Battery Half-Life

[bid_time]

I know there are some people that are knowledgeable in this cause I think I have seen this answer before. But if I have a fully charged battery, zero draw on it, an average temperature of about 40F, how long will my battery last before it gets to about 50 percent. I ask this because I just got a new battery in my TT, I fully charged it, I don't really want to take it out at this time if I don't have to. The TT will be going to the storage yard and I won't be using it for about 6 weeks. I have a disconnect switch so it will have zero power draw on it but I would prefer for the battery not to discharge to less than 50 percent. Average temperature here will probably be around 40F to beginning of May. I will be using it May 12. Any thoughts?

[westend]

kellertx5er wrote:

westend wrote:
Typical flooded battery, you will lose maybe 20-30 percent at 40f in a month+. Typical AGM, 5-10 percent in that same time.

BTW, I wish the administration of this website would allow the use of the percent symbol. It is ridiculous to set the formatting to exclude it as hackers aren't going to use it in a hacking attempt.

Can't find anything preventing use of the percent sign.

This thread. In fact, even had to edit the percent symbol out of your post to quote it.

[landyacht318]

http://www.pbase.com/mainecruising/self_discharge

I'd worry more about getting it a true 100% charged before removing a cable and letting it sit.

[kellertx5er]

westend wrote:
Typical flooded battery, you will lose maybe 20-30 percent at 40f in a month+. Typical AGM, 5-10 percent in that same time.

BTW, I wish the administration of this website would allow the use of the percent symbol. It is ridiculous to set the formatting to exclude it as hackers aren't going to use it in a hacking attempt.

Can't find anything preventing use of the %%%%% sign.

[Gjac]

As another data point, I charged my 2 6 v GC batteries and my 12 v starting battery on Dec 5th before I left for Florida and disconnected the batteries. I usually return in April and the batteries are fine. This year I had to return early so I checked the batteries on Mar 5th and they were at 12.6 v. In 3 mos the batteries were down 10 percent. I recharged them before I returned to Florida. The batteries are 9 years old.

[CA_Traveler]

westend wrote:
BTW, I wish the administration of this website would allow the use of the percent symbol. It is ridiculous to set the formatting to exclude it as hackers aren't going to use it in a hacking attempt.

You can post a % with the Woodall's portal or add https:// to the beginning of the link.

But I agree that it should be fixed.

[Boon_Docker]

Boon Docker wrote:

bid_time wrote:

pianotuna wrote:
If the battery is old as the hills 1 percent per day. If it is new 2 percent per week. If it is AGM self discharge rates are less.

The battery is the usual flooded cell, brand new yesterday, charged all night (TT plugged in/on board smart charger) still plugged in until I take it back to the storage yard tonight (24 hrs total charging time).

2 percent per week sounds fairly reasonable. My FLA batteries have been sitting idle for 4 1/2 months and when I went to charge them today they were at 70 percent. Temps have been averaging 35 to 40F.

[Boon_Docker]

bid_time wrote:

pianotuna wrote:
If the battery is old as the hills 1 percent per day. If it is new 2 percent per week. If it is AGM self discharge rates are less.

The battery is the usual flooded cell, brand new yesterday, charged all night (TT plugged in/on board smart charger) still plugged in until I take it back to the storage yard tonight (24 hrs total charging time).

2 percent per week sounds fairly reasonable. My FLA batteries have been sitting idle for 4 1/2 months and when I went to charge them today they were at 70 percent. Temps have been averaging 35-40F.

[scrubjaysnest]

2% a month self discharge is what the battery industry claims.

[MEXICOWANDERER]

Turn the switch and walk away. Unless of course, Global Warming brings a bout of -459.7F to Michigan.

[bid_time]

pianotuna wrote:
If the battery is old as the hills 1 percent per day. If it is new 2 percent per week. If it is AGM self discharge rates are less.

The battery is the usual flooded cell, brand new yesterday, charged all night (TT plugged in/on board smart charger) still plugged in until I take it back to the storage yard tonight (24 hrs total charging time).

[red31]

From Johnson Control marine battery info 2004

[RoyB]

My batteries sit disconnected in my OFF-ROAD POPUP over the winter months. They start out at 12.6-7VDC... I typically see around 12.3-4 when I bring them back to life in the spring. A 12.0VDC reading for me represents the approximate 50% charge state.

I will look at the batteries at least once a month and can do a normal re-charge then if necessary...

Roy Ken

[pianotuna]

If the battery is old as the hills 1% per day. If it is new 2% per week. If it is AGM self discharge rates are less.

[RJsfishin]

Make sure there is no draw bypassing the battery shut off,......preferably remove a battery cable, and it will be fine.

But better yet, connect a 60 watt solar panel to it.