In an electric car, you are also charging and discharging your batteries combined in a long series-connected string. Balance becomes important here. If different batteries in the pack have voltages that vary more than a slight amount, or charge at different rates, you will damage some of the batteries and shorten the life of the whole pack.
What you need is a well-matched pack of batteries that are properly suited to the job you want them to do. This is a strong reason to avoid "bargain" and house-brand batteries. Batteries from the same outlet under the same label may actually be from different production batches, and even built by different manufacturers, and have slight but significant variations.
To compare range capacity, you need to look at the battery's amp/hour rating. This is often given at the 20 hour rate, but the 1 hour rate is more relevant to electric cars, if that number is available from the manufacturer. The more amp/hours the battery has, the more range it will give you.
Conversions generally run from 96V to 144V. They draw 100 - 150 amps while cruising, and 400 - 550 amps during acceleration. The best all-around battery for this type of conversion is the flooded lead acid 6V golf car battery. They are affordable, provide relatively long range and long cycle life (about 4 years with good care), and are durable in use.
For small cars where battery space is limited, the 8V golf car battery is the next best choice. This saves some weight and bulk in exchange for sacrificing some range capacity. But it still has much better range than a 12V battery, and the same long cycle life and durability of the 6V battery.
We recommend the U.S. Battery brand. They are a manufacturer, not merely a distributor. We have found them to have durable construction and very good performance for DC conversion. Specifically, we recommend the US-125 XC model 6V battery and the USGC8V XC.
Another advantage is that U.S. Battery will supply the "L" style posts that are preferable in conversions. These posts must be special ordered from the factory, but there is no extra charge for them. Lead time is usually only a couple of weeks. In addition, you know for a fact that your entire battery pack came from the same production run, and so is as well matched as you can get.
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|US-125 XC||6||145||242||10 1/4"||7 1/8"||10 7/8"||67 lbs.|
|US-8VGC XC||8||100||170||10 1/4"||7 1/8"||10 7/8"||64.5 lbs.|
3496 Arden Road
Hayward, CA 94545
Jim has been providing these batteries for home-built electric conversions for many years. He understands the special needs of the EV, and will be sure you get a fresh, matched pack of batteries with the RIGHT post style. His prices are very reasonable, and he can have them delivered to you almost anywhere in the country at a modest charge.