Li-Ion batteries cannot supply 4-5A needed for drone operation

TECHNICAL SUPPORT Batteries & Power
1

Customer:

We received batteries for a drone and conducted testing based on your response. Voltage measurements on freshly unpackaged batteries showed 3.8 to 3.9V, rising to approximately 4.2V after charging. When measuring voltage on a fully charged battery during drone operation at maximum load (holding the drone in hand), voltage dropped below 3V and the drone shut down with a low battery alarm.

When powering the drone from a stable laboratory power supply set to 3.8V, the drone’s maximum current draw was slightly over 5A.

We believe the purchased batteries may have 680mAh capacity, but cannot supply the required 5A current. The drone’s control system is reporting an empty battery because the batteries cannot deliver the needed current. What is the maximum allowed current for these batteries?

Can we resolve this by replacing them with batteries matching the required parameters: 3.7V voltage, approximately 5A allowed current, 500 to 600mAh capacity?

Original message (Croatian)

javljam se vezano za upit gospodina Vinka Nerude iz Aerokluba
Požega, nakon kupovine baterija za dron. Baterije su donesene
nama na dodatno ispitivanje vodeći se vašim odgovorom na e-mail
gospodina Nerude.

Mjerenjem napona, ustanovili smo da baterije koje
su tek izvađene iz vrećice imaju napon 3.8 do 3.9V, a nakon
punjenja napon poraste na ~4.2V. Mjerenjem napona tek napunjene
baterije tokom rada u dronu (držeći ga u rukama), pri
maksimalnom opterećenju drona, napon padne na ispod 3V te se
dron isključi uz javljanje alarma prazne baterije. Napajanjem
drona iz stabilnog laboratorijskog izvora napajanja podešenoga
na 3.8V, maksimalna struja drona iznosi nešto više od 5A.

Mišljenja sam kako kupljene baterije možda jesu kapaciteta
680mAh, ali ne i ako se od njih traži struja od 5A, tj. one nisu
u stanju isporučiti traženu struju te zbog toga upravljački
sustav drona javlja kako je baterija prazna. Imate li podatak o
maksimalno dozvoljenoj struji ovih baterija?

Možemo li ovaj problem riješiti zamjenom baterija drugima koje
odgovaraju traženim parametrima, napon 3.7V, dozvoljena struja
~5A, kapacitet 500 do 600mAh?

Attachment omitted in migration: 8gsbI70j8b5SROas.jpg

Originally submitted via email support on 8 February 2024. Migrated to the forum for community visibility.

2

Soldered Support:

Are these standard Li-Ion batteries from the shop? Standard Li-Ion batteries generally can provide 1C (the battery capacity) - meaning this one can stably provide 680mA. The battery originally used with the drone must be a specialized model designed specifically for that purpose. Can you provide more information about it?

Original message (Croatian)

zanima me u vezi Baterije od gospodina Vinka, ove baterije manjeg kapaciteta koja radi dobro, je li to isto obična Li-Ion baterija iz našeg web shopa? Te Li-Ion baterije općenito daju mogu pružati 1C (kapacitet baterije) - što znači da ova može stabilno pružati 680mA. Pa pretpostavljam da je baterija s kojom se dron izvorno koristio neka posebna baš namijenjena za to. Možeš li pružiti više informacija u vezi toga?

3

Customer:

The battery that works properly in the drone is originally low capacity - it was supplied with the drone by the manufacturer Rewel. It is much thicker and heavier than the ones purchased from your shop. I currently don’t have detailed specifications for it other than 380mAh, 3.7V. Do you have data on the maximum allowed current for any of your other batteries? If it cannot supply the 4-5A the drone needs to operate at full power, then those batteries are not suitable.

I see you have a battery listed as 333278, model 602045, 500mAh, which appears considerably thicker and seems to have different construction than the ones we purchased. Do you have specifications for it?

Original message (Croatian)

baterija koja u dronu radi uredno, no
originalno je malog kapaciteta jer baterija koja je isporučena
s dronom, proizvođač je Rewel. Ona je puno deblja i teža od
ovih koje su kupljene u vašoj trgovini. Trenutno nemam posebno
podataka o njoj osim da je 380mAh, 3.7V. Imate li podatke o
maksimalno dozvoljenoj struji nekih drugih vaših baterija? Ako
ona nije u stanju isporučiti 4-5A koliko dronu treba da bi
radio punom snagom, onda te baterije svakako ne odgovaraju.

Vidim da je vaša baterija pod oznakom 333278, model 602045,
500mAh, prilično deblja i kao da je drugačije konstrukcije od
kupljenih. Imate li podatke o noj?

Attachment omitted in migration: Zw4lSvNjUlpNl8FW.jpg

4

Soldered Support:

That appears to be a different battery, specifically designed for that purpose.

The allowed current for our batteries follows the 1C rule as described earlier. A 380mAh battery can supply 380mA. A 1500mAh battery can supply 1500mA, and so on.

The 500mAh battery is not a special capacity - the same 1C rule applies.

Original message (Croatian)

hvala na odgovoru. Izgleda da je to malo drugačija baterija, posebno namijenjena za to.

Dozvoljene struje naših baterija su, kao što sam opisao za ovu ranije, 1C, tako da ako je baterija 380mAh, može isporučiti 380mA. 1500 mAh može isporučiti 1500mA, itd.

500mAh baterija nije posebnog kapaciteta nego ostale.