Reg Sense +/- to #1 House when House failed

[rgleason]

When I have wired the Regulator sensing wires + and - to respective House Battery terminals, what happens when the House battery fails?

Assuming House Panel and Starter are connected to the "C", Alt power (+) is direct to #1 house and the echocharger is not going to connect because the charger field is not activated and there is not adequate voltage to cause the echocharger to "combine".

1. Switch to #2 Bat Reserve to start engine. No problem.
2. Alternator Field - will not be activated if #1 Bat is 10.5vdc
3. Nothing will charge.

Yet we are told not to switch to "Both" as it may kill both batteries.
(If Both is selected, and if Batt #1 has enough partial charge current to activate the alternator field, then alternator may be put on a full load, pumping into both batteries.)

Do I have to move the Regulator Sensing wires to Battery #2 Reserve to get the alternator charging?
or reconnect the + / - sensing wires at the alternator?

[smac999]

the reg power still needs to come from the battery that starts the motor. a reg should have a b+ and a sense + like a balmar mc 614 does. (as well as ign wire)

the reg will power up off the engine battery. read 10v on the sense. and start charging the house full blast. once the house bank gets high enough the echo charger will kick in.

if you have an old reg that uses the power wire as the sense. consider replacing it. also consider replacing the 1,2, all switch. and separate the house and engine battery properly.

with a 1,2,all swtich I would likly have the sense, alt + and reg + all to the common. at bare min the reg b+ needs to.

get a blue sea add a battery kit. run the alt to the house, reg sense to the house batt, and reg power to the engine batt.

[Maine Sail]

You can use a pos dist busbar at the bank to connect to. You can then use a wrench to pull the banks main fuse or put a Blue Sea mSeries ON/OFF between the busbar and bank. In the event of an actual bank failure turn off the ON/OFF or pull the fuse then set to BOTH. These failures are extremely rare if practicing good battery care and you're replacing the bank before SOH gets too bad.

[rgleason]

Thank you, both.

I failed to state that the regulator is a Balmer ARS-5 which does not have a separate power + wire (sense and power + are the same wire).

I think I learned that:

1. If a #1 bank is at 10.5 volts (not entirely dead) that the alternator field will still be activated and the Alt will be able to fully charge.

2. If #1 bank is entirely dead, I will have to change the power & sense wire + to #2 bank reserve to get the alt charging. I should also probably move the - sense to #2 bank.

3. That if I select Both banks and just want #2 bank to be active, disconnect the #1 with a wrench or Switch.

4. This is a rare case.

5. I don't believe it is cost effective to replace the new balmar ARS-5 and I am continuing to use my 12Both switch with the starter and house panel on the "C" terminal.

Thanks for confirming that this could be an issue if you run your batteries way down.