The Noco GB40 portable power bank can experience problems charging due to improperly secured clamps, limited AC outlet power below 70V, a low voltage battery below 2V, unbalanced battery cells, connectivity issues with the wrong USB port or cable, a non-functioning electrical outlet, an internally damaged battery, a frayed USB cable, or a dirty, unusable USB port. Solutions involve checking and correcting these specific issues to allow proper charging.

Key takeaways

• Clamps must be properly secured for charging to work
• AC outlet needs 70-130V to charge; check outlet with another device
• Batteries below 2V may not charge; manual override can help
• Unbalanced cells can prevent charging
• Try different USB ports and cables to rule out connectivity issues
• Verify electrical outlet works by plugging in another device
• An internally damaged battery may need to be replaced
• Frayed/damaged USB cables can prevent charging
• Clean dirty USB ports with isopropyl alcohol

Problem	Solution
Clamps not secured	Properly secure clamps
Low AC outlet power	Use outlet with 70-130V; test with another device
Low voltage battery	Try manual override for batteries below 2V
Unbalanced cells	Needs service for cell balancing
Wrong USB port	Switch to different USB port
Electrical outlet not working	Fix/replace electrical outlet
Damaged internal battery	Replace battery
Damaged USB cable	Replace USB cable
Dirty USB port	Clean port with isopropyl alcohol

Clamps Not Secured Properly

The first and most common problem that can prevent charging of the Noco GB40 portable power bank is that the clamps are not connected or secured properly.

The black and red clamps are used to connect the GB40 to the battery of the vehicle that needs charging. For the GB40 to power on and start providing charge, these clamps need to have good electrical contact with the vehicle battery terminals.

The GB40 does not have any protection if the clamps are reversed or shorted, so it is necessary to exercise care when connecting. To attach properly:

• Shift the isolator switch to the "OFF" position
• Connect the black clamp to the black negative (-) battery terminal
• Connect the red clamp to the red positive (+) battery terminal
• Check clamps are securely connected with no gaps or looseness

Once connected properly with a suitable battery and DC power source, the GB40 will power on and the process of charging the dead battery in the connected vehicle will begin automatically. The LED indicators on the unit will start to "chase" from bottom to top showing charging is occurring.

If the clamps are not well connected and secure, the charging process will fail with no lights or a single blinking LED. It takes very little resistance in a bad connection to prevent functioning. Check both clamps carefully and tighten or reconnect if necessary – this alone may solve the charging problems with a seemingly "dead" GB40 unit.

Cleaning corrosion from battery terminals can also help improve connectivity for the GB40 clamps and ensure a stable, reliable charging session.

Applying some dielectric grease to the terminal contact points before or after charging can reduce corrosion build up over time. This keeps clamps conducting properly session after session.

Check your user manual for charging requirements, but most 12V lead-acid batteries can be revived with proper connections. By taking the time to securely attach and maintain the GB40 clamps, your charging problems can disappear.

AC Outlet Has No or Limited Power

Another common charging issue stems not from the GB40 itself, but from the AC outlets used to recharge the internal battery when it is depleted after giving a jump start.

The GB40 needs to receive consistent 70-130V AC power from a properly functioning grounded outlet to restore its internal battery. Using an outlet with wiring issues, incorrect voltage, missing ground, or other problems will prevent the AC charger from properly powering up the GB40.

Some signs of insufficient outlet power:

• No lights on the AC charger when plugged in
• Intermittent charging lights when moving the cable
• Lights flash but internal battery does not charge
• Charging takes much longer than usual

First, check your outlet with another device like a mobile phone charger or lamp. If other devices also do not charge or power on properly from the outlets, there is likely an issue with the general AC power to that area.

Causes for limited electrical outlet power include:

• Tripped breaker or blown fuse for the outlet circuit
• Loose, damaged, oxidized wiring connections
• Old wiring that cannot safely handle modern device loads
• Missing or incorrectly wired ground connection

If the issues seem to be isolated to just the GB40 AC charger, try other outlets in different rooms and different surge protectors. Use an outlet tester to check for proper voltage and grounding. The charger may have partially failed, not providing consistent 70-130V needed for the GB40 even though some LEDs light up.

