AB switch Q

[tekmunki]

replacing my two batteries with a starter and deep cycle--- need advice on making this work --- an issue I'm having currently is the motor running turns off the fishfinder/gps while underway- I would assume wiring at such and leaving the AB switch on "A" will alleviate the problem- assuming i don't need to recharge the deep cycle during the trip.

at the moment I have 2x deep cycles, no trolling motor (yet).


Did I get this right, or is there a problem with this design? Basically, charging the batteries before leaving home- and if I get stuck not cranking I can go to "AB" for an emergency start--- ?

 

[Silvertip]

Re: AB switch Q

No you did not get it right. Every accessory except for an automatic bilge pump should be powered from the COM terminal -- not directly from the battery. Will it work the way you have it -- yes but you are limiting the capability of the switch. Just one example is that you have the fuse panel powered from battery B. If battery B dies, you now have no way to power ANYTHING. Switching to BOTH would combine the two batteries but you now combine a dead battery with a good one. You also have no way to kill power to anything except the motor. If all accessories are connected to the COM terminal you can charge either or both (engine running), operate accessories from either or both (engine running or not) and you can start the engine from either or both, or kill everything. Use the switch properly to your advantage.

 

[sasto]

Re: AB switch Q

It is very difficult to go against anything the guru Silvertip posts, but I do it differently on our old boat. I realize it is common to wire the bilge pump to a dedicated battery. I have wired up many new boats and Silvertip's method is what I did. But, what works for me is to have the bilge pump run off the battery switch common instead. If anything would go wrong with the bilge pump, I have quick access to cut the power off. Also if my pump is connected to the common and the battery goes dead, I can switch to the other battery.

The drawback is leaving the battery switch on at all times while at a dock. This works for me, but I'm in the minority.

 

[Silvertip]

Re: AB switch Q

I am not worthy of guru status however I do subscribe to "logic". I by no means imply that my suggestions are the ONLY way things can/should be done. However I do see so many creative wiring techniques by folks who think their situation is genuinely unique and that they are really providing the ultimate hook-up. Fact is, many really don't understand how versatile a switch is and in the end are limiting its capability. One just needs to think about how it works and the best way to describe it is that it serves as a "traffic cop" for current flow in either direction (charging current to the batteries and load current from them). The knob is merely the "cop" and it directs where the current goes or comes from. There are many other ways to avoid dead batteries but short of a pair of jumper cables or a jump box, this is undoubtedly the least expensive, most reliable, and most versatile solution. Some folks are simply "Switch Challenged" and cannot get a grip on the system and for those, perhaps an ACR/VSR type of system is best. I also subscribe to Sasto's philosophy in that "whatever works for you is ok!". It may not be traditional but it's your boat so it should matter to no one else how you do things. When we provide an alternate method it is only meant to point out the way things are "usually done" just in case you hadn't thought about it or did not fully understand the functionality of a device.

 

[tekmunki]

Re: AB switch Q

I am not worthy of guru status however I do subscribe to "logic". I by no means imply that my suggestions are the ONLY way things can/should be done. However I do see so many creative wiring techniques by folks who think their situation is genuinely unique and that they are really providing the ultimate hook-up. Fact is, many really don't understand how versatile a switch is and in the end are limiting its capability. One just needs to think about how it works and the best way to describe it is that it serves as a "traffic cop" for current flow in either direction (charging current to the batteries and load current from them). The knob is merely the "cop" and it directs where the current goes or comes from. There are many other ways to avoid dead batteries but short of a pair of jumper cables or a jump box, this is undoubtedly the least expensive, most reliable, and most versatile solution. Some folks are simply "Switch Challenged" and cannot get a grip on the system and for those, perhaps an ACR/VSR type of system is best. I also subscribe to Sasto's philosophy in that "whatever works for you is ok!". It may not be traditional but it's your boat so it should matter to no one else how you do things. When we provide an alternate method it is only meant to point out the way things are "usually done" just in case you hadn't thought about it or did not fully understand the functionality of a device.

I went the all-things to common route as suggested, works flawlessly! Ty

Can I put my aux charger lead from motor to my second battery, or would it cause problems when that battery is selected via the switch and receiving both the main alternator and six charging?

 

[Silvertip]

Re: AB switch Q

Go back to the "traffic cop" thought process. If the switch is set to the second battery, current from the engine and the charger can ONLY go to that battery because "A" is disconnected. When "A" is selected current can only go to and from the "A" battery from the alternator on the engine because the charger is only on "B". When set to BOTH both will charge since they are both selected. Now how do you propose the charger would be able to charge on the water unless you are dragging a very long extension cord?

 

[tekmunki]

Re: AB switch Q

Go back to the "traffic cop" thought process. If the switch is set to the second battery, current from the engine and the charger can ONLY go to that battery because "A" is disconnected. When "A" is selected current can only go to and from the "A" battery from the alternator on the engine because the charger is only on "B". When set to BOTH both will charge since they are both selected. Now how do you propose the charger would be able to charge on the water unless you are dragging a very long extension cord?

No, sorry to confuse- what I mean is, my Yamaha 150 EFI SWS2 has a second lead from the alternator for charging a second circuit. I'm curious if it would cause problems putting it onto my (B) battery while using my (A) battery for starting and running, I just want to make sure that if I DO connect that second lead to the (B) battery it won't cause problems if I have the switch set to use the B battery and as a result the battery will get a charge, both from my aux charge direct to the battery and the alternator main charge coming from the selector.


Yet, in all seriousness, I'll likely wait to connect that lead to my trolling motor dual deep cycles when I do re-add a trolling motor and batteries to the boat. I figured, I could go ahead and run the lead for now and put it on the B battery until I installed the trolling batteries.