Charging Eneloop AA through USB

Other provisions not covered above that may make survival easier if your life is tossed out of the norm. This section is for discussing everything from arc welders to underwear.

Moderator: ZS Global Moderators

User avatar
quazi
* * * * *
Posts: 4584
Joined: Tue Aug 23, 2005 5:51 am
Location: AK

Charging Eneloop AA through USB

Post by quazi » Thu Sep 10, 2020 12:03 am

A couple years ago I switched to Eneloop AA rechargeable batteries because I was really burning through batteries during the winter. I've got a regular AC wall charger for them, but I've noticed that I've got a lot of ways to charge things through USB (including a small solar panel, and soon a hand crank radio that I ordered).

That got me wondering if there was a relatively inexpensive and easy way to recharge AA batteries through USB. I'm guessing there is something preventing this because when I googled it I didn't anything except for small AA battery banks (the opposite of what I'm looking for) and some weird AAs with USB connectors built into them.

Is there some small plug and play charger that would work without messing up the batteries? Would the solution be a bigger battery that I can slowly charge through USB and then use that to charge the AAs?

Note: I'm not looking to get into a real emergency power setup with big solar panels, a generator and battery banks at the moment. Some day, but not now.

User avatar
EBuff75
* *
Posts: 178
Joined: Mon Feb 06, 2012 1:29 pm
Favorite Zombie Movies: Shaun of the Dead, Zombieland, Scouts Guide to the Zombie Apocalypse
Location: SE Michigan

Re: Charging Eneloop AA through USB

Post by EBuff75 » Thu Sep 10, 2020 12:14 am

You mean like one of these:

Olight UC Universal USB Magnetic Charger
LiitoKala Smart Battery Charger
Klarus K1 Single Cell Smart Battery Charger

I have all three and they all work just fine. The Olight is the newest, I've only had that about a month. Haven't used it much, it was mainly just to try out. It's been fine through my limited testing, although I have seen some complaints about overheating/melting.

User avatar
quazi
* * * * *
Posts: 4584
Joined: Tue Aug 23, 2005 5:51 am
Location: AK

Re: Charging Eneloop AA through USB

Post by quazi » Thu Sep 10, 2020 1:20 am

Those look like just what I'm looking for, thanks! I'm not sure how I missed them when I was searching on Amazon earlier.

User avatar
EBuff75
* *
Posts: 178
Joined: Mon Feb 06, 2012 1:29 pm
Favorite Zombie Movies: Shaun of the Dead, Zombieland, Scouts Guide to the Zombie Apocalypse
Location: SE Michigan

Re: Charging Eneloop AA through USB

Post by EBuff75 » Thu Sep 10, 2020 9:20 am

Forgot that I also have the Vinninge Battery Charger from Ikea, but that appears to be discontinued here in the US (the link is for Canada). If you have an Ikea store locally, or you want to order online, their Ladda AA and AAA batteries are supposedly rebranded Eneloops. I have a number of those which I keep in rotation with my Eneloops and a few older Energizer rechargeables. To make sure that I always have some AA/AAA batteries charged, I have a large (12 bay) AA / AAA plug-in charger from Ikea (the Storhögen battery charger), which also appears to have been discontinued (although there is a similar one called the Tjugo which omits the LCD charge indicators).

If you want an overwhelming amount of information on batteries and chargers, you can always search through either the Candlepowerforums or the Budgetlightforum. Those are primarily about flashlights, but there is also a ton of info about batteries, chargers, LEDs, etc. Flashlight people (aka Flashaholics) can be a bit obsessive... :)

User avatar
raptor2
ZS Moderator
ZS Moderator
Posts: 729
Joined: Mon Apr 06, 2020 4:48 pm

Re: Charging Eneloop AA through USB

Post by raptor2 » Thu Sep 10, 2020 11:27 am

I use these 2 chargers for exactly the reason they use USB wall plugs. They work well for me.

https://smile.amazon.com/gp/product/B01 ... UTF8&psc=1

https://smile.amazon.com/gp/product/B07 ... UTF8&psc=1
Duco Ergo Sum


raptor2 is the new profile name for raptor.
memberlist.php?mode=viewprofile&u=8190

User avatar
quazi
* * * * *
Posts: 4584
Joined: Tue Aug 23, 2005 5:51 am
Location: AK

