My drill has been sitting in the case for few months. Tried to recharge and lights on charger show to be full but no power to driill. The second battery(Li-ion)showed to be defective. My qusetion is how do I know if it is both bad batteries or bad charger? I hate to buy a new charger and find out that both battierys are bad.

run all 3 batteries down to full dead then fully recharge. some times this can help

Try fully discharging the battery first and let it sit for a few days. Then fully recharge before use. What happens with battery operated drills is the batteries develop what is called memory of the charge level when they are recharged and will not charge past that point but the charge light will show full charge. It happens when the drill is used for a period of time and then the battery is placed in the charger ready for next time instead of using the drill until it is flat or leaving a partially used drill on the bench and not recharging it until it is flat

Rechargeable batteries do have a lifespan, they won't recharge forever. If you have fully discharged the batteries then fully recharged them and they still don't have full power or they only last a couple minutes then they are done. If they won't charge or the charger shows them as defective, the only fix is to replace them.

Directions say green light indicates that the battery is fast charging only,it does not indicate at exact point of full charge. I let my batteries charge for 12 hours for the first time charging,found out myself the same way. Try that and you will notice the difference.

Okay, might not be reading this right but here goes. If the camera shows the batteries as full then I'd go with that. The charger will come on for a few seconds even with a freshly charged battery because it take that long for the charger to realize the battery is already full. You can't feed an already full battery, so the charger is shutting off completely. Yes normally the light would stay on and the charger would continue to trickle a charge into it it until it is removed. In your case I think you have those batteries stuffed to the gills so the charger is shutting right down. One of the problems with these batteries is as much as the manufacturers deny it they form a memory. Best thing to do with these rechargeable batteries is drain them right down and then replace with a freshly recharged battery.

Has the scooter been sitting unused for a while? If so, the gel inside the rechargeable batteries may have gone solid. When you connect the charger, the light shows green indicating the batteries are full, but instead of being full of power, they are full of crud. The scooter can sit for just a few weeks and this will happen. If the batteries are new or have been properly maintained, try checking your fuses and all the connections/leads as this certainly sounds like a power problem.
Good luck!

Take it back to the store and tell them it is no good, and get a new pair of batteries, take the charger too. I had the same thing, brand new batteries, gone in weeks, they replaced them, no problem.

Write a registered letter to the black Max official headquarter stating that you did make your charger replace cpl times and asking for full refund otherwise you'd get into court procedures... Easy and effective way to have result.

Because it is Lithium Ion it is supposed to hold its charge for years.

So once it is charged what is the point of using electricity to keep it standing with a full charge in its cradle ?? (Does not compute)

My Bosch screwdriver sits on a shelf for months and has never failed to start when required.

If you are doing a lot of work then have the cradle handy and pop the drill on after a few operations and for 10 minutes before you put it away.

Once the full indicator comes on put it to bed ready for the next time it is needed

Newer rechargable batteries aren't like the older ones back from 5-10 years ago. They do not have a "memory" like old cell phone batteries and cordless tools used to have. So charge it whenever.

Stick it in the charger and when it's charged, the light will stop flashing. Usually takes a few hours for a full charge.

It's not recommended to leave it in the charger for extended periods. Not only does it siphon off your power bill, but it's harder for the battery I believe.

I've had mine for a few years and they done excellent. Just as powerful as the day i bought them.

If they ever do give out, be sure to recycle them, don't throw them away. Lowes and Home Depot have rechargeable battery recycling at the front desks.