Can I use 2 batteries on a golf cart?

[drpanda]

HELP! Of course I put off my mutant vehicle till the last minute so I am stressing out. So I have a gas golf cart. Last year, I had (2) 6v cart batteries (Trojan 105) that I wired up to make a 12 v battery. I used that to power up my LED strips, but I was always stressing out about them going dead and them charging then again during the day.

This year, I thought that I would wire them up in parallel, and hook them up to the existing 12 volt battery and starter/alternator in the golf cart, so that they would always be charging when the cart is running. As I understand it, I would simply have 3 batteries that are putting out 12v. I was wondering if this would put too much of a load on the alternator? Or does it not matter, since it is only a really big 12v battery? Thoughts?

Thanks for the help!

[FIGJAM]

It will work, but when you charge multiple batteries from one source it's better if they are a matched set.

[Captain Goddammit]

I'm not 100% clear on what you're saying.
If you keep the 6V batteries in series to make a 12V battery, then wire that 12V in parallel with the golf cart's system, you'll be fine.
The only thing to watch out for is if your lights use more power than the cart's alternator produces. If you have everything connected together, you could kill all your batteries at the same time, including your starting battery.

[drpanda]

If you keep the 6V batteries in series to make a 12V battery, then wire that 12V in parallel with the golf cart's system, you'll be fine. The only thing to watch out for is if your lights use more power than the cart's alternator produces. If you have everything connected together, you could kill all your batteries at the same time, including your starting battery.

Thanks for this comment. Yes.. the (2) 6V trojan batteries will be in the footwell of the cart in the back seat. I wanted to run wires in parallel to the cart battery. I am wondering, basically creating 1 big 12v battery, the entire batter would discharge all at the same time, so I really just need to make sure that there is enough charge to start the cart if it starts getting low. Is that correct? Is there any concern about putting too much load on the starter/ alternator? Or overheating? I don't want to start an electrical fire by doing anything wrong

[Captain Goddammit]

The alternator will only put out what it can, although if you are making it run at full output constantly it could get hot, which isn't good.
I like to set up M/V electric systems so that the power generation, at playa idle speed, is equal to or greater than the electric load. It's obviously too late to change anything now, so if your load is greater than your alternator can keep up with, the way I'd manage it would be to watch the voltage with a meter; when it gets low, shut off your lights and let it run and charge before shutting the motor off.
If you put in a battery cut-off switch, or can easily yank off a battery terminal, you could also disconnect the pair of 6Vs from the start battery if you just want to get the start battery charged back up quickly.

[skippy3k]

If you put in a battery cut-off switch, or can easily yank off a battery terminal, you could also disconnect the pair of 6Vs from the start battery if you just want to get the start battery charged back up quickly.

I did something similar to this. I also have 2 Trojan 6 volts wired together, along with a regular 12 volt battery in my MV. I have all of my LED's running off of the Trojans, leaving the 12v battery for the stereo, starter and whatever else the car needs to run. I put a battery cut-off switch in between the two battery "circuits", if you will. This gave me some options. If, for some reason, my alternator can't keep up with the load running all of the LED's at night, I can isolate the Trojan's from the alternator and let the LED's run straight from them. Then, during the day, I flip the cut-off switch back so the alternator is charging the Trojans.

[tink2011]

Well, I'm leaving for the playa tomorrow, so it's too late to run a connection from my MV 6-volts run in series to my starter battery with a shut off switch. Wish I'd thought of that sooner! This will be my first year with the 6 volts (Trojan 125s with 240ah) and with a load of 18 amps of LEDs (or total of 22 amps if I also run the underbody CCFLs). I'm REALLY hoping that I'm able to stay lit for at least 4 hours. I've used the online battery load calculators and it says I'll be okay. Dr. Panda, in years past how many amps of LEDs were you running and how long were you able to stay lit? I bought a marine 30amp charger that I'll use daily with my Honda 2000 gennie. HOPING THIS ALL WORKS! Any advice or a quick way I can also run everything to my starter battery (a new O'Riellys starter battery, not matching the Trojans)...Should I do this? How much will it help?

[tink2011]

I have heard it's a BIG NO-NO to run flooded batteries (Trojans) to an AGM battery (starter) even in parallel. Has anyone found this to be an issue? Also, If my switches and LED hook-ups are all run to my 6v Trojan series, is it okay to run to the starter battery? I assume the LEDs will all take what they need from the entire parallel system?

[Captain Goddammit]

Well, I'm leaving for the playa tomorrow, so it's too late to run a connection from my MV 6-volts run in series to my starter battery with a shut off switch. Wish I'd thought of that sooner!

You could just use a set of jumper cables.

[EspressoDude]

Well, I'm leaving for the playa tomorrow, so it's too late to run a connection from my MV 6-volts run in series to my starter battery with a shut off switch. Wish I'd thought of that sooner!

You could just use a set of jumper cables.

and CAPT. scores another 100 points !!

just don't let them short out