I’d not recommend running without a battery in place as it acts as an energy “sink” and stabilises the voltage in the system.
It is a sad truth that the lead/acid battery is something of a prima donna entity, they do not like standing about, and they are rather adverse to temperature changes, vibration, almost everything really. Indeed it is amazing that they do as well as they do given that they have a pretty rough time of it.
As a lead/acid battery discharges the sulphur in the electrolyte combines with the lead in the plates. When the battery is charged the sulphur re-entres the electrolyte. These sulphate crystals are very small and easily dissolved.
If a battery stands unattended for a period there is a natural tendency to self discharge due to parasitic cells within the batteries plates. Temperature changes and time tend to encourage the sulphate crystals to grow, they then become insoluble in battery strength acid.
The dreaded “sulphated” battery!
There are design and cost considerations in battery manufacture aimed at providing the maximum amps per cubic inch for your pound. Unhappily to get this the plates are largely a compressed powder sponge that changes size with the state of charge and then gets exposed to vibrations that will eventually lead to plate disintegration.
To best look after a battery have it on a maintaining “float” charge in a stable temperature. For a motorcycle battery this will be a few milliamps only. The cells will probably need topping up from time to time unless it is a modern sealed for life type. A new “dry” battery, (no acid), if sealed will keep for years by the way.
Another way to go is to use NiCad cells; they are tough brutes and actually stand better in a discharged state than full. I think they are to be had in fake black rubberised 6V cases these days too.
In the unlikely event the plates in a “dead” or “sulphated” battery are not crumbling a battery may be recovered by emptying the acid, filling with distilled water and charging until the electrolyte reaches a specific gravity of about 1.1. Empty and repeat the process until there is no appreciable rise in S.G. Refill with acid of the correct S.G. and charge. Not recommended for any but the utterly desperate but it does work.
If it’s any consolation atomic power stations have batteries so big that every so often they have to take the plates out and saw a foot or so off the bottom of them because they stretch under their own weight!
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