Can you charge a 18v lithium battery in a nicd charger?

My Ryobi 18V One+ charger blinks green while it's charging. When the battery is fully charged, the LED goes to a solid green. However, one battery recently had a faulty cell. After several hours on the charger, the green and red LEDs both were blinking. That indicated that the battery failed late in the charging sequence. It didn't fail the initial testing by the charger. The other battery I charged that day charged fine.

The extended capacity batteries can take 12 hours to charge in my experience. The regular batteries take less time. The charge time will depend on the battery chemistry(The older NiCd batteries take longer to charge then the Lithium batteries.)

I hope this helps. Assuming you aren't dealing with a cold or hot battery or charging environment, if you have any suspicion about a faulty battery, replace it.

Cindy Wells
(Note: I have a 12V drill as well. Those batteries takes longer to charge for the same relative capacity than the 18V NiCd batteries.)

check output on transformer, 2 check pcb ,could be a regulator

No, the P110, 18V NiCad battery charger, will not charge a 18V lithium ion battery. You need one of the dual-chemistry chargers. If you have the Ryobi ONE+ batteries, you can get the P117 charger ($30) or a charger with an extra battery (P126) from a store like Home Depot. A 6 battery charger and a 12V in-car charger are also available.

I wish that I had better news for you.

Cindy Wells
(who has the Ryobi 12V drill and charger, a few of the 4V tools, and a number of the ONE+ 18V devices and chargers. The single chemistry battery charger is not used much any more.)

NO THE OLD CHARGER FOR THE BLUE ONE+ TOOLS WILL ONLY CHARGE NICD BATTERIES. HOWEVER THE INTELLIPORT DUAL CHEMISTRY CHARGER WILL CHARGE BOTH NICD AND LION BATTERIES. ALL BATTERIES ARE COMPATIBLE WITH ALL ONE+ TOOLS

That is true the One+ 18V Li-Ion battery packs will work in any One+ 18V Ryobi tool. However the Lithium ion batteries will not charge in the original P110 NiCd charger. You will need one of the the new series Ryobi One+ 18V "dual chemistry" chargers for that. The will charge both types of battery packs.

As long as the voltage of the battery is the same as the tool, the tool won't mind if the power is coming from a NiCd or lithium battery. You do have to have a charger that works with lithium batteries to charge them up. Chargers that can charge lithium batteries can also charge NiCd and NMH batteies. NiCd chargers are not always programmed to detect when lithium batteries are full and may continue to charge them to the point of melting or starting on fire.

NO! Never charge lithium batteries in a charger designed for nickle based batteries like the NiHi your old charger was meant for. Ryobi did design the new Lithium charger to be backwards compatible so you can charge your older 18V NiHi batteries in the Lithium 18V charger.
Also note, NEVER miss-match the voltage, for example, make sure you are not trying to charge 12V batteries in an 18V charger unless the manufacturer has specifically stated that the charger is capable of multiple voltages.

no, I would not try this. You can charge a nicd battery on a lithium-ion charger but not the other way around.

Use
AC / DC Power Adapter Replaces Ryobi One+ Batteryhttp://lcdpayless.com/ryobi_one_power_adapter.php

I think your tryiong to charge NIMH batteries oon a charger designed for Lithium Ion batteries. With all the new style batteries such as NICAD, NIMH and LI-ION, charging becomes difficult. Most chargers pre NIMH and LI-ion, were designed for NICAD's. The best advise, match your batteries with the correct charger