Re: Charging Eneloop AA through USB

Post by quazi » Thu Sep 10, 2020 12:29 pm

EBuff75 wrote:
Thu Sep 10, 2020 9:20 am
If you want an overwhelming amount of information on batteries and chargers, you can always search through either the Candlepowerforums or the Budgetlightforum. Those are primarily about flashlights, but there is also a ton of info about batteries, chargers, LEDs, etc. Flashlight people (aka Flashaholics) can be a bit obsessive... :)
I might do that, since I use my headlamps and flashlights all the time now and consider them to be one of the most important parts of my preps, but on the other hand I really don't need a new hobby at the moment. :lol:
raptor2 wrote:
Thu Sep 10, 2020 11:27 am
I use these 2 chargers for exactly the reason they use USB wall plugs. They work well for me.

https://smile.amazon.com/gp/product/B01 ... UTF8&psc=1

https://smile.amazon.com/gp/product/B07 ... UTF8&psc=1
Thanks for the links, I ordered a couple of the ones Ebuff75 posted but I might order one or two of these too. I figure it would be good to have several extras in case one breaks plus I can pre-stock them at my BOLs.

User avatar
EBuff75
* *
Posts: 178
Joined: Mon Feb 06, 2012 1:29 pm
Favorite Zombie Movies: Shaun of the Dead, Zombieland, Scouts Guide to the Zombie Apocalypse
Location: SE Michigan

Re: Charging Eneloop AA through USB

Post by EBuff75 » Thu Sep 10, 2020 1:39 pm

quazi wrote:
Thu Sep 10, 2020 12:29 pm
I might do that, since I use my headlamps and flashlights all the time now and consider them to be one of the most important parts of my preps, but on the other hand I really don't need a new hobby at the moment. :lol:
Yeah, it's a DEEP rabbit hole to fall into! I've loved flashlights my whole life (still have some from when I was a kid) and finally jumped into the premium LED end of things 12 years ago. There's no going back for me now, but you still have a chance to save yourself!! :crazy:
quazi wrote:
Thu Sep 10, 2020 12:29 pm
raptor2 wrote:
Thu Sep 10, 2020 11:27 am
raptor2 wrote: ↑
Thu Sep 10, 2020 11:27 am
I use these 2 chargers for exactly the reason they use USB wall plugs. They work well for me.

https://smile.amazon.com/gp/product/B01 ... UTF8&psc=1

https://smile.amazon.com/gp/product/B07 ... UTF8&psc=1
Thanks for the links, I ordered a couple of the ones Ebuff75 posted but I might order one or two of these too. I figure it would be good to have several extras in case one breaks plus I can pre-stock them at my BOLs.
Raptor, I particularly like that PowerOwl charger and I saved it on Amazon in case I ever need another dedicated AA charger.

I tend to go with the smart chargers because I have a huge variety of batteries. My batteries include NiMH in AA, AAA, and D (also 9v, but I have a dedicated charger for those - both the 9v batteries and the charger are PowerOwl) and Li-ion in 14500 (which is an AA-sized Li-ion for flashlights designed to handle the increased voltage), 16340 (which are rechargeable CR123a), 18650, and 26650.

BTW, if you're not "in the know", Li-ion battery designations are just width and length, so an 18650 is approximately 18mm wide and 65mm long; 14500 would be 14mm wide and 50mm long. Also, the battery packs in electric cars, power tools, computers, and power banks frequently use common Li-ion cells like 18650, 21700, or 26650 connected together.

User avatar
quazi
* * * * *
Posts: 4584
Joined: Tue Aug 23, 2005 5:51 am
Location: AK

Re: Charging Eneloop AA through USB

Post by quazi » Thu Sep 10, 2020 3:10 pm

From the tiny bit of reading I've done 18650 is becoming a really common new standard, but the actual power output of different 18650s can vary, right?

Are most battery chargers these days smart chargers, or do I have to worry about overcharging with modern battery chargers? I do like the idea of being able to plug the batteries in and then not have to worry about them, which is how the charger that came with my eneloops seems to work.