Once finding an outlet that provides proper 70-130V AC power, most charging issues will disappear. You can also have an electrician examine any outlets providing low or intermittent power to trace down the exact issue. Repairing bad connections, replacing old wiring, or installing new grounded outlets will restore normal GB40 charging.

Low Voltage Battery

One of the most serious charging issues occurs when attempting to charge a battery that has discharged down to an extremely low voltage below 2V. This reaches a point where the normal charge circuitry cannot begin operating properly.

Common causes that can drain down the lead-acid battery inside the GB40 to a very low state:

• Repeatedly attempting to jump start a dead battery without success
• Accidentally leaving the GB40 switched on and connected, draining its charge
• Not recharging promptly after a jump start session
• Old battery at end of service life no longer holds charge

You may face a catch-22 scenario where the GB40 battery needs charging before it can charge other batteries. This can happen after several failed jump start attempts left the internal battery depleted.

In this situation, check all clamps and outlet connections first. Then try putting the GB40 into "manual override" mode. This bypasses normal charge circuitry and tries to force some charge current directly into the battery. The LEDs will flash in an error pattern with bottom-to-top chasing. Leave connected like this for a few hours and see if it can recover enough to activate normal charging.

A battery load tester can also check if the internal cells still have capacity or need replacement. Deep discharged lead-acid batteries may suffer permanent damage, no longer taking or retaining a charge. In that situation, the only solution is to install a replacement battery suitable for your GB40 model.

Regularly recharging after each use and maintaining the internal battery according to directions can extend its lifespan. But after several years of usage, obtaining a new battery will be needed to restore normal charging functionality.

Cells Are Out of Balance

Rechargeable battery packs have multiple cells wired together. Normally as charging cycles proceed, the cells stay reasonably balanced in voltage so they do not overcharge or undercharge.

But during heavy usage over time or due to defects, the cells in the GB40 internal battery can become "out of balance." Each cell may be at a slightly different voltage level out of the normal alignment needed for steady regulated charging.

Signs of possibly unbalanced battery cells:

• LEDs on the AC charger flashing errors instead of steady chasing
• Charger indicating "full charge" much sooner than expected
• Reduced runtime before needing recharge
• One area of the battery warmer than the rest when charging

Excess voltage differences between cells can trigger the GB40 charging system to stop functioning to protect the battery from damaging.

While moderate cell imbalance is protected against in the GB40, over time it can leave the jump starter struggling to take a full charge or hold that charge for decent runtimes. The cells become out of alignment enough that the charging system cannot properly regulate them.

Causes of cell imbalance include:

• Uneven charging/discharging cycles
• Internal battery defects present since manufacturing
• Cell oxidation build up increasing resistance
• Old cells losing capacity at different rates

Diagnosing cell imbalance issues requires specialized testing equipment to measure individual cell voltages and impedances under load. If you suspect the GB40 internal battery cells are becoming unbalanced, the best solution is replacement with an equivalently spec'd new battery. Only very large capacity packs meant for solar energy storage undergo cell balancing procedures – much cheaper to swap the battery.

GB40 replacement batteries cost $60-100 USD normally.Third party options may also be available. Installation just involves opening the case and disconnecting/reconnecting battery leads to the main circuit board. This will provide evenly balanced cells for maximum runtime between charges. Consult Noco support docs for battery ratings needed for your GB40 model and detailed installation guide.

Resetting the battery by this method should allow the integrated charging system to function normally again without odd errors or charge times. Imbalanced old cells cause many charging issues, so a new battery is the ultimate fix in that situation.

Connected to Wrong USB Port

The smaller USB ports adjacent to the large automotive clamps receive 5V DC power from those clamps when a vehicle battery is connected and charging properly. This 5V USB supply can then be used to charge small mobile devices like smartphones.

However, the USB ports cannot themselves act as a power source to charge the internal GB40 battery! The USB power being output is simply borrowed from the connected car or engine battery at the clamps.

Some users attempt to use the USB ports with phone chargers or power banks to charge the GB40 after it needs recharging post-jump start. This will never work – an AC outlet using the included charger is required to properly charge from a wall current source!

