Trickle charger question...

[Nick Bassett]

This might seem like a really stupid question, but I want to be sure of what I am doing... is it OK to attach a trickle charger to a battery while the battery is still in the car, connected? I'm pretty sure it is, just want to be certain!

Thanks.

[Jonathan Kay]

Yes, but...

Traditional "dumb" trickle chargers can overcharge because they're... dumb. So never leave them on all the time.

What many of us use are "smart" conditioning chargers (such as CTEKs) that won't overcharge and can recover abused batteries. They can be left on all the time.

Jonathan

[Paul Mason]

I've bought an Optimate which I have now attached a permanent cable and plug into the car and can just leave on. It was only £45 or so, really neat and has a really simple LED display to tell you what its doing. It will never overcharge, just continually discharge and charge I believe to keep everything topped up and healthy.

[John Vine]

+1

(Actually, I use an Accumate, which is pretty much the same thing.)

JV
 

[SJD]

I have a CSI Airflow permanently wired up. You do have to check the electrolyte level from time to time as it does go down.

[Piers300]

A constant potential battery charger, I.e. Accumate - CTEk ect, work on the basis that when the float charge level of the battery (13.2 volts approx) and the charger output voltage are equal , I.e. the battery is fully charged, then no current flows. So even though the charger remains connected, it is not charging. When the battery condition changes due to some internal losses, the voltage changes and the charger then operates to charge the battery. You just leave it on, but do check the electrolyte level occasionally.

A float charger normally has a boost and trickle switch and if left permanently connected, will boil the battery dry. 

Piers