Converted 36 Volt EZGO Golf Cart to 48 Volts With 72 Volt Boost

[sinkorslim]

I recently converted a 36 volt EZGO electric golf cart to 48 volts with a 800 amp GE controller, 2 guage wires and a custom built motor. I can creep nice and get to 32 mph with 10 inch tires. its a nice setup. I am about to go to 72 volts boost on command to a switch. I'm planning to put 2 12 volt batteries behind, then direct wire 1st to solenoid then to motor directly coming from a toggle switch. Has anyone tries a setup like this?

 

[dougmcp]

A controller bypass is not that difficult but doing it with a toggle switch won't cut it, you will need a high amperage contactor.
You mentioned 10" tires, did you really mean 10" wheels?
If so there are many tire sizes available and with a stock rear gear 32mph with stock 18.5" tires will have your motor spinning over 7000 rpm.
Most motors are rated for a max of 8000 and an increase to 72v will take it over 10000 rpm and blow it up.

 

[GarageBuilt]

That sounds more like a boost than a controller by bass... Which is great... But your controller will need to be able to handle the total voltage just to be safe...I you are unable to stop the back flow of the total voltage... It will smoke your controller... If you want to run your cart on 48-volts & boost 24-volts at the flip of the switch. Then you will need a 72-volt controller..

 

[sinkorslim]

I will be goin to 14 inch rims with low profile tires. Hopefully this will help the RPM. Am i hearing this correct that i need a 72 volt controller? Will this eliminate the on command 72 volt, because that is what i was looking for? Will the 48 volt system still work thru the 72 volt controller in 48 volt mode?

 

[cwayaustx]

Yes, most 72v controllers are rated 48-72volts. It is possible to do a boost setup w/out a 72v controller but requires a combination of solenoids with diodes and resistors and is safer on your controller if it is rated for 72v. The biggest concern here is you are spinning that motor at a high rpm already. Most of the guys that are running 72v are using a torque motor or a very well built high rpm motor.

 

[spidy]

I think the biggest deal is getting batteries so figure out if you want to run 6-12v or 9-8v then get everything you need and make it happen.

 

[sinkorslim]

i have 6 ...8 volt batteries 2ohm wires 700 watt 48 volt ge controller and a very high toque 9600 rpm motors modified..my friend uses this same motor on his 72 volt system,, he gets 58 mph out of his cart...the motor will take it,,,he says 2 more 12 volt batteries to a 600 amp solenoid and a switch directly to motors to flip the system to 72 volt on command or 24 extra on command ,, i guess no matter how u shake it i will end up with 72 volts at switch...if i am bypassing it why would i have problems with power surge or even need another controller??? what am i missing

 

[Pimp Daddy]

huh??? I don't THINK that it is a good IDEA to mix 6 volt and 12 volt batteries in a pack... But then again I've been wrong before....

 

[MrWicked]

couple of things... your buddy thats is running 58 mph on 72 volt must not be running stock gears...

why dont you want to run 72 volts all the time????

if the motor is built right they can spin the rpm... our race motor is spinning over 11000 rpm but was made to handle it...

 

[GarageBuilt]

It will take a contactor to send the extra voltage around the controller & to the motor. And that is what you are missing. A contactor can weld itself shut... Leaving your cart wide open.... What are you going to do now.... Jump yah right!!!! By the time you build a safe bypass or a safe boost.. It will be cheaper to just by a 72-volt controller.... The problem these days are no one wants to do or build any thing right... they just want to go fast as cheap as they can... That way will catch up with you sooner are later.....If you are going to run a boost are bypass build it with dual main contactors & a single contactor on the minus side of the battery pack.... Plus have a knife blade breaker that can cut the power to the battery pack if all else files..... And on top of all that you will need a cool head to think fast.. I say spend your money on a 72-volt controller & have peace of mind & a safe cart.....When you weld one shut then you will understand what I am saying. Good luck !!!!!

 

[sinkorslim]

so in a nut shell...if i am gonna run an extra 24 volt boost wired directly to the proper solenoid then directly to the ge modified rapture motor,,, i need a 72 volt controller even though i am not even goin through the controller simply because of back fead?

 

[GarageBuilt]

sinkorslim..The point is i dont want to be responsible for you getting hurt... Boosting 12-volts is a cake walk... But where does it stop.. I started with boosting 36-volts... Now way past 200-volts... A few things you should know....First off if it is not done right you can blow up not only your controller but also your motor...Even a $ 300.oo contacter can & will weld itself shut... What is your back up safty plan... How will you keep the extra voltage from back washing thru your controller...

 

[sinkorslim]

i understand a contactor is not the way to go..is that correct?? a solenoid can burn out to save problems , i do understand a contactor leasves no room for error and risks total meltdown...i am really just looking for a 5 mph edge do u think a 12 volt boost would suffice, can u do just 12 volt and be safe? or do i have to go to 24 boost? if i go to just a 12 volt boost am i safer on controller?

 

[sinkorslim]

i have a 700 amp ge controller and rature motor modifiedto handle 72 volt, and since i have 6 8 volt batterries the single or double 12 volt batteries would be okay for boost??

 

[GarageBuilt]

A 72 v0lt controller would be the safest way to go hands down... Plus yes it would handly the back wash of juice going back into your controller.. But you can do the same thing with a diode.. A dioed that will stop the juce will coast you 30-50 bucks.... A good contactor will start at 75 bucks & go up... Boosting is the cheapest way of speed.. Just remember !!! You always get what you pay for.... Good luck... I know that I sound like a hipacreat... Me telling you not to boost while I boost my sons ass off with our drag carts... Just be safe & think your way through ...I will say once you get it . Boosting is a blast...

 

[sinkorslim]

thank you so much for your help... do you have a 72 volt controller layn around to sell? also can i have your contact number to call u?

 

[geolue1]

SinkorSlim cannot stand to lose to me. I whooped him pretty good! Now he wants a cheap quick fix. Get over it Slim.

 

[GarageBuilt]

This sounds like the Hatfields & Mc Coys.... You boys have fun !!!!

 

[geolue1]

Hey GB, I'm not boosting anything yet. Just using my raptor motor, 700 amp curtis, 12" rims, 8" allsport lift, on a club car. Really having fun!

 

[geolue1]

Come on Slim, bring it on bro.