Issues arising from attempting to charge the GB40 improperly through the USB 5V DC outputs include:

• No charging of internal battery at all
• Error LEDs on attempting to jump start a vehicle
• USB ports appearing dead with no output power

The USB ports rely on the GB40 having an existing charge in its internal battery before they can output any power. Those same ports cannot directly charge the internal battery!

Only use the included AC adapter and NEMA 5-15 charger to plug into 120V residential/commercial outlets and give the GB40 a new internal charge. The USB ports are outputs only, not inputs.

Charge small mobile gadgets like smartphones from those USB ports when powered on and connected to a working 12V battery source. Never attempt charging the GB40 from any USB power source to avoid lingering charging issues.

Electrical Outlet Not Working

As covered earlier, a faulty, damaged, or improperly wired AC outlet that does not provide consistent 70-130V power will cause problems charging the GB40 internal battery.

However, some additional electrical outlet and charging issues to mention:

• Using outlets on the same circuit as major loads will result in voltage drops
• Extension cords, especially coiled ones, can reduce voltage
• Running an engine battery tender off the same outlet can also reduce available power

Check for these scenarios if your GB40 charging seems intermittent or fails despite multiple outlets being tested. High power devices like air conditioners, space heaters, machinery coming on/off can cause voltage fluctuations on those circuits.

Extremely long, thin household extension cords cannot properly handle the roughly 2A current of the GB40 charger. Thick 12 or 14 gauge cords only! The coiled shape of wrapped extension cords also induces reactive impedance lowering voltage. Always fully unwrap cords during charging.

Multiple lower powered devices like tiny LED lamps may seem to work fine from the same outlets and cords. But the ~20W charger in the GB40 needs consistent 70+ volt power which is impacted more easily.

Also beware engine battery tenders plugged into the same outlets, possibly even on a timer switch that cycles on/off automatically overnight. Voltage drops or on/off cycling from load sharing can disrupt GB40 charging.

Use a digital multimeter to check AC voltages directly at outlets with charger issues. Compare different outlets under load and no load conditions to pinpoint any that cannot maintain 70+ volts.

Electricians can permanently correct any miswired or overloaded outlets causing GB40 charging problems. Dedicated circuits help avoid voltage drops from other major appliances or devices operating on shared wiring. New grounded outlet installations are also recommended for any older ungrounded outlets that easily influence charger function.

With clean stable AC power sourced from a solid residential electrical outlet not affected by other loads, GB40 battery charging issues from the supply side will disappear. Use a meter and common sense to find and test outlets meeting that criteria.

Damaged Internal Battery

After several years of usage giving jump starts, the internal battery sealed inside the GB40 suffers age related capacity decline like all rechargeable batteries. Eventually it may fail entirely due to factors like:

• Repeated deep discharge cycles wearing out cells
• Corrosion from outgassing and moisture ingress
• Internal short circuit due to vibration or impacts
• Cell isolation breakdown allowing imbalance

A dead battery is the most severe charging system issue since the GB40 relies on that battery capacity to allow functionality. No internal battery = no output power.

Signs of a truly dead irretrievable battery:

• Zero runtime even right after a full charge
• Zero volts output from clamps when switched on
• No lights on AC charger when connected

Compare to just very depleted batteries that recover after proper external charging as covered previously. Batteries that cannot take or hold any charge no matter what requires replacement.

Swap out the dead battery by unscrewing the case, disconnecting wired leads, removing fasteners, then sliding the expired battery free from its compartment. Reverse steps with the new replacement battery, accurately connecting red and black leads to the charging circuit board.

Use plastic pry tools and follow online video tutorials to safely open the GB40 without cracking the case. Always take anti-static precautions before handling internal electronics. Torque compartment screws back evenly so sealing gasket makes good contact.

Spend the $60-100 USD for an genuine OEM Li-ion replacement battery from Noco or reputable third party to maximize runtimes and charging stability. Cheap counterfeit batteries often fail quickly or dangerously. Battery authentication smart chip may need programmed to the GB40 as well.

With an correctly installed new replacement battery, your GB40 can keep running strong for many more years! Internal power packs arewear items needing periodic swap out. Do it early once charging issues emerge to restore performance.

Damaged USB Charging Cable

The USB output ports included on the GB40 allow charging small mobile devices like smartphones when the jump starter battery contains adequate charge. This gives users stranded with a dead vehicle battery at least some way to gain extra phone power while waiting for rescue.

