Author Topic: Power bank with replaceable 18650 batteries  (Read 1040 times)

Online A_Northerner

  • stalker
  • ***
  • Posts: 275
  • SUSS 'til you die (Also BPC + CDG)
Power bank with replaceable 18650 batteries
« on: November 16, 2021, 02:30:04 pm »
Before I do a cursory Google search and end up ordering something completely unsuitable from China, does anyone have any suggestions for power banks with USB charging ports that utilise 1 or more 18650 batteries that can be replaced? I'm thinking about using one to charge PDAs/phones on long trips underground, but using what is quickly becoming the currency for underground power; 18650 batteries.

If anyone has one they can recommend that would be suitable for use underground (I.E. houses the 18650s inside a reasonably water-tight and shock-proof case) please let me know. Otherwise it's going to be trial-and-error buying multiple ones, and testing them by recharging the Bluetooth speaker in my dig!
Sweet is the sound of the pouring rain,
And the stream that falls from hill to plain.

UK Caving

Power bank with replaceable 18650 batteries
« on: November 16, 2021, 02:30:04 pm »
Warmbac

Online Benfool

  • forum star
  • ****
  • Posts: 592
Re: Power bank with replaceable 18650 batteries
« Reply #1 on: November 16, 2021, 02:41:40 pm »
That would be very easy to build....

1x Small Peli Case
1x https://www.ebay.co.uk/itm/222429896066?hash=item33c9dadd82:g:XggAAOSwXY5ZWNT2 (4x Parallel)
1x https://www.ebay.co.uk/itm/373723265394?hash=item5703a47972:g:hTYAAOSwuJZdXKiG

Difficult bit would be working out how to waterproof the cable coming out of it....

B


Online A_Northerner

  • stalker
  • ***
  • Posts: 275
  • SUSS 'til you die (Also BPC + CDG)
Re: Power bank with replaceable 18650 batteries
« Reply #3 on: November 16, 2021, 03:10:06 pm »
That would be very easy to build....

1x Small Peli Case
1x https://www.ebay.co.uk/itm/222429896066?hash=item33c9dadd82:g:XggAAOSwXY5ZWNT2 (4x Parallel)
1x https://www.ebay.co.uk/itm/373723265394?hash=item5703a47972:g:hTYAAOSwuJZdXKiG

Difficult bit would be working out how to waterproof the cable coming out of it....

B

In theory, this is what I'm looking for - but I don't have the skills or energy to make it myself!

Are you looking at something like these (other shops available)?

https://www.torchdirect.co.uk/battery-chargers/nitecore-f2-flexbank-dual-bay-li-ion-battery-charger.html

https://www.torchdirect.co.uk/battery-chargers/fenix-are-x1-charger-and-18650-2600-mah-li-ion-battery-set.html




Yes, except in both of those the battery is quite exposed, meaning a light shock will knock it out of place. I'd like something where the battery is enclosed, like it is in a torch, but with USB outputs as well.
Sweet is the sound of the pouring rain,
And the stream that falls from hill to plain.

Online aricooperdavis

  • Global Moderator
  • forum star
  • *****
  • Posts: 661
  • Cornwall to Cumbria
    • Cooper-Davis.net
Re: Power bank with replaceable 18650 batteries
« Reply #4 on: November 16, 2021, 04:30:40 pm »
Looks like more robust ones do exist: https://www.aliexpress.com/item/32832052308.html

Online Steve Clark

  • regular
  • *
  • Posts: 59
Re: Power bank with replaceable 18650 batteries
« Reply #5 on: November 16, 2021, 04:33:34 pm »
If it serves a useful purpose for you, you could also consider the Fenix LR40R monster torch.

https://www.torchdirect.co.uk/fenix-professional-torches/fenix-lr40r-rechargeable-led-searchlight.html

This has a massive pack inside, but also takes 1-4 18650 batteries. You can charge it by proper negotiated USB-C, plus it will output USB to other devices.

