Motor warranty covers material and manufacturing defects in the motor itself, and not issues related to installation or misuse. For instance, the following are not covered by our warranty:

• Problems resulting from Axle Spin-out: Probably the most common reason motors need servicing is because the axle is not properly restrained from spinning in the bicycle dropout. That is an installation issue and not a faulty motor issue. In fact, it means that the motor is doing exactly as it should. You can get axle spinout from: inadequately tightening the nuts, regen systems causing nuts to loosen, lack of a torque arm for systems that need a torque arm, improper torque arm installation, inadequate dropout strength, etc. When a spinout occurs, it can damage the threads on the axle, it can sever the motor phase wires, it can short the phase wires against your hall sensors and fry the hall sensors and in some cases the motor controller as too. It can also cause your bike to crash and have other consequences. Many of these things can be repaired, but none will be under warranty.
• Water damage: Even on motors that are relatively well sealed, water can still get inside the motor if the connectors are exposed in a way that water can puddle up and track inside the cable housing. The consequences of water getting in the hub are corrosion of the steel stator, and eventual misbehaviour of the hall signals. Most of the time simply cleaning and drying out the hub will restore normal operation. It is very apparent when a motor has water damage, because on opening up the hub a small pool of rusty water will pour out. 
• Overheating damage: Motors that are run for prolonged periods at well beyond their rated power levels will eventually get so hot inside as to cook the windings. This results in the enamel burning off the copper wire, the plastic insulation melting on the phase wires, demagnetization of the rare-earth magnets, and vaporization of oil from the ball bearings. Damage caused from running the motors above these levels is not covered under warranty. Higher power levels can work fine for short time periods, but in sustained use the above problems will show up. High power users should always get a motor with a thermistor temperature sensor and a V3 Cycle Analyst to activate thermal rollback. 
• Broken Spokes: Spokes breaking is not something unique to hub motors but is something that can happen to bicycle wheels in general. Heavy loads, hitting potholes at high speeds,  and neglecting to periodically check and adjust spoke tension, are all common causes of broken spokes. We recommend checking your spoke tension after the first 2 weeks of riding the bike, as even a wheel that is tight out of the box may need a break in period for the spoke heads to seat properly in the flange. We have very few issues with spoke failures on our custom built wheels, but we cannot give quite the same guarantee for prelaced hub motors. 

Controller warranty covers material and manufacturing defects in the controller itself, and not issues related to installation or misuse. For instance, the following are not covered by our warranty:

• Grinfineon Controller that fails when used with a motor not sold by GRIN: We don't warranty infineon-style controllers that are used with 3rd party motor systems. It is possible to have a hub with very low winding resistance (think short circuit) which would fry the controller mosfets when throttling from a stall, as these controllers have pulse-by-pulse current limiting to protect them in this situation. In particular, the 20A controller model is suceptible to this.
• Corrosion of connectors from water exposure: Damage to connectors themselves is not a warranty issue. It is a good idea to cover the connectors in a protective box if they are otherwise exposed to road spray.  
• Water Ingress in eZee Controllers: There are clear installation instructions with the eZee motor controller to keep the cable exit pointing down so that water cannot enter through the wire grommets. Most of the erratic behavior traced to water inside the controller is installation that have cables pointing up. 
• Controllers that are used above the rated voltage: Exposure of a motor controller to higher than the rated maximum voltage can fry the mosfets. The only controllers we have rated for more than 52V nominal batteries are the Phaserunner and the 72V 40A Grinfineon.   

Lithium batteries for ebikes will gradually lose capacity and eventually require replacement, that is to be expected. Modern batteries typically last 3-6 years depending on how hard they are used, and they will exhibit a gradual decline in capacity over time. If the battery suddenly stops working or has an abrupt change in behavior, that is a sign that there could be an actual internal manufacturing defect such as a broken tab weld or a failed BMS circuit. GRIN does not cover premature battery failure when caused by improper battery useage. For instance, the following are not covered by our warranty:

• Self-Discharge Damage: Lithium batteries that have self discharged below 2V/cell from being left on the shelf for an extended period of timeTIP: Lithium batteries are liable to self-discharge over time because the BMS circuit itself draws current from the battery pack. Although the amount of current is usually small ( < 1mA typically) it is still enough to kill a battery in 1-2 months if it is stored in an initially flat state. If you plan to store a lithium battery, be sure it is at least 50% charged when you put it in storage and have it unplgged from the motor controller.
• Water damage: Does not affect the cells but can lead to unreliable BMS circuit behaviour and can in some case lead to corrosion of the tabs. Most batteries have enclosures that shed water well when mounted in their intended orientation, but if they are mounted in an unusual orientation (like vertical, or hanging upside down) there is a higher likelyhood of water getting inside the casing. 
• Excessive Current Draw: Frequently running a battery pack at a very high power draw can dramatically shorten the available cycle life from the cells. Our warranty terms apply to batteries that are on average discharged at a 1C rate or lower.  If you have a small capacity battery and regularly discharge it at high currents (eg 35A from a 14Ah battery) then the expected cycle life is reduced. 

Due to the complexity of shipping batteries as Class 9 Dangerous Goods, most battery service and repair will need to be performed locally. You cannot simply ship your battery back to Grin for diagnosis and repair. Fortunately many of the battery issues we've encountered can be repaired with a soldering iron or basic circuit work. We may require that you open the battery pack and make measurements of cell voltages and other voltages to help us fully identify the issue and work out the best course of action.

The following are not covered by our warranty:

• Submersion damage: While the Cycle Analyst is warrantied against use in rainy conditions, we do not cover damage resulting from submersion of the Cycle Analyst in water.
• Improper wiring: Mistakes while doing custom wiring to the Cycle Analyst circuit board or while wiring to third-party sensors (eg PAS/torque sensors, etc) can easily damage or fry components on the Cycle Analyst. This is a user fault not covered under warranty, though in most cases the board can still be repaired for a fee. The most common failure that we see are people plugging in a torque or PAS sensor that is only rated for 5V power, which will get fried from the 10V present on the CA's PAS power plug and that in turn can damage the Cycle Analyst. 
• Improperly running a torque sensor with a 72V battery: As is stated frequently, the total accessory current draw on the Cycle Analyst becomes increasingly limited at higher voltages, and with 72V batteries there is not enough headroom to run a torque sensor, which typically draws 20-30mA of current. 

In general we try to be as fair and reasonable as possible in assessing what is and isn't a warranty situation with all our other products too.  For instance, we would not cover:

• Over voltage Failures : All of our DC-DC converters and ebike lights have strict maximum voltage limits that need to be respected. People using systems higher than 52V need to pay attention to the voltage rating of any peripheral devices powered from the pack. 
• Installation Damage: We see many instances of failures that are traced down to installation problems. For instance, cables getting severed as a result of being pinched by a hose clamp or tangled in a drivetrain. Batteries falling off their mounting cradle because the key wasn't locked. PAS sensors not working because the magnet ring was slipping or misaligned. 
• Broken Connectors: We sometimes see people who have damaged connectors from some mechanical incident or mishandling.