Brew Do you particularly want an on board charger? Pretty much any automotive charger will do the job for half that. The relationship you are looking for is between the battery and charger not motor and charger. Motor doesn't care what charger you use,, battery does. maybe something like this.
https://www.walmart.com/ip/STANLEY-15-Amp-Battery-Charger-with-40-Amp-Engine-Start-BC15BS/38243759

Academy has good prices as well.

There are four different kinds of lead acid batteries, and the best charger depends upon which of those you are using and the size or capacity of the battery. All lead acid batteries lose capacity to some degree if they are not charged ASAP, even after very light use, and die pretty quickly- if you drain them down to zero.

Cheapest lead acid battery is a car battery, which is damaged by deep discharge and may only work 30 times or less if you go below half (50%)of discharge capacity. A cheap car battery charger that charges at 10% of capacity will take about 10 hours for recharge, where is an expensive car battery charger might do it in 4 hours (if using 15 amps charger on a 50 amp hour battery) and the expensive charger might also provide a small trickle charge to keep the battery up. Not a bad battery choice if you only go out four times a year during holidays, but the battery shelf life may only be about 5 years even if it's properly maintained and never used. A marine battery is mostly like a car battery for starting boat engines but it might do a little bit better in deep discharges.

A deep cycle lead acid battery will last longer then a car battery if everything is done correctly and it is charged with a deep-cycle charger instead of a car battery charger. It can be drained down lower to around 20% and last for 200 or so recharges, if everything is done correctly. More expensive than the same size car battery.

A SLA gel lead acid battery is a deep cycle that uses a gel instead of liquids inside the battery compartment and it must be slowly charged over a long period of time with a gel battery charger. Similar to the deep cycle in longevity and characteristics. Most expensive of all lead acid batteries for the same size.

The AGM lead acid battery has a special separator for the gel liquids inside the battery compartment and last longer then all the others , if it is charged with an AGM charger. Best performance of all lead acid batteries, but 2nd most expensive.

Any particular charger can charge any of the other batteries, but may shorten the lifespan, sometimes a little and sometimes a lot. Just a rough overview for batteries from my experience of over 50 years, plus I also worked as a chemist before I retired.

30 lb thrust is plenty. A 55 lb trust is overkill and will use a lot more battery than a 30 lb thrust will. On a battery I personally don't care for lugging around a 65 lb battery and would go with lithium but they are pricey. In terms of SLA's I've had excellent results with Mighty Max batteries.

I got an Enduro, like grainraiser. They are inexpensive. Now, I use blue top gel cells (pricey) and a smart charger (also pricey). Here is the deal though...those blue tops cost a lot to purchase, but they seem to last forever, and they can be run down to 0 charge, without damage. Most wet cell batteries, will die if run down below 50 per cent charge very much. So, over a long period of time, it is usually the cheapest route available. Get batteries with 120 minutes of reserv capacity, if possible. Basically, I got tired of replacing batteries all the time, so I went the gel cell route.