Claims to be IP68, but like all fenix stuff this is dependant on you actually shutting the rubber flaps and them staying closed.

Caverkeith did a review on youtube.

Offline marysboy

  • obsessive maniac
  • ***
  • Posts: 359
Re: Power bank with replaceable 18650 batteries
« Reply #6 on: November 16, 2021, 05:07:20 pm »
i use this battery charger and it works well as a power bank.

https://www.inglesport.com/product/fenix-battery-charger-set/

put one in a tupperware box?

Offline ali_mac

  • regular
  • *
  • Posts: 55
Re: Power bank with replaceable 18650 batteries
« Reply #7 on: November 16, 2021, 06:02:48 pm »
That would be very easy to build....

1x Small Peli Case
1x https://www.ebay.co.uk/itm/222429896066?hash=item33c9dadd82:g:XggAAOSwXY5ZWNT2 (4x Parallel)
1x https://www.ebay.co.uk/itm/373723265394?hash=item5703a47972:g:hTYAAOSwuJZdXKiG

Difficult bit would be working out how to waterproof the cable coming out of it....

B

Cut your USB charging cable, thread through this, drilled into the Pelicase: https://www.ebay.co.uk/itm/383254402870
Then solder it back together and insulate with heat shrink inside the case.

Offline Ian Ball

  • forum hero
  • *****
  • Posts: 1263
Re: Power bank with replaceable 18650 batteries
« Reply #8 on: November 16, 2021, 06:42:31 pm »
If you want to go ultimate lightweight have a look at the nitecore LC10 single cell unit. Max output is 1A with a fully charged cell.  It's essentially two magnets that slot onto the ends of the cell and you plug into what you want to charge.  If you're trying to charge a phone from flat it''ll take a couple cells and a fair while. 

This site might be of interest to you

https://lygte-info.dk/


Offline Stuart France

  • obsessive maniac
  • ***
  • Posts: 301
Re: Power bank with replaceable 18650 batteries
« Reply #9 on: November 16, 2021, 07:03:14 pm »
OMG this is another nightmare in the making, straight after that other thread concerning soldering wires directly on to the bodies of 18650 Li-Ion cells.

First off, if you want a 5.0 volt output delivering reasonable current (like a USB socket on a PC does) then you won’t get it from 18650 cells either singly or arranged in parallel or series.

Li-Ion cells are 4.1 volts each when fully charged (so 4.1 for any number parallel linked or 8.2 for two in series, 12.3 for three in series etc).  These numbers are not 5.0, so you’d need a buck or boost power supply controller to drop 8.2 (or some other bigger number) to 5.0 or to raise 4.1 to 5.0 efficiently.  As the batteries are run down their voltage will droop from 4.1 to say 3.5 where you might consider them to be exhausted.  So wired in parallel your 8.2 becomes 7.0 as the battery runs down.  The raw battery voltage isn’t anywhere near constant.  The only way to do voltage level shift and regulation efficiently is a good switch-mode power supply that was not designed by either you or some random online seller.

Second, it isn’t going to be waterproof for two reasons.  A USB inline plug or a panel mounted USB socket by its very nature isn’t waterproof.   Cases tend not to be completely waterproof either, or to some extend develop condensation inside over time.  “IP” ratings are meaningless too if you read the small print as they allow “reasonable ingress” of damp or liquid and the item still passes the IP test.





Offline Ian Ball

  • forum hero
  • *****
  • Posts: 1263
Re: Power bank with replaceable 18650 batteries
« Reply #10 on: November 16, 2021, 07:57:52 pm »
In wades Mr Positivity.





Online aricooperdavis

  • Global Moderator
  • forum star
  • *****
  • Posts: 661
  • Cornwall to Cumbria
    • Cooper-Davis.net
Re: Power bank with replaceable 18650 batteries
« Reply #11 on: November 16, 2021, 08:35:21 pm »
The only way to do voltage level shift and regulation efficiently is a good switch-mode power supply that was not designed by either you or some random online seller.

