Originally Posted by
goose
Well, the battery switch and recommended switch location has been a point of controversy over the years and internally we probably all don't see it the same way. The most conservative approach is to recommend the consumer leave the switch in the 1 or 2 position. IF you do that, and IF you charge your batteries often, then IF you were to be sitting on the lake all day listening to the stereo and the battery went dead, then you could theoretically switch it to the other battery, start your engine and go merrily on your way.
However, what I have found is most consumers do NOT charge their batteries often. And many consumers leave the switch in 1 position forever, never turning it off. If you leave the switch in the 1 position, then you would never be charging the 2nd battery as the alternator is completely separated from the 2nd battery. If you left it that all way all season without charging it, it is likely that if you ever did need the 2nd battery, it might be dead. In addition to that, running the engine and all accessories off 1 battery only will draw that battery down very quickly. Then discharging and charging that one battery often will then make that battery fail prematurely. Worst case is you end up having 1 battery that dies premature or doesn't hold a change very long, only to find out the other battery is also dead from not being charged.
That is why I personally always run my battery switch in both and charge often. One of the highest premature failures of deep cycle batteries is not charging them often enough or leaving them in a lower voltage situation for long times. In addition to that as I said before, if you are in the both position, then you have a true dual battery bank and it will not draw down your voltage near as quick when running ballast or stereo. In addition to that, the alternator will always be charging BOTH batteries when switch is in both. Granted, it can charge one battery at a time faster than 2, but I currently trailer my boat and I almost always end up having a decent run back to the dock at the end of the day when I am finished. Running the boat at a higher RPM increases the alternator output and seems to do a decent job of recharging the batteries. And like I said, we try and plug up the R&D boats very regularly which again tops off the charge to the batteries.
As a side note, I personally think some of the low voltage codes seen in some of the newer boats are also because most people are running the battery switch in 1 position and not charging the batteries enough. If you were to fill the ballast for 15 minutes, while listening to the stereo with key off, I could definitely see the one battery getting into the 11 volts or less range. That is when we start seeing "low voltage" and this amplifies the possibility of seeing the O2 sensor codes when you start back up. That is another reason we changed the 2018 ballast to only filling when the engine is running. While some people may not like it, with the 6 pumps running, it can drain the battery fairly quickly, especially with the battery in 1 position and key off. IF you do decide to run with the battery switch in "both" but want to sit and listen to the stereo for long times, then you can still move the switch to 1 battery only while you are sitting there. If you did that, then you would probably have a good backup battery if you run the 1 battery dead. Just remember to switch it back to both after you get started and then recharge the battery when you get home.
Hope that makes sense. Sorry about change in topic, but thought it might be helpful as some of you might want to try running the battery in the "both" switch and I hope that everyone will try and charge the batteries more often. Trust me, it will help!
