Okay, so I'll admit up front that I made a stupid mistake by forgetting to do something I new better than.
So, I left my Lowrance sounder hooked up during the early fall and it drained my house battery on my boat. It takes a little draw all the time, even when turned off, and I forgot to disconnect it. When I pulled the batteries back just before the first snow I went to top them up and found it was dead. The starting battery is fine but the other is ruined. I tried to charge it but it was drained too far down. Then the charger I have, supposed to be a good one, boiled it when it wouldn't take a charge. Supposedly this isn't odd as it was really drained. The batteries I have are both Optima Blue Tops 34M. Way to expensive for my tastes.
So for my question. I know you are supposed to match batteries so they aren't draining one another. But a new 34M is $225. I can get a D34M at Costco for $160. They differ just a little but I don't want to match it up if its a problem. The specs can be seen here....http://www.optimabatteries.com/optim...etop/specs.php I know there can be some problems with matching batts with different specs, but then it sounds an awful lot like a tire salesman telling you to get a matched set. So my questions is, does the Perko switch isolate the batteries from one another? I realize in the "Both" position it doesn't, but what about the others? Is it that big of a deal to buy these two batteries that are just a bit different? What are the costs to matching these two batts up? Any other suggestions?
Also, is there a way to isolate the sounder so it won't draw power? I don't want to have to keep unplugging it or I may forget again.