Another Battery Issue

[Edward Buker]

I did not have a Xantrex Echo Charger or Big Boy in my earlier Beaver coach. It also did not have as much of a draw down on the chassis batteries as the new ECMs do but at least once a month while in storage you did need to charge the chassis batteries to keep them up. I changed the momentary boost switch to a regular rocker switch so about once a month I would leave it on for a day and the house charger would bring up the chassis batteries also. If you have a continuous duty solenoid, but no other chassis battery charging system, then this is another option for you.

Later Ed

[Bill Dean]

I chose to engage the boost switch for two hours after calling Ken at BCS in Bend. He stated that he's had customers who lost their alternators drive across country with no problem - further mentioning that the solenoid would "get a little warm" used that extensively but would not overheat or fail.
It worked great and may be of useful reference for BAC members as I may not be the only one where all batteries are drawn down too far.
I still need to install a chassis battery isolator but am a little concerned with the battery post bar switch as what I've seen look "thin" compared to the cables.  

[Edward Buker]

Bill,

Most of those battery knife switches are made with a plastic base that can become brittle or break from vibration. The ones I have seen are not very sturdy. The other issue is that the diesel engine starter can pull several hundred amps while cranking depending on the load involved, the colder the higher the load. The knife switch design out of copper and exposed to the elements is not very sound electrically. If the plastic was to fail while driving you could have a hot lead from the alternator coming to the battery and short out to the frame and as a minimum lose power with a shut down while driving. I am not saying that this will happen tomorrow and that there is a big rush here, just that you need to be sure that the 12V cabling and connections going to the chassis battery system is very sound given the issues that can be caused by failure.

This is a sealed marine switch made to handle diesel starter loads from a very reputable company. You would mount it so that the current chassis battery cable goes to one lug and you would measure and have someone make up a cable with lugs on each end of a similar gauge as the existing cable to go from the switch lug to the battery post. It is a more expensive proposition but you would never have to worry about this again.

http://www.defender.com/product3.jsp?path=-1|328|2290051|2290060&id=341919

The only other caution is that you never turn this switch off with the engine running, the alternator needs to see a battery load while it is in operation.

Later Ed

[Bill Dean]

Thanks Ed.  I was thinking the same as we previously owned sailboats (the last one being a 40' Beneteau First. I'm familiar & much more comfortable with the sealed rotary marine switches. As you state, I won't worry about it again.
Thanks!  Bill

[Edward Buker]

Nice boat, well made and laid out for a sailor. Glad you are onboard :-) Way back when I had a Ranger 29 on lake Champlain and sailed a lot in my youth. Good days...

Later Ed