How to convert a 36 volt golf cart from 6 to 3 batteries

[enzo1]

Anyone done this? My 6 volt batteries are toast, can u substitute (3) 12 volt batteries. What about amps? eHow | How To Do Just About Everything! | How To Videos & Articles | eHow.com

[9dreizig]

Should be easy, if they are running 36 volts now that means they are hooked up in series.. You will do the same with 3 12V batteries.. Pos to neg in progression. same voltage and ultimately probably lot's more current capability

[ben parrish]

Standard car batteries will not have enough reserve capacity to keep the cart going very long.

[James Brown]

won't go 18 holes but will put around for a long time. I do this at the airport, have 3 carts all running 3 cheap auto batteries each. there fine to get around the ramp and always plug in when idle. I even tow Cessna's with them!

[mikester]

So long as your amperage on the 12v batteries is equal to or better than the 6v batteries then you should be fine.

So, if you had 6 - 6v, 10amp batteries you would need to replace it with 3, 12v 20amp batteries. Since you are not increasing the voltage you don't need to add amps to maintain the life of a charge (when you increase voltage to a given system you also increase its amp draw). If you were to actually decrease the voltage your amp draw would go down (not saying you should).

comprende?

[Grady Clay]

Been there, done that (in my ‘evil’ youth).

The problem comes with the speed control.
If you have a 36V solid-state speed control, it doesn’t care if it has six 6 V or three 12 V.

Post the wiring diagram or a link.



My challenge (in 1963) was I had four 6 V batteries and a 12 V motor.
Control was 6 V (all batteries in parallel) to the 12 V motor for ‘low’ speed.
‘High(er)’ speed was with each pair of batteries in parallel and the two ‘doubles’ in series for 12 V to the 12 V motor.
Control was by several 6 V relays (contactors).

Well this wasn’t fast enough for me to navigate the GE Appliance Park (nine 1,000,000+ sf buildings) at 3 AM.

‘Simple’, I rewired it for 12 V to the 12 V motor on ‘low’ and 24 V to the 12 V motor on ‘FAST’.
I just had to be careful to not pass any ‘suit’ too fast.

More to the story.

The contacts in these relays were serviceable.
Needless to say, I went through contacts.
The problem was they were pure silver.
The maintenance departments weren’t happy about the cost.

The ‘solution’ was to insulation wrapped refrigerator door ‘U’ magnets (plentiful supply from the refrigerator department).
Add some phenolic brackets to maintain the “Right-Hand Rule” across the contact’s opening.
Presto, no more severe contact erosion as the perpendicular magnetic field ‘blew out’ the induced arc.

The 12 V motor was so conservatively rated, it took the abuse.

When I was just about to return to Carnegie Tech, I submitted the idea as an “employee suggestion” (after re-wiring to original).
After a fancy presentation, I got one of those BIG checks for $35,000.

That was a LOT of money for a 20-year old in 1963.
I invested it.
GE saved millions.
I paid cash for my first new 911 in ’68 and an RS-60 and a 904….

Best,
Grady

[enzo1]

these are what are in there...Trojan T-105 6V, 225Ah (20Hr) Flooded Lead Acid so the 12 volt batteries need to be double that(225Ah)??I was going to put 3 optimas (yellow top) doesn't look like i'd be saving much$$$ except weight and would discharge too fast... right?

[James Brown]

What are you doing with the cart?

[enzo1]

Originally Posted by James Brown

What are you doing with the cart?

no golfing, just putting around the neighborhood... resort lake area... also use it to carry tree limbs and stuff out of the yard, etc.... those t105's are 105$ a piece plus tax

[Grady Clay]

What is the intention here?
Less cost?
Faster?
Longer battery life?
Fewer batteries (less cost)?
Lighter weight?
Other?

Here is an Interstate Battery that is probably similar to what you are using.




Best,
Grady

[enzo1]

Grady: less cost without affecting the other things...

[James Brown]

Cost was the factor for us, The 6 volt cart batteries are $600 per set and last about 2 years. The 12v ones are $150 and last on a full charge about 5 miles. Plenty for a days work. And we can plug them in when back at the office.

[jpk]

225Ah is the capacity, kind of like how much "fuel" the battery holds; 225 amp-hours. That means each battery can provide 1 amp for 225 hours, or 225 amps for 1 hour, or anything in between; like 5 amps for 45 hours.
The motor in the golf cart probably wants around 100 amps at full load, so the run time on a fully charged set of fresh batteries would be around 2 hours and 15 min.
Good 12v marine deep cycle batteries are rated at about 120 amp-hours these days, so if you used 3 of those, you'd have a bit better than 1/2 the range or around 1 hour 12 min run time.
I'm really simplifying things here, but that's the jist of it.
You want to stick with deep cycle batteries as they are much better at resisting plate sulfation which happens when you run a lead-acid battery down to low charge levels.
Check out Costco or Sams; Last time I looked they had the group 27 size deep cycle marine batteries for around $80ish

[enzo1]

thanks for the replies, I get it now...

[ben parrish]

JPK has good advice. If you keep any lead/acid battery from getting down below 50%, you will greatly increase it's life span.
When I had our sailboat, I relied on two 8D's and three deep cycle marine batteries for the "house"; there was a seperate, isolated crank battery. I had the microwave via the inverter ran to the 3 "trolling" batteries due to the extreme load placed on them by the microwave and other high usage items. The 8D's were for all the lights, fridge/freezer, fresh water pumps, radios, etc. The 8d's would rarely get below 50% but the trolling batteries would often get to 30%....end result was the trolling batteries were toast in about two years. The 8d's lasted about 4 years.
Keep em' charged regardless of the way you go.

[Joeaksa]

Originally Posted by Grady Clay

Been there, done that (in my ‘evil’ youth).

That was a LOT of money for a 20-year old in 1963.
I invested it.
GE saved millions.
I paid cash for my first new 911 in ’68 and an RS-60 and a 904….

Best,
Grady

Why does this not surprise me one bit! Excellent work Grady!

Wish you were a bit closer as I have about 40 of those 225 Trojan batteries in my back yard. I use them for my solar system and have a good source on getting them used from contractors. They usually have good half life left in them and I pay $20 a piece for them.

[nota]

Originally Posted by mikester

So long as your amperage on the 12v batteries is equal to or better than the 6v batteries then you should be fine.

So, if you had 6 - 6v, 10amp batteries you would need to replace it with 3, 12v 20amp batteries. Since you are not increasing the voltage you don't need to add amps to maintain the life of a charge (when you increase voltage to a given system you also increase its amp draw). If you were to actually decrease the voltage your amp draw would go down (not saying you should).

comprende?

NO comprende at all

volts times amps = watts [with volts = pressure, amps flow,
and watts = work done

so if you increase volts you need LESS AMPS NOT MORE to do the same work
and less volts needs MORE AMPS to do the same work

the V x A = W must stay in balance


I would buy 3 truck sized D8 battery if you want the range to be = to the 6 6volt
but they are huge heavy and costly
but cheap vs ni-cad or Li battery

[9dreizig]

hey Nota , what's the penalty for violating Ohms law?

[nota]

all the smoke comes out of your el-tricks stuff

[red-beard]

How big is the area for the batteries? Interstate sells lots of deep cycle batteries, under a lot of different names. I picked up some 12V 250Ah batteries for around $400 each. They are BIG. I need a lot more of them...