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The 22AH UPG UB121220 AGM battery

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.
Lowes still has these 40 volt 2.5 AH weedwhackers with battery & charger for $51.40

Item # 796787 | Model # KST 130X-06
Kobalt 40-volt Max 13-in Straight Cordless String Trimmer with Edger Capability (Battery Included)
Was $129.00
A friend at the airport bought a gas one for $5 at a yardsale, safery wired it to a bicycle, carved a prop & with peddeling to get started could maintain 40mph+
"If a law is unjust, a man is not only right to disobey it, he is obligated to do so." - Thomas Jefferson
The Foxtails are sprouting, and the hedge clippers and batteries have been getting a workout. I make a pass along their base and pick them up in a bunch so as to keep them from discharging their evil foxtail spawn. A weed whacker would certainly be faster at cutting them down, but would simply fling the foxtails everywhere, which is what i am trying to avoid.

The Andersons make it easy to hook the batteries in series for 25 volts, and I would switch the batteries via the andersons AB, then BA in series, trying to see if they would discharge more evenly.

I've been charging them in parallel, just letting them suck up as much as they want from a 94 amp adjustable voltage power supply set at 14.8v

The New heavier battery accepted amps at the level of depletion I had them at, which was likely still well above 80%.

The 18Ah sucked up 12.5 amps while the 22Ah sucked up 14.8 amps initially.

I just let them feed for a while at 14.8v, neither appeared to warm up, and then an hour or two later checked amperage into each battery, The new one tapers below the 0.11a threshold which is considered fully charged. The Old has not been tapering to the 0.09a which is considered its full charge threshold.

The new battery drops to 13.32V an hour after removing it from the charging source, the old one is still 13.7v an hour later, but 24 hours they are within 0.05v of each other. I will not leave them in parallel resting

Each battery now has two sets of 45 amp Anderson powerpoles . I could easily pop my hood, and hook up one or the other to powerpoles I have in there, Turn one 1/2/both/Off Switch and start my engine on either battery by itself.

I originally Thought I would be storing the battery underhood, but I have room for both in my Electrical cabinet, and can parallel them there easier than i could popping the hood, and have a shorter circuit to Starter, alternator and solar too.
Well cancel that previous declaration of resting voltage 24 hours later.

some 48 hours later the old 18Ah AGM reads 13.36v and the 'new' 22Ah AGm reads 13.16v.

When I hook them in parallel with my Wattmeter in between, 0.38 amps flowed from old to new, but tapered quickly to below the resolution of the wattmeter and now they both are at 13.20.

I'll not be leaving these two in parallel for any duration, and the 18's voltage retention being so high for so long might be an indication it has dried out some.
I did remove the cover and rubber cell caps and used a dropper with some distilled water but 2 drops revealed they were already full, or impervious to additional watering.

2 weeks or so ago, I was needing to employ a vacuum, somewhere where there are no AC outlets.

I have no battery powered vacuum, but that would have been nice.

BUt I can power my '4.0' amp 115vAC buckethead shopvac vaccuum, by batteries.

4 amps x 115 volts ahould be a 460 watt load
4 amps x 120 volts should be 480 watt load
460 watts divided by 12 volts DC should be a 38.3 amp load.
The inverter is only 85% efficient or so

Actual ammeters inline from batttery to inverter show it is in fact a 32 to 34 amp load through my 800watt MSW inverter. 34 amps with a clean filter element, 32 amps with it slightly loaded and partially occluded.

So much for that 4 amp motor rating Wink

I did an experiment. I put my 18 AH and my 22Ah batteries in parallel, used my 8awg 'jumper' clamps with 45 amp powerpoles , directly on the inverter's DC input.

It had no issues running the ~32 amp load for ~10 minutes in the workshop, until I had nothing more to really vacuum but cobwebs from the ceiling

I then tried it on the older 18AH AGM by itself, without recharging it, and it was able to power the vacuum for 5 more minutes or so, before the low voltage alarm on inverter started chirping. I read 10.45v on the inverter terminals when the chirping started.

The 18AH AGM, when new, could start my overnight cold v8 engine by itself, ~ 180 amps. It no longer can, but, the 22AH battery still can, as of 5 months ago anyway.

