I like the BLueseas Mini 6007m series switch way more than Guest or Perko brands.
http://www.amazon.com/Blue-Sea-Systems-m-Series-Selector/dp/B015ZPJL7MThe Studs on back are still thick with a lot of threads for multiple Lugs, and they are rated at very high continuous amperage and their small size opened up my electrical wall.
I actually use three of these switches. One for switching all stock vehicle loads, one for house loads, and one for the Solar, so that I can easily choose either battery for either duty.
But for the last 4.5 months, I've only had one battery, and all 3 switches are set to 2, which is my Northstar group27 AGM battery, and I've never come close to not being able to start my engine, even when I took 60 of the 90 Available AH from it.
It can pull over 100 amps from my 120 amp alternator when depleted this much, and it appears to love these extreme charging amps. They key is to charge it fully every day and not partial state of charge cycling of it.
Alternator + 200 watts of Solar makes it happy. When I don't drive and can plug in, a Meanwell RSP-500-15 adjustable voltage power supply can dump 40 amps into it and then hold 14.46v for as long as it takes amps to taper to 0.42a.
A fully charged battery is a happy battery.
