NOCO Genius 2 Battery Charger Repair - What is this? - Page 1
Forum section: electronics / repair

author: ThermallyFrigid
author_rank: Frequent Contributor
timestamp: August 28, 2025, 01:33:34 am
content: Hello,I'm in the middle of a diagnostic and repair of a NOC Genius 2 battery charger and I believe I've found the faulty components but there is something on the PCB that is throwing me off a bit. It looks like a capacitor but the markings suggest it's an inductor. I don't have enough experience to figure it out since it may be damaged and I can't trust readings I try to take.So is this an inductor with 680nH or a 25v capacitor? And do inductors normally have a voltage rating on them?It's approximately 5mm in diameter and about 20mm tall.I attempted to measure capacitance and got 700uF. (Pretty close to the 680 number on it?)Thanks

author: Uunoctium
author_rank: Frequent Contributor
timestamp: August 28, 2025, 02:51:04 am
content: pink or red writing points to solid or polymer electrolytic without a "K" or "cross" shaped explosion-proof groove on the top of the capacitor.680µ, 25V

author: kite31
author_rank: Regular Contributor
timestamp: August 28, 2025, 03:40:31 am
content: Probably a low ESR type (ULR).

author: ThermallyFrigid
author_rank: Frequent Contributor
timestamp: August 28, 2025, 03:58:46 am
content: Any idea why an electrolytic capacitor would have 680 nH on it?

author: kite31
author_rank: Regular Contributor
timestamp: August 28, 2025, 04:17:08 am
content: The same reason it has ULR 25V and 25V 680? That is, they are on separate lines so are likely refer to different things.Perhaps it means no hair when the capacitor implodes to a singularity. I haven't a clue on that one, I just see no necessary relationship between those two lines.

author: Swake
author_rank: Frequent Contributor
timestamp: August 28, 2025, 07:21:23 am
content: This is an X-con capacitor of 680 µF / 25 V / 105°C / Low ESRSee attached spec sheet page 14.

author: ThermallyFrigid
author_rank: Frequent Contributor
timestamp: August 28, 2025, 01:24:02 pm
content: Since there is no Cap on the Manufaturers list matching the one found on the PCB, I assume it was a custom ordered Cap.The one on the board is actually 8.2mm x 17mmThere is also nonHcode on the manufacturers listing.They do have one 8 x 16mm with the 680 reference. I suppose that could be it?

author: Swake
author_rank: Frequent Contributor
timestamp: August 28, 2025, 01:55:18 pm
content: The F16 size spec and tolerances (see page 14 bottom) for this cap is 8 (+/-0.5) mm x 16 (+1.5/-1.0) mmI'd say your measurements are within spec.

author: ThermallyFrigid
author_rank: Frequent Contributor
timestamp: August 28, 2025, 03:07:56 pm
content: Thanks for finding the link and the assist Swake.Much appreciatedAll replies appreciated as well. Thanks guys (and gals?)

author: ThermallyFrigid
author_rank: Frequent Contributor
timestamp: August 28, 2025, 03:12:50 pm
content: After close examination of the board, (for anyone who might also have a NOCO battery charger), at first I thought water or condensation intrusion had caused this failure, but now I believe that that ULR aluminum capacitor failed and leaked on the PCB. Here is a photo....what do you think?I didn't actually find any water or condensation inside when I first opened it.I guess it's just a likely some other component failed and caused the cap to leak as well.Truth be told, I've had 3 NOCO Genius charger failures now and I promise I take care of them to keep them out of any rain or wet location.It's possible I may have reversed the connection a time or two but most devices like this have protections against reverse connections anyway.Appearance wise and component wise, they seem to be of good quality build so it surprises me how many failures I've had with these.

author: Swake
author_rank: Frequent Contributor
timestamp: August 28, 2025, 04:58:14 pm
content: Always the same model failing? After how many uses or how much time?The cap might have leaked indeed but you also mentioned the cap still measures 700µF. Unless you have an RCL meter that can confirm other parameters such as ESR are still good I'd suggest to change that cap. Any cap 680 µF / 25 V that is small enough to fit will do.Of course clean that area very thoroughly.The 'NH' marking is likely the manufacturers date code or something like that.

