Batteries are containers that store energy. This energy self discharges as time goes on. The longer the battery sits unused, the more energy that is lost. It does not have to be hooked up for this to happen and it has to be offset by putting more energy back in.
Typically in a car the alternator puts this energy back in as you drive. Depending on the size of the battery and the strength of the alternator is how long it takes. The RPM of the motor typically has to be up around 2000RPM for the alternator to deliver the amperage the battery needs to charge. This can take up to 30 minutes. This is why it is recommended to drive at higher speeds for longer, to give everything a chance to do the best it can.
Just starting the car up once a month for 10 minutes will eventually lead to battery failure. By starting it you have drained more energy from the battery. Now at idle speed the alternator is expected to not only put back the energy it just used to start the car, it has to put back what self discharged energy was lost while it was sitting. The alternator can not do this at those RPM’s for that length of time, leaving the battery to continue to be in a weaker state, eventually leading to failure.
A battery charger is the way to combat this. If you were to put a decent quality battery charger on the battery once a month overnight, it can put that lost energy back into the battery much better, and it will keep your battery at it’s maximum lifespan.
There is a difference between a battery charger and a battery maintainer. Much like it sounds, a battery maintainer only keeps the battery at it’s current state of charge. If the battery is charged up to 100% when the maintainer is put on, it keeps the battery at 100%. If the battery maintainer is put on at 80% state of charge, it is not typically strong enough to bring it up to 100%, it usually only maintains it at 80%. While this is a good thing, it is not as good as keeping the battery at 100%.
A good way to get the most you can from a stored battery is to use a decent battery charger that switches from charging to maintaining automatically. Something like the Genius 5 from Noco will do just that.
For motorcycle and quad batteries, they are much smaller than a car battery, and need less strength from a charger. While your car battery will appreciate 5 amps of charge/maintainer, your smaller battery will be happy with less than 1 amp. You can put the maintainer on in the off season and just leave it on and it will keep your smaller battery charged all winter. You don’t have to leave it on, you can unplug it for a week and then put it back on for a night, and do that for the entire off season, whichever way works better for you.
When it comes to deep cycle batteries like in your RV it is the same system but higher power going in. It takes about 15 to 20 amps of charge to give a lot of energy back to the battery. Most RV’s have a built in chargers at something like 30 or 40 amps. If you can plug in for a night every couple of weeks in the off season this is ideal. You can leave it plugged in all winter, the only danger is if your built in charger malfunctions and continues to charge the batteries when they are full, it can lead to destroying the batteries.
If you can’t plug in then an alternate method must be used. You can use an independent battery charger of sufficient strength plugged into a generator. This isn’t ideal, but is better than nothing. The last 20% of charging takes a long time and uses a lot of gas, so it’s generally best to shut it off at the 80% mark and then when you can plug in, do so. Also if the generator has a built in DC port they typically aren’t that great. You are better off to plug a decent battery charger into the AC outlet.
Solar is another option. It doesn’t work very well in the winter, and even in the summer you need enough watts to give it an actual deep charge, but anything is better than nothing. To get 20 amps of charge from solar you would need about 400 watts of panels. This is for one pair of six volt batteries.
Batteries do not like cold, and they do not like heat. It does help to have solar even in the winter as any current going through the batteries will help keep them from freezing.
Wheelchairs and mobility scooters and electric mopeds are also things that have batteries not in use year round. They too need to have their batteries kept in good condition by charging them up. For these ones plugging the charger that comes with them in once a week or even once a month is a good idea. When the green light comes on saying that they are charged up, unplug it, and then plug it back in periodically to keep them topped up.
There is a distinct difference in the type of battery you have and how long it takes to charge. A starting battery like in your car does not take as long to charge because it is typically not as drained as “deep” as a deep cycle battery. Same for motorcycle and quad batteries.
On the other hand applications with deep cycle batteries in them like your RV, or wheelchair, or electric scooter will indeed take longer as they are drained more “deeply” than the starting type. Another big factor is how many amps the charger you are using has. If it is a small amp charger it will take a lot longer than a big amp charger.
No matter what batteries you have, car, truck, quad, scooter or lead acid or AGM, they all lose energy when stored, and even more when there is a small drain from say the cars computer, all of them need to have that energy put back in or the batteries health will deteriorate.
Here at Pacific Batteries we can explain to you all of your options to keep your batteries healthy and happy.