quality vendors in the Golf Cart domain.

I would also like to create an Overhead Console to house various things. I welcome any ideas to include. I am not interested in putting the stereo/speakers up there (that is too common). I am thinking maybe a dome light, and possibly a backup camera. I will fabricate my own Overhead Console, so we are not limited to conventional wisdom.

If you could design your own Golf Cart, what accessories would you include?

Thanks in advance.

Cart specs:
Year = 2008
Drive = Electric
Batteries = year 2020, ie brand new.
Has the rear (dunno what you call it) pickup truck bed, ie no seats.
Model = TXT
Conversions = basically none, except the car stereo

[webwarmiller]

I think you first need to decide how you plan to power all those 12v accessories. There are 3 common ways.
1. Off two of the batteries. This isn't recommended as you will be taxing those 2 batteries more than the rest of the pack. This is especially true if you plan to have a bunch of 12V accessories which is sounds like you do.
2. A voltage reducer. You connect it to the whole pack and it outputs 12V. Now you are pulling off the entire pack which is better. There are 2 basic kinds of reducers, a 4 wire and a 5 wire. The 5 wire simply adds a turn on wire so that the reducer is completely off when the cart is off. The 4 wire ones will have a parasitic draw even when the cart is off; most add a on/off toggle in order to prevent this.
3. Separate Aux Battery(s). The advantage here is that your 36v pack and 12V accessories are now completely separate from one another. The disadvantage is having to charge another battery. You'll need to calculate the draw from your accessories and desired run time to determine how many Ah you need.

[RobotObsession17]

Thanks @webwarmiller , I appreciate your help. That is the part if have down pat, but don't let me make a mistake if you feel otherwise.

I actually already installed a buck-converter, that is fed by the entire battery pack. I agree with your assessment of the pros and cons...so I don't want an extra battery, nor do I want to pull down just 2 of the batts.

To prevent this buck-converter from running all the time, I did this:

1. Installed a Bosch automotive style pull-in-relay. Amazon, https://www.amazon.com/gp/product/B07QLB9CZM/

2. Installed this key switch that supports OFF / On / Lights (but for my application lights and all the accessories).
https://www.amazon.com/gp/product/B07G423Y2C/

...the reason is, to your point, with numerous accessories it would be easy to leave one on. Thus the key switch will whack everything - just like a car.

The key switch will not be handling the electrical current of the accessories...just a trivial amount for the relay (the relay does the heavy lifting of carrying the electrical current / load). I measured the current when I received it, but I honestly don't remember, maybe 10 milliamps (to energize the relay's coil) is what is traversing through the key switch.

One comment, golf cart pros will notice, but I wired the key switch backward - so it would be the same experience of a car. Now it functions OFF / Accessories / ON. I also 3D printed a new key switch plate:

Finally, I added a barrier strip to act as my Low Voltage Bus (12V bus in this case). That way I can connect / disconnect / troubleshoot any single accessory. Pic below, that is located under driver's seat.

Thanks again for the advice, I agree 100%.