The USB ports rely on proper electrical connectivity from the internal GB40 battery through to the port contacts in order to function as expected. Issues like frayed, cracked, or bent cables can prevent this power flow.

Common USB cable problems:

• Loose partial unplugging from the USB port
• Broken/missing internal wiring connections
• Pin connector bent out of alignment
• Cracked or peeled shielding/insulation
• Brittle cabling broken over repeated bending

Visually inspect your GB40 USB cables for any signs of damage. Jiggle cables while connected to check for intermittent charging. Test cable voltage with a multimeter to confirm if wires are intact. 5V should be present between specific pins.

If USB power cutting out or staying extremely low, most likely the USB cable itself has an internal break. The minimal power draw of small mobile devices may initially hide a partial cable failure. Attempting to charge a completely dead phone can better reveal issues.

Replace suspected faulty USB cables with fresh equivalently rated parts. Both USB-A to USB-C and USB-A to Lightning cables are available widely online for under $10 USD. Install firmly into GB40 ports without bending or pin distortion for reliable device charging again.

Quality ruggedized cables with ample strain relief perform best for hardcore portable use of the GB40 and charging of delicate phones or tablets when stranded roadside. Never yank sharply from the cable ends to unplug!

Dirty USB Port

The last common charging issue to cover for the Noco GB40 lies not in the battery, clamps, cabling, or electrical outlets – but in the small USB ports themselves where mobile devices get connected.

Dust, pocket lint, dirt debris, moisture, and general grime contamination can all build up inside these ports over time. Small particles wedge inside to coat or corrode contacts until power flow drops too low for effective charging.

Signs of dirty GB40 USB ports:

• Mobile device charges erratically or too slowly
• Frequent connect/disconnect when charging
• Device shows charging but no actual power gain
• Excess debris visibly packed into USB port

Check closely with a flashlight and pick for any lint, hair, sand etc. stuck down in the USB port. Also smell for any foul odors from mold or moisture. Darkened discolored contacts indicate oxidation and corrosion as well which hinders conductivity.

Carefully clean out the USB ports using a toothpick, thin tweezers, or canned air duster to remove as much packed debris as possible. Check any tight fit phone cables for trapped dirt up inside their connector ends as well.

For more stubborn contamination or corrosion, use electrical contact cleaner spray or electronics grade isopropyl alcohol with cotton swabs. Scrub gently across each port contact to dissolve and absorb away grime buildup for restored conductivity.

Prevent future foul USB ports by:

• Installing port dust plugs when not in use
• Storing the GB40 case zipped in a bag or box
• Using an air duster to periodically blow out ports
• Carrying the unit vertically to avoid debris ingress
• Keeping mobile device connection ends clean

Maintain the GB40 away from wet muddy conditions that could deposit contaminants into ports as well. Mud may warrant very careful rinsing to remove. If liquids are suspected to have entered ports, allow 1-2 days of air drying before attempting to use.

Dirty degraded USB power connectivity causes plenty of charging headaches. But with some basic inspection and cleaning, you can have those GB40 USB ports working like factory fresh! Quality prevention and maintenance gives mobile devices their needed roadside charging once again.

Reviving Noco GB40 Units Unable to Charge

The importance of battery maintenance and charging system care for the Noco GB40 cannot be overstated. Once this compact lithium jump starter stops taking a charge from your home or shop power outlets, its ability to rescue a dead vehicle battery out on the road disappears.

While the previous guide covered common charging issues in depth along with solutions, some GB40 units may face more severe faults requiring advanced troubleshooting or repair methods. We will summarize a systematic process for reviving seemingly “dead” GB40s to restore their charging ability.

Initial Triage

• Visually inspect unit for damage
• Check battery age and capacity status
• Review recent charging and usage history
• Check clamps, wiring. USB ports for problems
• Consider trauma events before “death”

Open investigation broadly before assuming the GB40 itself has suffered critical failure. In some cases, the battery may test as totally dead and need replacement. Or an outlet issue exists upstream. Careful initial checks of the whole system save time before invasive work proceeds. Battery swap may resolve it!

