Solar Lithium Ezgo

EzgoSun

New Member
My project is to refurbish a 1996 Ezgo TXT, 36 Volt, with the plans to put a very large solar panel on top with the end goal of having an electric cart that is charged by the sun completely and is powered by Lithium batteries. I grew up around golf and rode in a few carts over the years, so am sure the golf memories will come, once its complete. This cart will not see a golf course, but a remote ranch in the southwest USA where we have 300+ days of sunshine and no utilities.

The project cart came with out batteries, and 3 - 75 w 12V nominal solar panels mounted on an aluminum frame above the roof.

So now I will chronicle the progress.....

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HotRodCarts

Cartaholic
Interesting project. I'm looking forward to see how the solar powered charging works out with the lithium batteries.
 

EzgoSun

New Member
After a trip from the carwash and into the shop, we installed a 6 inch lift kit in prep for custom 12" rims and aggressive tires. My background is more mechanical so we worked on that first.The floor mat was removed to find 3/4" of clay mud under it over the years and the floorpan rusted.
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Paint it or replace it. ??? Replaced it with aluminum diamond plate. (Then would get the mat back in place)
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From the looks of the battery frames they are rusted and corroded but serviceable.
Next would be a hitch to pull wagons around...
What to do with the steel pickup bed on the back? The piano hinge is so weathered and rusted it won't open. Soaked it in PartsBlaster penetrating oil for days. At last broke it loose.
What if it tilted to dump stuff from it?
 

EzgoSun

New Member
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Hinge fabrication

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Latch fabrication

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lift spring struts to raise once handle releases the latch. Rebuilt the frame from 3/4" x 1.5" rectangular tubing. You have to put considerable weight on the bed to push it back down to latch. Rubber bumpers keep it from rattling. Too you can see the new wheels and aggressive tires from the stock ones. Two weeks later of fabrication trial and error, the bed project was mounted and primed. ( I tried to post a operation video without success )
 

EzgoSun

New Member
From Loyd-ss

"Hey EZGoSun,
Sounds like a great project and the solar charger will be the icing on the cake. The records from my cart showed an average consumption of 135 watt hours per mile.

( this is very Encouraging Loyd-ss!! , I thought it would do well , but didn't have a clue on consumption numbers)

If you can get 5 hours of sunshine a day ( don't know where you live so might be way off) that could be 1740 watt hours per-day (5 hrs x 435 watts x .80 efficiency) or almost 13 miles a day. Sounds darn good.

These would be conservative hrs for my region, maybe even winter hours here.

Does the solar panel feed into its own combo control box and battery charger?

Yes, I have selected a nominal 48v output , 100V max solar input, 20A Victron Mppt charge controller This controller is to have Bluetooth to connect to my phone.

I am assuming that it will put out the correct voltage for the battery modules to charge the batteries directly?

Yes will have options to customize battery charge settings

Monitor the first charging cycle carefully, but first verify that all cells start out at the same voltage. There are 4 cells in each module, set up as 2 in-series cells connected in parallel to 2 more cells in series. Recommended max charging voltage per cell is 4.05 vdc, or 8.1 vdc per module. If they are uneven, top them up (or discharge any that are overcharged). The reason it is such a big deal to keep the voltages even is because these batteries get permanently damaged if outside their operating range of 8.14 VDC max per module and 7.0 vdc minimum. Since your solar charger will be putting out up to 9 amps at 48v (maybe) it will need to be monitored by you, or a BMS.

Ultimately by BMS , yet I have not ordered that yet. I haven't been able to get time to determine how I will mount the 7 Nissan Leaf G2 modules. The BMS I was looking at during Battery purchase may not fit if battery modules are not all secured together . Work and obligations take precedence. winter weather is not as comfortable in the shop.

The charge and discharge curve of these batteries is very flat in the middle operating range (50 volts to 56 volts), so you need to closely monitor the first charge or 2, till you get confidence in the design.
Good deal!
Please keep us informed!

Started a new thread at last.

Lloyd"
 

EzgoSun

New Member
Well as I jump ahead in progres the cart is now a 48v system, the wiring, motor, controller, soeinoid, Reverse / Forward all upgraded to 2014 vintage. The old wiring was well old, and brittle. This project needed to be reliable.
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All that was left was key switch, buzzer, throttle pedal.
I had hoped I would make up a pigtail, to go from old throttle plug to new controller 4 wire connector, yet have been unable located the matching connectors
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