I'm after a mains powered battery charger that will maintain a 12vlead-acid bettery at or near the ideal 'float' voltage while thebattery is in use.All the chargers I have, including a recently bought one that soundedas if it work don't do what I need. They charge the battery fully (upto 14.4v or so) then drop back to a trickle charge which doesn'tmaintain the battery at 13.5v or so. I have to restart the batterycharger each time I see the voltage has dropped down towards (orbelow) 12v.All these chargers would be good for keeping a disconnected battery ingood condition but are useless for maintaining a bettery in use.Chargers that run from solar panels mostly do what I want (I have oneon my boat which works very well) so it's definitely possible to havea charger that works like this.So, has anyone any ideas how I can specify what I want? I.e. somemagic keyword that might work?

A Smart Charger designed for caravan / motorhome leisure batteries shoulddo the job. In essence, many motorhomers in particular ( including myself) do just thiswhen they keep their motorhomes on ‘hook up’ ( plugged into the mains)while on their drive. The modern smart chargers are designed to follow thecorrect charging profile, including a ‘float’ stage. They can also workwith a solar charger.They are also used while ‘onsite’ and the Motorhomes or caravans are onhook up. In modern leisure vehicles, the lights, even the TVs, tend to runof 12v. In ours, only the microwave uses 230VAC ( the heating is dual gasor 240, ditto the water heater. The fridge is a 12V compressor one. ) As aresult, vehicles have leisure batteries which are ‘float charged’ if mainsis available. The down side is, motorhome kit carries a price premium. You could trylooking for a second hand one.A lot of people are changing to Lithium batteries and changing theirchargers. You may be able to pick up a...

Well I had no idea so I asked... pretty authoritative to me.

Mains battery charger to keep a battery that's in charged?

Dec 31, 2025 Last reply: 6 months ago 21 Replies

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The Natural Philosopher 6 months ago

Well I had no idea so I asked...

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Looks pretty authoritative to me.

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Chris Green 6 months ago

The best chargers 'refresh' the battery to 14.4 volts once a week or so, it helps keep the electrolyte mixed up and prevent sulphation.

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