How to Charge a Lead Acid Battery

[DiploStrat]

It is time for the 2018 update to my paper on battery charging. Of late, there has been much discussion of this subject. Some of the information has been contradictory. So, as this paper is due for an update, I would invite all to:

-- Read it, and,
-- Offer comments and questions, either as thread posts or as PM's.

https://cookfb.files.wordpress.com/2016/09/battery-charge-slides.pdf

An older, deeper document on this subject, much in need of revision, is here: https://cookfb.files.wordpress.com/2015/04/electrical-power-for-the-overland-camper-the-problem.pdf

This is the paper that I wrote when I was first trying to come to grips with the subject and sort my way around the various concepts.

 

[Climberclimb]

A good read - thanks for posting! Cheers

 

[Stumpalump]

That was a good read. I got to battery monitors and thought to myself great, maybe I'll be able to understand the garbage I read on my Morningstar controller. Next line says Monitors and why they don't work. I feel better now and am glad I mounted it in a hard to veiw area.

 

[DiploStrat]

That was a good read. I got to battery monitors and thought to myself great, maybe I'll be able to understand the garbage I read on my Morningstar controller. Next line says Monitors and why they don't work. I feel better now and am glad I mounted it in a hard to veiw area.

My Tiger had a Bogart TriMetric and a Blue Sky solar controller, both wired to the same shunt. It was fascinating to watch their readings move in and out of sync.
My current XPCamper has a GoPower PWM solar controller and a shunt based Magnum battery monitor. Most of the time the GoPower is convinced that the batteries only reach a SOC of 90% while the Magnum reports 100%. Recently the GoPower reported 90% (and a correspondingly high voltage) while the Magnum reported a SOC of 68%. Sooooo, I plugged the Magnum into shore power. I would have expected the Magnum to jump into a high amp, bulk charge. Instead, it dropped to float charge. 24 hours later, both monitors are convinced that the batteries are at 100% SOC.

Dark arts.

The moral of the story is charge whenever you can, for as long as you can.