Re: [A/S] batteries (again) was boondocking in the snow

[Rick Kunath <k9ao@xxxxxxxxxxx>]

> So, for my trailer, I've gotten deep cycle (so I can
> drain them completely over and over again) with again,
> big CCA's.

You shouldn't drain them "completely" if you want long battery life, but 
I don't think you really meant total discharge. There is a lower limit 
on discharge that shouldn't be exceeded to preserve battery life. By the 
time you get near it, the output voltage has dropped considerably, so 
you'll know it's time to stop anyway. And limiting depth of discharge a 
little can really extend the battery life.

Generally (though not always)... if you're looking for a deep-cycle 
battery, and it has cold-cranking amperes stated in the specifications 
or on the case, you have a hybrid battery and not a true deep-cycle 
battery. These don't last as long as a real deep-cycle battery, and are 
not as well suited for stationary power. Going by cold-cranking amperes 
(rather than ampere-hours only) is the wrong way to specify stationary 
(for photovoltaic use, which is a better match for how we use our) 
batteries. Any decent deep-cycle battery should have available as a part 
of it's specifications, a discharge current vs. time vs. battery life 
chart. Looking at that is very revealing about battery suitability for 
our purposes.

Check the PG series batteries on this site (below), and take a look at 
the charts at the end of the spec sheets. They'll help a lot in planning 
what you need in the way of battery ampere-hour capacity for your 
intended current draw.

http://www.power-sonic.com/

Also, check this FAQ:

http://www.windsun.com/Batteries/Battery_FAQ.htm

Reading through the sites should shed some hight on batteries, battery 
designs, and what to look for.

As for me, I prefer Powersonic AGM (absorbed glass mat) deep-cycle 
stationary batteries. Look for something designed for photovoltaic use. 
I have several thousand of the Powersonics out in the field as backup 
batteries for high-power public safety trunking radio base stations, and 
have had good luck with them. There are other good brands out there too, 
ask folks what they use and prefer.

Also give a lot of attention to the charger you're going to use. Nothing 
can ruin a battery quicker than an improper charger. Talk with your 
battery supplier to find out what is recommended for your setup.

And lastly, keep them charged up when the trailer is sitting idle and 
not being used and recharged regularly. Again, your battery supplier can 
help with requirements for their products.

Rick Kunath
WBCCI #3060
Michigan