[gsmith191145]

I currently have a 96 VDC system with a curtis 1231C controller and a Prestolite MTC 4001 Series Wound DC 20 hp motor, lester 96VDC charger.

I plan on adding 4 additional 6VDC 232aH batteries under the back seat of my car. I am adding the same brand and model of batteries. Also my current batteries are only a month old.

question 1. Should I series or parallel them? To my understanding the motor and controller will do up to 144 volts with no issues.

Question 2. How much range will I gain by adding these batteries?

Question 3. How will this effect the charger? Will i need a new charger if I parallel them?

 

[Ziggythewiz]

You'll want to add them in series; these are the same size and type as the ones you already have, correct? How long have you been running at 96V?

You're adding 24V to 96V, so you can expect a 25% boost to your current range.

 

[MN Driver]

Not quite 25% boost to the range since lead-acid is so heavy it will take more energy to get moving and waste more energy through the brakes when stopping and a small amount of extra rolling resistance. You would want to series them, again you only want to add more if they are the same batteries as you already have installed. You need to consider all of your high voltage components, the charger needs to be a higher voltage charger, DC-DC needs to handle it, etc.

There are also issues with adding cells that aren't substantially the same age, so if your pack isn't very new it might cause issues as far as balance goes with lead-acid. If you are within a year of battery replacement in the first place I'd hang on to the ones you have and change them all out when the time comes. I support lithium though as it doesn't require replacement, is more efficient and is much lighter.