Mixing Batteries?

Hi! I’m ready to go with my EV, but I just need to buy batteries. I decided to use Optima Yellow Tops, but I had one question: Is it bad to mix batteries with different AH ratings, or does the AH just get combined? My logic tells me that the lower AH batteries will drain out first, which means I lose 12v each time that happens. Is that right, or do they all drain evenly somehow? The reason I ask is because it’s much cheaper to buy on ebay or craigslist, and you can get good deals from time to time… But even though they’re all Optima Yellows, slightly different models have different AH ratings! Thanks for your help!

you SHOULD match batteries. But realize, that they all will discharge at the same rate, and when one runs out of juice, the whole pack is weak. That is if they are in series.

Your battery pack is only as good as the weakest battery.

Thanks for that… I kinda thought that would be the case. I’m just going to bite the bullet and go buy matching batteries. Thanks again for your help!