It depends what you mean by efficiently, but I have tested eBay voltage regulation chips much like the one Ben posted and found them to be completely satisfactory for powering small projects over USB. What do you think most USB battery banks use?

Offline mountainpenguin

  • regular
  • *
  • Posts: 70
Re: Power bank with replaceable 18650 batteries
« Reply #12 on: November 17, 2021, 10:27:43 am »
I have a small adapter for bosch 18v battery to give 2 usb and a 12v.
This is very handy for running a fridge when camping and charging stuff.
A fast charger for the 18V batteries at 8A
Not what your asking for but handy to think about.

Online aricooperdavis

  • Global Moderator
  • forum star
  • *****
  • Posts: 661
  • Cornwall to Cumbria
    • Cooper-Davis.net
Re: Power bank with replaceable 18650 batteries
« Reply #13 on: November 17, 2021, 11:13:46 am »
You can get also get USB adapters for Makita batteries too.

Many cave headlamps don't use loose 18650s but wrapped battery packs with RCY connectors. Some cavers charge these packs over USB using a simple charging board, but you can also get boards that can be used "in reverse" to power a USB socket from the battery pack, if you so wished.

Offline JoshW

  • junky
  • ****
  • Posts: 824
  • YSS, WSCC, BCA Youth & Development, BCA Group Rep
Re: Power bank with replaceable 18650 batteries
« Reply #14 on: November 17, 2021, 12:36:06 pm »
For some reason in my head i thought little monkey made an adapter for 187650 batteries to provide output to usb, but can’t seem to find anything now.
All views are my own and not that of the BCA or any clubs for which I'm a member of.

Offline Shapatti

  • newbie
  • *
  • Posts: 15
Re: Power bank with replaceable 18650 batteries
« Reply #15 on: November 17, 2021, 01:44:27 pm »
For some reason in my head i thought little monkey made an adapter for 187650 batteries to provide output to usb, but can’t seem to find anything now.
I think he made a very short run of them, mainly based on something he made for himself to charge phones and lights whilst out cycling...

Offline royfellows

  • forum hero
  • *****
  • Posts: 1591
    • mineexplorer.com
Re: Power bank with replaceable 18650 batteries
« Reply #16 on: November 17, 2021, 01:45:17 pm »
Without going into the question of why anyone would want to take, and be able to recharge, a PDA or a phone underground, I agree with previous comments that the "waterproof" bit is the main issue.

The problem with any one off build is that components of quality have to be sourced from suppliers such as Farnell or RS Online who have a minimum spend to get free postage.

The way i would go about it would be to test the electronics from a cheap, off the shelf, USB power bank, and then enclose in an aluminium case rated at IP68, manufactured by Deltron or similar. They probably best. The case would be drilled and tapped to accept a threaded sleeve sealed with FT 101, and would take an IP 68 plug by someone like Hummel. I use this in some of my lamps, but its M16 not large enough for a USB plug, else I would give you the part numbers.

If you wanted to be able to see the charging - charge completed - low power level etc LEDs then there is a fresh challenge.

One can spend many hours sifting through different components, and then when in the lab find them unsuitable for purpose. There is quite a lot to this sort of thing.

Not particularly robust, but fairly waterproof and with a transparent lid, how about just sticking an ebay power bank into a transparent lidded  Appleby Box?
I used to put network cameras into them many years ago for outside use.
My avatar is a poor likeness.


Online PeteHall

  • Global Moderator
  • forum hero
  • *****
  • Posts: 2029
  • ChCC, GSS, SWCC, WCC, WCDG
Re: Power bank with replaceable 18650 batteries
« Reply #18 on: November 17, 2021, 02:44:42 pm »
Without going into the question of why anyone would want to take, and be able to recharge, a PDA or a phone underground...

