Trashed NOCO Genius2 By Reverse Polarity Hookup

[Jim Lewis]

The other day, I sleepily hooked up my NOCO Genius2 charger the wrong way round to the jump start points on my truck. I immediately got the reverse polarity warning on the charger display, unplugged the device, and hooked it up the right way round. Now it appears to be charging (AGM mode LED lit white, single red LED slowly pulsing), but the device doesn't raise the voltage across the terminals as measured by Car Scanner or OBDLink, or on a free-standing AGM battery measured with a multimeter. The borked Genius2 can remain attached for hours without charging my 12V battery.

In a chat with NOCO tech support, the agent swore reverse polarity circuitry should absolutely protect the NOCO charger and the device will reset itself within seconds of being unplugged and disconnected from a battery, if hooked up in reverse. However, online, one can find a number of posts from users who've found the NOCO reverse polarity protection didn't prevent their device from being trashed if hooked up the wrong way. The NOCO agent pointed out that the Genius2 comes with a three-year warranty and suggested I take advantage of that.

Since shipping mine back to NOCO will cost me a few bucks, I thought I'd ask if anyone knows of any magic tricks for "resettting" such a failed charger. I also have a Deltran Battery Tender Plus. Deltran claims it handles AGM batteries just fine, even though its interface doesn't differentiate between being hooked up to a standard lead acid battery vs. an AGM.

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[cal]

Wow I’m a big NOCO fan and really thought they were pretty good at this. Disappointed to hear it’s actually “Not so much”.

 

[chl]

So NOCO didn't tell you how to effect a manual reset if the timer doesn't turn it back on so I guess it doesn't have that feature, alas.

I assume the internal fuse didn;t blow if the thing powers up:

"Genius uses a Mini® Blade fuse which can be purchased at hardware or automotive stores.

GENIUS2

4 AMP MINI® Blade Fuse

But maybe that is the problemo?

If it were out of warranty I might open it and see if it was possible to fix the reverse polarity circuit that got fried, for example, if it was a diode in series (the simplest and cheapest) or a mosfet (still cheap and simple) sometimes in combination with a resister to limit the reverse current, any of which might have gotten fried and could be replaced.

Some mosfet versions operate by turning off to stop the reverse current and then will turn back on when connected correctly.

Your charger apparently has a timer on-board, apparently a microprocessor with programming that would shut it off then after a time period of disconnect, turn it back on.

" Compact, yet powerful battery charger. A mix of electrical engineering and industrial design pack a powerful battery charger into a tiny footprint. The GENIUS2 uses high-frequency switch-mode technology to efficiently convert A/C power into safe D/C power for battery charging. And its onboard microcomputer precisely controls the charging to minimize power loss to create an incredibly compact form factor....

Safety

Short-Circuit: Yes
Open-Circuit: Yes
Overheating: Yes
Overcharge: Yes
Spark-Proof: Yes
Reverse Polarity: Yes..."

Something went wrong with the protection circuitry (obviously) and it might be impossible or not worth the effort to fix, of course.

If under warranty, I'd just get a new one and be more careful to have my morning coffee before hooking it up, lol.

One of the first things we had to do in electronics 101 was build a power supply that had reverse polarity protection. There are many ways to skin that cat, some simpler than others.

I just searched and found this AI report:

"NOCO battery chargers incorporate reverse polarity protection to prevent damage to the charger and the battery being charged. This protection typically involves a timer and a visual indicator. If reverse polarity is detected, the charger will disable and display a red light or blinking sequence to indicate the error. To reset and continue charging, the charger can be powered off and back on, or the manual override feature can be used, according to NOCO."

https://no.co/support/manual-override-guide

"To use the Manual Override feature, press and hold the Manual Override Button, the red exclamation point icon inside a red circle, for three seconds. "

But that manual override does not apply to your model I assume.

 

[chl]

By the way, a fool proof (or sleepy person proof) protection circuit:

Bridge Rectifier – The most foolproof for reverse polarity protection. For about a dollar or two, the bridge will correct the polarity no matter how you connect the power supply. With a bridge there are always 2 diodes conducting (which can result in greater losses of than a single diode protection circuit, around .8-1.5V. )

From: https://kc9on.com/ham-radio/station-accessories/reverse-polarity-protection/

For a car/truck battery these diodes might have to be hefty if using the charger with higher currents, but for trickle charging, not so much.

 

[Jim Lewis]

https://no.co/support/manual-override-guide

"To use the Manual Override feature, press and hold the Manual Override Button, the red exclamation point icon inside a red circle, for three seconds. "

But that manual override does not apply to your model I assume.

Thanks for the suggestions. The manual override button for the Noco Genius Boost devices sounds a bit like Force Mode for the Noco Genius2, which is activated by holding down the Mode button for five seconds. I tried that. Not sure I entered Force Mode (or maybe that's no longer working, too?). I'll have to give that another try.

 

[chl]

Thanks for the suggestions. The manual override button for the Noco Genius Boost devices sounds a bit like Force Mode for the Noco Genius2, which is activated by holding down the Mode button for five seconds. I tried that. Not sure I entered Force Mode (or maybe that's no longer working, too?). I'll have to give that another try.

I think it was a different version though that had the manual reset button.

If other owners of the NOCO Genius2 had the same problem, must be a defect in design or manufacture.

Anything that calls itself a "genius" is suspect to me...lol...especially any person who refers to themselves as "a stable genius" if you get my drift.

Like coffee makers, the simpler ones seem to last longer and be more reliable than the ones with all sorts of bells and whistles.

Same with software usually - the simple free versions have never crashed my Windows, the full versions always seem to cause havoc eventually.

Always something...Murphy's law...and then there's entropy...and the Spanish Inquisition which no one ever expects.

Good luck.

 

[Jim Lewis]

The manual override button for the Noco Genius Boost devices sounds a bit like Force Mode for the Noco Genius2, which is activated by holding down the Mode button for five seconds. I tried that. Not sure I entered Force Mode (or maybe that's no longer working, too?). I'll have to give that another try.

Perhaps my problem with testing Force Mode on the Genius2 is that it's for reviving ~dead batteries with less than 2V across the terminals, and I'm trying to turn it on by connecting it to healthy batteries that are at 12.5 to 12.7V.

Edit_Update: Yes, Claude by Anthropic (Sonnet 3.7) AI says that Force Mode will not work on a normal battery and is intentionally designed on a Genius 2 to only come on when it detects a battery voltage less than ~2 to 3 V. From everything I've told it, it says it looks like my Genius 2 control circuits are functioning normally, but I've likely fried the power delivery circuits. It did suggest testing Force Mode as a way to reset the Genius 2 if its problem were just a software state glitch. Thanks again to @chl for suggesting a manual override test. Claude agrees I should just turn to NOCO for help now.

 

[chl]

Good to have a warranty.
It always surprises me that more battery chargers don't use the full wave rectifier output circuit so that polarity misalignment doesn't matter.

I guess it is a cost benefit calculation.

This one is pricey (link). but there must be less expensive ones? - it is such a simple way to protect against reverse polarity mistakes - maybe the Mosfet type is cheaper to make? - go figure.

https://www.impactbattery.com/quick-charge-no-polarity-charger-12-24-volt-25ah-qp122425.html

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