---

Hi,
I run a 2001 Ventura 21 w Merc 200 OPTI SaltWater ( Runs Well ). Now used only in freshwater
As this boat is new to me (2021), I have had a few battery issues occur. I have 2 Group24 batteries.
Both batteries are 2 yrs old. and when charged, seem to run great. But over a weekend of use after a full charge Friday, it seems to be depleted by Sunday uses?
Last season when the weather was cold( 10 degC Ontario CDA-late OCT), even after a 3 hr trickle charge, I could not start the engine. Only after a booster was added could we get it started.

I would like some feedback or practical guidance on proper battery selection and USE.
I have the standard Perko selector. [2 | BOTH | 1 | OFF]
If you plan to run the boat all day, with radio and GPS,VHF,12v Fridge....etc. [family days]
When/do you switch from a dedicated starting batt 1 to ALL or Batt 2?
I understand Battery 1 is the Crank/Start battery(it is 1000CCA) and Battery2 is my HOUSE battery and should be a Deep Cycle(it is). I just don't know the practical situations when/how you should switch between Power Uses.

Is there any 'rule of thumb' for when to switch between batteries? Maybe a good youtube instruction recommended?
BOAT USE 1: FISHING We may fish with engine off, but listen to radio or Garmin fishfinder (I assume Batt 2 selected?)
BOAT USE 2: PLAY But we also have Ski days for 2-3 hours and radio/GPS...etc. ( Is this a BOTH circumstance?)
BOAT USE 3: RELAX Chillling at a dock(no plug in available) or sand bar-Music/12 v fridge...etc (I suspect BATT 2 only?)

The boat also sits for a few weeks at a time between uses and sometimes I will Connect a trickle charger(Noco 2.0AMP)for a few hours, the day before, to each battery independently (I don't have an ONBOARD charger -YET).
I can't seem to leave the boat on the trailer for 2-3 weeks without needing a good charge. This LOW Batt issue has killed a few planned weekend trips last season. Sometimes, BOTH has helped to start the boat, but it seems in the other forums here, that is not recommended?

This also brings me to another question for another forum (Q: BUYING A BATTERY CHARGER -Which is best option for a Dual/Triple battery sys on a small boat?
10/10-2 bank or 5/5/-2 bank? how do you choose? I was told slower charging is a 'better' charge?)