Uma isibambi sebhethri le-18650 ekilasini lakho noma elabhorethri yezamarobhothi sincibilika, ibhethri ngokwalo alivamile ukuba yimbangela eyinhloko. Lokhu kuhluleka cishe kuhlala kuvela kusibambi sebhethri ngokwaso: izibambi zepulasitiki ezishibhile nezejwayelekile zisebenzisa iziphethu zensimbi ezicwebezeliswe nge-nickel ezinokumelana okuphezulu kukagesi. Lapho i-ESP32 ithumela idatha nge-WiFi noma lapho injini ye-DC eshibhile imiswa ngenkani (stalls), umsinga kagesi odonswa kuleyo phethu evimbayo uguqula amandla kagesi abe ukushisa okukhulu okugxilile. Ipulasitiki iyathamba, isiphethu silahlekelwa ukuqina kwaso, ukumelana koxhumano kuyenyuka, bese isibambi sincibilika.

Ukubalwa Kokushisa kwe-Joule: P = I²R

Ukuze uqonde ukuthi kungani lezi zibambi zincibilika, bheka ubudlelwano obuyisisekelo phakathi komsinga kagesi nokukhishwa kokushisa: ukulahleka kwamandla ngama-watt kulingana nomsinga ophindaphindwe kabili uphindwe ngokumelana (P = I²R).

Iphrojekthi ejwayelekile yezamarobhothi yasekilasini ingahlanganisa i-microcontroller (njenge-ESP32) nesishayeli se-H-bridge esineziteshi ezimbili kanye nezinjini ezimbili eziphuzi ze-TT gearmotors noma i-N20 micro metal gearmotors. Cabanga ngokwenzeka ngesikhathi sokusebenza okuvamile:

• Ukunyuka kwemvamisa yomsakazo (RF) ye-ESP32: Ngesikhathi sokuthunyelwa kwe-WiFi okusebenzayo noma ukulungiswa kwe-calibration, i-ESP32 idonsa amaphulisi omsinga wesikhashana aphakathi kuka-250 mA no-500 mA.
• Imisinga yokuqala nokuma kwenjini: Ngesikhathi isebenza ingenamthwalo, injini ejwayelekile ye-DC engu-6V ingadonsa u-150 mA kuya ku-200 mA. Nokho, ngesikhathi umfundi ebambe isondo, irobhothi lishayisa udonga, noma uhlaka luqala ukuhamba phansi kukhaphethi, injini ngayinye ingadonsa kalula phakathi kuka-1.2 A no-1.8 A. Izinjini ezimbili ezimisiwe zidonsa cishe u-2.4 A kuya ku-3.6 A.

Uma kuhlanganiswe, ukudonsa okuphelele kwaleso sikhathi ngesikhathi sokuma noma ukusheshisa okunamandla kungafinyelela ku-3.0 A kuya ku-4.0 A.

Kusixhumi esisezingeni eliphezulu, ukumelana koxhumano (contact resistance) kuncane kakhulu (ngaphansi kuka-0.01 Ω). Kodwa kusibambi se-18650 esishibhile nesingenawo uphawu, isiphethu senziwe ngocingo lwensimbi olusongwe olunongqimba oluncane lwe-nickel. Insimbi inokumelana kukagesi okuphakeme cishe ngokuphindwe kasithupha kuya kayisishiyagalombili kunezingxubevange zethusi (copper alloys). Kubude besiphethu kanye nendawo encane yokuthinta esiphethweni esinegethivu sebhethri, ukumelana koxhumano kuvame ukukala phakathi kuka-0.3 Ω no-0.6 Ω ngendawo ngayinye.

Uma umthwalo ongu-3 A udlula kusiphethu esinokumelana okungu-0.4 Ω:

P = (3 A)² × 0.4 Ω = 3.6 Watts

Amandla okushisa aqhubekayo angama-watt amathathu nengxenye agxile esihlokweni sesiphethu esingamamilimitha amabili kuphela ububanzi azoshisa insimbi ifinyelele ngaphezu kuka-100°C ngemizuzwana embalwa. Izibambi zamabhethri ezijwayelekile zenziwe ngepulasitiki ye-ABS esezingeni eliphansi noma i-polypropylene eshibhile, ethamba cishe ku-80°C kuya ku-105°C.

Umjikelezo Wokushisa Okungalawuleki Eziphethwini Ezishibhile

Uma ukushisa sekuqala ukwanda, kulandela umjikelezo owonakalisayo:

1. Ukulahlekelwa ukuqina kwesiphethu: Njengoba isiphethu sensimbi seqisa izinga lokushisa okufanele sisebenze kulo, siyathamba bese silahlekelwa amandla aso okubuyela emuva.
2. Ukuncipha kokucindezela koxhumano: Isiphethu esithambile siyagoqeka kancane, okunciphisa amandla okuthinta esiphethweni esinegethivu sebhethri le-18650.
3. Ukwenyuka kokumelana: Ukwehla kokucindezela koxhumano kukhulisa ngokushesha ukumelana kagesi.
4. Ukukhiqizwa kokushisa okuphezulu: Ukumelana okuphezulu kukhiqiza ukushisa okwengeziwe kumsinga ofanayo, kusheshise ukuncibilika kwepulasitiki ezungezile kuze kube yilapho isiphethu sitshona ngaphakathi noma sidala i-short circuit esiphethweni esiseduze.