User avatar
EBuff75
* *
Posts: 178
Joined: Mon Feb 06, 2012 1:29 pm
Favorite Zombie Movies: Shaun of the Dead, Zombieland, Scouts Guide to the Zombie Apocalypse
Location: SE Michigan

Re: Charging Eneloop AA through USB

Post by EBuff75 » Thu Sep 10, 2020 5:13 pm

quazi wrote:
Thu Sep 10, 2020 3:10 pm
From the tiny bit of reading I've done 18650 is becoming a really common new standard, but the actual power output of different 18650s can vary, right?
The 18650 is quite common (it is frequently used in power packs, battery hand tools, etc. I have probably a dozen flashlights that use them, so I have quite a few batteries. What you're thinking of as "output" is probably the milliamp hour rating (mah). This is a measure of the amount of stored energy in them (think of it like the capacity of the gas tank in a car). The voltage for Li-ion cells is 3.7v, but will usually be a little over 4v right after being fully charged and they're considered empty at 3v. Common mah ratings for 18650 cells usually range from 1800 to 3500. If you see one which claims 5000, 8000, 10000, those are usually fake ratings for cheap batteries from China. The Project Farm channel on YouTube did a great video where he tested a bunch of 18650 batteries if you're curious (he also did several for AA batteries: ep1, ep2, 1yr follow-up). Due to the risk of fire from Li-ion batteries, you're best sticking with name brands here. The best are (surprise, surprise) usually from LG/Panasonic, but Sony and some name brand Chinese (Fenix, Olight, Nitecore) are quite good as well.
quazi wrote:
Thu Sep 10, 2020 3:10 pm
Are most battery chargers these days smart chargers, or do I have to worry about overcharging with modern battery chargers? I do like the idea of being able to plug the batteries in and then not have to worry about them, which is how the charger that came with my eneloops seems to work.
The majority of them that I've seen are at least semi-smart. True dumb chargers are pretty rare now. Those were the ones which you used to have to pay attention to, as they never shut off. They'd just keep charging as long as the battery was connected. The new ones usually have an automatic shut-off (think of red/green indicator LED) for the batteries. Once they're charged, the charger shuts off.

True smart chargers can do quite a bit more. They an usually sense what type of battery chemistry is being used: lithium ion (Li-ion), nickel cadmium (NiCd), nickel metal hydride (NiMH), or lithium iron phosphate (either LiFe or LiFePO4). They're frequently able to vary the charging voltage to either speed up the charging (which is harder on the battery) or slow down the charging (to increase battery life) as well. Smart chargers also usually monitor for high temperatures and will shut off if a battery overheats.

Some smart chargers may have refresh or conditioning modes which can help to revive heavily used / frequently drained batteries and some are even able to revive completely dead (0 volts) cells. However, most smart chargers require at least some voltage is present in the battery in order for them to recognize it, so a 0 v battery may just show an error. This is an area where having a dumb charger can be useful. Dumb chargers will try to recharge any batteries which are put into them, even if they're at 0 volts. This can sometimes provide enough voltage in the battery that a smart charger can then recognize them, at which point you can swap the batteries over to the smart charger to finish the job.

A note on charging speed for NiMH batteries, the rule of thumb is that you want to keep the charging speed at 10% or less of the battery capacity for best life and to reduce the risk of damage. So for a battery with 2500 mah capacity, it shouldn't be charged at more than 250 mah. Fast chargers work, but they do so at the expense of cutting the battery's life short. Some chargers may have preset values to pick from, like 100 / 250 / 500 / 1000 mah. They may be able to select an appropriate speed themselves, or you might have to adjust it manually. Some simple USB chargers will set the charge speed based on the input amperage from the USB port that they're running from. If they're on a 1a connection they may charge at 500 mah; if on a 2.1a connection the charge speed may be 1000 mah.

Trickle charging NiMH batteries isn't usually recommended, although some chargers are supposed to be okay for it. My Ikea Storhogen charger is meant to be mounted on the wall and used as a charger/storage unit for batteries, but I'm not sure how that is going to impact battery life in the long-term. I should probably do some research and see if I can find out what the trickle rate is on it.

I have a TON of NiMH AA and AAA batteries, far more than I actually use. I have an older set of Energizers, a bunch of Eneloops, a bunch of the Ikea Laddas, plus a big box of no-name Chinese batteries that I won online and have never even bothered to open (they're meant as replacements for cheapo solar garden lights). I still use the Energizers (although they're pretty worn out from years of charging on a fast-charger), but the Eneloops and Laddas are the go-to for my mouse, remote controls, AA / AAA flashlights.