To answer the question you didn't ask, for surveying.  :smartass:

Offline royfellows

  • forum hero
  • *****
  • Posts: 1591
    • mineexplorer.com
Re: Power bank with replaceable 18650 batteries
« Reply #19 on: November 17, 2021, 03:10:57 pm »
Without going into the question of why anyone would want to take, and be able to recharge, a PDA or a phone underground...

To answer the question you didn't ask, for surveying.  :smartass:

Of course!
All you need now then is a waterproof phone to go with the waterproof power bank
 :lol:
My avatar is a poor likeness.

Offline darkandmuddy

  • newbie
  • *
  • Posts: 8
Re: Power bank with replaceable 18650 batteries
« Reply #20 on: November 18, 2021, 08:33:59 pm »
Just bought one of these online to power my bike light using my caving light 18650s. It takes two or four and has a USB output and an 8.4v output. Claims to have protection included as well. Seems well made and the unit looks quite well protected against water and is quite tough. Power ports would probably need protecting more for underground. I can report back once tested next week but looks ok so far. I'll be charging my cells outside of this so won't be testing the charging capabilities it claims since I don't trust it for that!

Sent from my SM-T290 using Tapatalk


Offline Ian Ball

  • forum hero
  • *****
  • Posts: 1263
Re: Power bank with replaceable 18650 batteries
« Reply #21 on: November 18, 2021, 09:49:09 pm »
One of the best names for a product that can catch fire if incorrectly charged ;-)

I think that is spot on but I think the cables are a weak point, you can get them for about £10 on ebay. Looking forward to your review.

Offline royfellows

  • forum hero
  • *****
  • Posts: 1591
    • mineexplorer.com
Re: Power bank with replaceable 18650 batteries
« Reply #22 on: November 19, 2021, 10:11:06 am »
These have been around for quite a few years and it was a few years back that I obtained and tested one as a possible lamp battery case. I found that the waterproof integrity was very weak. Recommend testing in this way without the batteries.
My avatar is a poor likeness.

Offline Ed

  • stalker
  • ***
  • Posts: 276
Re: Power bank with replaceable 18650 batteries
« Reply #23 on: November 19, 2021, 03:57:09 pm »
Without going into the question of why anyone would want to take, and be able to recharge, a PDA or a phone underground...

To answer the question you didn't ask, for surveying.  :smartass:

Of course!
All you need now then is a waterproof phone to go with the waterproof power bank
 :lol:

Got one - goes with me caving instead of a camera these day

Offline darkandmuddy

  • newbie
  • *
  • Posts: 8
Re: Power bank with replaceable 18650 batteries
« Reply #24 on: November 24, 2021, 09:41:34 pm »
Done a bit of testing and further poking and in terms of waterproofing, it's got a reasonably convincing seal between the lid and box but this is very dependant on tolerances so might not be reliable. I think the weakest point is the blue knurled knob and possibly the buttons and lights. However for cycling it's fine in a bag. For caving it would be fine as long as it's in something else as well.
In terms of using, the polarity is very important as it uses two batteries in series and then the other two in parallel with these. There are tiny symbols to show this but I've added white paint to make it easier and also to the lid to get the right position. This is otherwise only lined up with a small hard to see plastic bit.
I also tested the USB charging using only two cells fitted. The result was that the two 3500mAh cells (7.4v in series) managed to add about 3500mAh to a single 3.7v mobile phone cell. So some losses here between the various DC to DC conversions and charging. However this gives an idea about the capabilities. Some more efficient things might be possibly with external circuitry using the other (bike light) output which is labelled 8.4v which is top end for two cells.
All in all, for what it cost I'm moderately impressed and should work well for me to let me use my caving cells for cycling to work!


Sent from my SM-T290 using Tapatalk


 

Main Menu

Forum Home Help Search
SimplePortal 2.3.5 © 2008-2012, SimplePortal