Recharging a USB rechargeable headlamp from dead

A.I.

A 10,000mAh power bank can typically recharge a USB headlamp multiple times, likely between 2 and 10 full charges, depending on the specific headlamp’s battery capacity and energy conversion efficiency. A headlamp itself usually takes between 2 to 4 hours to recharge from zero.

Number of Recharges

The exact number of recharges depends on two key factors:

Usable Capacity of Power Bank: Due to energy loss during voltage conversion and heat generation, the actual usable capacity of a 10,000mAh power bank is typically around 6,000 to 7,000mAh.

Headlamp Battery Capacity: Headlamps have varying battery sizes. Common capacities range from:

Small/Compact headlamps: ~900mAh to 1250mAh.

Standard headlamps: ~2000mAh to 3400mAh.

High-performance headlamps: ~4000mAh to 4600mAh, or even up to 10,000mAh with external battery packs.

Estimated Charges:

For a 1,000mAh headlamp: You could expect roughly 6 to 7 full charges.

For a 2,500mAh headlamp: You could expect roughly 2 to 3 full charges.

For a 4,000mAh headlamp: You could expect roughly 1 to 1.5 full charges.

Recharging Time for the Headlamp

The time it takes for a power bank to recharge the headlamp from zero to full will generally be:

Standard charging (around 10W): 2 to 4 hours.

Fast charging (if both devices support it): Could be faster, depending on the input power the headlamp can accept.

In summary, a 10,000mAh power bank provides ample power for multiple headlamp recharges, making it a reliable backup for camping or hiking trips.

I have a rechargeable headlamp.  I don’t use it that much so I never have to recharge while I’m backpacking.  Make sure it’s fully charged before your trip.  If you did a lot of night hiking you might have to recharge.

Yeah, what TT said – except maybe it’s 50% – if you have a 10,000 mah power bank it would recharge a 1,000 mah headlamp 5 times.

Actually, most of the inefficiency is charging the headlamp.  If the 10,000 mah battery has 38 Wh, it will deliver maybe 35 Wh of USB energy, which will charge the headlamp battery with maybe 19 Wh of energy.  But only a bored engineer would care :)

A battery labeled 10,000 mAh may not actually have that.  The only way to know is to actually charge the headlamp.  See how many times you can do that before power bank is discharged.

AK: Which headlamp?

If I cut them 8’4″, I can get 7 lines out of a 50′ hank.

Do you typically use your headlamp enough on a trip that you need a full recharge? Or would just a partial recharge be enough?

AK,

#charges = battery size/Headlamp battery size (mAh)*charging efficiency

Headlamp Example

• Anker 10000 mAh Powercore, efficiency ~ 65% (Anker’s own spec)
• Nitecore NU20 Classic, battery size = 500 mAh

#charges ~ 10000/500*0.65 ~ 13

I validated this formula using my iphone 11, predicting 2.1 charges from the Anker 10k, and that’s exactly what I got.

On-line tests of Nitecore NB10000 and NB20000 and INIU 20000mAh Power Bank also showed about 65% efficiency.   Efficiency drops if using fast charge and I’ve seen test results ~ 55% in that mode

where did you get the on-line tests?

that would be interesting to look at

Right now my old headlamp is a Petzl, can’t remember which one. I hardly ever change the batteries, and it lasts a long time. I use it only for when I get into camp and it gets dark quicker than I’m ready for, or if I need it middle of the night (rarely, I usually have good night vision), and early morning starts.

If I change it to a lighter weight minimal one like the Nitecore 20, that is rechargeable, I won’t need to carry any extra batteries, plus it’s just less bulk and slightly less weight. I’m hoping it would last an entire weeklong hike, and then take not too much charge off a 10k mah charger, since I have to charge my phone at least twice or 2.5 times for the week. The 10k mah charger gives me about 2.5 phone charges, so not a lot left for a headlamp.

If you’re not night hiking, the Nu20 will easily last a week.  The NU20 classic on medium lasts over 6 hrs.

I even get a week from the tiny Nitecore Tube v2 using it that way.  I take it on summer trips where I don’t need a red light and I know the risk of night hiking is really low.

I also have the NU20 Classic and the NU25UL (plus a Petzl, and a Fenix and…).

The Nu25 buttons are maddening making me reach for the Nu20 more often.

But the Nu20 classic can’t hold strong output very long though and automatically drops itself down to medium after an hour or two so isn’t the best option if you need to do night forested hiking longer than an hour or so.  If my trip has that risk, I bring the Nu25UL.  The NU20 also has a tight beam but I find that OK

Battery life drops fast as temp drops below freezing.  If your current headlamp is using AAA or AA, any Li will be  better in the cold.  Its why I got a Fenix with a big LI battery for <-10C nighttime snowshoeing.  The Petzl and its NiMH AAA batteries would quickly die. Alkaline is even worse below freezing.

BTW, why do you need to charge your phone so much?  Reading? Pictures? If just navving, don’t track your route it burns GPS in real time.  Just open the nav app and spot check where you’re at when you need confirmation, then close the app to stop the GPS.  I can burn just 10% a day doing that.

It says it has a 500 mAh battery, so, charging it completely would take about 10% is of your 10,000 mAh power bank.

But, based on the usage you mentioned you probably won’t need to recharge it

I like my rechargeable because I can recharge before a trip and then it will be 100%.

With disposable batteries I start with partially charged headlamp.

I switched to rechargeable for main light years ago and never went back.Your usage will determine if you need to size up your current power bank, I’m guessing not.  I’ve got a couple different nitecores, I charge right before trip. Can’t remember ever needing a recharge on a summertime several day trip. That’s with limited night hiking. Late fall or winter trips I’ll proactively top it off in the afternoon if it starts to look like there’s a chance of night hiking especially with bad weather and a long way yet to go. Similarly I make sure the Inreach is over 50%. I try to budget for  one extra recharge on my phone depending on length of trip….the “I did something stupid like didn’t put it airplane mode and ran the battery down overnight” 10k has been largest I’ve needed.

one other thing is to have a contingency plan

if you’re draining your powerbank too fast, and you can predict you’ll run out, then set your phone to use less power

Don’t take a GPS track of your hike.  Or, you can set your battery to power saving mode (on an android, I assume there’s something similar for iphone).  Then, the GPS will only take a track point when you look at the phone display.

Don’t listen to podcasts

My usage goes from about 6% of the phone battery per hour to 1%.

If that’s not enough, just power down the phone and save it for an emergency

Sensing an echo in here…Back to limericks…:)

We haven’t had a poem from Doug in a long while. Thread drift is ok if it’s a poem.

Doug’s limericks were better than the AI generated ones

In my opinion

at risk of drifting the thread.  Again…

I’ve got a few devices that I could charge and use once, but then they wouldn’t recharge.  Or have much lower capacity than I would expect.

So, whenever I get a new device, like the NB10000 that I recently bought, I’ll charge it up, then discharge one time.  I use a 1A load and a USB power meter to calculate Wh, but you could just see how many times it will charge your phone – that comes close enough.

If that works then I’ll figure it’s reliable enough to take on a trip where I depend on it working.