Originally Posted by Diesel
The only issue I have with not isolating a parallel set of batteries is the continous voltage flow between the batteries. This is a non-issue in most vehicles (including diesels) because they are driven frequently. As a result the alternator has an opportunity to keep both batteries at full voltage to minimize discharge between the two batteries. Since a boat is not driven every day two batteries stored in parallel will eventually destroy each other.
In addition it is easy to see why you have never drained the two batteries since your stereo is only pulling two amps
. At 90% my current system will pull 165 amps
. I can drain two brand new optima blue tops in 3 hours very easily.
As a result, isolation not only give me the security of knowing I can make it back to the dock but it also gives me the security of knowing the two batteries are not going to kill themselves.
I think he may have meant 2 amplifiers. Maybe not, just my thinking. At any rate, thanks for the write-up Diesel! I am wanting to add a battery, this will come in very handy.