Newbie battery question

[markallen]

HI Gang,

I'm a first time boat owner ('92 Trophy 2159) and am curious what is the proper way to charge the two batteries using the alternator while the boat is under power.

The battery switch has: Off > Battery 1 > Battery 2 > Both.

I understand the two batteries are isolated from each other so there is redundancy, but when running the boat and I want to make sure they are both charged, do I position the switch to "Both" or toggle between "Battery 1" and "Battery 2"?

Thanks in advance for the help and I apologize for such a dumb question.

Cheers,

Mark

 

[tpenfield]

'BOTH' will connect the 2 batteries and charge them while running.

When you anchor and using electronics, etc. it is a good practice to switch to one of the batteries (#1 or #2) so you don't drain 'BOTH'.

 

[sam am I]

Charging batteries in parallel isn't always best practice either on the bench in the garage or even in the boat due to slight difference due to age, type/makeup or even a slight difference of connection resistance to name a few factors............That said, when I just ran a perko switch, I'd always start on my start battery #1, run for 5 or 10, typically enough time to be back at 14VDC, then switch over to #2 (while still running) allowing for the alt to charge #2 all by itself and thus allowing it to draw exactly what it required. At the point where #2 was at 14VDC more or less and equal to #1, if so desired, while still running, go back to #1. Never really used "both" (parallel)much ever.........Worked out best for my needs anyway.

 

[markallen]

Thanks guys. This makes perfect sense now.

Cheers,
Mark