Review: Rechargeable Batteries, and Why They’re Awesome

Now that we’re final­ly see­ing the dig­i­tal age slide into matu­ri­ty, the best advice any­one can take to heart is find­ing the per­fect bat­ter­ies. While dis­pos­ables remain in exis­tence even today, includ­ing the famil­iar alka­line cells com­mon­ly sold by depart­ment stores, the real­i­ty is these tech­nolo­gies have become out­dat­ed and are com­plete­ly inad­e­quate for meet­ing the needs of today’s advanced electronics.

With usage pat­terns form­ing as they have, and the pub­lic’s bur­geon­ing appetite for an ever-increas­ing ecosys­tem of gad­gets, any­one choos­ing the route of dis­pos­ables will, giv­en suf­fi­cient time, end up throw­ing out many tonnes of tox­ic mate­r­i­al over the course of a life­time, pay­ing tens of thou­sands of dol­lars for the privilege.

The good news is, there’s a bet­ter way! Sev­er­al game-chang­ing recharge­able sys­tems have made their way to the fore­front and make it pos­si­ble to not only get supe­ri­or per­for­mance in your devices, but also to do so at an extreme­ly low total cost of ownership.

The Origin of Modern Rechargeables

Bat­ter­ies have a ven­er­a­ble his­to­ry, and I rec­om­mend read­ing more on the top­ic if you have time. In a nut­shell, there are two main branch­es of bat­tery (more prop­er­ly, cells when referred to in the sin­gu­lar) chemistries in exis­tence today: pri­ma­ry and sec­ondary cells. Pri­ma­ry cells are sin­gle-use, and these make up the dis­pos­ables of yes­ter­year that most of us are famil­iar with (dry or ‘heavy duty’ cells, zinc-air, alka­line, and oth­ers), while sec­ondary cells are mul­ti-use and can be recharged after each time they’re dis­charged, some­times for many thou­sands of cycles.

As far as giv­ing con­ve­nient pow­er to the mass­es, the bat­tery is an amaz­ing inven­tion, but we are only now begin­ning to real­ize its true inno­va­tion and con­ve­nience thanks to the advent of rechargeables.

The reign of pri­ma­ry cells for the past hun­dred years has meant the accu­mu­la­tion of immense vol­umes of man­u­fac­tur­ing and han­dling process­es that have proven to be quite waste­ful. Pro­duc­tion of a typ­i­cal pri­ma­ry cell requires 150 times the ener­gy con­tained in that cell by the time it reach­es mar­ketable form! The dis­pos­al of deplet­ed cells fur­ther con­sumes sub­stan­tial land and ener­gy assets, cre­ates a huge sol­id waste stream, occu­pies a lot of land­fill space, and leach­es cor­ro­sive com­pounds into the soil after dis­pos­able bat­ter­ies are buried.

The Rise and Fall of Nickel-Cadmium

Dur­ing the 1980s, the first seri­ous effort was brought to mar­ket in an effort to cre­ate a solu­tion to the prob­lem of dis­pos­able cells. The ini­tial gen­er­a­tion of every­day-use recharge­ables, nick­el-cad­mi­um cells (NiCd), was launched. These achieved a very lim­it­ed amount of suc­cess due equal­ly in part to low con­sumer brand recog­ni­tion and inad­e­quate per­for­mance in real-world appli­ca­tions. Issues like low stor­age capac­i­ty, a lack of appre­cia­ble recy­cling pro­grams, rapid self-dis­charge, mem­o­ry effect, and high mate­ri­als tox­i­c­i­ty served to chip away at the rep­u­ta­tion of ear­ly NiCds, pre­vent­ing the prod­uct being seen as a viable alter­na­tive to the alka­line cell.

