Which Voltage of Battery to Choose

by Jeffrey
(Kamloops, BC)

Bank of Batteries: In Trojan We Trust

Bank of Batteries: In Trojan We Trust

What difference does battery size make...I mean, as in different voltages? I've seen 6 volt, 8 volt, and 12 volt batteries for sale, and is it merely a matter of preference as to which battery size to get, or are some of them better for different motor/controller configurations?


Hi, Jeffrey -

Did you really think I was gonna tell you size doesn't matter?

As a matter of fact, I noticed there's a relationship between voltage, range, and whether the system is AC or DC.

Here are my observations, for what they're worth:

6 volt golf cart batteries, like the T-105, last a long time, are cheap, and give good range...but they tend to be heavy. These are most commonly used in simple DC conversions.

8 volt golf cart batteries, like the T-875, are also most often used in DC conversions, and are best in situations where you need to lighten your load; they'll take a couple hundred pounds off your battery pack.

12 volt golf cart batteries, like the Optima yellow top, work best in those lovely AC conversions. I think because the rate of amp withdrawal is less with an AC system than just the semi-civilized, torque-happy muscle of a DC motor (but that's just my own impression, I can't show you the physics; ).

Regards,
Lynne

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Rating
starstarstarstarstar 		Batteries must be matched.
by: Roy

It does not matter how many batteries are connected in series to get your desired total voltage. If you need 48 volts you can use 8 6volt, 6 8volt, or 4 12volt. What does matter is that all batteries are identical. Mis-matched batteries will have different charge/discharge characteristics that will lead to problems over time.
Rating
starstarstarstarstar 		Battery configeration
by: gary

so, using 6, 6V is a longer lasting set-up then 3, 12V for a 36V system
Rating
starstarstarstarstar 		Battery vs CELLS
by: Anonymous

This stuff on battery voltage is a lot of hooey.
Everyone should be thinking cells.
The basic component of a battery is a cell.
A cell is composed of an anode and cathode or positive and negative plates. More plates in parallel yield more capacity ie amp hour. Cells connected in series multiply the cell voltage (commonly 2.1 VDC per cell).

So what this all comes down to is yes you need to look at the
1. ampacity (maximum current) battery can supply for a very short time.
2. Amp hours - how long battery can supply X current for Y hours.
3. Kw Hrs how much power you can pull out of battery over Y time. The reason for this is that motor amps times the same time frame should be equal or less than battery Kw hrs.

So If I had to pick only one value for a battery of XX cells it would be Kw hr. Actually you can almost buy them based on weight since weight of battery = total weight of pos and neg plates. Kw Hr sounds more scientific though.

Just thoughts of former submarine electrician (5,000 AH 250 VDC 126 cell battery)

Dan Bentler
Rating
starstar 		Not Sure that Answered the ??s
by: Craig

I don't claim to know the answer either and have the same question only a slight difference in how I would say it. Is there a real determining factor in the selection of a 6, 8, 12 volt battery setup other than cost and size/weight constraints to the donor vehicle? If all other things being equal; is a 6V, 8V or 12V better than the other of the same total voltage?

Cycle life.
The 6v will give you the most miles for your money.
-Lynne

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