sundance-communications.com/forum Forums TDM Business Telephone Systems Nortel Telephones & Systems Norstar T7406E Battery Replacement?

Two 7406E phones have been in use for about 13 months, and the Ni-MH batteries are no longer holding up through the day. Is this normal life? Any recommendations on best place to order replacements? Lots of outlets for the old 7406 packs, but I can't find any listings for the 7406e packs part # NT8B45AH. Thanks.

I don't think that there is a "normal" life expectancy for any rechargable battery. Your vendor should have a replacement.

A Google search for T7603e battery brought up nothing. A battery the Chinese haven't copied yet, simply amazing.

Not so considering you searched for the wrong part number

Thanks for the comments and for the specific help with sources via private replies. I purchased replacements from MetroLineDirect. For the info of others searching this topic, the supplier advised me that annual replacement of the T7406E battery pack should be anticipated.

That sounds about right, we usually get a call from T7406e users about a year later wanting new batteries. We try to get them to purchase 2 at a time.

The saga continues. I installed the new packs in the two 7406e phones, fully charged them before use, but the phones are still getting only about 8 hours max of STANDBY time, same as the 14 month old packs they replaced. When the system was new, and for at least the first 12 months of use, the phones would standby for well over 24 hours including an hour or two or more of talk time and still have some charge left.

Not aware of anything that has changed, and can't see anything in the manuals that would explain this. While I could believe one defective battery pack or set, the system has 2 sets and 3 new packs and they are all now exhibiting similar behavior.

Suggestions welcome!

For anyone following this thread, I have solved the problem. While not addressed in documentation as far as I can tell, there is clearly some "memory" process in the T7406e itself regarding the battery pack charging. Using the Sherlock Holmes approach of when you have eliminated everything else, in this case the battery packs, the chargers, the back-light settings etc, the problem must be in whatever is left - in this case the phones, I decided to "reset" the phones and then re-register them. This solved the battery life problem. I am guessing there is some kind of intelligent charging process with memory, that is designed to normally to get the best out of packs with declining capacity, but that it needs to be reset when you change battery packs.

Interestingly the documentation DOES discuss keeping spare battery packs and changing them on-the-fly to get more talk time during the day, so a caveat here, not mentioned, is that if you do that you should presumably ensure you rotate the packs consistently to ensure they remain roughly "matched".

Hopefully these insights will be of help to others supporting these phones.

We made a replacement battery pack for the T7406e. Our stock is new. We have battery load testers and QC every lot to ensure quality.

We have a web page with more information on this model: Nortel T7406e Battery

Unlike many battery manufacturers, we do not exaggerate our battery capacity. These were made with "950mAh" cells but we requested 900mAh to be printed on the label because load tests were all slightly under 950.

I do not believe the phone keeps track of the battery condition. I'm thinking the replacement batteries you purchased may have been on the shelf for a few years before landing in your lap.