Reader Question: Tenders and Chargers?

Here’s the latest reader question, along with my reply! 

M asks: Hi, I have been shopping for a battery maintainer. So far, I have about settled on the NOCO Genius 5 (or Genius 2 maybe) or the Griot’s Garage (4-amp) Battery Manager V. While these are more expensive, I like the various features that they have especially in terms of “repairing” a battery. I have a 6-cylinder midsize sedan and an 8-cylinder large sedan. I’d like to be able to use the maintainer on both cars, if needed. Someone told me I’d need to know the amp-hours of my batteries (which I do not know) to determine the correct amp maintainer to buy. Is that necessary? Are these the best maintainers from which to choose? Any guidance would be appreciated. Thank you for any help and for your website.

My reply: The good news is that most over-the-counter battery tenders are automatically set up to charge any 12V battery in a safe/correct manner. Most of these come with either alligator clips or a quick-connect that you splice into the battery’s positive and negative terminals. Then you just plug the thing into any household 115V outlet and it will maintain your battery’s charge – shutting itself off and on as necessary to keep it “topped off.”

Fast chargers on the other hand are another matter; these you need to be more careful with – as in read the instructions and make sure the charge rate etc., is appropriate to the battery you have. Some 12V batteries – e.g., absorbent glass mat (AGM) batteries – are more sensitive than standard liquid electrolyte batteries.

I’d go with the tender rather than the fast charger. And maybe get a jump box for those times when you have a dead battery and need to get going right away. That said, slow charging is preferable in terms of battery longevity than fast charging.

Hope this helps!

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