Ungayithola Kanjani Inkinga Etafuleni Lakho Laselebhu

Ungahlola ukumelana koxhumano ngokuqondile usebenzisa i-multimeter yedijithali evamile ngaphambi kokuba noma iyiphi ipulasitiki iqale ukushunqa umusi:

1. Setha i-multimeter yakho ukukala amavolthi e-DC (ebangeni lama-millivolts).
2. Beka iphrobu eyodwa ngqo engxenyeni yensimbi enegethivu esicaba yebhethri le-18650.
3. Beka enye iphrobu endaweni yokushisela (solder lug) noma ephini le-PCB lapho isiphethu esinegethivu siphuma khona kusibambi sepulasitiki.
4. Vula irobhothi lakho bese uyala izinjini ukuthi ziphenduke ube ubambe amasondo okwesikhashana imizuzwana emibili ukuze ulingise ukumiswa kwenjini.
5. Funda ukwehla kwamavolthi (V_drop) kuxhumano.

Uma ubona ukwehla kuka-0.5 V noma ngaphezulu ngaphansi komthwalo, lokho kuxhumana okukodwa kwehlisa amavolthi amaningi futhi kukuqondisa ekubeni ukushisa ngokuphelele. Ukwehla kuka-0.5 V ku-3 A kulingana no-1.5 W wokushisa kusiphethu esisodwa.

Izindlela Ezine Zokuxazulula Le Nkinga

1. Thuthukela Ezibanbeni ze-Phosphor-Bronze Leaf

Ungalokothi usebenzise izibambi eziphethwe yizinsimbi zemithambo (steel coil-springs) emithwalweni eyeqa ku-1 A. Esikhundleni salokho, khetha izibambi zamabhethri ezineziqeshana ze-phosphor-bronze noma i-beryllium-copper leaf-spring (njengezibambi zezimboni zesitayela se-Keystone ze-SMD noma ze-through-hole). I-phosphor-bronze inikeza ukumelana okuphansi kakhulu futhi igcina amandla wesiphethu ngisho nalapho izinga lokushisa lendawo lenyuka.

2. Sebenzisa Amabhethri e-18650 Avikelwe

Abafundi besikole samabanga aphezulu bavame ukwenza amaphutha okuxhuma izintambo. Ibhethri le-lithium-ion le-18650 elingavikelekile lingakhipha ngaphezu kuka-15 A kuya ku-30 A lapho kune-short circuit, okungancibilikisa izintambo kalula futhi kubangele ingozi yomlilo. Hlale uhlomisa amakhithi esikole ngamabhethri e-18650 avikelwe anebhodi elakhelwe ngaphakathi lokuvikela (PCM/BMS) esiphethweni esinegethivu. Lawa mabhodi acisha amandla ngokuzenzakalelayo uma umsinga weqa umkhawulo ophephile (imvamisa u-3 A kuya ku-6 A) noma uma amavolthi ehla ngaphansi kuka-2.5 V.

3. Hlola Ubukhulu Bezintambo (Wire Gauge) Nezindawo Zokushisela

Izibambi zamabhethri ezishibhile ezifika zinezintambo zivame ukuba nezintambo ezingu-28 AWG noma 30 AWG ezifihlwe ngaphansi kwe-PVC ewugqinsi. Ngaphansi kwemithwalo engu-2 A, intambo ngokwayo isebenza njengento yokushisa. Kwezerobhothi zasezikoleni ezidonsa amandla amaningi, qinisekisa ukuthi izintambo zikagesi zangaphakathi zisebenzisa intambo engu-20 AWG noma 22 AWG efakwe i-silicone.

4. Faka Amafyuzi e-PPTC Akwazi Ukuzilungisa kabusha

Faka ifyuzi eshibhile ye-Polymeric Positive Temperature Coefficient (PPTC) ekwazi ukuzisetha kabusha—ekalwe cishe ku-2.0 A kuya ku-2.5 A—ngokulandelana (in series) nentambo ephozithivu yesibambi sebhethri lakho. Lapho umfundi emisa injini ngokuphusha edeskini, i-PPTC inyusa ukumelana kwayo ngokushesha ngaphambi kokuba isibambi sebhethri sifinyelele emazingeni okuncibilika, iphinde izilungise ngokuzenzakalelayo uma amandla kagesi esusiwe.

Ukuhlomisa Ikilasi Lakho

Ukwakha amaphrojekthi abafundi athembekile kuxhomeke ekukhetheni izingxenye ezifanele imithwalo kagesi eshintshashintshayo yama-microcontroller nama-actuator. Uma uhlola ihadiwe yelebhu yesikole sakho noma ufuna izingxenye zikagesi ezilungele amakilasi ezikwazi ukumelana nokusetshenziswa ngabafundi, hlola izingxenye zethu ezikhona ku-Sheen Robotics Store noma uthintane nethimba lethu nge-Lab Sourcing Solutions.