Trim battery connections

rasbury

It seems an odd way to do it- my trim is hooked to bat one directly. If I switch to house. I have no trim?

Formulaben

If it is hooked directly to Bat 1 then the battery switch should have no bearing on its use...and that would be correct, as you'd want to be able to "trailer" the drive up even if the battery is off. 

rasbury

What if that battery is dead, I have to move them to the house battery @Formulaben ? Right now I have the gen hot on the house as I use 1 most of the time. If i put the trim hot on 1 and the neg on 2, does that pull from both? I love being able to ask stupid questions here and not seeing the look on peoples faces that know electricity...

Formulaben

rasbury said:

What if that battery is dead, I have to move them to the house battery @Formulaben ? 

If the battery is dead then I guess I would FIRST be addressing what is draining it...if it is wired correctly, then with the BATT SWITCH to OFF then the only hot items on it are 1) trim, 2) bilge pump(s), and 3) *maybe* stereo memory.  YMMV, some put VHF radio on hot bus, etc.

rasbury said:

Right now I have the gen hot on the house as I use 1 most of the time. 

What exactly do you mean by this?  Generator (GENSET) "hot" as in battery charger, or engine alternator, or ?  This statement is highly ambiguous, so please let us know...

FWIW, I would absolutely wire any charging solution to charge the battery banks separately.

rasbury said:

If i put the trim hot on 1 and the neg on 2, does that pull from both?

No, unless the batteries are paralleled, in which case it's pointless to have a 1/2/OFF switch. 

For the purpose of this conversation, here is how I rewired my 270:

• Battery isolator: remove it, tie off the cables, and throw it away, it's trash.
• Main (house) battery bank: two (2) large deep cycle batteries paralleled together for all house loads and main engine start, wired via the BATT MASTER SWITCH.
• Other battery: wired through BATT MASTER SWITCH to GENSET starter ONLY.
• BATTERY CHARGER: upgraded to 50amp marine 2-bank charger so each bank gets charged separately and with plenty of power for normal use.
• BATT MASTER SWITCH: ON, OFF, and COMBINE. Combine is the only time battery 1 gets used besides GENSET starting; really only used in an emergency, as a low house bank would be jumped with the jump pack for main engine starting if necessary; prior to this, the GENSET would be turned on and the battery charger turned on!  ALL DC electrical loads go through this switch except bilge pumps, which are on separate circuit breaker switches (so that I can turn them off if necessary.) When I turn the BATT MASTER SWITCH to OFF there is ZERO power leakage possible except for bilge pumps if the float switch turns them on. 

None of this "rewiring" was all that difficult, just a bit of tracing wires, removing some hardware from the back of the switch panel (diodes on bilge pumps), and re-crimping/re-routing wires as necessary. I actually cleaned up quite a bit.

All of this, and I mean ALL OF THIS is a result of the trash battery isolator that came with the boat causing discharging issues.  IMHO it is trash, get rid of it and use a modern ACR to charge the other battery bank if you must, e.g. if you're not ever running your GENSET then an ACR from the main bank (BATT 2?) to the other bank (BATT 1?) will charge it but will NOT allow it to somehow discharge or try to supplement the main bank.  Also, given the electrical loads possible on this boat, the main house bank *MUST* have 2 large deep cycle batteries, IMHO.

rasbury

I will do some studying on that!