Advanced Electrical Testing

If no obvious issues found from exterior visual check and the battery measures >2V, dig deeper electrically:

• Check continuity on DC charge input wiring
• Check continuity on AC wiring through transformer
• Load test battery with carbon pile unit
• Probe charging board signals during charge routine
• Monitor individual cell voltages and temperatures

Here lab grade equipment becomes invaluable. An autoscan tool and multimeter alone cannot trace complex intermittent charging faults. Watch voltage ripple patterns for instability and scope/log other signals to diagnose.

Attempt Battery Recovery Charging

If the batteryTests as functional but utterly depleted <1V, try aggressive charge conditioning:

• Slow trickle current at ~.1C for 8-16 hours
• Periodic load resistance pulses help align cells
• Top balance cells once at 2.0V minimum
• Avoid heating battery above 45C

This approach may coax cells back towards normal voltage and balance. But the risk of shorts or internal resistance still lurks. Continually monitor temperatures for stability. Quit at the first signs of trouble before venting or thermal runaway. Batteries too far gone get replaced.

Electronics Repair

For charging boards, transformers, or wiring exhibiting issues themselves, meticulous soldering repair may resolve faults:

• Carefully disassemble module or harness
• Remove old solder and prep conductors
• Inspect PCB, wiring for cracks/burns
• Solder replacement components if needed
• Seal against moisture re-exposure

Surface mount construction necessitates a fine tip iron, magnification, flux, desoldering braid/wick and steady hands. Seek professional assistance for complex multi-layer PCBs. Heat damage can introduce further charging reliability problems if not done properly.

Total Replacement

For GB40 units with well-worn batteries that failed load testing along with charging system electronics too far degraded for servicability, total replacement serves as the final option before scrap:

• Source correct model replacement board
• Transfer usable chassis components to new shell
• Shred original GB40 after scavenging
• Update new serial number records

This path essentially creates a refurbished GB40 but may beat purchasing a brand new one at current prices. Just ensure full electrical compatibility first. Transplant the valuable high wear items like contacting clamps and cabling since tiny electrical variances matter.

With patience and the right diagnostic approach, even GB40 units initially thought to be complete losses can come back online after solving out whatever specific charging issue each one faced. Don't hastily discard fixable safety equipment!

FAQs

Q: Why does my GB40 have no power or charging despite new clamps and outlets working fine?

A: An internally damaged or worn out battery that no longer holds charge is the likely cause. Battery replacement is needed.

Q: The GB40 LEDs flash oddly instead of charging smoothly. What does this mean?

A: Flashing LEDs often indicate over/under voltage or battery cell imbalance issues. Letting it discharge fully then recharge may help. If not, the battery likely needs replacement.

Q: Can I revive a GB40 unit that has been in storage a while and won't turn on?

A: Try slowly trickle charging for 8-16 hours at low current to recover deeply depleted cells. But batteries unused for very lengthy periods may suffer irreversible chemical breakdown.

Q: Why won't the USB ports charge my phone when the GB40 seems fine otherwise?

A: Check for debris/corrosion in the USB ports using cleaning tools and contact cleaner spray. Also inspect your USB cable for damage.

Q: I tried charging the GB40 from a portable power station but it doesn't seem to work. Why not?

A: The GB40 can only be charged using the included wall charger plugged into an AC outlet. It cannot charge directly from external batteries or DC power sources due to voltage requirements.

Q: My GB40 charger light shows full charge complete but it still won't jump start a car. What's wrong?

A: If the GB40 isn't jump starting properly, the internal battery likely needs replacement even if the charger still powers on. As batteries age, capacity decreases.

Q: How do I know if my GB40 clamps are making good contact with the battery terminals?

A: If properly connected, the GB40 will power on and the LEDs will start chasing up and down. Any looseness or gaps in the clamp contacts will prevent charging.

Q: Does leaving my GB40 plugged in all the time even when charged reduce its overall battery lifespan?

A: It's generally best to unplug the charger once fully charged to avoid potential overcharging and increased heat exposure which can degrade batteries quicker over time.

Q: Can I repair a dropped or water damaged GB40 unit that no longer charges right?

A: It depends on the severity and electronics exposure involved. Best to contact Noco support about potential service options for heavily damaged units with charging failure.