How to charge batteries?

[Cheeze1617]

So I read some stuff about the voltage range. Can I not just charge my battery and use it? Do I have to buy a multimeter and check it? Every time?
So how do you charge your batteries?

 

[thedoc007]

You can just charge and go, and many people do just that with no issues. But when you are talking about batteries like 18650s, that are $10-20 per cell, I personally think a little TLC is definitely worth it. It also makes it much less likely for anything to go seriously wrong if you check the status of your batteries and charger regularly. It only takes about 20 seconds to check four batteries, and a digital multimeter can be had for less than $20 which will be accurate enough for simple DC voltage testing.

It really depends on how much money you are going to spend on your lights...I have over $1000 worth of lights, a couple hundred dollars worth of batteries, and so the extra money for maintenance/monitoring is no big deal. If you just want one light in the car for occasional use, I'd just buy some primaries and avoid charging altogether. Only you can decide what makes sense for your situation.

 

[Cheeze1617]

So using something like the xtar charger on a 18650 I should do just fine without a multimeter?​

 

[Kick]

So using something like the xtar charger on a 18650 I should do just fine without a multimeter?​

Hey fellow Utahn,
It is all about safety and redundancy. I will assume you are talking about the VP1, with the built in display. You could just rely on what the display shows you and will probably be fine, even though the reading may not show if the cell is above 4.20 volts, according to the battery and charger guru HKJ.
Personally, I use a Fluke dmm, just to make sure everything is as safe as it can be because of the amount of stored energy in cells can be hazardous to the health and safety of myself and others. So I pull my cells out of my lights periodically, to make sure they aren't below 3.7 volts, and if they are getting close, I charge them. I also check the voltage when they come off to charger, to make sure they are charged fully, and to make sure they are not overcharged. I may be a nerd when it comes to this, but I'll be a safe nerd.
I ordered a VP1 in mid February, but have been waiting for it to be back in stock, but I will still double check the voltage after the cells come off of this charger as well.

 

[TEEJ]

Essentially, yes, that's about all you do, except you insert one new step that become habit:

When the cells come out, see what the voltage is (You are simply putting a lead on each of the -/+ of the cell, and its says the voltage....and takes about 5 seconds or so.) You see how low they went, and you now know how much you discharged them, and, if they went too low for example, or, don't really NEED recharging yet, etc....


After charging them, you do the same thing...and confirm that they recharged to the state you expected.

If you only have lights with only one cell, some of this can be overkill...but, if you use lights with 2 or more cells, you do want them to be at the same state of charge when they are in series. (So you can use cells that are matched)



Once you get used to it, its literally a few seconds to touch the cell's poles with the DMM and you're done....very fast and easy. I have a DMM with the leads right next to the charging station...and where I stack the charged cells.


For older cells that are starting to show differing charge rates (After 3-5 years or so...it happens), so you might have some that come off at the low end of 4.1 v and some at the higher end of 4.1 v (~4.17 v might be a rested new cell for example).

If I have some 4.10's, they go together, and the 4.17's go into another group...so I can load a light with cells that are similar more easily when sorted by voltage.

As I have many many lights, and cells, I also tend to sort them by history (What light they go in...so the cycling history is also similar).

I don't bother with history for single cell lights, as there's no cell matching on internal resistance to worry about.


Anyway, if you measure the voltage regularly, its a LOT easier than you think, and it gives you a lot of info you didn't know you needed yet.

 

[Cheeze1617]

So if I use a battery tell the led gets down to about 100 lumen(it starts with 950) would it be close to the minimal voltage? Or should I be ok?

 

[TEEJ]

So if I use a battery tell the led gets down to about 100 lumen(it starts with 950) would it be close to the minimal voltage? Or should I be ok?

LOL

You won't be able to to tell lumens that well...lux maybe...but anyway, depending on what flashlight you have, maybe, maybe not.


Some flashlights have protection built-in that prevents the light from over discharging your cell. Of those, some just turn the light off if the cell goes below a set voltage, say 3.0 v, or 2.5 v, etc....and some blink a few times once in a while to tell you you are getting low.

Some do what's called a step down to manage heat, so the light might dim to help deal with over heating, but not be dimmer at that time due to the cell charge.....the cells might still be fine even though the light got dimmer.

Some el cheapo lights don't have any protection, but might have a boost circuit to maintain brightness, and the light might simply stay bright, and then over drain your cell, etc.

Some might be direct drive (No boost, etc) with no protection, and those tend to start bright, and gradually get dimmer from the get go...so they are dimming the entire time....and, if you let them get dim ENOUGH, then the cell can be over discharged, etc.

Measuring the cells when you take them out tells you what happened though...and, you'll get a feel for even direct drive lights, as to how dim is too dim, etc...eventually.

 

[Cheeze1617]

LOL

You won't be able to to tell lumens that well...lux maybe...but anyway, depending on what flashlight you have, maybe, maybe not.


Some flashlights have protection built-in that prevents the light from over discharging your cell. Of those, some just turn the light off if the cell goes below a set voltage, say 3.0 v, or 2.5 v, etc....and some blink a few times once in a while to tell you you are getting low.

Some do what's called a step down to manage heat, so the light might dim to help deal with over heating, but not be dimmer at that time due to the cell charge.....the cells might still be fine even though the light got dimmer.

Some el cheapo lights don't have any protection, but might have a boost circuit to maintain brightness, and the light might simply stay bright, and then over drain your cell, etc.

Some might be direct drive (No boost, etc) with no protection, and those tend to start bright, and gradually get dimmer from the get go...so they are dimming the entire time....and, if you let them get dim ENOUGH, then the cell can be over discharged, etc.

Measuring the cells when you take them out tells you what happened though...and, you'll get a feel for even direct drive lights, as to how dim is too dim, etc...eventually.

thanks for the help, I understand that you can't tell the lumens, I was just speaking generally about if the light is almost out of battery

 

[TEEJ]

thanks for the help, I understand that you can't tell the lumens, I was just speaking generally about if the light is almost out of battery

If the light is "almost out of battery", if you judge that by dimness, depending on the light, you either ruined a $17 18650, had it go dark when you weren't ready, or, got a few warning flashes a few minutes apart to remind you you were getting close....or, have a boost circuit that simply keeps the light bright until its dead, etc.

IE: There's no one answer. Its a bit like "If I'm fishing, and my bobber goes down, what kind of fish will I have caught?"



If you HAVE a light that you are talking about...it would help to fill in that blank at least.


We'd then at least have a clue as to what pond you were fishing in.


PS - A DMM is ~ $7 for a cheap one that will work well enough for this...at Harbor Fright, etc.