User avatar
quazi
* * * * *
Posts: 4584
Joined: Tue Aug 23, 2005 5:51 am
Location: AK

Re: Charging Eneloop AA through USB

Post by quazi » Thu Sep 10, 2020 5:44 pm

Thanks for all the info, I'll definitely check out those review videos.
EBuff75 wrote:
Thu Sep 10, 2020 5:13 pm
Trickle charging NiMH batteries isn't usually recommended, although some chargers are supposed to be okay for it. My Ikea Storhogen charger is meant to be mounted on the wall and used as a charger/storage unit for batteries, but I'm not sure how that is going to impact battery life in the long-term. I should probably do some research and see if I can find out what the trickle rate is on it.
So even though the USB chargers I got will work they probably won't be good for the batteries long-term if I'm using them with a janky power source like the dynamo on a radio or a tiny solar panel? I'm still happy to be able to do it in an emergency, but I guess this means I should still figure out some sort of battery that I can trickle charge and then use to charge up my rechargeable AAs.

User avatar
EBuff75
* *
Posts: 178
Joined: Mon Feb 06, 2012 1:29 pm
Favorite Zombie Movies: Shaun of the Dead, Zombieland, Scouts Guide to the Zombie Apocalypse
Location: SE Michigan

Re: Charging Eneloop AA through USB

Post by EBuff75 » Fri Sep 11, 2020 12:24 am

quazi wrote:
Thu Sep 10, 2020 5:44 pm
So even though the USB chargers I got will work they probably won't be good for the batteries long-term if I'm using them with a janky power source like the dynamo on a radio or a tiny solar panel? I'm still happy to be able to do it in an emergency, but I guess this means I should still figure out some sort of battery that I can trickle charge and then use to charge up my rechargeable AAs.
Having a power bank / battery of some type which you charge off of the solar is probably the easiest way to go. Some battery chargers may have trouble staying active if the solar is interrupted, or if you're not able to provide a steady current. Most of them also require a minimum input (usually 5v and at least 1amp), but a power bank should be better able to handle the fluctuations. I happen to really like these RavPower units and I've gotten several of the "renewed" variety which are very inexpensive. Granted, this model is a few years old now, so there may be better options available, but mine work really well. Be aware that they're fairly large/heavy, so this isn't necessarily something you want to lug around in a backpack!

As long as you have a solar panel which doesn't have issues with resuming charging after a cloud (yes, there are some that are like that) and which doesn't allow backfeeding from the battery into the panel you should be okay. I have several fold-up, portable solar panels from RavPower (similar to this one) which I can use to charge up power banks, along with some power banks which have built-in panels (the ones that unfold) like this or this. The built-in panels aren't all that fast, but they will charge up one of those power banks if left out in the sun for a few days.

The scenarios that you're talking about are precisely why I have the set up that I do. Solar panels which I can set up and charge several power banks at a time. Then use those power banks to power USB lights or recharge batteries, charge phones, etc. I'm considering getting a larger solar power system which also has 110v output, but haven't stepped up to that level yet (systems like those made by Jackery, Anker, EcoFlow, Bluetti, GoalZero, Suaoki, etc.).

User avatar
raptor2
ZS Moderator
ZS Moderator
Posts: 729
Joined: Mon Apr 06, 2020 4:48 pm

Re: Charging Eneloop AA through USB

Post by raptor2 » Fri Sep 11, 2020 12:03 pm

That is good advice ^^^.

One alternative to a battery bank is a simple lead acid 12 volt battery.

This battery is $20 and provides 70,000 mah (7 amps). It is a lead battery that is designed for a batter back up.
https://www.amazon.com/Mighty-Max-Batte ... ENF7CTZBYB

Combine it with this and you have a USB charger and battery bank.
https://www.amazon.com/Ginsco-Charger-S ... 171&sr=1-8
Duco Ergo Sum


raptor2 is the new profile name for raptor.
memberlist.php?mode=viewprofile&u=8190

User avatar
EBuff75
* *
Posts: 178
Joined: Mon Feb 06, 2012 1:29 pm
Favorite Zombie Movies: Shaun of the Dead, Zombieland, Scouts Guide to the Zombie Apocalypse
Location: SE Michigan

Re: Charging Eneloop AA through USB

Post by EBuff75 » Fri Sep 11, 2020 1:13 pm

raptor2 wrote:
Fri Sep 11, 2020 12:03 pm
That is good advice ^^^.

