Googling the battery, Amazon says it weighs 18,040 pounds.
Moving on, different source:
The
Deka replacement battery ETX18L Battery Specifications:
- Voltage: 12 Volt
- CCA: 340
- Capacity: 20 AH
- Chemistry: AGM
- Length: 8.13"
- Width: 3.56"
- Height: 6.38"
- Weight: 15.5 Lbs
Ok a 15.5LB 20 amp hour battery with 340 CCA is a battery built for high CCA. Thinner porous plates and likely high specific gravity. High specific gravity of the electrolyte means more aggressive sulfuric acid, and an overall shorter shelf life, especially if stored in a warm spot.
I have similar size/weight AGM batteries, but Chinese AGMS @ 18 and 22AH capacity, the UB 12180 and Ub12220, 11.1 and 14Lbs respectively.
No CCA figures but I expect the 12180 has about 170 and the 12220 about 210. Either of these batteries, on their own, can start my overnight cold 5.2 liter V8, the 12180 just barely though.
While these two batteries say 5.4 and 6.6 amps max charging rate, I usually double that rate, and they when well depleted, they can accept 5x that amperage, and I will let them, for a few minutes.
If You were to give me your battery and say do your thing, After taking initial voltage, I'd attach it to a 40 amp power supply set for 14.7v, see how much amperage it takes for how long, and when it tapers to 0.1 amps I would remove charger, and watch voltage drop over a few hours, see where it levels off, and note how quickly it does so.
Then I'd likely drain the battery fully, using an old sealed beam headlight, about a 5 to 6 amps load, see how long it takes for voltage to hit 10.7v.
Then I'd attach it to my 40 amp power supply set to 14.5v. See how long it takes 40 amps to bring it to 14.5v, then watch amperage taper towards 0.1 while held at 14.5v. If any charging battery's temperature started approaching 100f, I'd reduce voltage sought by the charger, which lowers the amperage, 110f Max is what i will allow, 120f is danger zone. My charger has a meter attached counts amp hours delivered. Note how many it counts, how long it took.
Once amperage in the 14.2v range tapers to 0.1 amps I'd drop it to 13.6v and let it go for 12 more hours.
At this point I could run the same sealed beam light, and see how long it takes for voltage to hit 10.7v, compare to initial test.
Technically a new fully charged 20 amp hour battery can provide 1 amp of current for 20 hours before it is fully discharged.
This does not mean the battery can provide 5 amps for 4 hours though, or 20 amps for one hour.
Peukert effect says the bigger the load the less overall capacity the battery has to give.
A sealed beam light will start about 4.5 to 5 amps at 12.8v, and amperage will decrease as battery voltage decreases.
Batteries love being fully charged, but in my experience AGMS held at float voltage forever, get lazy. I believe it to be good to exercise them once in a while, do not overdischarge them, do not slowly discharge them dead, do it relatively quickly, over no more than 20 hours., and do not fear high amp charging of AGM's, just be wary of their heat gain, and once it starts, it accelerates, and over 120f is the danger zone one needs to avoid.
An old sulfated depleted battery will require lesser amperage for lesser duration to achieve high voltages( mid 14's)
A new healthy deplketed battery will accept much higher amperages for longer before voltage rises to the mid 14s at the battery terminals.
Both, if discharged to under 12 volts cannot be fully charged in less than 5.5 hours and the sulfated one is likley 2 to 3 times as long, assuming the charger is seeking mid 14's and has ampple amperage available to raise battery voltage to mid 14's in less than an hour.
This amperage accepted and the duration until it hit absorption voltage, is very revealing as to its condition.
Seeing how much it accepts for how long, is one data point in figuring out the health of the battery.
repeating the same test, after discharging it, gives one the ability to compare to see if some capacity has been restored by a proper full recharge with battery heating high initial amperages. voltage limited to mid 14's.
Same with the discharge, a sealed beam discharging it to 10.7v, is a LOAD test, comparable to itself. How long can it power it before voltage drops to the same level as before?
Every time I am given older AGM batteries to restore This is my recipe. Some of them gain 20 to 30% on the initial charge and another 10 on the second. Some of them are so obviously compromised it is obviously not worth the effort to try and restore them by cycling them deep and high amp recharging. Sometimes I am not sure and try anyway, and sometimes the battery actually surprises me and other times the battery jumps off the cliff, as the actual load test and recharging are a bit abusive to it.
Since the battery in question has a very high CCA for its weight, I'd not stress hitting it with 40 amps when well depleted.
Odyssey AGM are a thin plate pure lead design, and have very high CCA ratings.
Their reconditioning process:
Any charging source applied will be better than no charging source applied, but some maintainers/smart chargers will not be able to ever fully charge an older questionable battery even if a smaller AGM.
Waking up an older lead acid battery that's been sitting or mistreated, takes more than just a maintainer.
Don't fear recharging AGM's at higher amperages, the regular low and slow trickle charge them mentality, can tickle them to death, and if they are already at relatively high state of charge, they can't be high amp recharged, and mush be discharged some first. Generally 12.2v rested, is 50% state of charge/ depth of discharge, and generally lead acid batteries should not be drawn below this level. If going below this level it is paramount to quickly recharge them and then recharge them to a true full, certainly not just 85% - 92%, like many smart chargers will do.
The charging sources available to you are likely highly limiting factors. Some smart chargers are not so smar, despite their marketing and well know brand recognition and vociferous fanboys, yet usually quit well before the battery is fully charged. The green light only means it has stopped holding the battery at absorption voltage, and is now holding float voltage.
Some smart Schumachers can goto way too high a voltages sometimes , even on the AGM setting which should never go above 14.8v. Other times they quit prematurely. Baby sit these.
Self discharge of any given battery has a lot of influencing variables, but heat is always the biggest, followed by state of health, and state of charge of the battery when left to self discharge.
While 2 to 3% self discharge per month is a good Average for an AGM, it really depends on teh brand and its condition. Lifeline NOrthstar and Odyssey can be under 1% per month as 77f when new and healthy. Some other AGMS can be 5 to 7%..
Lifeline Northstar and Odyssey are basically double the price of most AGM starter batteries sold, to the general motoring public, and overkill for 99.99% of them.