Since those days, con­sid­er­able inroads have been made in terms of recy­cling and qual­i­ty con­trol, but mod­ern NiCds still suf­fer from most of the same prob­lems as their pre­de­ces­sors, those being the high tox­i­c­i­ty, low stor­age capac­i­ty, and ten­den­cy to self-dis­charge so quick­ly as to be use­less in stand­by appli­ca­tions. After being super­seded by oth­er emerg­ing tech­nolo­gies, it’s now fair­ly rare to see NiCds offered on the con­sumer mar­ket at all out­side of spe­cif­ic appli­ca­tions (most­ly old pow­er tools or solar gar­den lights).

One might visu­al­ize NiCd as the pio­neer that took all the arrows in the back, paving the road for mod­ern­iza­tion of the bat­tery indus­try and giv­ing us an incen­tive to seek out clean­er, more prac­ti­cal tech­nolo­gies. Per­son­al­ly, I’m thank­ful that we’ve seen cell tech evolve so much since then.

Nickel Metal hydride

If you’re on the hunt for a true alka­line cell replace­ment, this is the tech­nol­o­gy you need. More com­mon­ly writ­ten as NiMH, these cells don’t use tox­ic heavy met­als in their man­u­fac­ture and thanks to recent advances in chem­istry and cell struc­ture, their per­for­mance has advanced by leaps and bounds over the years, final­ly mak­ing them far supe­ri­or to any dis­pos­able cell tech­nol­o­gy on the market.

Unlike alka­line cells, whose stored pow­er capac­i­ty dimin­ish­es steeply as the amount of cur­rent (amper­age) being drawn ris­es, NiMH sys­tems are able to main­tain a spe­cif­ic reserve ener­gy capac­i­ty at all times and fea­ture a rel­a­tive­ly flat dis­charge curve that stays pre­dictable and con­sis­tent even at dif­fer­ent cur­rent lev­els. What this means for the user is NiMH cells end up run­ning two to ten times longer than alka­line cells of the same size. Because of this abil­i­ty to deliv­er a con­stant volt­age and cur­rent for long peri­ods of time, they’re ide­al for medi­um or high drain appli­ca­tions includ­ing flash­lights, shavers, dig­i­tal cam­eras, and oth­er com­plex elec­tron­ic devices.

In addi­tion to this, the old prob­lem of cells self-dis­charg­ing when left on the shelf has most­ly been solved by a num­ber of advances in cell struc­ture and chem­istry. The new gen­er­a­tion of low self-dis­charge (LSD) NiMH cells have the abil­i­ty to be used as a stand­by pow­er option much like alka­lines are known for. Typ­i­cal­ly mar­ket­ed as ‘pre-charged,’ ‘ready to use,’ ‘hybrid,’ or ‘low self dis­charge,’ LSD NiMHs can be left on the shelf for more than a year with­out los­ing much of their stored power.

Charg­ing and main­tain­ing NiMHs has also become an attrac­tive rit­u­al of own­er­ship. This was­n’t the case a decade or even five years ago! Thanks to some tru­ly awe­some advances in micro­proces­sor ‘smart’ charg­ers, which use the cel­l’s inter­nal resis­tance and volt­age to deter­mine charg­ing needs, it’s now a mat­ter of sim­ply pop­ping the cells into a charg­er and com­ing back when it’s con­ve­nient. The charg­er takes care of the rest, from set­ting the charge cur­rent to mon­i­tor­ing bat­tery capac­i­ty to auto­mat­i­cal­ly turn­ing itself off once the task is fin­ished. Thanks to this, NiMHs can be charged any time a user wish­es to top them up, regard­less of how much they’ve been dis­charged. That being said, it’s bet­ter to recharge cells before they become com­plete­ly exhaust­ed, as this helps pro­vide longer ser­vice life and more charge cycles over the long run.

