CHANGES TO JIM MOE'S WIRING DIAGRAM - ECHO CHARGERS

[Stu Jackson]

CHANGES TO JIM MOE'S WIRING DIAGRAM - ECHO CHARGERS

In the Battery Acceptance topic (http://c34.org/bbs/index.php/topic,4787.0.html) I mentioned that Jim Moe had CHANGED his echo charger connections FROM the 1-2-B switch connections TO the bank (+) posts.  This is Jim's classic wiki article: http://www.c34.org/wiki/index.php?title=Catalina_34_Electrical_System_Upgrade

This is a VERY IMPORTANT modification.  I updated the wiki accordingly.

In a discussion recently on co.com (see: http://forums.catalina.sailboatowners.com/showthread.php?t=107109) we discussed this very issue. It is an operational, not electrical design issue.  This is a copy of the pertinent ideas from that full thread.  When I learn wiki updating, I'll post this there or link the wiki page to here.  [DONE, Nov. 2009 - Stu]

Bob wrote:  "It looks to me that if that switch [reserve bank on/off switch] was off the echo charger wouldn't be doing it's job."

I replied:  As Jim's wiring diagram is set up, you are completely correct. I spoke with Jim since he published this in 2004, and he noted that based on my suggestion he has moved the echo charger from as shown to the battery (+) posts as recommended by the echo charger manufacturer.

The following is very IMPORTANT to understand: Since his operating concept is to turn the reserve bank switch ON when he gets on the boat and he doesn't leave it plugged in when he's away, what you point out, quite correctly, is not an issue for him if wired this way. Again, you're right: if the reserve bank switch was OFF, and wired this way, the echo charger would NOT charge the reserve bank. Period. If wired to the banks, it wouldn't matter and would always work.

The co.com link also explains how you can change Jim's wiring diagram with two switches to my "preferred" single 1-2-B switch design with just two simple wiring mods.  And given this link, there are way more other designs out there, too.

Here's how:  

Here's what you CAN DO  - based on Jim's diagram ONLY

1. Take the reserve on/off switch and throw it out
2. Conceptually: Run the reserve (+) DIRECTLY to the #2 post of the 1-2-B switch for power TO the switch and run a wire from the output "C" post of the switch to the starter

To do this you need to do two things:
1) Take what's shown as the "Existing #4 red" between the starter & the #2 post and MOVE it FROM the "2" post TO the "C" post of the 1-2-B switch, and leave it on the starter. This gives you power TO the starter from either bank. It also lets you parallel the banks if your echo charger fails (backup, backup, backup...)
2) Run a new wire from the (+) output of the reserve bank to the #2 post of the switch, without that pesky on/off switch. Do not run ANYTHING from the reserve bank to the starter, go only directly to the switch. (The wiring sizes are your choice.)

You're done.

Bob, what this does is make the 1-2-B switch THE controller for the output to the starter from either of the 2 battery banks (and, of course, to the DP).

It also does exactly what I've been suggesting all along - uses the simple 1-2-B switch to control everything. It changes Jim's design to mine!!!

1. The 1-2-B switch is only used for battery bank selection and output to two things; the DP and the starter (the "always on" loads can be left as shown or run directly to the house bank or other switches and fuses - your choice)

2. The alternator output goes to the house bank [nowhere near the switch!!!] with a combiner, echo charger, etc. used to supply the reserve bank.

Simple, eh?

For more thoughts on this, see: Alternator Output & Battery Switch Wiring:  http://c34.org/bbs/index.php/topic,4934.0.html