One alternative to a battery bank is a simple lead acid 12 volt battery.

This battery is $20 and provides 70,000 mah (7 amps). It is a lead battery that is designed for a batter back up.
https://www.amazon.com/Mighty-Max-Batte ... ENF7CTZBYB

Combine it with this and you have a USB charger and battery bank.
https://www.amazon.com/Ginsco-Charger-S ... 171&sr=1-8
That's a good method. You could add one of those inexpensive solar battery maintainers (like this) for RVs and help to keep the battery charged up too.

User avatar
raptor2
ZS Moderator
ZS Moderator
Posts: 729
Joined: Mon Apr 06, 2020 4:48 pm

Re: Charging Eneloop AA through USB

Post by raptor2 » Fri Sep 11, 2020 1:24 pm

EBuff75 wrote:
Fri Sep 11, 2020 1:13 pm
raptor2 wrote:
Fri Sep 11, 2020 12:03 pm
That is good advice ^^^.

One alternative to a battery bank is a simple lead acid 12 volt battery.

This battery is $20 and provides 70,000 mah (7 amps). It is a lead battery that is designed for a battery back up.
https://www.amazon.com/Mighty-Max-Batte ... ENF7CTZBYB

Combine it with this and you have a USB charger and battery bank.
https://www.amazon.com/Ginsco-Charger-S ... 171&sr=1-8
That's a good method. You could add one of those inexpensive solar battery maintainers (like this) for RVs and help to keep the battery charged up too.
That is good solar package.

I use this; since it is a small battery it works fine.
https://www.amazon.com/PeleusTech%C2%AE ... 602&sr=8-9

The other thing you can do is buy/find or otherwise procure an APC battery UPS with a dead battery. Then use the connections on that device to charge and maintain by simply hooking up the battery to UPS leads.
Duco Ergo Sum


raptor2 is the new profile name for raptor.
memberlist.php?mode=viewprofile&u=8190

User avatar
quazi
* * * * *
Posts: 4584
Joined: Tue Aug 23, 2005 5:51 am
Location: AK

Re: Charging Eneloop AA through USB

Post by quazi » Fri Sep 11, 2020 5:25 pm

Thank you both for all the advice!
raptor2 wrote:
Fri Sep 11, 2020 1:24 pm
The other thing you can do is buy/find or otherwise procure an APC battery UPS with a dead battery. Then use the connections on that device to charge and maintain by simply hooking up the battery to UPS leads.
I do happen to have two APC UPS with dead batteries. A former employer was throwing them out because they got money to replace all of theirs with new models, so I snagged them rather than throw them in the trash. (I also have another one that I purchased that my computer is hooked into, it is usually enough to keep a fan running and keep my phone charged during most power outages.)

So if I understand right I can get replacement lead acid batteries for the APCs and leave them plugged in so the battery is maintained, and then if I want I can pull the battery and hook it up to a USB input to charge it? (It looks like the Ginsco adapter would be used to charge USB off of the lead acid battery, but would not charge the lead acid battery off of USB, unless I read the description wrong.)

boskone
* * * * *
Posts: 1391
Joined: Wed Oct 17, 2012 4:07 pm
Location: Aggieland-ish

Re: Charging Eneloop AA through USB

Post by boskone » Fri Sep 11, 2020 5:53 pm

You could use an APC UPS to charge a 12v SLA (sealed lead-acid) battery. In effect, it would be a self-contained battery maintainer.

I will note that UPSes generally charge batteries much slower, because they're not emergency battery chargers like you'd use on your car battery.

The "batteries" in a rackmount or other high-capacity UPS may actually be a battery array. Our APC5000XLs where I used to work had--IIRC--6 small-format SLAs wired in series. Those were mounted in small chassis, which were what slid into and connected to the main part of the UPS.

You could swap charged for discharged batteries, but bear in mind that a UPS probably will not maintain power during the process. Many good UPSes support hot-swapping batteries (e.g. if you have utility power, you can swap the battery without dropping load), but I've never heard of one that can swap the batteries without dropping load while utility power is off.

