DC Main Wiring Mystery

[Capt.Don]

Originally Posted by hellosailor

Doin, just brea in mind that West/Yandina have limits on the size and length of their sense lead, because of voltage drop. Check with them to make sure the wiring you have is adequate for the job, or it won't be switching at the right voltage.

I've been discussing this with Yandina. They are very responsive and very helpful. Thanks again,
Don

[Capt.Don]

I keep revisiting this topic and have gone back and forth a few times. There's definitely advantages to different wiring schemes. Bottom line - with the boat mostly charged on shore power, I don't need the electronic battery combiner (at this time). The charger has an echo charge, so both banks should be properly charged.

With the house bank drawn down, it is a bad idea to put house and start banks in parallel. Because of that, I've removed the Cole Herse solenoid combiner from the circuit. If I want them in parallel, I can always put the Battery Selector switch on Both.

The remaining questions are -

The alternator is wired straight to the house bank, with a Xantrex digital alternator regulator. This makes sense, as the Xantrex module monitors voltage, temperatures, etc. I am going to keep this. However, the only way to charge the start bank is to put the battery selector switch on "Both" -or- to add back the electronic battery combiner.

Finally, the starter is wired direct to the start battery - I'm thinking about moving this to the common of the Battery Selector switch (1-2-Both-Off). Then I can select which bank is used to start. Does anyone see any issues with moving the starter to the battery selector switch?

I know it has taken a while to get to this point. I think I'm understanding the wiring, pros and cons, and making decisions on the best configuration for our intended use. This drasticly cleans-up the engine compartment, removing 4+ heavy wires and rerouting others! I appreciate everyone's input.

Don

[btrayfors]

Maintaining the start battery is easy: get yourself a Xantrex EchoCharge. It will bleed off some charging current, as needed, whenever it senses a charge on the house batteries. No need for switching anything...it's fully automatic, easy to install, and not very expensive.

As to moving the starter battery cable to the Common pole on the 1-2-Both-Off switch, I'm not sure you want to do that, since you'd be combining the starting circuit with the house load circuit. I know that lots of boats are wired this way, but I much prefer to keep the circuits separate, except for emergencies.

Bill

[capn_billl]

I got the best results with the starter battery used just for the engine. And directly to the starter. It should only take 15-20 minutes to top off the starter battery. so start and leaves the alternator going to the starter battery until charged, then switch to charging the house bank, and leave it until charged or shutting off the engine, (whichever comes first). I personnaly would have an alternator just for the starter. And look for another source of power for the house bank. (solar, wind, etc...). And just use the engine to charge the house bank when the other sources fail to keep up.

[capn_billl]

I found wiring the starter through a switch more trouble than its worth. (corrosion, more failure points, heavy starting current through the switch, voltage drop when starting, etc...). Mine was connected that way I changed it to direct. If I need to parallel the batteries to start I use jumper cables.

[btrayfors]

Originally Posted by capn_billl

I got the best results with the starter battery used just for the engine. And directly to the starter. It should only take 15-20 minutes to top off the starter battery. so start and leaves the alternator going to the starter battery until charged, then switch to charging the house bank, and leave it until charged or shutting off the engine, (whichever comes first). I personnaly would have an alternator just for the starter. And look for another source of power for the house bank. (solar, wind, etc...). And just use the engine to charge the house bank when the other sources fail to keep up.

Capn Bill,

That's a strategy which is bound for trouble. There's no need for two alternators, or for manually switching the alternator (or other charging source) between the start battery and the house batteries.

MUCH BETTER to route ALL onboard charging sources (generator, alternator, battery charger, solar panels, wind generator, etc.) to the HOUSE battery bank, and maintain the start battery with a fully automatic and trouble-free voltage follower device like the EchoCharge or the DuoCharge. Start batteries don't need much charging at all...not 20 minutes; maybe 20-60 seconds (typically, starting a mid-sized diesel uses less than 1 amp hour of power). House batteries, by contrast, are the ones which need constant charging, hence the strategy to connect them to all charging sources.

Bill

[Capt.Don]

Bill/Capt. Bill,
Thanks - agree on the charging sources to house and the use of the electric battery combiners. Moving the starter wire is easy - I just need to move from the stud/post to the combiner switch. At least I'll have control over which bank is used to start the boat.

Mixed messages on whether to move the starter to the combiner switch or leave on the start bank. The boat was originally wired with the starter to the combiner switch. Everything I've read seems to support this configuration.

Still very odd that this boat had the battery selector switch (1-2-Both), solenoid combiner and electrical battery combiner.

Don