Zuke 17.5
I forgot to mention that I connected the out-put of the charging unit to the battery connection of the main motor, which in turn comes off the downstream side of the switch. I also installed a quick connect plug-in type connector inside the kicker cover so that the kicker can be disconnected and removed.
Lure-washer

I am not sure you want it on both, if you don't have a charging system? You need to protect one battery for a starting battery. Once started switch the selector to the other? IMHO!

Yesterday I was talking to a fellow that we were camped beside and Darrell is a boat rebuilder and he offered the following:
1) one battery should be an RV/Marine deep cycle battery for running your downriggers and electronics and these things should be "hard wired" to this battery.
2) the other battery should be for starting your engine and as such should be bought for the high cranking amps. Could be an RV/Marine battery or a straight auto battery.
3) Don not "fish" on the "BOTH" position as both batteries are then put in parallel and the better battery will be pulled down to by the worst battery
4) The 1-BOTH-2 is really just switching which battery you want to select to start your engine (the electronics/downriggers are already hardwired to the one battery). However, should this battery go low, then you could switch the BOTH position to wind up your downriggers.
5) After starting the engine, occasionally switch between batteries or go to BOTH to recharge the batteries. Remember, once you stop the big engine, you need to get off the "BOTH" position.
Make sense?
DD

I think your downriggers should be wired through the battery switch and you decide whether to run on #1 or #2-never on both. I try to alternate the batteries daily so over time they are both getting equal usage . If by some chance both batteries go dead I can pull start my kicker and charge up one battery to start my main motor.
Scott

So what your saying is to connect the downriggers to the battery directly. By doing this, will it matter which selector switch it is on

Not sure Zuke which one of us you are directing our question to but if it is me, my downriggers are wired directly to Battery #1 and do not go thru the switch. The only thing that gets "switched" is which battery is going to start my big motor. However Scott is suggesting another option to wire the downriggers through the switch as well. Either way will work. One of the main basic ideas of this whole discussion is not to have your battery switch in the "BOTH" position without your motor running and recharging it. Otherwise the worst battery will draw down the better battery and if you run like this for a while, you may find that they are both so low, that neither will start your motor. I have an older 150 (1990) Merc and there is no way of pull starting that puppy let alone just try and get the cover off when out on the water. And my trolling motor is not having a charging circuit so I have to stay on top of my battery charge and which battery is doing what...lest an otherwise good fishing trip gets screwed up as what happened a couple of weeks ago. But I'm okay now...have two brand new batteries and a good strategy on how to operate the switch. Think I will get rigged up and head out tonite.
What's the best suggestion - Fingers or Gabriola for an evening bite?
DD

Cheers Done Deal,

I was out today on two charters and hit fish at Gabriola in A.M. and P.M.

Tonight we lost a 40 right at the boat...but managed a 25 lbs. Guest took it better than I did and is rebooking for another this summer.

thanks Done Deal. I will definitely take your advice. Fishing Guide, nailing a 40 is my dream. I have been using anchovies on 1 rod and a spoon on the other a different depths. Can you give me some advice for fishing springs? I feel after all the help everyone has given me, I need to buy a round of drinks or something. This site and all you people are great. Thanks again, until the next thing I am troubled with.