I did one ear at a time & hear above average on both but my right isn't as good as my left from years of long gun shooting.
https://www.youtube.com/watch?v=_SHFwmPQ_rQ  Here's an eye test I haven't tried 
https://www.youtube.com/watch?v=YAxLueEKqmU

https://www.batterystuff.com/files/388-40696.pdf

I wanted another portable 12v battery, to hook in series with my existing 12v 18AH mightmax AGM battery to power  24v hedge trimmer. I want to cut down some foxtail weeds as they grow and are still green, before they dry out and enter Fiona's paws/ ears/sinuses, on the property where I park.  A weed whacker would disperse the foxtails far and wide, but the hedge clippers I can cut them and easily collect them whole for proper disposal.



I thought I could get away with using a DC voltage boost converter to directly feed the 24v motor 24v+, but the load of the motor is too dynamic, changes too quickly with changing load, and a second battery was a much better bet. The 24v motor @ 12.7v was too weak to be of much use, but it did work, slowly and could get bogged down easily.

@25v+ and freshly lubed and sharpened the hedge clippers chew easily through tall thick grass and weeds.

The 22Ah battery is the same exact dimensions, as the 18AH battery, but weighs nearly 2 pounds more.

The two batteries are mismatched in age/ capacity and resistance. Charging them in series @~29v one battery was mid 13's one was mid 15's.  Have to charge them separately.  

On discharge in series, one battery was doing more of the work too.  One might think the battery doing more of the work powering loads and sucking more charging current in series, would be the newer larger capacity one, but it is not.  The older battery has a higher resting voltage and retains the surface charge voltage for longer than the new one does, at this point.  Whether this is due to a stronger electrolyte, or the fact that the 'new' battery was actually 8 months old on arrival and not yet broken in/partially sulfated, is unknown at this point.  Online batteries are always at risk for being old.It was a 42$ battery that arrived 2 days later. So be it.

Every newly acquired battery I've ever cycled has not performed as it later did, and the hedge trimmer's use so far has hardly put a dent in the capacity of either battery, So I expect improvement once I get a deep cycle and a proper recharge into it.

The 18+22Ah battery gives me an additional 40Ah of theoretical  'emergency' capacity, to add to my 103AH of the g31 Northstar, should I ever need it, which seems unlikely.

I have not yet tried to start my engine solely on the 22Ah battery, as I did successfully with the 18Ah battery when it was new to me. I suspect the 2 Lbs of extra lead will have higher CCA and more ability to crank the engine than the 18Ah battery.  The 18Ah battery is marketed towards the boom boom stereo crowd, and might be more of a hi-rate battery, but who an tell the difference between marketing and maximum profit in this day and age.  MightMax told me to use the spec sheets and charging recommendations of the UPG/UB 18AH agm batteries, when I inquired.

The Printing  on the new battery case says NO initial Limit on current/amperage, if voltage limited to 13.6 to 13.8v, but limit current to 6.6 amps @ 14.6 to 14.8v in cyclic duty.  Previous batteries would say limit to 3.3 amps or 30 to 33% , at 13.6 to 13.8v standby duty.

6.66 amps x 3 =22, so they want  no more than a 33% charge rate if seeking 14.6 to 14.8v in deep cycle duty.
Many lesser AGMs say no more than 30% charge rate applied until 14.x volts is attained
Lifeline AGM says no Less than 20% when deep cycled and more is better and 500% is acceptable
Odyssey AGM says no less than 40% when deep cycled and no upper limit on amperage as long as voltage limited to 14.7
Northstar does not say specifically but my experience says more, is better and I often fed my 90Ah NS- AGM-27, 65 plug in Amps and more from the alternator, with enough rpm.  

I'll greatly exceed those  recommended maximum recharge rates when the UPG battery and ambient temps are cooler, and monitor for excessive temperature rise, I'll go to mid 90's no problem but over 100f and I get nervous.  I do expect ~25f temperature rise when reaching absorption voltage instantly from a low state of charge with high amperage available, by the time the battery is ~95% charged.  If it is above 95f I back off the voltage accordingly and can watch temp fall with it.