Gen­er­al advice on NiMH:

  • The charg­er makes or breaks the user expe­ri­ence, so get the best one you can find and do some research on its spec­i­fi­ca­tions before mak­ing your purchase.
  • The best charg­ers are micro­proces­sor man­aged, will have indi­vid­ual cell chan­nels (mean­ing they can han­dle one, two, three, or four cells), and should deliv­er a com­plete charge with­in one to three hours.
  • The charg­er spec­i­fi­ca­tions should men­tion ‘delta V’ (volt­age change), volt­age mon­i­tor­ing, ‘delta T’ (tem­per­a­ture change), or tem­per­a­ture mon­i­tor­ing. Oth­er indi­ca­tors like LCD read­outs or indi­vid­ual progress meters for cells are good tip-offs that you’re look­ing at a smart charger.
  • Nev­er charge at a rate greater than 1C (1x the capac­i­ty of the cell in mAH). This short­ens cell life and might cause them to poop out pre­ma­ture­ly. It also means you’d do well to avoid any prod­uct that adver­tis­es the abil­i­ty to charge bat­ter­ies from 0% to 100% in less than an hour. This tech­nol­o­gy is evolv­ing, but at the time of this writ­ing it’s not yet ful­ly mature.
  • For the best per­for­mance, buy only low self-dis­charge (LSD) NiMH cells. These can be rec­og­nized eas­i­ly from mar­ket­ing terms like ‘hybrid,’ ‘ready to use,’ ‘pre-charged,’ or ‘low self-dis­charge.’ If all else fails, check the specs. They should be able to retain at least 80% of their charge after a year on the shelf.
  • Charge capac­i­ty is mea­sured in mil­liamp-hours (mAH), or less com­mon­ly, amp-hours (AH); one amp-hour is equal to 1000 mil­liamp-hours. Buy cells rat­ed at 2000 mAH or above.
  • Bonus: if your devices use bat­ter­ies in even num­bers, it can help to orga­nize cells into pairs and num­ber each pair with a unique iden­ti­fi­er (Set A, Set B, etc.). This assures even wear across their full ser­vice life, max­i­miz­ing per­for­mance. Of course, a per­son can mix and match cells with­out any issues. This last tip is most­ly for peo­ple like me, who strive to get the absolute best from their gear.

For sev­er­al years, I’ve owned the Sanyo Eneloop charg­er (NC-MQH03U), as well as a com­bined inven­to­ry of 30 AA cells by Sanyo Eneloop and Pres­i­den­t’s Choice and 24 AAA cells by Sanyo Eneloop and Viv­i­tar. With the excep­tion of the two AAAs I acci­den­tal­ly left out­doors in the rain dur­ing my first month in Vic­to­ria, all of my stock is work­ing as per­fect­ly as it did on the day I bought it (that’s actu­al­ly say­ing a lot, con­sid­er­ing some have endured ‑60 Cel­sius wind chills, blaz­ing desert sun, and extend­ed peri­ods of high ambi­ent mois­ture, and it just does­n’t faze them). I’m a big pro­po­nent of dura­bil­i­ty and tor­ture tests, so as I’m con­cerned NiMH has earned its stripes and my rec­om­men­da­tion. This is a mature, sta­ble tech­nol­o­gy that’s already supe­ri­or to alka­line, and is being improved even more as time goes on. You’ve got noth­ing to lose (and much to gain) from adding it to your life.

Lithium Ion

If you’ve ever won­dered about the mag­ic behind lithi­um-ion (Li-Ion) bat­ter­ies, look no fur­ther than your mobile phone. Durable, depend­able, and capa­ble of hold­ing onto a large amount of ener­gy for a very long time, the Li-Ion cell has become the dar­ling of the IT indus­try and resides in vir­tu­al­ly every mobile device on the mar­ket. With a shelf life of well over a year between charges, these cells are ide­al­ly suit­ed to high-end elec­tron­ics, and in this, their wild suc­cess has real­ly been a no-brainer.

There are sev­er­al sub­cat­e­gories and fam­i­lies of Li-Ion that com­prise a mul­ti­tude of form fac­tors and vary­ing bat­tery chemistries, but from the per­spec­tive of the end user, they all do rough­ly the same thing, with a few dif­fer­ences here and there in han­dling and charge recommendations.

