Ok, here's the situation...

I have an electric golf kart that is 36 volt. It currently takes 6 12volt 18 amp hour sealed batteries which are wired in two banks of three batteries in series to yield 36 volts each which are then wired in parallel. Wired as such, what is the amp hours of this configuration?

These things currently need replacing and I'm wondering if I couldn't replace these with three 12 volt car batteries wired in series? And if so, what would the difference in amp hours be? Automotive batteries don't show "amp hours" per se but I imagine the "reserve" would play into the longevity of a charge.

Are you sure you have those amp hours right? 18 amp hours isn't much, wired the way they are it would be 36 amp hours. A standard 6 volt golf cart battery is 225 amp hours in most cases.

If indeed your amp hours are right and you have room for 3 12 volt marine batteries it would be a good upgrade, a 12 volt marine battery is usually 50-70AH for the smaller group 24 size. So it would be an upgrade. But I am afraid this is either a really small golf cart, or you are reading your batteries wrong.

If you dig you can find the amp hr ratings of a car battery. I had to do that for my BMW, since BMW codes the battery by Ah ratings and when you put in a new battery you have to tell the computer you did and what you put in it, in Ah.

However, car batteries are a poor choice for a golf cart. You want a deep cycle battery as they are designed for deep discharge between charges whereas starting batteries are not. The life of a car battery would be shortened.

Your Ah rating of your existing setup would be 36 Ah. The math

You have three 12v 18 Ah batteries in series, that would work out to be 36v 18Ah.

Two of those in parallel is 36v 36 Ah.

https://batteryguy.com/kb/knowledge-base/connecting-batteries-in-series/

Just put a cheap lithium in it - these can be run down 100%, they save another 20AH so they dont get damaged

With my electric golf cart I had to use a special charger to get the right amps in the batteries when they ran down. Today's AGM batteries require a special charger also. LI batteries do also. Just reminding people about my garage fire that was caused by and LI battery from a drill. If you use them DO NOT charge them indoors, and I wouldn't park the cart inside either, a buddy lost his race car and trailer along with his cart...

Where was that LI battery made? China? The ones catching fire in e-bikes are from WISH

This says 22ah but in reality they are only 18ah. Takes six of these. Yes, its a small golf cart.

Already answered. Sorry.

I understand the "deep cycle" need for this application. Looking at what's out there it looks like its going to be more of a fitment issue getting three larger "deep cycle" batteries that will fit the space.

Yeah given the size of that thing you are pretty much tied to that size battery.

Golf cart Where do you hang your golf bag
Looks like a nice scooter to me, especially for the pits

I don’t golf, and I didn’t know that would be a type of golf cart. Ice chest? Cigar ashtray?

Handicap grocery cart.

are lithium iron phosphate batteries the same as lithium ion batteries ?

No. LiPo handles heat better, and has a higher cycle life. Li-on however has better energy density. There are other differences too.

I use this for large swap meets ONLY - haven't the slightest interest in golf. Here's what it looks like in "golf" configuration.

It has a small basket with spots for your beer, a scorecard holder and a rack for your bag and clubs. It also had an umbrella holder but I had already removed that.

That would work really well for me in the pits at our local drag races Small enough to store in my trailer easily and it looks like it may be light enough to move around easily in the trailer after the car is tied down
What brand and model is that?

Comparing battery types interests me. (and the related fuel cells)

Using battery powered mining vehicles,
repairing their faults, and “souping up them up” interests me,
and is potentially a life and death matter.

Flea markets, swap meets, and getting to examine old equipment designs or tools, interests me
and I will go out of my way to do this (Highway 127 yard sale).

But the old TV show phrase

“Danger, Danger Will Robinson! “

pops into my head when the discussion turns to
walking less, and riding more.

Walk more,
eat less Fructose.

Its mainly for the Carlisle events. Severe arthritis in one knee and lingering plantars faciitis in both feet can cut it short and take the enjoyment out of it pretty quick.