Trickle Charging While on Vacation?

Use a battery Tender Jr. It will switch on and off automatically and keep the battery up to charge with no hassle.

Keeping the battery charged is definitely better thatn letting it discharge. A full discharge is very hard on a standard (not deep cycle) battery and should be avoided like the plague. It is also very hard on the battery to sit in a discharged state for any period of time. There are a number of trickle chargers that will keep it in good chape while stored. Alternatively, simply ensure it is fully charged before storing the car and disconnect the battery. It will loose a little charge over a 2 month period, but not enought o be a problem.

Even deep cycle batteries suffer from a full discharge unless they are NiCads. The Battery Tender Jr. seems like a great battery maintainer, and will also charge batteries if given enough time. You can find them for $30 on Ebay.

Thanks to all who have responded. It sounds as though the Jr. is the ticket.

Java

You're welcome. The Tender also comes with two sets of plug-in leads: alligator clips and a separate set of ring terminal leads that you can install on the car, so you can just plug it into the Tender when you leave it sitting.

Aside from purpose chargers, is it a Relly Bad Thing(tm) to just hook up a regulated power supply to the battery or will that also do the trick? I have the same problem with my oldtimer convertible which does not see the light of winter.

Maarten

I'm thinking of a laboratory power supply, set so 12 or 13 V. It will not give more than that voltage and the current will drop to almost 0 when the battery is full. I'm wondering if that is bad for the battery or not.

Oh, and I'm Dutch ;)

Maarten

That depends on what you mean by "regulated." If it switches off when the battery voltage hits 13.6 or so, and doesn't try to charge at

Is the power supply happy connected to a 13V unlimited current supply if the mains fails?? Many are not.

Steve H

There are standing recommendations to use only chargers and not power supplies for charging batteries, however, the failure mode that Steve mentions above, which is probably the reason for such recommendations, is easy to protect against. Just fit a blocking diode of a large enough amperage rating on the +ve lead, and crank up the output voltage by .2V to take account of the voltage drop across the diode. This prevents the battery supplying voltage to the output terminals of the power supply if the mains fails, or, if someone 'helpfully' turns the PSU output down.

Ken P.

A battery charger is just a regulated power supply with the voltage preset and a high current capability. A trickle charger is just a regulated power supply with the voltage preset and a low current capability.

The problem with using a normal regulated power supply is if you make an error in setting the voltage. If it is too low you won't get a full charge and if it is too high you will burn off the electrolyte and ruin the battery. I think the power supply should be set at 13.6 volts or slightly less, not 12 or 13 volts. That makes a big difference.

Battery manufacturers should have a spec sheet which lists the optimum trickle charge voltage.

Also, never set a battery on a concrete floor. That shortens the life. I am not sure exactly why except the floor is a huge thermal sink and causes condensation in humid weather. It also causes a thermal gradient in the battery.