Unlike NiMH and dis­pos­able cells, Li-Ion are ridicu­lous­ly finicky when it comes to their han­dling needs and charge char­ac­ter­is­tics. Over­charg­ing or short­ing a Li-Ion cell will usu­al­ly cause it to fail cat­a­stroph­i­cal­ly, with gas vent­ing or flames. Con­verse­ly, if a Li-Ion cell ever becomes ful­ly dis­charged (deep cycle), it imme­di­ate­ly los­es the abil­i­ty to take anoth­er charge! Bat­tery man­u­fac­tur­ers have long since fig­ured out how to avoid both prob­lems, and all mod­ern bat­tery packs and cells meant for con­sumer use are shipped with pro­tec­tion cir­cuits that con­tin­u­ous­ly look after bat­tery dynam­ics and pre­vent excess charge or discharge.

Unsur­pris­ing­ly, Li-Ion cells require sophis­ti­cat­ed smart charg­ers due to the com­plex­i­ties of the pro­tec­tion cir­cuit­ry and the inher­ent­ly sen­si­tive nature of each cel­l’s inter­nal com­po­nents. The Li-Ion charge cycle demands con­stant volt­age and cur­rent mon­i­tor­ing, cell response mon­i­tor­ing, and occa­sion­al­ly the need to reset a tripped pro­tec­tion cir­cuit. As not­ed in the link, there are sev­er­al phas­es best shown via graphs in which the charg­er must be able to mea­sure and respond appro­pri­ate­ly to each part of the cel­l’s nat­ur­al cycle in order to make it reach full charge.

In terms of their form fac­tor and case design, Li-Ion bat­ter­ies are often man­u­fac­tured to fit the phys­i­cal spec­i­fi­ca­tions of the device they’re intend­ed to be used in. This means that you’re not going to find any ‘stan­dard’ sizes that fit all devices. Rather, the ecosys­tem is frag­ment­ed and you’re bound to encounter as many dif­fer­ing shapes and sizes as there are fish in the sea.

Cylin­dri­cal Li-Ion cells do exist, and a few are even in cir­cu­la­tion that have the same phys­i­cal dimen­sions as the more com­mon AA and AAA cells. There’s a catch, how­ev­er: they run at com­plete­ly dif­fer­ent volt­ages and have dif­fer­ent capac­i­ty rat­ings. While a user might encounter a NiMH AA cell rat­ed for 2000mAH at 1.25 volts, a Li-Ion cell of the same phys­i­cal size and dimen­sions would be rat­ed for 750 mAH at 3.7 volts! This is why, if you own any sort of high per­for­mance gear that makes use of Li-Ion, you need to ver­i­fy the deliv­ery volt­age before installing the batteries.

Apart from this, there’s also a flour­ish­ing com­mu­ni­ty of peo­ple world­wide who’ve includ­ed cylin­dri­cal Li-Ion cells in their day-to-day gad­get use in much the same way as oth­ers would use AA and AAA cells. In this case, how­ev­er, the gear is designed to han­dle the high­er volt­age and the bat­ter­ies are most often used for high-drain items like flash­lights and bicy­cle vis­i­bil­i­ty gear. In these envi­ron­ments, the long-term reli­a­bil­i­ty and light weight of the Li-Ion sys­tem real­ly stand out. In terms of bat­tery sizes, there are lithi­um AA (14500) and AAA (10440) cells, as well as the stan­dard 18650 cell, which make up the bulk of these con­sumer favourites.

Gen­er­al advice on Li-Ion:

