This is my first post on BITOG (please let me know if I am breaking any forum rules with this post), though I have been reading and lurking for many years. I am mainly making this post because I found a post on the forum that helped me really put some thoughts together in a very constructive way. So I hope that others who have the same or similar issue as me, will find my post or this very insightful post by user wrcsixeight. I had purchased an Odyssey Group 48 Performance series battery 25 months ago. It was a deal at Autozone that I could not pass up on a battery that was NOS (at the time about 18 months old by the date on the battery). Never had any problems with it, but after having a battery issue on another vehicle a few months ago, I thought I should test my Odyssey just to see where it was. I used the well regarded Ancel BA101 and found it was at 12.5v (otherwise healthy). So I put it on my AGM charger that I had on hand which was a Schumacher SC1280 15A (charges on AGM mode at 14.6-14.9v measured). The highest the battery would charge was 12.69v . I tried a couple more times with that charger and with a Optimate 6 Select on 14.7v AGM mode (awesome device). Every single time exactly 12.69v.
Meanwhile I read every document I could find on Odyssey batteries and every white paper I could find on TPPL batteries in general. I watched every Odyssey Academy video on youtube (every last one). At times, Odyssey does give out contradictory information, which lead me (and I am sure others) to not take some of the key instructions as absolutely necessary. The first thing that wrcsixeight reminded me of in his post was that to properly charge an Odyssey TPPL battery, Odyssey recommends a charger with a minimum of 40 amps per 100ah of battery capacity (40%). The second thing that was key in this same post was so simple, yet a revelation: "The deeper the discharge, the more important it not only is to recharge quickly, but recharge to truly full. So if intending to exercise an AGM, which is acting a bit lazy, I would recommend draining it to ~11.8v under load, with a load large enough that can do it in 3 to 6 hours, then immediately apply their higher amperage charging source. with the ammeter and the voltmeter, see how long it takes that amperage to get battery voltage up to the 14.4v to14.8v range. Then once the charger is holding that absorption voltage, see how long it takes for amperage to taper to low levels. A new healthy battery will take about 3.5 hours for amps to taper to 0.5% of the amp hour capacity."
Then it all clicked. I bought an adjustable bench power supply with 30A and 9-15v ($95). Three days ago, using a 400w inverter, I connected a small heater to discharge the battery down to precisely 11.8v under load, which took about two hours. I then immediately connected the battery to the power supply and set it at 30A (32A measured) and 14.7v. It took exactly 5 hours for the battery to slow its amp draw to about .35 amps. I let it sit for 5.5 hours (Odyssey Academy recommends at least 4 hours rest) then tested it with my new Autel BT608- 12.87 volts! Again, according to Odyssey, they consider 12.84v to be fully charged. I checked it again today and it is still at 12.87!
All this information was already in my head, and readily available online, but I had not quite put it all together to remedy my particular "lazy" battery issue. I am again very thankful for this forum and for this very insightful post by user wrcsixeight. It really completed the puzzle for me.
I also want to say that I always knew that AGM batteries and all different chemistries of batteries have there own specific requirements. But some of these requirements are more impactful than others. I see people all the time being very dismissive of these requirements with statements like "I just by these $20 trickle chargers from Amazon or Harbor Freight and my batteries are all fine." etc. If you don't care about your money or your batteries, do whatever you want. However, if like me, you want to get every last day for your battery dollar, I humbly suggest doing your homework and following the battery manufacturer recommendations for charging and care of your very expensive AGM batteries.
Lastly, for extra measure, I am now maintaining all of my Odyssey/AGM batteries with an Odyssey approved BatteryMinder 128cec1. I chose this after testing it side by side with the Optimate 7 Select (like the 6 Select, I LOVE this charger). I mainly chose the 128cec1 because it offers the additional benefit of constant de-sulfation (Snake oil you say? TBD) and explicit Odyssey mode/approval.
Here is the before test of my battery (Of note the BT608 considers an AGM battery 100% SOC when at 12.9v, hence the 96% here. It is also important to note that the 2016 Mercedes E350 that this battery lives in has a 100% healthy electrical system with an 180A alternator that charges at 14.6-14.89v with a very low 16mv ripple):
And here is the test after the charge:
Meanwhile I read every document I could find on Odyssey batteries and every white paper I could find on TPPL batteries in general. I watched every Odyssey Academy video on youtube (every last one). At times, Odyssey does give out contradictory information, which lead me (and I am sure others) to not take some of the key instructions as absolutely necessary. The first thing that wrcsixeight reminded me of in his post was that to properly charge an Odyssey TPPL battery, Odyssey recommends a charger with a minimum of 40 amps per 100ah of battery capacity (40%). The second thing that was key in this same post was so simple, yet a revelation: "The deeper the discharge, the more important it not only is to recharge quickly, but recharge to truly full. So if intending to exercise an AGM, which is acting a bit lazy, I would recommend draining it to ~11.8v under load, with a load large enough that can do it in 3 to 6 hours, then immediately apply their higher amperage charging source. with the ammeter and the voltmeter, see how long it takes that amperage to get battery voltage up to the 14.4v to14.8v range. Then once the charger is holding that absorption voltage, see how long it takes for amperage to taper to low levels. A new healthy battery will take about 3.5 hours for amps to taper to 0.5% of the amp hour capacity."
Then it all clicked. I bought an adjustable bench power supply with 30A and 9-15v ($95). Three days ago, using a 400w inverter, I connected a small heater to discharge the battery down to precisely 11.8v under load, which took about two hours. I then immediately connected the battery to the power supply and set it at 30A (32A measured) and 14.7v. It took exactly 5 hours for the battery to slow its amp draw to about .35 amps. I let it sit for 5.5 hours (Odyssey Academy recommends at least 4 hours rest) then tested it with my new Autel BT608- 12.87 volts! Again, according to Odyssey, they consider 12.84v to be fully charged. I checked it again today and it is still at 12.87!
All this information was already in my head, and readily available online, but I had not quite put it all together to remedy my particular "lazy" battery issue. I am again very thankful for this forum and for this very insightful post by user wrcsixeight. It really completed the puzzle for me.
I also want to say that I always knew that AGM batteries and all different chemistries of batteries have there own specific requirements. But some of these requirements are more impactful than others. I see people all the time being very dismissive of these requirements with statements like "I just by these $20 trickle chargers from Amazon or Harbor Freight and my batteries are all fine." etc. If you don't care about your money or your batteries, do whatever you want. However, if like me, you want to get every last day for your battery dollar, I humbly suggest doing your homework and following the battery manufacturer recommendations for charging and care of your very expensive AGM batteries.
Lastly, for extra measure, I am now maintaining all of my Odyssey/AGM batteries with an Odyssey approved BatteryMinder 128cec1. I chose this after testing it side by side with the Optimate 7 Select (like the 6 Select, I LOVE this charger). I mainly chose the 128cec1 because it offers the additional benefit of constant de-sulfation (Snake oil you say? TBD) and explicit Odyssey mode/approval.
Here is the before test of my battery (Of note the BT608 considers an AGM battery 100% SOC when at 12.9v, hence the 96% here. It is also important to note that the 2016 Mercedes E350 that this battery lives in has a 100% healthy electrical system with an 180A alternator that charges at 14.6-14.89v with a very low 16mv ripple):
And here is the test after the charge:
