Customer:
I need to redesign my power supply because a 9V battery cannot supply enough current/voltage. When I turn on a solenoid valve, the voltage drops below 4.5V, which is not enough even for a relay module, let alone the valve. The battery recovers later but in practice it’s unusable. With a 12V accumulator it works perfectly, but the battery size is unacceptable. I’m thinking of doing the following: use a single Li-Ion cell and connect two step-up modules to it. One would provide 5V for electronics and another 10V for the solenoid valve. According to the solenoid valve manufacturer’s data, it draws around 280 mA, and even if the Li-Ion discharge rate is 1C (which it probably exceeds) this should work.
I haven’t worked with step-up modules before, so I’d like your opinion on this. I read through the documentation and understood the concept, but I don’t have a feel for what will happen when you step up from 3.7V to 10V. According to the module specifications it can do it, but I don’t know if the current drops like in a transformer or if there’s some other hidden problem.
A few questions about the module with XL6009:
- Does it have reverse polarity protection diode or should I provide it?
- One module will power the solenoid valve directly. Would it be good to solder a reverse-biased diode on the module output for protection against self-induction?
Original message (Croatian)
[name removed] bok!
Morat ću promijeniti koncept napajanja jer 9V baterija ne može dati dovoljno struje/napona. Kad se uključi el. mag. ventil napon padne ispod 4,5V što nije dovoljno ni za relejni modul a kamoli za ventil. Baterija se kasnije oporavi ali u praksi je neupotrebljivo. S 12V akumulatorom stvar radi savršeno jedino mi je veličina akumulatora neprihvatljiva. Stoga sam mislio napraviti slijedeće. Uzeo bi Li-Ion bateriju (jednu ćeliju) i na nju bi spojio dva step-up modula, Jedan bi dao 5V za elektroniku, a drugi 10V za el. mag. ventil. Prema podacima od proizvođača el. mag. ventil vuče oko 280 mA pa čak da je struja pražnjenja kod Li-Ion 1C (a sigurno je veća) to bi trebalo držat vodu.
Do sada nisam radio sa step-up modulima pa me zato zanima što misliš o tome. Pročitao sam KKM i shvatio koncept ali opet nemam osjećaj što će se dogoditi kada se s 3,7V digne na 10V. Prema specifikaciji modula to ide, samo ne znam je li tada pada struja kao kod transformatora ili ima još negdje kakav skriveni problem.
Par pitanja vezana uz modul S XL6009:
Ima li zaštitnu diodu od krivog polariteta ili da je ja predvidim?
Jedan modul će napajati el. mag. ventil direktno, bilo bi dobro da na izlaz modula zalemim kontra okrenutu diodu radi zaštite od samoindukcije?
Originally submitted via email support on 2 May 2018. Migrated to the forum for community visibility.