battery charger

Leave it on full time

xantrex battery charger specsImage Could Not Be FoundMaîneÿ . . .

Permanent 240VAC - personally I'd not use any batteries at all, just use the charger in power supply mode to power all your 12V gear.
But I guess you've got your reasons to have the batteries in there, maybe for backup as your 240VAC supply might be unreliable?

Turn off or leave on permanently, that's a good question!

I'd say it depends on battery capacity versus load, or daily DOD requirement, and the battery design.
Say if your daily DOD was 10%, and you recharge every three days, you can expect your (deep cycle) batteries to last for around 1200 cycles, or 10 years.
If the batteries are more of a standby design which are to be left on float 24/7, then you'll probably get maximal life out of them when you leave them permanently hooked up to your charger - as Maîneÿ already posted in his famous one line replies.
For permanent float charging, you want two things:
temperature compensated float charge voltage, and ideally, only little variation of the battery temperature in the band between 20 and 30 degrees. If there are temperature fluctuations outside this band, temperature compensation becomes increasingly important.

Best regards, mr.batteryvalue

If you leave a Three-Stage Charger connected to a battery which also has a load connected to it, it will damage your battery.

The charger has to supply the continuous load current - but it doesn't know whether the current is going to the battery or the load - so it assumes the battery hasn't charged fully and it stays in Absorption mode and keeps on putting out 14.4 volts - which will damage your battery after a few days.

Option A - get a Power Supply which can put 13.6 volts (or whatever the correct FLOAT voltage is for your battery). This volatge will charge your battery to 100% slowly, but won't overcharge it, and will supply your loads. That's what I have at home to run radio and backup power.

Option B - get a Three-Stage Charger that can be locked into putting out FLOAT voltage.

Option C - get a charger with multiple independant outputs and connect one output to the batteries and one output to the loads. I can't tell from the Xantrex 40 data if the outputs on it are toatlly independant and suitable for this.

. . . or maybe simple one-line answers give you more confidence !

we are on perm 240v at the moment because we are spending a few months in a caravan park but that will change when we move on

thanks for your help

Mikes answer to use a multiple outlet charger makes a safe job of charging .

The ProTech and ProNautic range of chargers from ProMariner of USA we stock are all multiple outlet where you can use one outlet for power supply and the balance for charging.

ProTechi go from 10A to 40A with the 10A having two outlets and the rest all have three outlets.

The ProNautic are 40A to 60A and two chargers can be interconnected to give a maximum odf 120A @12V or 60A @24V with 6 outlets which work well to cover a large cruieser with twin engine crankers ,bow thruster and house bank.

The outlets can be uses independently for batteries to offset potential parallel charging deficiencies.

They are competitively priced and are up with the best in the world for efficiency of charging.
Ian