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MightyMax 18Ah AGM battery
The Northstar NSB-27M has been relegated to workshop duty after nearly failing to start my warm engine yesterday when fully charged in mild ambient temperatures.

Sometimes recently, I was paralleling the MM battery to it, just so the stereo would not shut off when starting the engine, but not always. Other times I just had the Ideal diode passing charging voltages to it whenever they were present to keep it topped off.

Today, it was in parallel with the NSB-27M for a few starts on the way to the battery distributor and kept at 14.7v there and back.

While I was charging up the New NSB-31M battery, I plugged in the better of 2 wattmeters to top charge the MM, and found amps tapered down to 0.09 at 14.4v. I then removed the New Northstar and cranked voltage upto 15 and it tapered quickly back to 0.08. Often this battery decided to taper to no lower than 0.15 @14.7v before rising again.

I should see if it alone can still start my engine as all I do is plug in two 45a powerpoles and flip a switch from 2 back to 1. Such low voltage is likely difficult on the starter but the New NSB-31M is going to be maintaining 12+ volts during starting, for several years yet.

I think the next time I have to use the 24v hedge clippers, I will shop for another AGM battery in the 22AH range and put them in series in the backpack.
I'd forgotten what year i bought this 18ah MM branded agm, but its capacity has now declined to near uselessness.

My wattmeter is now saying it has delivered 1.08ah over 4 hours and it is now holding 10.56v powering 0.47 amps.of Jaro fan.
Remove load and 30 seconds later reads under 11 Volts.
5 minutes later 11.5v.

Ill say i money's worth from it. It did a lot of 9.6v drill powering, spinning wire wheels, powering a vacuum through inverter, powering leds.

The 22ah UB12220 i bought a year later, seems to be retaining its capacity far better, but ive also used it less and less hard when I did.

This battery's capacity has taken a steep nose dive. A month or two ago it was still able to deliver just over 6 ah.
I've no real need for it anymore, and will not replace it.

Probably squeeze some more fan duty from it before.pulling the 8 awg 45 amp powerpoles and giving it to a battery retailer for recycling
So warm off the charger, the mm battery charged one phone,15 to 85%, and powered jaro fan at 0.22 amps for 1.5 hours, while charging other phone 14 to 32% when phone said please plug into a real charging source.

MM battery fell to 8.93v. Having delivered well less than 10% of its rated capacity.

Done and done.
But 1 amp hour remaining capacity proved adequate, powering 6 individual RGB leds on red only, 12 hours a day, till now.

Easier than making another USB supplied red led nightlight option, the prototype which has found a good home elsewhere.

Would throw MM battery on meanwell at 13.6v for about 10 hours here and there. Sometimes try 14.5v.

I'd watch for that initial hookup amp spike, but it was rarely more than 1 amp, and tapered quick.

This evening, that initial spike was only 0.2 amps, at 14.5v, but .M battery will now heat , when held up there for too long.

Earlier this evening, I measured 12.42v unloaded, after sitting 10 hours disconnected.
Hooked led up, and measured 9.42v and fallng fast

My wattmeter is now reading 0.04a, at 12.51v, on a 3S 18650 holder with Red leds at brightest level on cheapo RGB controller.

Dimmest level reads 0.00, but is likely around 0.015a wattmeter not accurate down low.

Not gonna bother hooking DMM inline.

I want an ampclamp which can read low currents accurately.
I pulled everything off the MM battery, even the rubber cell caps, and sent it off to the recyclers today.

I was still asking it to power the red LED bathroom nightlight, over night on minimum brightness, at 8p. 13.65v fresh off of meanwell. within 2 hours,under 11 v by 8 am down in the 7's and super dim.

my ub12220, in same usage, 12.78v at 8 am.

3s 18650 pack powering it now.
got to make another usb wall wart powered red night light i can dim even further, or crank way higher.

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