I was pleasantly surprised at how long the 18Ah agm battery by itself was able to support the 32 amp load of the buckethead shop vac through the inverter.

When I vaccuumed the storage unit, I carried up only the fully charged 18Ah battery and the 800 watt inverter in a group 31 battery box, and had more than enough time to vacuum every cobweb and spec of dust from every surface within.

So much better than standing in a toxic dust cloud if I were to sweep instead, and much more effective.

I actually got my full deposit back on the storage unit.
They obviously could not find any rational reason to keep it.

What's also surprising is this 800 watt coleman MSW inverter, I got at Kragen autoparts, on special, for 40$, in 2004, has lasted this long.

I could slap a 12v powerport and a USB outlet on the group 31 battery box, and call my 18Ah battery and 800watt inverter a 'Solar Generator', and in fine print...'solar' not included.

The buckethead shopvac fits on a 3.5 gallon bucket, as well as a 5 gallon one. The 3.5 gallon one is much more compact and fits under my bed nicely.
While topheavy, for 25$ it is an amazingly capable vacuum. and 95% of the time I need a shopvac, I run it, instead of the 12 amp jet engine loud, full size one I have in the workshop. It has no issues on a router speed controller when its full power, or noise, is not needed/desired.

I took out the 'safety device'. It has a ball that stops it sucking liquids if it were to tip over. Since it tips over so easily, and I do not intend to vacuum liquids with it, I removed that ball.

I've gotten way more that 25$ of use from it, over the last 5 years or so, and if it were to fail tomorrow, I would get another one with no hesitation.

If you need a vacuum for your rig, the buckethead on a 3.5 gallon bucket, is relatively compact, highly capable, and a very inexpensive choice. extension 1.25 inch hoses are nice, not only for vacuum reach, but to direct that pecliar stinky vacuum bag exhaust stank, outside of the van.

The filter socks are cheap, and I usually rinse and dry them a dozen times or more before bringing another one into the rotation.
A vacuum vacation!

I had never heard of these 'bucket head' vacuums. I own a large rolling shop vac which is too big and cumbersome for small jobs and a couple of small light duty shop vacs that are too small for a mess larger than a bowi of spilled cereal (for example) I will be buying one of these the next time I make a run into the 'big city'...

Looks like the buckehead vac is right there in the 'Goldilocks' zone: Just right!
Wondering About Wandering.
Lowe's has a version with a 4.5 amp motor for similar price to the despot's buckethead 4 amp motor

It, atop a bucket, would be significantly taller than the buckethead version and would not fit under by bed platform right side up.  The smaller gallon 3.5 bucket allows this feature, and still has enough room inside to store the hose and some attachments.

I did have to replace the rocker switch on my BH.

experience would suggest that using the router speed controller, powering devices at reduced power, is hard on such switches.  I had a rocker switch burn up on a 1600 watt hair drier when using the RSC, and on the buckethead.

I replaced the rocker switches on both with larger higher rated versions, and 80% of the time, turn the devices on and off with the router speed controller's switch, rather than the switch on the devices themselves, and no more issues, but the new switches are much higher rated too..

The larger toggle switch I employed on the vacuum makes it much easier to turn on and off though, I can swing the vacuum hose attachment at it.

The buckethead vac, i took apart on purchase to see how it worked.  One of the gaskets was not properly compressed, and would have affected the amount of vacuum to some unknown degree. Very easy to spit and polish it out of the box for better performance.

I put a canvas strap atop the buckethead to use  as a handle and to hold the coiled power cord.  
I have some large rubber bands around the bucket to hold extra filter socks.
I keep thinking about a permanent van mount so I would not have to drag it from workshop to van, but All the locations and solutions I have come up with so far are not desirable for one or 15 reasons.

Vacuuming is so much nicer than sweeping, especially when the exhaust is directed outside the van/workshop.
Made the run today to buy some lumber and look what hopped onto my cart and ended up as 'plunder' at YARC Bar!


Wondering About Wandering.
I have a HD Rigid shop vacuum where the rocker switch stopped working. Opened it up, the external rocker switch, plastic about 2" L by 1" W, looks robust on the outside. The actual toggle switch inside is a cheap, small toggle switch with a bat handle that is inserted into a hole under the larger plastic piece. The hole for the bat had broken apart. Cheap ass part.

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