Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Charging 18650 Li-Ion Batteries - A New Experience

Status
Not open for further replies.

Musicmanager

Well-Known Member
Hello Guys

I need some advice and I'm hoping there's someone around with experience of 18650 Li-Ion Batteries.

I've got a project on the go for my Grandson which involves 5 separate units each containing an Arduino Nano and an SG90 Servo motor both of which work best at 5vdc

I'm planning on using a single 18650 Li-Ion Rechargeable Battery in each unit with an MC34063 Boost Converter to get from 3.7 to 5vdc and a TP 4056 BMS module for charging with a DPDT switch between the two.

I've tried all this out in prototype and it all seems to work perfectly well, but .. .. .. .. . I've never done anything with this type of battery before and I'm a bit wary of the usual MM type errors that pervade my work and I don't think it will go down too well with the Senior Manager I married if I bump off one or more of the grandkids.

I'd appreciate a perusal of the attached schematic for any errors, glaring or otherwise.

The batteries are marked ' Ultrafire TR 18650 9900mAh 3.7v ' ;

I appreciate the decoupling caps are missing on the schematic, they will be present on the assembly.

Many thanks

S
 

Attachments

  • Charging Schematic.pdf
    37.8 KB · Views: 246
The batteries are marked ' Ultrafire TR 18650 9900mAh 3.7v ' ;
The best 18650 batteries are around 4000mAh. The Ultrafire ones are a complete ripoff and normally less than 1000mAh. I would buy new ones but would be interested in the actual capacity of your 9Ah batteries.

Mike.
 
Hi Pommie

Thanks for that; I did consider they were probably less than ideal because they were so cheap ! However, whilst at a prototype when I'm not even sure if I can get the whole project to fruit I'd decided they'd do.

As for capacity, I think there's a '9' too many in the markings; This morning I ran one down with a little motor, when the motor stopped, I recharged it with a TP 4056 - rated at n.m.t. 1Amp - ammeter attached went from 800ma down to about 120ma and then it switched to 'fully charged' just under an hour .. .. . my maths isn't brilliant, but that makes sense to me !

S
 
Whenever I use 18650's I tend to use one of the TP4056 modules off of ebay (<$1 each) and (so far) not had any problems.

Mike.
 
Here is a video showing what is inside a cheeeep Ultrafire 18650 battery cell. You get what you pay for.
 
Be careful! The fake battery might explode and/or catch on fire when it is charged.
 
Hi Guys

Thank you very much for that warning, it's heeded !

Before I bought a pack of 4, I did consider they might be fake, but was consoled by finding an 'Ultrafire.com' website with quite a range of products and an extensive infrastructure to view. It has to be said also that of all the damning comments on the net, most will only say . .. .. there are SOME Ultrafire batteries that are fake .. .. this is supported by the fact that I have already charged 2 of my pack of 4 to about 800mA without any issue whatsoever, so they may be OK.

BUT … .. .. I'm not going to take the chance, I will dispose of them ( responsibly, of course - drop kick over the garage roof ! ) and acquire some from a reliable source. I much appreciated the advice.

Talking of advice, can I take it that the lack of any negative comment of my schematic means it's OK ??

Thanks again

S
 
Ian .. .. .. .

A very kind offer, Thank you .. however, I will need more than one .. .. ..perhaps you could provide the product ID and a source of supply, if possible ??

Thanks

S
 
Hi Guys

Thank you very much for that warning, it's heeded !

Before I bought a pack of 4, I did consider they might be fake, but was consoled by finding an 'Ultrafire.com' website with quite a range of products and an extensive infrastructure to view. It has to be said also that of all the damning comments on the net, most will only say . .. .. there are SOME Ultrafire batteries that are fake .. .. this is supported by the fact that I have already charged 2 of my pack of 4 to about 800mA without any issue whatsoever, so they may be OK.

BUT … .. .. I'm not going to take the chance, I will dispose of them ( responsibly, of course - drop kick over the garage roof ! ) and acquire some from a reliable source. I much appreciated the advice.

Talking of advice, can I take it that the lack of any negative comment of my schematic means it's OK ??

Thanks again

S

I think if you weigh them, it gives a good idea if they are 'real' or not (fakes are lighter), but that claimed power is nonsense anyway. I bought some from Banggood which claim 4000mAH - and while I've not seriously measured them, they work pretty well - only concern, they are slightly larger than normal 18650's :D (which is perhaps how they manage a little higher power?).

The ones we buy at work are branded 'Samsung', although I've no idea if that's real or not though we buy them from a UK specialist battery supplier in 100's - not sure of the power rating off hand, but it's not at the top end of 18650's.
 
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top