No solar or refrigerator?

[dig255]

Originally Posted by EMrider

Fully agree. There is some hassle with a generator.
R

A Honda eu2000 generator is about as easy as it gets.
Glad I will have both gen and solar.
DIG

[dhally]

It seems that few on this forum use a propane frig. We've got one and a 7 gallon propane tank. it allows us to camp for several days no problem. We haven't tried making ice yet, but the frig stays around 42F.

[slfjas]

Slight thread hijack here:

We have the original 4-d AGM and no solar yet, and we have the larger Norcold Frig. We don't have solar yet. The battery is 9 years old!, and not yet replaced.

Our electric draws are primarily the frig, a few lights, the water pump (obviously very intermittent), and occasional use of the Suburban propane heater. We find that the battery does get low (way below 12.2)- as low as 10.7 or so at times, but the frig seems to work fine (unless we are stationary for more that a couple days, or our other electric draws are above normal).

Obviously, we need a replacement house battery soon, and I'd love to put solar in as well.

But- what does it mean for the house battery to be so much lower than the supposed minimum? Is it just that much less efficient? Or is there another problem with it being so low?
Thanks

[yvrr]

Regarding AGM batteries, the Lifeline website advises: "For maximum battery life in cycling applications, do not discharge the battery bank below 50%. Discharging the bank repeatedly to 100% [I think that they mean 10%] will shorten the battery life."

The accompanying chart lists 12.2v as 50% and 11.9v as 25%. So, basically, discharging the battery to below 12.2v will ultimately mean that it will no longer hold a charge for as long as when new.

[rockbender]

Originally Posted by yvrr

The accompanying chart lists 12.2v as 50% and 11.9v as 25%. So, basically, discharging the battery to below 12.2v will ultimately mean that it will no longer hold a charge for as long as when new.

Keep in mind that these voltages are for when the battery is unloaded. When it is pulling a load it will drop the voltage a bit depending on how large the load is. For example, your battery may be at 12.3V with no load, but will drop down to 12.2 when the fridge kicks on. After the fridge is done cycling, the voltage may pop back up to 12.3 after a brief period. The 12.3v is your reference point for approximate state of charge, not the 12.2.

In a nutshell, yes - deeper discharges will shorten the life of your battery. Nine years is a pretty good service life, especially if you've been doing deep discharges often.

[rionapo]

After watching voltages climb to 14.8 during our recent trip only to drop to 12.5 as soon as the sun went down (and knowing nothing about this stuff), I asked a good friend who sells PV systems and has lived off grid for decades to 'splain it to me. Here's my interpretation:

Voltage essentially measures pressure. When there's lots of sun, there are lots of amps heading into the battery so the pipe expands to as much as 14.8 volts before a protective shutoff mechanism kicks in. As soon as the panel stops making electricity, the pressure drops and the voltage pipe shrinks to its standard size, 12.5. If the amperage stored in the battery drops too low to hold that pressure the voltage falls. At 12.2, the reservoir is going dry and can't maintain minimums.

[daveb]

Plenty of good info in the FAQ's about batteries. Here is one:
viewtopic.php?t=1833