Keeping Leisure Batteries charged (1 Viewer)

[Revolvor]

I have two Lead-Acid leisure batteries (100 Ah and 75 Ah) that I want to keep in the garage over the winter. They don't need to be fully charged all the time, but I do not want them to deteriorate through discharging too much.

I have a Halfords Smartcharge 100 battery charger. If I charge each one fully individually, will it be OK to then connect them in parallel, and use the "maintenance" setting to keep them both charged - at about 13.55 volts, it seems?
Thanks, John

 

[Jaws]

Once charged and removed store them up off the floor on wood
They should hold their charge for several months 'as is'
Just top them up a week before you intend using them

 

[Don Quixote]

Many people have the impression that when batteries sit on concrete, energy "leaks out" or they are ruined. The short answer is that letting modern batteries sit on concrete does not harm or discharge them in any way. However, this legend is historically based in fact. The first lead-acid batteries consisted of glass cells that were enclosed in tar-lined wooden boxes. A damp concrete floor could cause the wood to swell, breaking the glass inside.

Energy can in fact "leak" out of battery banks — though in different ways. The first is from current between the battery terminals, caused by dirt, dust, and grime becoming carbonized (and therefore electrically conductive) from acid released from the cell. This is easily preventable. Use a clean rag to carefully clean the tops of the battery cases every time you perform your regular battery bank maintenance routine.

The second way happens to all batteries—it’s called "selfdischarge." Due to reactions within the plates, all lead-acid batteries will lose part of their charge over time. The warmer the battery compartment and the older the battery, the higher the self-discharge rate.
Buy a 3 or 4 stage charger that will condition the batteries just before using them and your good to go.

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[Jaws]

Dunno about legend or whatever John..
Last year we did an experiment with two brand new YTX12-BS bike batteries
One sitting on the floor and other on the bench
4 months later the one on the floor was on the critical list, the one on the bench.. still sat at 12.2 v
I have always believed it to be just a temperature thing to be honest..

 

[Don Quixote]

@Broken Link Removed there are to many factors to consider before confirming your tests, but modern batteries can sit on the floor without problem. Temperature can effect the results as well.

 

[Jaws]

Well we did reverse the batteries but only did a 2 month test as I ran out of time ( I retired and all the stock went to new owners ! )
The results did back up what I had previously found though ( and to be fair the tests were not done in exactly lab conditions, so temperatures changed with the season )

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[Revolvor]

Thanks for the advice guys. I will fully charge and store them, and then fully charge again just before I refit them. Not sure that my Halfords Smartcharge 100 charger actually qualifies as

a 3 or 4 stage charger that will condition the batteries

but I am sure it will suffice.
They are actually off my boat, and normally hold their charge well, although they are only charged by the outboard motor. However, since getting my MH and subscribing to this forum, I have become much more aware of the intricacies of 12v electrics! I have plans to fit a small Solar Panel in the future, to help the charging situation.
John