Accucell-6 Temperature Probe

I just got a Turnigy Accucell-6 based on recommendations from this site. I like it and appreciate the information provided here.

I was charging some new Eneloop AAs and monitored temperature with a probe from my multi-meter. These particular cells terminated 1300mA charging on delta V with a temperature of 38C. Occasionally, it would miss the termination voltage and temps would steadily increase. I manually stopped charging at 45C.

At this point, I decided that I would like to have the ability to terminate based on temperature as a backup to delta V. I had a hard time finding the info needed to make a sensor although it's gotta be on here somewhere. I finally found this:

http://turnigy.co.uk/accucell-6.html

It was stupid simple to make and the parts total was $2.28 (I had wire and heat shrink on hand). The Digi-Key part numbers I used are LM35DZ-ND for the sensor and 3M9514-ND for the connector.

The connector doesn't have the extra material to insure correct alignment. I ran out of patience trying to find one. This one can be installed up side down. Doesn't hurt anything, but doesn't work, either. I put some paint marker on it to note proper alignment. Anyway, it works fine and terminates just like it's supposed to. Maybe someone will post a part number for the "proper" connector.

This is OT and I don't know much about the hobby chargers but from the little I do know may be try changing the delta-v sensitivity if it's missing termination?

That's true. Mine is set at 5mV. There is really not 100% termination reliability using delta-V over the entire range of acceptable charging rates. It can be extremely reliable within certain parameters.

Even when the charger terminates using delta-V, the cells could be hot enough to be harmed. I'll stick with delta-V as the "best" way to terminate using "typical" charging paramiters. Max temperature termination has excellent safety and battery life benefits when used as a secondary method. Hard to go wrong for a few bucks and 15 minutes.