Keeping my car battery from going dead

[micky]

Is there a good device that disconnects the car battery when the voltage
gets too low? '

For almost 15 years I used Battery Buddy, and it worked great. IIRC the
first one lasted 13+ years, and I had prepared myself for when it broke
by buying a second one. However the second one lasted only a year. It
came in plain brown box and I think it was a 'second' that they sold off
when they ended production, and maybe went out of business.

Then I bought the consumer version of Priority Start, which it seems is
marketed largely to those with fleets of trucks, some of which may not
be driven regularly. It was much more expensive, but had the advantage
that it is reset without getting out of the driver's seat, just by
pressing the brake pedal, which puts a drain on the battery.

I've had it for 5 or 6 years, ut it wasn't installed for 3 of them, and
I had a new batter for the final year. So had only tripped 3 or 4 times
when I first installed it, and yet it's not working right. It keeps
tripping for no good reason, sometimes within seconds of being reset
(and it confuses my car radio when it does this.)

It costs about $104. Would you buy a second one in these circumstances?
Did I get a defective one?

Or is there another similar product?? (Googling didn't find anthing.)

I really wish there was another similar project. That's the biggest
reason I'm posting.

I plan to buy, tonight or tomorrow night probably, one of those small
battery jumpers*** like
https://www.amazon.com/DBPOWER-18000mAh-Portable-Starter-Charging/dp/B01D42TYFC/ref=zg_bs_318336011_2?_encoding=UTF8&psc=1&refRID=SXMBZFMB1NHTRB6FAGF0
(This onee is probably bigger than my 3.3L engine needs) But those are
more effort than Battery Buddy and Priority Start are. I'd rather have
both.

For many years I wouldn't replace my battery until it was worthless, and
at first by geting jumps from passersby and later with the help of
Battery Buddy, in one case I was able to go 5 years on a battery anyone
else would have replaced. In that case, I saved $100 afaic. Now I have a
1-year old battery, good charging system, and a car that turns off the
headlights after 30 seconds and iirc other lights after 30 minutes, but
I still like the security of knowing if I drain the battery, maybe by
parking and listening to the radio with its external amp, or charging
the cellphone while talking on it while using the radio/amp as the
speaker, it will disconnect when there is still plenty to start the car
with.

***If you have a mini battery jumper you like, I'd also appreciate a
recommendation. I like that you can power your phone even with some
small ones.

[wws]

Just put in a second battery but don't connect it until you need it.