I'm guessing the pro would also disconnect the positive cable as well?

 

I am having trouble deleting this redundant message! Pressed edit, delete, and the second delete button – and the message is still here! You might want to ignore it! One could cut the plastic tray with hand tools. No adapter is needed. I bought a used tray on ebay. I forgot what is cost but I'm think $15 or so with free shipping or shipping for maybe about $5. I think a new one is about $45. Get it from local Honda dealer and there is no shipping cost. Just sales tax. Bought a new Fit in april 2015, Battery was starting to become borderline by Nov 2021. So to make sure I would get thru the winter of 2021-2022 I bought a new battery around Oct of 2021. 51R at Home Depot was about $120 plus tax and core charge. I strongly advise checking the manufacturing date of the battery. It is always on the battery somewhere. It may be in code. I'd say any battery that is less than a year old should be ok. I think mine was about 9 months old. I checked the voltage before putting it in the car. It was approx 12 v as expected. Then I checked the voltage while starting the car and saw that it didn't drop below about 10.5, which is good. Didn't lose much power while sitting idle at the Home Depot store. Old battery dropped to about 8.5 volts when the car was started. I think the spec for an acceptable battery is 9 volts but don't quote me on that. A year and a 4 months later and battery is still working.

I haven't tried cutting the original tray. You could probably dispense with a tray altogether as new batteries are made out of plastic and usually do not leak (battery acid on painted metal is not good). I'm guessing you could cut the tray with hand tools, a fine-tooth wood saw, a coarse tooth hacksaw, or even sheet metal snippers.