Going from (6) 6 volt batteries to (3) 12 volt

[scottyb]

You are probably safest with automotive chargers. It's not necessary to disconnect the batteries to recharge them when using 3 separate chargers. Chargers only 'see' what is between their leads, not the batteries to the left and right of them.
You can put a 12v charger on each battery and recharge them separately without having to disconnect anything.
Do your cranking batteries a favor and recharge often. Keep the discharge shallow and the charge quickly after use for the best results.

[reinman88]

Thanks.

That will make it a lot easier if we don't have to unhook anything.

As for use it will be minimal. Mostly just run it around the place some to make sure things work properly, and let the kids enjoy themselves a bit going up and down the driveway.

Scotty, one charger has 3 setting, trickle, normal, or boost which charges in an hour or so. Would it make a difference if we used that charger on boost and gave each battery an hour or so of quick charge, rather then set 3 chargers up for a normal charge?

[Andy4639]

As you stated you could use the 36 volt charger just don't leave it on them and walk away for the night. Keep a eye on them and check the voltage readings as they charge. If at anytime while you are charging them they feel hot cut them off.
I personally wouldn't use the boost charge on the 12 volt charger. I'd use the regular setting.

[gornoman]

Originally Posted by Andy4639

I personally wouldn't use the boost charge on the 12 volt charger. I'd use the regular setting.

Agreed. Boost setting on an automotive charger could be 75 amps, which could lead to BOOM!

[reinman88]

Sounds good we'll just set them for a normal charge. Hopefully they won't be used much before we go with 6 volt batteries, so there shouldn't be too much charging that will need to be done.

[lewy44]

What is a battery? Better yet, what is a lead-acid battery. The individual cells in a lead-acid battery have a nominal output voltage of 2.1 volts. A 6 volt battery is composed of 3 individual cells in one case for a total of 6.3 volts. This is why a 6 volt battery will have 3 individual filler caps. Internal to the battery case are connections between each of the cells, positive to negative all wired in series. Similarly an 8 volt battery will have 4 fillers and a 12 volt battery 6 fillers. Concievably battery manufactures could build 36 volt or 48 volt batteries by adding more cells for golf cart application, however a single large battery would get very heavy to handle.
The individual cells of a battery are built with special characteristics to comply with the intended use. A typical automotive battery is designed for very high current delivery to drive powerful electric motor which start internal combustion engines. A deep cycle battery, perhaps labeled a marine or golf cart battery, is designed to provide a lesser amount of current over an extended time.
Internally a fully charged lead-acid battery is nothing more that two plates of lead submerged sulfuric acid. As a load is placed and current is drawn from a battery, a chemical process takes place inside the battery. The sulfer from the acid combines with the lead on one of the plates forming lead sufate. The liquid remaining without the sulfate becomes water. When the battery is completely discharged all of the sulfuric acid is now water and the lead is lead sulfate. Charging the battery is nothing more than returning energy to the battery and the process is reversed. The sulfer from the lead sulfate returns to the water forming sulfuric acid and leaving pure lead behind.
The amount of energy that is contained in a battery is proportional to the amount of lead and sulfuric acid in a battery. Thus a larger and heavier battery will generally have more amp/hour capacity and handle larger electrical demands.
Amp/hour capacity is just as it implies. Amps per hour. A 10 amp/hour battery will therotically produce 1 amp of power for 10 hours, 10 amps of power for 1 hour, or any multiple. The new CCA (cold cranking amps) rating is a little harder to understand. Since the chemical process described above slows down in cold weather, manufactures have decided to use this measuring method. Realistically the number doesn't apply well to golf carts or marine usage as CCA is a method of calculating maximum power for starting at cold temperatures. Still a larger CCA number indicates the battery will operate a golf cart longer as it will have more amp/hour capacity.
A typical automotive battery is designed for maximum lead plate exposure to provide maximum chemical reaction and potential rapid discharge as during engine starting. A deep cycle battery is designed such that the plates are capable of enduring the complete conversion of lead to leadsulfate and sulfuric acid to plain water and back again over and over. Either battery perform the same process, however each is designed for the intended application.
So, what is the difference between 6 volt and 12 volt batteries? Technically a 6 volt battery has 3 individual cells and a 12 volt battery has 6 individual cells. If you were to connect 2 six volt batteries in series that had 100 amp/hour ratings, you would have exactly the same power capability as a 12 volt 100 amp hour battery.
So, why do some manufactures use 6 volt batteries, other use 8 volt, and other use 12 volt? Realistically it makes no difference other than the configuration they selected to physically fit into the golf cart and the motor voltage requirements.
So, what battery to use in a gasoline powered golf cart? Either battery type should work fine. Golf carts have small engins and do not require high cranking curents typically required of automotive applications. The deep discharge disign of a deep cycle battery are a moot point as the engine should keep the battery charged.
Find a battery configuration that meets your needs. A set of good condition golf cart batteries should take you atleast 20 miles before needing recharging. If you elect to save on batteries, surely you will want to consider deep cycle batteries. you may have to charge them more frequently. Deep cycle batteries are typically similarly priced to automotive batteries of the same size. Afterall you are buying lead and acid with a little plastic to contain the elements.

[Andy4639]

Thank you lewy44 for that great battery analysis.

[reinman88]

Somewhere right now there is someone trying to figure out how many AA batteries it would take to run a cart.

[todo_brane_ded]

Excellent info lewy44

You're right in saying that cart manufacture's dictate the use of a battery for physical fit, and the primary design element is "real estate" under the seat ....

Likewise, I believe that battery manufacture's can make a larger capacity battery (in amp/hours), given the same physical case size (Volume- LxWxH) in a three cell configuration than in a 4 cell or 6 cell configuration......so there are some trades going on between battery voltage, "real estate" and amp/hour capacity of the batteries used in a cart design that ultimately relates to the cart's speed and range.

[wizardket]

Originally Posted by reinman88

Somewhere right now there is someone trying to figure out how many AA batteries it would take to run a cart.

I like my 2300 mAh Nickel-Metal-Hydride rechargeable AA. I use 40 banks in series of 100 batteries connected in parallel for a pack of 48v @ 230 Ah. At only $9 for 4 batteries it is only $9,000, what a deal!

I need to get a better charger though as the one I have only charges 4 at a time and this takes a while and I lose track of where I am at.