  • Lithi­um cells are a spe­cial­ist device. Make sure you’re using the right tool for the job.
  • Get the best charg­er you can find. For ref­er­ence, here’s the one I picked out. Because of the way these cells work, hav­ing a qual­i­ty charg­er on hand is even more impor­tant in assur­ing safe­ty, reli­a­bil­i­ty, and long ser­vice life.
  • Do your research. Learn about the dif­fer­ent chemistries, the ways bat­ter­ies charge, the algo­rithms used by charg­ers, and most impor­tant­ly, the data post­ed online by trust­wor­thy review­ers. Sites like Can­dle­pow­er Forums and Bud­get Light Forum are a valu­able aid, and CPF Mar­ket­place is a great place where the user can get in touch with many of the best man­u­fac­tur­ers and distributors.
  • NEVER use Li-Ion cells with­out pro­tec­tion. Unpro­tect­ed cells are typ­i­cal­ly sold for use by qual­i­fied man­u­fac­tur­ers who install them in tool or RC packs which already have some sort of pro­tec­tion built in. Using them in any­thing else is risky at best because it intro­duces a chance that the cell will be dam­aged by improp­er charg­ing or exces­sive discharge.
  • Buy from rep­utable ven­dors. My per­son­al favourites are Solar­force and AW. Invest­ing in qual­i­ty equip­ment from the begin­ning ensure you’ll have a good expe­ri­ence and your equip­ment will last for may years. Beware of any­one claim­ing to be offer­ing super-high capac­i­ty cells for rock bot­tom prices, almost invari­ably it’s a scam where some­one has re-pack­aged dead or recy­cled com­po­nents sourced from unscrupu­lous third par­ties (this is every bit as dan­ger­ous as it sounds).
  • Buy about 150% of what you need. Unless you’re prepar­ing for a zom­bie apoc­a­lypse, what’s the joy in own­ing entire case­loads of cells? Get just a bit more than you need to get the job done.
  • Cycle and rest. It’s best to let fresh­ly charged cells sit on the shelf for 12 to 24 hours after they’ve been removed from the charg­er. This aids sta­bil­i­ty and helps ensure the longest pos­si­ble ser­vice life. While one cell is rest­ing, you can make use of anoth­er that’s fin­ished its rest phase.

For the past few years, I’ve owned a 4Sevens Sin­gle Bay V3 charg­er and a small stock of Solar­force 18650 cells (of which two are the orig­i­nal S18650P and two are the S18650P[V3]). I pur­chased the charg­er based on its incred­i­ble ver­sa­til­i­ty, com­pat­i­bil­i­ty with vir­tu­al­ly every bat­tery size/chemistry, well-regard­ed algo­rithm, and addi­tion­al USB and 12V charge options. The cells them­selves have been sub­ject­ed to extreme weath­er, much the same as I did with the NiMHs.

My orig­i­nal pair of S18650P cells are now two years old, and hav­ing tak­en them through con­sis­tent dai­ly use and hun­dreds of charge cycles in that span of time, I’ve noticed a slight drop in per­for­mance (about 15% reduced capac­i­ty) due to wear and tear. Oth­er than that, there have been no prob­lems with charg­ing, dis­charge, or per­for­mance, and I feel the tech­nol­o­gy has had ample time to prove itself. I bought my sec­ond pair of 18650 cells this year think­ing I’d need replace­ments by now, but that sim­ply has­n’t been the case. The orig­i­nal two are still going strong.

Apart from this, I took it upon myself to get a pair of AW 14500 cells for my Xeno E03 (a spe­cial type of hyper-dri­ven LED flash­light from Hong Kong). These, too, have per­formed well in reg­u­lar service.

Look­ing back, I think that my biggest rea­son for not jump­ing into Li-Ion ear­li­er was a lack of infor­ma­tion and expe­ri­ence. There have been hor­ror sto­ries cir­cu­lat­ing in the media about these bat­ter­ies for years, and sad­ly what news crews don’t tend to give air­time to is the fact that the acci­dents and safe­ty con­cerns in the pub­lic con­scious­ness have arisen as the result of coun­ter­feit goods or seri­ous fac­to­ry defects. Thank­ful­ly the rate of defects has been dras­ti­cal­ly reduced due to stricter qual­i­ty con­trols and improved man­u­fac­tur­ing process­es, but there is still the issue of shady deal­ers know­ing­ly sell­ing fake, recy­cled, or defec­tive items to con­sumers who don’t know enough to guard them­selves from it.

So again, fol­low the tips in this arti­cle and learn before you leap.

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