Panasonic Cordless Telephone Battery (HHR-P104A)

A battery is a device that converts chemical energy directly to electrical energy. It consists of a number of voltaic cells; each voltaic cell consists of two half-cells connected in series by a conductive electrolyte containing anions and cations. One half-cell includes electrolyte and the electrode to which anions (negatively charged ions) migrate, i.e., the anode or negative electrode; the other half-cell includes electrolyte and the electrode to which cations (positively charged ions) migrate, i.e., the cathode or positive electrode. In the redox reaction that powers the battery, cations are reduced (electrons are added) at the cathode, while anions are oxidized (electrons are removed) at the anode. The electrodes do not touch each other but are electrically connected by the electrolyte. Some cells use two half-cells with different electrolytes. A separator between half-cells allows ions to flow, but prevents mixing of the electrolytes. Each half-cell has an electromotive force (or emf), determined by its ability to drive electric current from the interior to the exterior of the cell. The net emf of the cell is the difference between the emfs of its half-cells, as first recognized by Volta. Therefore, if the electrodes have emfs and , then the net emf is ; in other words, the net emf is the difference between the reduction potentials of the half-reactions. The electrical driving force or across the terminals of a cell is known as the terminal voltage (difference) and is measured in volts. The terminal voltage of a cell that is neither charging nor discharging is called the open-circuit voltage and equals the emf of the cell. Because of internal resistance, the terminal voltage of a cell that is discharging is smaller in magnitude than the open-circuit voltage and the terminal voltage of a cell that is charging exceeds the open-circuit voltage. An ideal cell has negligible internal resistance, so it would maintain a constant terminal voltage of until exhausted, then dropping to zero. If such a cell maintained 1.5 volts and stored a charge of one coulomb then on complete discharge it would perform 1.5 joule of work. In actual cells, the internal resistance increases under discharge, and the open circuit voltage also decreases under discharge. If the voltage and resistance are plotted against time, the resulting graphs typically are a curve; the shape of the curve varies according to the chemistry and internal arrangement employed. As stated above, the voltage developed across a cell's terminals depends on the energy release of the chemical reactions of its electrodes and electrolyte. Alkaline and zinc-carbon cells have different chemistries but approximately the same emf of 1.5 volts; likewise NiCd and NiMH cells have different chemistries, but approximately the same emf of 1.2 volts. On the other hand the high electrochemical potential changes in the reactions of lithium compounds give lithium cells emfs of 3 volts or more. And it fits perfectly into my old cordless phone.

I have a Panasonic telephone set of 3. Two of the satellites were misplaced when my wife, new to the country decided to completely rearrange my house. When I finally found them, they wouldn't hold a charge for long, and did not recognize the base. When deciding to fix problem, I went to an Office Depot where they sold similar phones, and they had batteries for over $20. and the clerk suggested that I charge the phones in the base, and that would probably reconnect them. I went home and took the battery out of one of the phones, and then to Amazon where I found the batteries for less than half of what the Office supply store was charging. I matched up the numbers, found the picture on the package to be an exact match for the removed battery, and ordered two batteries. When they promptly arrived I was a little alarmed to see that the batteries did not match the colors; instead of the olive green and black on the website, they were orange and black, but the numbers were correct. When I started charging the batteries in the phones with some of the time charging in the base unit to pair them, they were very warm to the touch. I have a VOIP Ooma Teleo set-up at home, and once the charging of the satellite phones was complete, there was a couple of missteps, not sounding quite right, but then both working properly. The phone that was left in the base unit still has the original battery, but it has never been completely discharged and left alone depleted. The phones with the new batteries, despite the color difference from what was advertised, are now cool to the touch, and working. So I have high hopes that this resolves the problem. I have had the Panasonic phones for about seven years now, they are 5.8 GHZ. I have the Ooma VOIP for a little over two years, also acquired through Amazon, and I like it very much, especially the $3.75/mo. phone bill. Update July 9, 2015. Still have the original battery in the phone by the base unit. And the phones with the batteries bought through Amazon are still working very well. So I think that as long as you don't leave the phones out of the charging units for very long (as in lost), they work even if they don't match OEM colors. No problems. Revising rating to 5 stars.

Needed some new batteries for all of the cordless phones in the house, so I decided to check Amazon for any possible deals. Batteries are EXPENSIVE as you all know, so I'll take all the help I can get. I stumbled across these batteries available through DependableResource for..$8.95 (at the time of purchase)?! Did I read that right?! This price was SIGNIFICANTLY cheaper than any other retailer's price that I knew of (about $15.00 elsewhere). Of course, you can't have your cake and eat it too, so something like this naturally made us a bit doubtful. I mean, for that kind of deal, there's gotta be some kind of catch, right? Fake batteries, perhaps? But, seeing that the seller had a great rating and excellent reviews, we decided we'd give it a try, and bought three batteries for a total of $26.88 (with Super Saver Discount, therefore no S&H, and no tax) with a cautious "we'll see" attitude. If anything was wrong with the product, we were immediately going to send it back. Well, the batteries arrived, and we were pleasantly surprised to learn that they are GENUINE! Yay! So I guess you really CAN have your cake and eat it too sometimes! :) The only thing I can think of that wasn't even really a problem is that the package took a little while to arrive (about 9 days). But, we were in no hurry, therefore we didn't need the package right away, and didn't need to spend a lot on shipping to get it here quickly. I think we were just excited, that always makes things seem like they're taking forever. :) These guys are the real deal, thanks, DependableResource, for selling my family genuine batteries, and saving us a ton of money! :)

This replaces my old land line battery. Works great

Works well.

I was disappointed that the battery was not the one advertised. After I complained the vendor did tell me that the BMC-3, that I ordered, is now discontinued and if anyone has them in stock they will be no good as they will be out of date. That may well be the case,but why advertise something that is out of date then send an different version, without at the very least, including an explanation with the delivery. The initial charge only lasted a short day, with only one call. It is charged again and I am waiting to see how long this charge lasts. I did read reviews that said this Ni-MH battery is not the best for my wife's old phone, that was why I specifically ordered the BMC-3 type. The battery was not in manufacturers packaging, just loose in an envelope. It actually was scuffed and looked like it had been used for years. Who knows. If it holds charge better in future I may come back and increase to 4 star. PW Lincolnshire

Doesn’t hold charge for long time according standard

Extremely happy with this battery. Getting after-market batteries from unknown manufacturers has been a mistake I made in the past, so I went with the real deal and I am glad I did. It works as good as the original and the original lasted many years. It's worth the money to pay a little bit extra for the quality and SAFETY of using the orignal.

Producto original, llegó un poco antes de lo previsto, concuerda con lo que solicité, funciona como se espera.