MightyMax 18Ah AGM battery

[sternwake]

While I can fit 3 group 27 batteries in my van, since June of 2015 I have been using just one single group 27 Northstar AGM battery for both engine starting and house battery duty. It is rated at 90Ah capacity and 930CCA.
     This battery turned 5 years old in late November, and now has over 1000 deep cycles on it to the 50 to 60% state of charge  range, perhaps 150 of those thousand to as low as 30% state of charge.  Even when brought this low it has had zero issues starting my v8 engine in mild temperatures. 

I really do not expect it to live for too much longer, but have been impressed with it to this point.  I am not going to replace it before it fails, nor start babying it, but since it is my only battery, and it is also my engine starting battery, I need to have a backup plan. So I bought this 18 Ah AGm battery linked below for 37$:

https://www.amazon.com/dp/B01CYLHUC8/ref...B000LUBQ4I

This particular '600 watt" model is marketed for the Audio/ Stereo crew but the 18Ah MightyMax battery is basically the same price and weight, 11.9 lbs.

https://www.amazon.com/Mighty-Max-Battery-Portable-Generator/dp/B019Z7VI7M/ref=sr_1_51?s=automotive&ie=UTF8&qid=1546898828&sr=1-51&keywords=18ah+agm

If one plugs in '18Ah AGM' battery into amazon search there will be hundreds of hits, and the batteries themselves might be exactly the same inside, or might not be.  There are some differences in the output terminal design.

I bought this particular model as I like the recessed terminals, that are much less likely to be shorted with a dropped wrench, and I am not really planning on deep cycling it, intending to use it more as a portable 12v source and the occassional jumpstarter battery.  Will this battery be able to provide more CCA, and recharge safely at higher rates than the others?  Well, its marketing might indicate that it was designed for this, but I am skeptical to say the least.   If it were more expensive than the others I would not have bothered getting it over the other batteries in the sub 40$ range.


The UB12180 might be the base battery and all these other 18Ah agm batteries might be the same exact thing internally, or not, the only visible external differences being the terminal design.  Some of them do list slightly different weights, but I do not really trust this figure.  The heaviest one I found was 12.1 lbs, though the UB12180 linked below states  11.4 lbs.

https://www.amazon.com/Universal-Power-Group-Wheelchair-Replaces/dp/B00D8CX54K/ref=sr_1_50?s=automotive&ie=UTF8&qid=1546899146&sr=1-50&keywords=18ah+agm

These 18Ah AGMs are used in many of the lead acid jumper packs.  Back in the early 00's before I had dual batteries i had a smaller jumper pack that employed a 12Ah AGM and it was effective in assisting my group 27 starter batttery when i drew it down too low.

Anyway, it arrived today, and read 12.87v out of the box.  I peeled back the sticker but did not see the UB12180 printed below it.

I hooked it up to my 40 amp adjustable voltage power supply and 15 amps instantly took it to 14.7v and began tapering quickly from there.  90 minutes or so later it is still accepting 0.75 amps at 14.7v, so it was not top charged and could have been sitting waiting to be sold for quite a long time, self discharging.  or it might not have left the factory full charged, and most likely some combination of both.

A Brand new battery seems to behave a bit differently than one with a cycle or two on it.  
I am starting this thread to document the lifespan and capabilities of this battery,  using this thread as data storage for future reference.

I intend to see if this battery alone can start my engine, and perform various other experiments on it through its life.

I am not really sure where I am going to store it.  I could put in in my engine compartement, which currently has no battery no battery tray.