Don't cross-connect decent UPSes, one of my former coworkers did that and the UPSes each decided that power was bad and flipped to battery. I've seen cheapie UPSes work in that configuration, though.

I'm not sure why you'd want to take a battery out of a UPS to charge it over USB; even with USB-PD, that would take absolute ages.

CrossCut
ZS Member
ZS Member
Posts: 241
Joined: Mon Mar 18, 2013 6:32 am

Re: Charging Eneloop AA through USB

Post by CrossCut » Fri Sep 11, 2020 5:55 pm

Just a thought quazi, but you might consider a Stanley portable power station/jump starter for the battery. 19Ah sealed lead acid battery, and can charge it with solar power (or an alternator) through the cigarette lighter port. I did a post on it last year, viewtopic.php?p=2719326 , will try to fix the pic links this weekend as I see they got deleted.

Expensive for just a battery alone, but if you don't have another grid-down jump start solution then it might make sense being multipurpose. I do a fair amount of light off-roading and wood cutting in semi-remote areas so I like having my own jump start battery with me just in case, besides for bugout purposes. What led me to get it was pretty much the same problem you're trying to solve, I wanted to be able to charge small electronics (and batteries) but from our BOV if needed, and not risk draining the truck battery while doing so.

This was the first "solution", 15 watt solar panel -> small lead acid battery -> cigarette lighter voltage adapter -> battery charger (which normally uses a 110 vac wallwart to convert it to 12v dc).
Image

It works too, as long as you don't drain the battery too deeply. I like the jump starter better since it lives in the truck and charges automatically off the alternator.

User avatar
quazi
* * * * *
Posts: 4584
Joined: Tue Aug 23, 2005 5:51 am
Location: AK

Re: Charging Eneloop AA through USB

Post by quazi » Fri Sep 11, 2020 7:48 pm

boskone wrote:
Fri Sep 11, 2020 5:53 pm
You could swap charged for discharged batteries, but bear in mind that a UPS probably will not maintain power during the process. Many good UPSes support hot-swapping batteries (e.g. if you have utility power, you can swap the battery without dropping load), but I've never heard of one that can swap the batteries without dropping load while utility power is off.

Don't cross-connect decent UPSes, one of my former coworkers did that and the UPSes each decided that power was bad and flipped to battery. I've seen cheapie UPSes work in that configuration, though.

I'm not sure why you'd want to take a battery out of a UPS to charge it over USB; even with USB-PD, that would take absolute ages.
Just to clarify, what I have is a good amount of rechargeable AAs and a couple things that can provide a very meager amount of power through USB until they break (a small solar panel and a hand crank radio). What I'm looking for is an inexpensive way to recharge the AAs using the solar panel or radio. The lead acid battery would just be an in-between.

I do realize that the batteries would take an awfully long time to charge. This is more of a long-term last resort thing and not something I'm intending to do during a normal power outage (I've got enough charged batteries to get me through those). I am going to get a more serious off-grid setup some day, but not right now.
CrossCut wrote:
Fri Sep 11, 2020 5:55 pm
Just a thought quazi, but you might consider a Stanley portable power station/jump starter for the battery. 19Ah sealed lead acid battery, and can charge it with solar power (or an alternator) through the cigarette lighter port. I did a post on it last year, viewtopic.php?p=2719326 , will try to fix the pic links this weekend as I see they got deleted.

Expensive for just a battery alone, but if you don't have another grid-down jump start solution then it might make sense being multipurpose. I do a fair amount of light off-roading and wood cutting in semi-remote areas so I like having my own jump start battery with me just in case, besides for bugout purposes. What led me to get it was pretty much the same problem you're trying to solve, I wanted to be able to charge small electronics (and batteries) but from our BOV if needed, and not risk draining the truck battery while doing so.

This was the first "solution", 15 watt solar panel -> small lead acid battery -> cigarette lighter voltage adapter -> battery charger (which normally uses a 110 vac wallwart to convert it to 12v dc).
My extended family have a bunch of things like that, I'll probably have to look into getting one eventually.

boskone
* * * * *
Posts: 1391
Joined: Wed Oct 17, 2012 4:07 pm
Location: Aggieland-ish

Re: Charging Eneloop AA through USB

Post by boskone » Fri Sep 11, 2020 8:01 pm

quazi wrote:
Fri Sep 11, 2020 7:48 pm
Just to clarify, what I have is a good amount of rechargeable AAs and a couple things that can provide a very meager amount of power through USB until they break (a small solar panel and a hand crank radio). What I'm looking for is an inexpensive way to recharge the AAs using the solar panel or radio. The lead acid battery would just be an in-between.

