From Hagerty's: How Battery Chargers and Maintainers work

[elagache]

Dear mid-60s Buick caregivers who allow their beauties a long winter's nap,

Hagerty's has a neatly done piece on battery maintainers:

https://www.hagerty.com/media/maintenance-and-tech/battery-chargers-and-maintainers-how-they-work/

There isn't anything earth-shattering in the description, but it is a nice pulling together of all the issues.  It also might reassure some of you as to whether or not you want to use one of these devices.  According to the piece, even completely disconnecting a battery from the car isn't as healthy for the battery as using one of these maintainers.

Edouard

[TrunkMonkey]

With batteries nearing $200, tenders make very good sense.

I have a battery charger/booster (starting mode) and it goes into "maintenance mode" automatically after bringing the battery to a full charge connected to one car.

VIKING 2/15/50/250 Amp, 6/12V Wheeled Battery Charger, Engine Starter, and Alternator Tester ($200).


And a "battery tender" connected to the other car. Same thing, brings battery to full charge, then maintains.

1-Amp Smart Battery Charger - GENIUS1 ($30)

[elagache]

Dear Michael and mid-60s Buick caregivers,

With batteries nearing $200, tenders make very good sense.
. . . .

Since even in good weather classic cars don't get driven that much, battery maintainers are a good way to make sure when you can drive your classic, the battery won't let you down.

A car friend of mine shamed me into upgrading to Optima batteries and chargers.  AGM batteries cannot leak like regular lead acid batteries.  Another friend of mine had a car "die" when the battery leaked and damaged the frame so badly that the car was wrecked.

I understand the worry of chargers malfunctioning and causing a fire.  I still have confidence that the manufacturers are aware of this and design the circuity to make this basically impossible.  Certainly if you buy a known brand, hopefully you are in good hands.  Our house ended up with a whole-house surge protector as part of the standby generator.  I suppose you could further "harden" the electrical system feeding your classics at a modest cost.

Edouard