California Dreamin wrote:The low amp (3.5amps) Ctek copies will do the job (as you describe your usage) but in general, when recommending a 'permenant' charger, the simple maths dictates that you should fit a unit which exceeds the maximum possible draw of the setup to prevent a flat battery senario whilst 'ON CHARGE' so to speak.
Think about it....even if you don't usually have the 12v side of the fridge running, the stereo, the interior LED's, a laptop running off your 12volt socket (via an in car adapter) there is a possibility that all of a sudden you have a 10 - 12amp draw, far exceeding the input charge from a 3.5amp Ctek.....
Under these (rare) circumstances the leisure battery is in DEFISITE (discharging) even though the charger is plugged in. Eventually the battery will go flat.
This is worrying as eventually all those consumers will be running directly from the charger causing it to overload and or overheat.
Martin
All good advice - my charger does have a cut off though to prevent it effectively becoming the power source and I have a voltmeter fitted that gives me an audible warning when the battery voltage drops below a certain level. That said I don't run a fridge or laptop so my draw really is relatively low! I only have the 2 leisure battery set up because I like to be off mains for a few days withouit having to worry about going flat! Plus the single lesiure battery fits under the seat but is only 85Ah - it was cheaper to buy a second (matched) 85Ah battery and put it in the adjacent buddy box (via a 25A fuse!) than to upgrade the 85Ah battery to a 110Ah unit!
kevtherev wrote:The C tek charger eventually switches off the supply Martin, although you're correct the battery will be past the recall as the charger will crutch it down past 11 V
OK! so I'm guessing each time it cools it restarts thus entering into a thermo cycle....protecting itself but with the same resultant flat battery senario.
However, I have to agree that the chances of this happening are slim and under 'normal' mixed usage you are unlikely to have any problems.
kevtherev wrote:The C tek charger eventually switches off the supply Martin, although you're correct the battery will be past the recall as the charger will crutch it down past 11 V
OK! so I'm guessing each time it cools it restarts thus entering into a thermo cycle....protecting itself but with the same resultant flat battery senario.
However, I have to agree that the chances of this happening are slim and under 'normal' mixed usage you are unlikely to have any problems.
Martin
it's more of a demand type of thing if the charger cannot supply the demand it simply doesn't.
I tried it on a very old 27ah battery.. ran a TV at 5 amps, with the 4 amp charger on... it supplied power till the battery was utterly shagged and no longer contributed to the TV demand
The battery was destroyed and not retrievable...
The specific feature you need is a charger that auto senses and goes to 'float charge' state (trickle charge) when the battery is fully charged so the battery is not boiled dry if you leave the mains plugged in permenantly.
Normally these charges are refered to as 'Smart' or Automatic..somewhere in their description.
Another cheaper alternative....if money is driving your choice.
so I'm guessing each time it cools it restarts thus entering into a thermo cycle....protecting itself but with the same resultant flat battery senario.
