How long should a new battery stay charged without use?

[lakelover]

I have a brand new battery in the boat that I fully charged on my charger & ran the boat a few times, so it charged while it was running. It could sit up to 2-3 weeks between uses, so how long will it stay charged enough for a start? I ask because I'm trying to figure out whether I need to haul my charger back and forth to the lake every time I've been away for a while, sometimes space in the car is at a premium.

 

[Maclin]

Re: How long should a new battery stay charged without use?

It should be ok for several weeks, even 3 months or so. If your "luck" is like mine then you will only need the battery charger the one time you do not take it. So I recommend you take it along every time anyway, that way you will probably not need it.

 

[H20Rat]

Re: How long should a new battery stay charged without use?

It depends on the temperature you store it at. (batteries are a chemical reaction, the cooler it is, the slower the reaction). At 80 degrees, a lead acid will self-discharge at 4% per week.

Personally I don't set foot in my boat without a portable jump box stuffed away in a storage compartment. They aren't that expensive, and using it just once is more than justification for the cost!

 

[dwparker99]

Re: How long should a new battery stay charged without use?

I would take the charger. I would want to know that the battery was fully charged before I let it set for 2-3 weeks between uses. You will get more life out of it that way.

 

[lakelover]

Re: How long should a new battery stay charged without use?

Thanks, I'm going to take the charger along. Would be a whole lot more hassle if I needed & didn't have it! Really didn't have any reference to how long a charge will hold. The car probably only sits without running a max of 3-4 days, once in a while.

The battery I replaced was 9 years old! and would start the motor, but would only hold a charge for 2-3 days without use.

 

[ZacMaster]

Re: How long should a new battery stay charged without use?

I just read in the west marine catalog this morning that most batteries self discharge at a rate of 3-5% per month. I'm sure this is the manufacturer's number, and you won't see that small of a discharge in real-world operations (well...non operations).

 

[ssobol]

Re: How long should a new battery stay charged without use?

I just read in the west marine catalog this morning that most batteries self discharge at a rate of 3-5% per month. I'm sure this is the manufacturer's number, and you won't see that small of a discharge in real-world operations (well...non operations).

If you have any electronics that hold memory or an electronic clock you will run down the battery keeping the memory alive. The average car will run down the battery in about 3 weeks due to the radio preset storage, the clock, and the alarm system. The car is not really off unless that battery is disconnected.

A lot of boats have isolation switches to disconnect the batteries from any loads.

Even when disconnected there can be discharge paths from the battery though the dirt that accumulates on the battery case. The battery also degrades (loses capacity) due to chemical changes inside the battery when unused for long periods.

 

[NYBo]

Re: How long should a new battery stay charged without use?

If you have any electronics that hold memory or an electronic clock you will run down the battery keeping the memory alive. The average car will run down the battery in about 3 weeks due to the radio preset storage, the clock, and the alarm system. The car is not really off unless that battery is disconnected.

I have had vehicles sit for months at a time with no starting problems.

 

[SteveMcD]

Re: How long should a new battery stay charged without use?

My boat went into drydock in November. After reading this thread, I got curious and hooked up my brainbug controlled charger, and it indicated both were still 100% after 7 months.