Minimum battery voltage while boon docking

tkranz wrote:
We spend long periods boon docking using our diesel generator and a 2000 watt zantrex inverter charger and a bank of three "deep cycle" so called marine RV batteries. We use power liberally for tv, etc.

I know that battery banks are most happy when discharged only slightly, so I tend to use my genset often to keep the charge level up. I currently have been starting the genset and recharging when battery voltage gets down to 12 volts.

How about a simple thread telling what minimum voltage you try to keep before using your genset to recharge? I have talked with people who say they run down to 11.8 volts.

X2 on Wolfe10's comments above. Also, if you just like plinking around and having fun, you might consider installing an amp-hour meter. There are lots of different versions around. You can get simple ones for about $60 that are pretty darn functional. The PowerWerx meter gets good reports: http://www.powerwerx.com/digital-meters/dc-inline-watt-meter-power-analyzer-powerpoles.html.

I don't start the generator unless battery drops to 12.10 volts.
But now with solar I don't even bring the generator anymore.
If I need air conditioning all day/night I am looking for hookups or sweat it out.

To minimize generator run time... verify your charging system is putting out 14.2+ volts.

Brett

Thank you for that enlightenment.

"The higher the amp draw when monitoring voltage, the lower you can go before recharging. Said another way, under high load, a 50% charged battery may only read 11.8 VDC. Shutting down the load and letting the batteries rest can bring the "at rest" reading back to 12.2 VDC."

I have experienced the effect but thought I had weak batteries or a faulty meter.

As I get older I listen better and learn more. :)

With 12V marine hybrid batteries especially, keep them above 50% which is around 12.1V. Like wolfe10 said, that's at rest with no loads. A lot of boondockers will check voltage in the morning before breakfast when there isn't much load.

Solar

Get some solar collectors. They are cheaper now than they were years ago when we installed ours. get the best controller you can afford.

tkranz wrote:
We spend long periods boon docking using our diesel generator and a 2000 watt zantrex inverter charger and a bank of three "deep cycle" so called marine RV batteries. We use power liberally for tv, etc.

I know that battery banks are most happy when discharged only slightly, so I tend to use my genset often to keep the charge level up. I currently have been starting the genset and recharging when battery voltage gets down to 12 volts.

How about a simple thread telling what minimum voltage you try to keep before using your genset to recharge? I have talked with people who say they run down to 11.8 volts.

11.9 or 12 is a good indicator. You can go further but may reduce battery life over time.

OK, first disconnect.

Most "don't discharge below" recommendations are for BATTERIES AT REST-- meaning no charging and no discharge for at least an hour.

So, the first thing you need to do is tell us whether the "how low should they go" voltage is:

AT REST
UNDER 10 AMP
OR LESS LOAD OR UNDER HIGH LOAD

The higher the amp draw when monitoring voltage, the lower you can go before recharging. Said another way, under high load, a 50% charged battery may only read 11.8 VDC. Shutting down the load and letting the batteries rest can bring the "at rest" reading back to 12.2 VDC.

There are some excellent meters that monitor power usage and help make the decision. If you want recommendations, let us know. They are NOT inexpensive.