Battery Monitor w/o starter battery configuration

In an earlier thread I had asked about running my starter through a shunt so I could monitor my total usage with a Victron unit and now understand that the 500A shunt would be too small.

I only want to monitor my house bank, (6x6v 235A ea). How do I also charge my starter battery at the same time with the alternator? An echo type charger won’t work in this configuration. My 110v battery charger can charge 2 banks so that is not a problem.

What am I missing?

Why is it that an 'echo type' charger won't work?

Have you considered a combiner like this Blue Sea Automatic Charging Relay(ACR)?

I'm under the impression that if the large house bank is being bulk charged that the start battery on the other side of the combiner would get cooked. ASm I misinformed?

meridian said:

I'm under the impression that if the large house bank is being bulk charged that the start battery on the other side of the combiner would get cooked. ASm I misinformed?

Click to expand...

The Eagle has one 60 amp charger that charges 4 bank, house -three 8-D deep cycle.. main start - one start 8-D, gen start - one start 8-D, that charges all the 8-D batteries for the last 15 year with no damage or shorting the live. The house bank is used 24/7 365 days and the start may a dozen times per year. I have a volt meter that reads each bank and the all read 13+ volts.

An echo charger is not the same as a battery combiner. The echo charger will provide a controlled charge to the 2nd battery bank whenever the main bank is being charged but the charge parameters for the two banks will be completely different.

And you're right that a simple combiner is not likely a good idea with 2 battery banks that are significantly different in size.

I have a Yandina combiner which does not appear as stout as the Blue Sea ACR. It has a feature I like which is the option for installing a switch to override the auto combining feature. This allows you to prevent combining or initiate combining independent of battery voltage or charging state. In the event of an extended engine run, preventing the tie of the house and start banks would be beneficial in preventing overcharging of the smaller start bank.

I'm under the impression that if the large house bank is being bulk charged that the start battery on the other side of the combiner would get cooked. ASm I misinformed?

Sort of as the mfg of complex electronic crap want you to forget reality.

A start batt will normally be in a car or truck , and will see about 14.4V on tap constantly , even with many loads operating.

Your house bank will see at least 1V over its off charge voltage, if it is to charge at all.

So your almost dead 12.3 V batt will see at least 13.3 in order to charge.

As the house eventually gets full the voltage will rise to 13.8 .or even 14.4

Then it should (if not a "one wire" alt ) lower the charge V to about 13.6 -13.8 for the remainder of engine on time. The "float" voltage.


SO? since 14.4 is what the start would expect almost 100% of the time , simply going to 14.4 and then back down to float does ZERO to the battery.AT 13.8 float , no harm is done .

The simplest solution is to have the alt voltage regulator "see" the house, not the start bank.\

Then the house will receive the fastest charge best charge your alt can produce.

A simple solenoid (RV about $18.00) will join the two banks together any time the engine is operating.

The house would be shunted for SOC meter use.

KISS works just fine , but alas does little for the electronic stuff sellers bottom line.

Call Ample Power. (206) 789-0827

Ample Power Company Home Page

Here's our set up, The Trawler Beach House: Batteries and Battery Chargers For The Boat , it's been working great for us for over 3 years now even while doing some extensive cruises or tied to the dock for extended periods. Chuck