Question about portable power banks.

This may be a stupid question, but I need to ask it anyway.
Will those portable power banks you can charge your cell phone or iPad with charge your USB rechargeable flashlight?

Think of a portable power bank as just another USB port exactly like the ones on your wall wart or PC. Two things to watch out for - make sure the capacity of the power bank is enough to charge your equipment, and some of the cheaper power banks that have you put AA cells in to power them apparently aren't regulated. We had a member a while back that had one that he had put four regular alkaline AA cells (6v) into, and he was having problems. When he replaced them with four NiMH cells (4.8v), the problem went away.

sarge1967 said:

This may be a stupid question, but I need to ask it anyway.
Will those portable power banks you can charge your cell phone or iPad with charge your USB rechargeable flashlight?

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Yes.

The one I am looking at getting is a 16000mAh model made by RAVpower. The light I will be charging is a Nitecore MH20 with a 3400mAh battery in it.
So all should work well then.

sarge1967 said:

The one I am looking at getting is a 16000mAh model made by RAVpower. The light I will be charging is a Nitecore MH20 with a 3400mAh battery in it.
So all should work well then.

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Your light doesn't have a swappable battery?

Yes it does. I just want the option to charge it while out camping and such. This power bank should last a weekend to five days charging my phone and light depending on usage.

sarge1967 said:

Yes it does. I just want the option to charge it while out camping and such. This power bank should last a weekend to five days charging my phone and light depending on usage.

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Don't.... You're taking a max 4.2v battery and boosting to 5v, then dropping back to 4.2v max.....
You're wasting power.
Get a light with swappable batteries and keep a set with you.

FRITZHID said:

Don't.... You're taking a max 4.2v battery and boosting to 5v, then dropping back to 4.2v max.....
You're wasting power.
Get a light with swappable batteries and keep a set with you.

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So is it not safe to use a recharging bank?
I do have extra 18650 batteries I just thought since I will have the recharging bank for my phone anyway I could use it for the light as well.

sarge1967 said:

So is it not safe to use a recharging bank?
I do have extra 18650 batteries I just thought since I will have the recharging bank for my phone anyway I could use it for the light as well.

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If the device is charged via a USB power cord I don't think it matters if it's plugged into a 5 volt wall adaptor, computer USB port or power bank IMHO but no expert on all things electronics.

sarge1967 said:

So is it not safe to use a recharging bank?
I do have extra 18650 batteries I just thought since I will have the recharging bank for my phone anyway I could use it for the light as well.

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Fritz is not saying it's unsafe. He's saying that to upconvert from 4.2V to 5.0V and then downconvert from 5.0V to 4.2V (which is what you're doing if you use the power bank) will waste battery power from the banks' cells. Battery power from the power bank is expended to do the upconverting and more battery power is expended downconverting so a portion of your banks' battery power is going to "feed the conversion process" and not going into your phone/flashlight, ect.

sarge1967 said:

This may be a stupid question, but I need to ask it anyway.
Will those portable power banks you can charge your cell phone or iPad with charge your USB rechargeable flashlight?

Click to expand...

Yes.



Your flashlight should have a regulation circuit for max input it will take from a USB plug, but even if it doesn't, most power banks have a 5v/1A output USB port that will EASILY charge any lithium battery. The trick is to know the charge rating for your batteries.
Most high-discharge (10+ amps) batteries will accept a 2C charge current with negligible lifespan shortening issues (That means a 3400 MAH 18650 can be charged at 6.4 amps without issue) Though I recommend keeping it at or below 0.7C (2.4A).

As for the power bank, be sure it is regulated at 5v output. There are "smart charger" battery banks that step up the voltage to 6 or 9 V, but reduce the current. Only devices capable of dealing with that extra voltage I.E. the protection / "smart charge" circuit will be able to safely make use of that extra voltage.

TL/DR: Use a battery bank with a regulated 5v/1A output, it will work perfectly. There will be a little total available capacity charge ability lost due to charging voltage conversion, but it's basically insignificant.

Camo5 said:

Yes.



Your flashlight should have a regulation circuit for max input it will take from a USB plug, but even if it doesn't, most power banks have a 5v/1A output USB port that will EASILY charge any lithium battery. The trick is to know the charge rating for your batteries.
Most high-discharge (10+ amps) batteries will accept a 2C charge current with negligible lifespan shortening issues (That means a 3400 MAH 18650 can be charged at 6.4 amps without issue) Though I recommend keeping it at or below 0.7C (2.4A).

As for the power bank, be sure it is regulated at 5v output. There are "smart charger" battery banks that step up the voltage to 6 or 9 V, but reduce the current. Only devices capable of dealing with that extra voltage I.E. the protection / "smart charge" circuit will be able to safely make use of that extra voltage.

TL/DR: Use a battery bank with a regulated 5v/1A output, it will work perfectly. There will be a little total available capacity charge ability lost due to charging voltage conversion, but it's basically insignificant.

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Thanks for that info, it really helps! The charging bank I was planning on getting would not be the best option. It has one of those "smart charge" circuits at 4.5A. I will pick one up that has 5v/1A output.

*smh*

As for camping: Also be aware that you loose easily 20% - 30% of energy during the charging of electronics with the power bank (depending on the efficiency of the step-up/-down converters). So, if you have a 16000 mAh power bank you get probably less then 11000 mAh charged battery capacity -- OR: You can not charge your 1600 mAh cell phone battery 10 times, but only about 6 times. So plan accordingly.

drmaxx said:

As for camping: Also be aware that you loose easily 20% - 30% of energy during the charging of electronics with the power bank (depending on the efficiency of the step-up/-down converters). So, if you have a 16000 mAh power bank you get probably less then 11000 mAh charged battery capacity -- OR: You can not charge your 1600 mAh cell phone battery 10 times, but only about 6 times. So plan accordingly.

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Thanks for that info.