Dead batteries.

plcpitt said:

Any recommendations on brands for replacing coach batteries (two 6V in series) for 2007 Roadtrek SS Agile? A worse than normal winter in Pittsburgh combined with our first year with an RV = coach batteries that froze & cracked cases. Specs call for two 6V lead acid deep cycle batteries.

Looking for recommendations - brands to use & brands to avoid.

Will need to pay more attention to this in the future; I lived in upper Midwest for 35 years and never had a car battery freeze; we use the vehicle around town regularly - hopefully no other surprises resulting from the cold (for PA) winter.

Click to expand...

FWIW....your coach batteries froze and cracked because the were not charged. A fully charged battery has a higher specific gravity (i.e. More acid) than a discharged one, thus a lower freezing point. Your vehicle battery didn't suffer the same fate because it was used daily and that kept it charged. Very important to keep lead acid batteries charged in those very cold temps.

Thanks for the info, Icarus. I have been on those posts when we got the vehicle last year - thanks for the reminder to me (and others reading this post) about those great resources.

Trekker - We use the RV enough to keep the coach batteries charged. The batteries were original to the RV (2007); we have owned it only for the past year and I should have taken a reading with a hydrometer. Batteries were probably near end of life so overall an inexpensive lesson.

Trekker said:

FWIW....your coach batteries froze and cracked because the were not charged. A fully charged battery has a higher specific gravity (i.e. More acid) than a discharged one, thus a lower freezing point. Your vehicle battery didn't suffer the same fate because it was used daily and that kept it charged. Very important to keep lead acid batteries charged in those very cold temps.

Click to expand...

I had my Coach battery freeze and cracked mid work day after getting to 2 jobs and I use my van 6 days a week.

Not disproving what you said, but perhaps its possible in my case it was -35C

A fully charged FLA battery won't freeze AT LEAST until -40 (or colder!). If your batteries are freezing and cracking, they are not fully charged!

It should be noted that batteries have self discharges that will kill a batter in a matter of months of it is not supplimentaly charged mean time. In addition, most RV aux batteries ae controlled through a relay, which has a considerble parasytic draw on the auz batteries. (I believe we have talked about it previously in this and other threads) The OEM one in RT agiles draw about .5 amps, enough to kill the aux battery in a matter of a week or so.

The simple solution (save installing a isolator relay that draws little or no current) is to simply install a postiv off switch on the battery negative, and whenever you park for longer than a day or so, simply turn off the aux battery. Turning the battery "off" from the control panel does not disconnect the battery entirely and indeed it will continue to discharge.

Finally, one should learn to check battery condition as a regular thing, especially in cold weather. Simply checking battery voltage is not enough, checking specific gravity in a flooded cell is essential. (one advqntqge of flooded cells over AGMs. )

Icarus

T.J.T said:

Not disproving what you said, but perhaps its possible in my case it was -35C

Click to expand...

Well, that's mighty cold!! At that point, all bets are off for most consumer items. When I worked at Motorola, -35 C was about the lower limit we would even run accelerated life tests on our two way radios. We only spec'd them to operate to -20 F. I am constantly amazed that mechanical or electrochemical equipment operates at those temperatures, as most is not designed to withstand it. And even if a battery didn't crack, at -35C it doesn't put out much power.

BTW, although it was cold in Pittsburgh (the OP's location), I'm pretty sure it didn't get to -35 C.

Canada got really cold this year! I'm staying in Florida!

Correct that Pittsburgh did not get that cold - maybe hit -5 to -10 F for a number of nights. Cold for Pittsburgh but I grew up in Green Bay so it actually felt great! Cold nights & sunny days - better than the typical gray and gloom of winter in the 'burgh.

A good hydrometer will be on my shopping list when I get new batteries this weekend.

Thanks to everyone for all the info and, again, hope it helps others prevent problems. That is the best advantage of sharing knowledge on this forum.

I just posted my recent experience with one dead battery (both AGM) on the Leisure Travel Free Spirit forum. My one battery was absolutely croaked while the other was good. Not being aware of all the information that one contributor to this thread has slightly offered, I just plugged in to my 3-stage converter/charger. My charge is being held very nicely. And it wasn't the first time I let the batteres get well below 10v.