DIY USB power bank?

donnybrook · 2018-04-21T21:18:39.000Z

Been thinking about buying a couple of those roll-your-own style power bank enclosures since I have some spare 18650s (specifically the cylindrical “lipstick” style ones). But most of them are made by companies I’ve never heard of and I don’t want to end up with something shoddy that could be a safety hazard. Does anyone have experience with these, or is there a brand you can recommend that seems well made? Thanks for any tips.

SIGShooter · 2018-04-21T21:40:38.000Z

I have 4 of these and I haven’t seen any problems with them. They all cut-off at around 4.18v when charging the batteries (pulled immediately after charging is done). One thing to consider is that they don’t accept protected batteries (at least the Panasonic ones I have don’t fit).

Here is a HKJ’s review on them.

Jtm94 · 2018-04-22T03:18:45.000Z

I have a Tomo M4 and it’s been working good for me. I don’t use it religiously, but I find it being useful every other week or so. Takes a while to charge 4 batteries, and the screen gets flickery if you move it around, but it will fast charge my phone 2 to 3 times on one charge.

Lightbringer · 2018-04-22T03:34:15.000Z

Yeah, was gonna suggest simplifying your life and just getting a Tomo. They take 1-4 cells, sport independent channels, and have decent-enough displays.

Think I got a T4 and M4, no idea which is which or what the diffs are other than one has an add’l Apple-type connector whereas the other doesn’t. Goggle ’em for more details, but either one should be fine, and you get to burn off 4 cells at once.

agent80 · 2018-04-22T04:53:33.000Z

I am looking for a 1-2 battery DIY charger with an output of 2 amps. Most seem to have an ouput of 1 amp. Can anyone suggest. Thanks

ludolf · 2018-04-22T07:26:46.000Z

http://www.xtar.cc/products_detail/productId=189.html
(not yet released, “coming soon”)

agent80 · 2018-04-22T09:47:01.000Z

Impressive. Thanks

leaftye · 2018-04-22T10:31:26.000Z

I also have a Tomo. It’s slow, but it’s nice that each bay is operated independently.

If you’re just trying to use your 18650’s, a case is good, but I wouldn’t go this route to save money over a prebuilt powerbank. The only problem I’ve had with powerbanks is that they cut off earlier than I’d like, so if I try using it for charging my rc batteries, the powerbank will turn off as the rc battery is in the last 10% of the charging cycle because the current draw is low enough that the powerbank shuts itself off.

donnybrook · 2018-04-22T16:25:08.000Z

Thanks everyone. I’ll check out the Tomo unit though I was really looking for something more compact that takes only a single 18650.

Don

cu42 · 2018-04-22T20:17:48.000Z

I have seen very portable small cables that can snap onto the end of any 18650 allowing it to be recharged from any USB port.
It would be nice if these could be used in reverse as well to charge another device.

GreenLights · 2018-04-22T22:14:08.000Z

cu42:

I have seen very portable small cables that can snap onto the end of any 18650 allowing it to be recharged from any USB port.
It would be nice if these could be used in reverse as well to charge another device.

agent80 wrote: I am looking for a 1-2 battery DIY charger with an output of 2 amps. Most seem to have an ouput of 1 amp. Can anyone suggest. Thanks

This satisfies both requests:
Mini Magnetic Emergency Charger Portable

agent80 · 2018-04-23T04:57:18.000Z

GreenLights:

This satisfies both requests:
Mini Magnetic Emergency Charger Portable

The Xanes is very good. Unfortunately the battery is exposed. I wouldnt want to assemble the battery everytime I want to use it. Nor do I want to keep the battery connected and throw it in a pack. Without a case, the battery could be punctured.

jerm03 · 2018-06-02T18:41:08.000Z

If we consider that DIY Power banks cost $14 for a 2 cell bank, and $10 for the 2 cells the cost is $24. Now when one can get a Xiaomi 10,000 mAh power bank for $20.00 do the DIY banks make sense?

SIGShooter · 2018-06-03T01:23:20.000Z

jerm03:

If we consider that DIY Power banks cost $14 for a 2 cell bank, and $10 for the 2 cells the cost is $24. Now when one can get a Xiaomi 10,000 mAh power bank for $20.00 do the DIY banks make sense?

For me it made sense because I already had many 18650 batteries so no cost for cells. Also it gives me the ability to swap in charged batteries and not have to wait to charge up the powerbank. One of my daughter also carries one when she goes backpacking and there’s no ability to charge a powerbank.

BlueSwordM · 2018-06-03T02:01:13.000Z

Also, it is environmentally better to buy a DIY powerbank first, as you can easily replace the cells.

Also, they include nice features, like balanced parallel charging, meaning in you put in a 4V cell and a 3.5V one, one won’t dangerously charge with the other, higher efficiency, better looks, and easily swappable cells.

jerm03 · 2018-06-03T13:56:34.000Z

BlueSwordM:

Also, it is environmentally better to buy a DIY powerbank first, as you can easily replace the cells.

Also, they include nice features, like balanced parallel charging, meaning in you put in a 4V cell and a 3.5V one, one won’t dangerously charge with the other, higher efficiency, better looks, and easily swappable cells.

Which ones do ” balanced parallel charging” ?
I have to admit I never use any of mine, as I am at home or in the car. I’m curious to know if you or anyone uses the power bank often and for what?
Thanks, Jerry

BlueSwordM · 2018-06-03T15:29:04.000Z

There are the Tomo power banks, and the XTAR PB2 which I am using currently.

jerm03 · 2018-06-03T16:05:54.000Z

Thanks, I have the PB2 on order.
Regards, Jerry

Zulumoose · 2018-06-03T17:37:45.000Z

jerm03:

If we consider that DIY Power banks cost $14 for a 2 cell bank, and $10 for the 2 cells the cost is $24. Now when one can get a Xiaomi 10,000 mAh power bank for $20.00 do the DIY banks make sense?

Yes they do, for a number of reasons.

We already have the batteries, and don’t generally pay $14 for a 2 cell, I bought a 4 cell for under 10 a few months ago.

A DIY can do everyting a fixed cell can, PLUS you can charge your other batteries with it, reload it instantly, use it to reload any other 18650 device instantly, use an empty slot to store the cable and adaptors or something else, use your flashlight battery to charge your phone in an emergency.

Also, if the circuitry blows, the cells are unaffected, and immediately available, if one of the cells goes bad, the bank is unaffected and immediately available.

nquinn · 2018-06-03T17:45:07.000Z

The reason I plan to use something like this is for travel. I carry an 18650 headlamp (skilhunt h03), so I can hot swap batteries directly between the powerbank and headlamp as needed.