Dual Battery Switch question

[warthogwon]

So I just installed a second battery along with a Guest (2111A) battery selection switch. My boat did not come with a switch at all, so it's nice to be able to shut down power between trips and not worry about battery drain. My question is regarding the fragile MPEM and switching between the Battery 1 position and the BOTH position. I have put in a Group 24 starting battery along with a deep cycle marine battery. I'm wondering it it is potentially dangerous to be switching between batteries while the engines are running or while the DESS key is in place? Any experience out there? Specifically, I may want to start up with the starting battery and then switch to the BOTH position to recharge the deep cycle while running.

 

[ialonso]

I have a 99 Sportster 1800 that I equpped with such a thing for many years, and I did that from time to time. no ill effects.

Most of the time, I would crack up on 1, later switch to "both" and then swicth to 2 as I arrived, then set back to both before leaving, ensuring I would not be stranded,

I know many times I would also run both all day except when I stopped for a while, and I would switch to 2...this had a risk that if 1 was toast I might not have noticed...It was never an issue, but I can see how it could have been

So I just installed a second battery along with a Guest (2111A) battery selection switch. My boat did not come with a switch at all, so it's nice to be able to shut down power between trips and not worry about battery drain. My question is regarding the fragile MPEM and switching between the Battery 1 position and the BOTH position. I have put in a Group 24 starting battery along with a deep cycle marine battery. I'm wondering it it is potentially dangerous to be switching between batteries while the engines are running or while the DESS key is in place? Any experience out there? Specifically, I may want to start up with the starting battery and then switch to the BOTH position to recharge the deep cycle while running.

 

[RFoster130]

It doesnt hurt to switch it while the boat is running. I have the same switch in my speedster 200 with a starting battery and a deep cycle. I start it on 1 and then will switch it over to both when its running. Once a member here tried to tell me i was wrong, so i called the manufacturer and talk to their engineer. He said on the internals of the switch, it never breaks contact when going from any of the positions, so it will have no bad effect.

 

[warthogwon]

Thanks guys, It's nice to know I'm safe in switching. I'm always nervous about frying the MPEM.

 

[Dr Honda]

Yes to the above.


The Guest switches "MAKE" the contact before they "BREAK" the old. SO... if the switch is working properly, at no time, will the system go open... unless you switch it to off while the engine(s) are running.


With that said... NEVER... switch to off while the engines are running. The power/voltage spike can kill the MPEM !!!!!!

 

[MEDOO]

Good info- I was wanting to significantly upgrade my sound system this winter, but I was nervious about having the one battery...