How to Charge and Test Absorbed Glass Mat (AGM) Batteries

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How do you charge and test absorbed glass mat (AGM) batteries? The Delphi Training Series breaks it down for you.

[Hopeless_and_Forlorn]

This video is a model of how to disseminate the needed information clearly and succinctly. Thank you. As a bonus, I learned a lot from reading the informed comments.

[cringycook]

I actually learned a lot of this guy he explains everything well👍

[leisuresolarltd]

Good information from a knowledgeable presenter. Thanks!

[jdantigua]

Thank you because I have a used battery and it does not identify as AGM or conventional. At the beginning of your video, you answered my question.

[rickwaisanen]

On the optima batteries ive had several 10 yrs and a couple 12yrs they have a website that explains how to charge them using any other old battery works great for me i have found 3 at yard sales for 20.00 all still working at least 4 yrs for the mot recent one they cost 300 plus very good tutorial on the website

[bob_frazier]

Thanks for showing me how completely inept the local battery store is for load testing my AGM Deep Cell batteries.

[shiloh]

Good video. Question...should I install an AGM battery in my 2017 Subaru WRX?

[kisbushcraftdownunder]

I have had multiple AGM batteries in campers I was always quoted a life expectancy of five years 😢 but living in Australia in a hot 🥵 state I am lucky to get two years

[lastdaystravellastdaystrav]

for my application i have 2 6 volt agm deep cycle batteries hooked up in series. i have been using an older 6-12 volt battery charger when i m home and i just realized that i need to get one for AGM specifically, can you recommend something that its going to be more than 1.6 amp and on the affordable side? can i get something rated 20 amps or should i get 10 amps or 30 amps. thank you .

[josemedeiros]

Great video and information, I wasn't aware that AGM batteries have a higher voltage. What is your opinion on Battery Chargers with desulfation mode built in such as CTEK, Noco Genius, and Pulse Tech charger's have?

[curtchase]

good explaining there. Unless I'm dead wrong, when you measured 960 CCA on the battery I assume the battery was near room temperature. That's normal. Put the battery in a deep freezer for a day, yank it out and do test again. I bet it will be closer to the rating. Thanks.

[somaday]

The conductance/ capacitance battery capacity testers do a good job when comparing batteries of the same manufacturer's model and can point to weaknesses even on new batteries, and different tester mfg's can give different capacity numbers for the same battery, and they can give very consistent results. The CCA capacity calculated is just that, it is not directly measured. Tests are non-destructive so the current draw is minimal. Narrowed your selection for a new battery to a specific model? Use the tester to check several of those same models on the shelf and select the one giving the highest test results. Some brands vary as much as +/- 15% even within the same lot/ same day code, so why not take the best? Other brands may vary less than 2%. Btw, the tester used in this video looks like a variant of a Midtronics EXP800, one that wil give consistent results. Another reliable tester that gives slightly higher CCA results than the EXP800 is the Snap-On YA2636, and its results are about 10% that carbon pile results, which are the most definitive.

Performing a couple of back to back carbon pile tests, (with a several minute break between tests to allow internal cooling), gives the most definitive results. And testing at the high current will sometimes cause even a new battery to fail open. (Out of a lot of 3000 one year old charged but unused AGM batteries from a well-know AGM brand mfg, fully one third failed my carbon pile test, which in this case, tested an 800 CCA rated AGM battery at 600 A for 15 seconds at 60 F. Interestingly, it was the internal bus of the cell at the same location in each battery that was responsible for the majority of the failures.) Besides the venerable Sun VAT40 carbon pile tester mentioned in this video, other good ones are the Sun VAT28 and later versions, and Snap-On MT1560 and MT1590. (A not so-good CC pile tester is from Harbor Freight, whose flimsy construction is borderline dangerous and steel terminal clamps will melt grooves into the battery's terminals at high current testing.) (If the carbon pile tester has not been used recently at high current, perform some low level current tests to drive off the absorb moisture from the carbon disks to reduce spalling.)

[Mickytdi]

My start stop AGM battery reads 515 EN amps ( rated 680 EN amps ) also says 50-55% SOH. Will it last long?

[fknows]

why is it you talk about AGM but then only show testing on a flooded battery

[Rebel]

Good to know. Fixing to get a zero turn mower that comes with an agm battery and all I have are old fashioned schumacher battery chargers and a very old 1amp trickle charger, so when that battery eventually goes bad, I'll replace it with a standard battery that I can recharge normally.

[ghiyathkhelik]

What's better AGM or standerd battery?

[johnnywinter]

It's cool every once in a while to bump into a video where someone actually knows what he's talking about, when you realise you haven't lost precious time once you wached it...

[PaulBarry.]

Good informative video, thanks for posting.

[jims]

Thanks for explaining charging batteries, charge %, etc!

How does the load tester calculate battery health (roughly)? How reliable is the battery health calculation (will it be different based on temperature, charge level, internal resistance)? What is internal resistance?

[jeandede]

What max charge current should be used for an AGM 660ah battery park?