author: floobydust
author_rank: Super Contributor
timestamp: August 28, 2025, 06:02:06 pm
content: NOCO (and the CTEK) chargers are cheap builds unfortunately. Despite all the tech hype and marketing. I'm not sure who the CM is but they save pennies to the detriment of these expensive battery chargers.They are notorious for using cheap electrolytic capacitors which dry out. Check the little ones as well, for bulged top or leaks or low value.They did splurge here on using a Samxon polymer output cap, but you measured it OK at 700uF?I would pull it and see if that caused the mess or it's sloppy board wash etc.Connecting the battery backwards the mosfet ideal diode nearby should not allow that to reach the cap.

author: ThermallyFrigid
author_rank: Frequent Contributor
timestamp: August 28, 2025, 09:20:23 pm
content: Not always the same model.I bought 3 of the NOCO Genius 5A chargers and two of the 2A chargers.Of those, 2 of the 5A and 1 of the 2A chargers have failed within 6 months of purchase.Before anyone thinks I'm abusing them, I assure that is not the case. I'm very careful to keep them away from moisture, only use them as prescribed (charging 12v LA automotive batteries), make sure they are properly connected, make sure no shorts of the alligator clamps and store them in a cool dry place when not in use.That said, I do leave them attached sometimes for up to a week if not using the vehicle so even though they are under the hood and away from any water, they are in the outdoors and it can be very humid.At $70 each for the 5A models and $40 each for the 2A models, I needed to learn to repair them. That's where I am now. I "think" this 2A unit has a good chance of working once the replacement components arrive and I replace them. I'm replacing one Mosfet that is definitely shorted, one Electrolytic capacitor, a 1watt resistor and possibly one optocoupler.

author: floobydust
author_rank: Super Contributor
timestamp: August 29, 2025, 01:55:35 am
content: Are these permanently installed in the car? That's a pretty lousy track record- which makes me question if they are getting killed by vehicle transients and surges, or heat if mounted by the rad or exhaust.They have a 3-year limited warranty, I'd be using that.Here $CAD Genius 2 $83, Genius 5 $118 way too much for what they put out.You could sketch a schematic of the sections with failed parts, it could make it easier to troubleshoot them.

author: Swake
author_rank: Frequent Contributor
timestamp: August 29, 2025, 06:08:41 am
content: Under the hood should never be a problem. Actually that is a normal and expected use case for me.As floobydust already writes: Absolutely disconnect and remove them after use. Don't let them connected while starting or running the engine.I agree these things are way overpriced. Got some 5A Ctek chargers and, while these are over 10 years old now, one of them has a failed button so the mode cannot be changed any longer. Easy repair you would think, until you see that the casing is glued. Either I use some chemicals and force to break the glue and then loose the waterproofing or keep it forever in the 5A normal mode as it is now.

author: ThermallyFrigid
author_rank: Frequent Contributor
timestamp: August 29, 2025, 02:28:36 pm
content: Quote from: floobydust on August 29, 2025, 01:55:35 amNo, they are not permanently mounted. They are not used when the vehicle is running.That said, it "may" happen accidentally once in a blue moon that I forget that it is connected and start the engine. I cannot honestly say it has "never" happened.What I can say is that I have not noted a correlation between that and unit failure so far.If you check the Amazon comments on these, warranty service is not readily available. as with MANY such items, they offer the Moon and the Stars, until AFTER the purchase.

author: ThermallyFrigid
author_rank: Frequent Contributor
timestamp: August 29, 2025, 02:33:39 pm
content: Quote from: Swake on August 29, 2025, 06:08:41 amThe one good thing about the NOCO chargers is that they are very easy to get into...need be.If I can learn to diagnose and repair them then I should be able to get much better usage from them.If I do all that, I would likely add more fuses to offer better board protection in the revamp.Of course, that won't save the board from a leaking / faulty cap...so those will be replaced with the best available.It's not even out of the question that I might duplicate the circuit board in KiCAD and make some extra PCBs in case the board gets ugly from repairs.The styling and function fits my needs. If only they were more durable.

author: BILLPOD
author_rank: Frequent Contributor
timestamp: August 29, 2025, 07:32:51 pm
content: Cut your losses and get an Optima Battery charger. They aren't cheap, but you will never need to buy another.https://www.amazon.com/Optima-Digital-Performance-Battery-Maintainer/dp/B009M3PQFA?th=1

author: floobydust
author_rank: Super Contributor
timestamp: August 30, 2025, 09:32:29 pm
content: OP let us know what semiconductors (i.e. mosfets) fail, I wonder if they are just too low voltage rated to take some (cranking) transients etc.I know a guy with the NOCO permanently connected on a 1950 Mercury, which is a fairly dirty electrical system. It's mostly 12V no longer 6V. I'll ask him about his luck with them, if my theory has any merit.