I do realize that the batteries would take an awfully long time to charge. This is more of a long-term last resort thing and not something I'm intending to do during a normal power outage (I've got enough charged batteries to get me through those). I am going to get a more serious off-grid setup some day, but not right now.
In those conditions, I think you'd be better off just letting the UPSes stay charged, and plug a regular battery charger into 'em. If you really want a USB charger for connecting to the solar panel or such as well, I'd just put a wall-wart on the UPS to connect it to.

That'd let the SLA batteries stay charged, and give you probably the overall most flexible method of power-delivery from them.

User avatar
quazi
* * * * *
Posts: 4584
Joined: Tue Aug 23, 2005 5:51 am
Location: AK

Re: Charging Eneloop AA through USB

Post by quazi » Fri Sep 11, 2020 8:15 pm

boskone wrote:
Fri Sep 11, 2020 8:01 pm
quazi wrote:
Fri Sep 11, 2020 7:48 pm
Just to clarify, what I have is a good amount of rechargeable AAs and a couple things that can provide a very meager amount of power through USB until they break (a small solar panel and a hand crank radio). What I'm looking for is an inexpensive way to recharge the AAs using the solar panel or radio. The lead acid battery would just be an in-between.

I do realize that the batteries would take an awfully long time to charge. This is more of a long-term last resort thing and not something I'm intending to do during a normal power outage (I've got enough charged batteries to get me through those). I am going to get a more serious off-grid setup some day, but not right now.
In those conditions, I think you'd be better off just letting the UPSes stay charged, and plug a regular battery charger into 'em. If you really want a USB charger for connecting to the solar panel or such as well, I'd just put a wall-wart on the UPS to connect it to.

That'd let the SLA batteries stay charged, and give you probably the overall most flexible method of power-delivery from them.
I think I must have missed something, how are the UPSes going to get recharged if I've already drained them powering stuff after the power has gone out?

User avatar
pasha
ZS Member
ZS Member
Posts: 538
Joined: Sun Oct 26, 2008 6:44 pm
Favorite Zombie Movies: Night of the living dead(both), 28 Days later, 28 Weeks later, The Last man on earth, Night of the comet, Dawn of the dead(both of them), Day of the dead(old one), Shaun of the dead, Lifeforce, Dance of the dead, Night of the Day of the Dawn of the Son of the Bride of the Return of the Revenge of the Terror of the Attack of the Evil, Mutant, Alien, Flesh Eating, Hellbound, Zombified Living Dead Part 2: In Shocking 2-D, Zombieland
Location: tacoma

Re: Charging Eneloop AA through USB

Post by pasha » Fri Sep 11, 2020 8:31 pm

The Olight UC Universal Magnetic USB Charger is my favorite for portability.
You can even charge 3 AAA at once, if you put them in a little bundle.
Your greatest adversary hides in your mirror
ZS:OO5 Facebook group
https://www.facebook.com/groups/433432705260/

boskone
* * * * *
Posts: 1391
Joined: Wed Oct 17, 2012 4:07 pm
Location: Aggieland-ish

Re: Charging Eneloop AA through USB

Post by boskone » Fri Sep 11, 2020 9:22 pm

quazi wrote:
Fri Sep 11, 2020 8:15 pm
boskone wrote:
Fri Sep 11, 2020 8:01 pm
quazi wrote:
Fri Sep 11, 2020 7:48 pm
Just to clarify, what I have is a good amount of rechargeable AAs and a couple things that can provide a very meager amount of power through USB until they break (a small solar panel and a hand crank radio). What I'm looking for is an inexpensive way to recharge the AAs using the solar panel or radio. The lead acid battery would just be an in-between.

I do realize that the batteries would take an awfully long time to charge. This is more of a long-term last resort thing and not something I'm intending to do during a normal power outage (I've got enough charged batteries to get me through those). I am going to get a more serious off-grid setup some day, but not right now.
In those conditions, I think you'd be better off just letting the UPSes stay charged, and plug a regular battery charger into 'em. If you really want a USB charger for connecting to the solar panel or such as well, I'd just put a wall-wart on the UPS to connect it to.