The older MM 18Ah battery had 2 pairs of 8 awg cables with 45 amp anderson powerpoles.  I moved one pair of these to the new 22Ah battery, and this makes wiring them in series quite easy, but I need more 8awg and thick walled ring terminals as having a pair on each battery was mo bettah.

Unless the new battery decides to have the same full charge resting voltage as the older one, I will never leave them in parallel, and likely never charge them in series or either, at least not to near full, perhaps just a small between trimming blast. I'll charge them in parallel no worries, one will just take longer.

For charging, I am using a sub 3$ 150 watt voltage booster I housed within an old inline powerbrick.  It is modifed with a 10 turn pot and its own voltmeter and 50mm fan, and will go upto 32 volts. I use a wattmeter to see amperage voltage and wattage going into the other battery.

 This is effectively a battery to battery charger, as even when I am charging them separately at 12v nominal, my dc source on workbench is a few tenths of a volt below the main battery voltage, which might not be anywhere near 14.7v, and too low for proper charging of the battery, so i use this booster on the workbench to take 12.x volts, and raise it to 14.80v.

These newish voltage buckers and boosters have so many dang uses. I am impressed with their functionality, usefullness, and their low price. I might incorporate one into a portable power pack I will be building for a friend who will be driving his truck to central America and wants a modest modular System separate from main engine battery.

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https://youtu.be/7yO0vEzYeOs
History hunters video. Kind of cool channel.

https://slickdeals.net/f/13860293-ryobi-...=frontpage

https://www.nature.com/articles/d41586-018-03267-5

been having ear,balance and just feeling like crap since last spring,amoxicillin did nothing,so my doc gave me 750mg levofloxacin,the reviews were scary but a nurse friend talked me in to it   

i took one pill,instant breathing problems,muscle spasms,tingling in left hand,went and got me some cheap magnesium to try and counter it,back to doc,he gave me another antibiotic,no issues,head feels better

numbness/tingling in left hand has spread to both feet,up the shins,and other hand(peripheral neuropathy),seems i developed a bad reaction to bread too,lucky compared to others

might go to the er tomorrow because the numbness/tingling has spread,might not,dr scheduled for next week,this very well could be life long and progress in many horrible directions,one pill could have doomed me



trust yourself and never take  fluoroquinolones unless near death

https://floxiehope.com/

I know my posts are generally not cheap fixes or the most frugal way to do it. Time for some is money. Learning how to do it right takes time. I am basically a believer in buy and cry once. Good for the environment too as less junk in the ocean and landfills. 

Ok so Russian manufactures are cheap ass mo$Fu:$:. Battery cables on our Lada village 4x4 stranded me and the monsters. First eight gauge wire for mains positive and negative. Really? So I got some two gauge and tried to get it correctly terminated. What a pain in the...

I've used Genesis battery systems for years and I remembered the awesome customer service and some slick two gauge terminations. I checked. Yes still aviailible. Two gauge is pretty much overkill for most projects. So I called when I got the monsters home, forgetting the time difference. The owner answered!! I reminded him of my quad set up universal mount for the Viper truck and he remembered me. Only 2000 SRT 10's sold in the USA that year and I was probably the only one stupid enough to jam 4 group 24 batteries under the hood.

Asked him if he would toss a twin pack into a FedEx package and ship to Russia. He said he would and pass along shipping fees via email pay me please request. Got them today. Four days is incredibly fast shipping for here. I expected two weeks even with stupid level shipping costs. 

Easy breezy terminations. No big crimp tools or guess work. Heat poke in just shy of an inch stripped wire and let cool. Done like Trotsky. 

Here is the link. 
http://www.genesisoffroad.com/Heavy-Wall...p_134.html


There dual battery set ups are pricey but as I said, for me, buy and cry once. For those with little skills this is a no brainer option anyone can do. Saves on doing it wrong and smoking relays, batteries,rigs. 

The link takes you to the two gauge terminals but the menu is clickable.