author: ThermallyFrigid
author_rank: Frequent Contributor
timestamp: August 31, 2025, 09:42:38 pm
content: Quote from: BILLPOD on August 29, 2025, 07:32:51 pmI took a look at this one but at the end of the day it appears to be more of the same old same old, but for a LOT more $$$Too many reviews saying they don't last and warranty is sketchy (just like the issue I'm already having with the much less expensive NOCOs).And those have much more to fail.I'm gonna stick with the NOCOs and just get good at repairing them. I'm even gonna duplicate the 5A and 2A PBC's and have them on hand in case the repairs render the board unserviceable.Only for the units I have purchased. It's illegal to duplicate them for any other reason. Can NOT sell them or give them away as much as I'd like to help others. :-(ALSO...if you have or get a NOCO charger (trust me on this), get some Silver HVAC Aluminum tape and cut a thin strip and carefully adhere it along the seam to make sure no moisture can enter the device. Most of mine suffered damage fro moisture intrusion even without ever being near actual water in liquid state (only via condensation).

author: ThermallyFrigid
author_rank: Frequent Contributor
timestamp: August 31, 2025, 09:45:04 pm
content: Quote from: floobydust on August 30, 2025, 09:32:29 pmOk. Just keep in mind every failure could involve different components. (I'm sure you already know this)As for the guy with the NOCO, I think their 2A and 1A chargers are more geared toward maintaining the battery. The 5A and up seem to be more intended as dedicated chargers.

author: jerryk
author_rank: Regular Contributor
timestamp: September 01, 2025, 06:00:51 pm
content: Quote from: ThermallyFrigid on August 31, 2025, 09:42:38 pmThat's a lofty project. Do the 5A and 2A unit have a micro controller in the circuit? If so I'm curious which Holtek they are using.Jerry

author: BILLPOD
author_rank: Frequent Contributor
timestamp: September 01, 2025, 07:19:39 pm
content: I see your point about you sticking with the NOCOs,ThermallyFrigid, I was just suggesting the OPTIMA because I have had one for over 5 years and charged lots of batteries, and it just works. I wish you the best with your NOCOs.

author: ThermallyFrigid
author_rank: Frequent Contributor
timestamp: September 01, 2025, 11:16:06 pm
content: Quote from: jerryk on September 01, 2025, 06:00:51 pmHello Jerry,Fortunately the 2A version does not have an MCU on the MAIN PCB. But it does have one for the Controls panel which is a secondary board under the one shown, 96G148CLN. Even more reason to choose it for learning to repair it.The marking96G148CLN smd refers to a specific variation of the A96G148 8-bit microcontroller, packaged as a surface-mount device (SMD).Part number breakdownA96G148: This is the base model of the microcontroller.CLN: This suffix indicates the specific package type and features:C: Specifies the package type, most likely a 48-pin LQFP (Low-profile Quad Flat Package).L: Often indicates lead-free packaging, which is compliant with RoHS directives.N: Can specify additional options, though without a full datasheet it's hard to be certain.smd: This is a general term confirming that the component is a surface-mount device, intended for mounting directly onto a printed circuit board (PCB).Key features of the A96G148 microcontrollerAccording to the datasheet, the A96G148 is a robust 8-bit microcontroller based on the M8051 core and includes a variety of built-in peripherals.Core: 8-bit CISC M8051 core.Memory: 64 kilobytes of on-chip flash memory and 256 bytes of internal RAM.GPIO: 46 general-purpose input/output ports, with 8 capable of a high sink current.Timers: Includes a watchdog timer, basic interval timer, and five 16-bit timers.Communication interfaces: Multiple USI channels, which can be configured for USART, SPI, or I2C communication.Analog-to-Digital Converter (ADC): Features a 12-bit ADC with 16 input channels.Operating temperature: Can operate in a wide temperature range from -40°C to 105°C.

author: jerryk
author_rank: Regular Contributor
timestamp: September 02, 2025, 01:01:19 am
content: Interesting. It's not a Holtek. That's the first time I've seen a different MCU brand. I know nothing about the ABOV MCU. I do know that if you work on any of these NOCO devices that use the Holtek MCU's be very careful as the seem to be very sensitive to ESD events. At least with the 2A there are some fairly good teardown video's out there. I saw one where the guy used xray images of the board to help with fault location. It could be useful in your efforts.https://youtu.be/-bZB39oFunM?si=Mwj-k7LhAb8-mf7N.Good luck.Jerry