That'd let the SLA batteries stay charged, and give you probably the overall most flexible method of power-delivery from them.
I think I must have missed something, how are the UPSes going to get recharged if I've already drained them powering stuff after the power has gone out?
I wouldn't. Small UPSes (those that don't require forklifts to move) would be pretty shit at the job. They're designed to only occasionally have to actually charge the batteries, so their charging efficiency is low (in order to keep the size and cost of their circuitry reasonable, and temperatures down).

I'd use them as a power reserve, because you already own 'em; basically zero up-front cost.

But if I wanted to recharge the batteries during a disaster, just about anything would be a better option. A battery monitor, for instance, is going to have a lot more volume dedicated to it's circuitry, and won't be concerned with a bit of heat. It'll probably be way more efficient.

A home battery bank (or at least the controller) is a bit different, because it's rather larger than the circuitry in a small UPS. It's more akin to a building UPS, which can afford to have more space for the circuits than the full volume of the small UPS; that's plenty of room for cooling and high-efficiency doodads.

In your case I'd just use the UPSes to keep the batteries topped off, and use them as secondary power stores; I wouldn't even bother trying to actually charge them until utility comes back up (or I got a generator to plug 'em into).

User avatar
quazi
* * * * *
Posts: 4584
Joined: Tue Aug 23, 2005 5:51 am
Location: AK

Re: Charging Eneloop AA through USB

Post by quazi » Mon Sep 14, 2020 8:50 pm

pasha wrote:
Fri Sep 11, 2020 8:31 pm
The Olight UC Universal Magnetic USB Charger is my favorite for portability.
You can even charge 3 AAA at once, if you put them in a little bundle.
Is that the same thing Ebuff75 linked? It looked great to put in a BOB. The reports of things melting were a little concerning, but maybe they have that fixed now.
boskone wrote:
Fri Sep 11, 2020 9:22 pm
I wouldn't. Small UPSes (those that don't require forklifts to move) would be pretty shit at the job. They're designed to only occasionally have to actually charge the batteries, so their charging efficiency is low (in order to keep the size and cost of their circuitry reasonable, and temperatures down).

I'd use them as a power reserve, because you already own 'em; basically zero up-front cost.

But if I wanted to recharge the batteries during a disaster, just about anything would be a better option. A battery monitor, for instance, is going to have a lot more volume dedicated to it's circuitry, and won't be concerned with a bit of heat. It'll probably be way more efficient.

A home battery bank (or at least the controller) is a bit different, because it's rather larger than the circuitry in a small UPS. It's more akin to a building UPS, which can afford to have more space for the circuits than the full volume of the small UPS; that's plenty of room for cooling and high-efficiency doodads.

In your case I'd just use the UPSes to keep the batteries topped off, and use them as secondary power stores; I wouldn't even bother trying to actually charge them until utility comes back up (or I got a generator to plug 'em into).
I'd be down to just use the UPSes as a small, temporary power reserve.

What I'm wondering is if there is a cheap way to keep my AA batteries charged up through USB if I had to, specifically using devices that would not generate much power. I've got a few USB battery chargers that people linked earlier, but it was mentioned that trickle charging them might not be good for them.

boskone
* * * * *
Posts: 1391
Joined: Wed Oct 17, 2012 4:07 pm
Location: Aggieland-ish

Re: Charging Eneloop AA through USB

Post by boskone » Mon Sep 14, 2020 10:06 pm

quazi wrote:
Mon Sep 14, 2020 8:50 pm
I'd be down to just use the UPSes as a small, temporary power reserve.

What I'm wondering is if there is a cheap way to keep my AA batteries charged up through USB if I had to, specifically using devices that would not generate much power. I've got a few USB battery chargers that people linked earlier, but it was mentioned that trickle charging them might not be good for them.
If you buy Eneloops, Tenergy, or other low self discharge (LSD) cells, I wouldn't worry too much about keeping them topped up. I think Eneloops are supposed to stay above 90% charge for a year or two, so if you cycle your batteries through normal use you'll probably be fine.

If you want, you could drop a few bucks on a higher end charger/exerciser, and run the batteries through that instead of just charging. That would also let you check the health of each battery as it gets charged.

Post Reply

Return to “Other Gear”