Explosion happens if the voltage per cell is too high. So there's no explosion risk from going too low afaik. The only risk is the cells becoming useless.
Worklog (IT'S FINISHED) The Mumble Driim (Making my very first portable)
Mumble
.
- Joined
- Jan 28, 2017
- Messages
- 174
- Likes
- 82
- Portables
- 0
Okay good. All else fails honestly I can just buy more cells. I'm not taking this thing a part lol.
LiPos can potentially cause issues if you try to charge them after they have been over-discharged too much. I would suggest a low battery indicator at the very least, so the cells aren't drained too low. Under 3v per cell will significantly shorten the life of the batteries. If you ever leave it on and drain the batteries way low, I would suggest replacing them. If you don't, then keep a close watch on them as they charge, and make sure they don't get too hot.
Also, as a general good idea, charge them at a fairly slow rate so they last longer. It might take a couple hours longer to charge, but it will extend their life significantly
Also, as a general good idea, charge them at a fairly slow rate so they last longer. It might take a couple hours longer to charge, but it will extend their life significantly
I'd actually recommend people not build their own battery circuits unless they've researched it extensively. I've done a huge amount of reading on Li Ion cells and still don't feel comfortable building my own pack. They can be dangerous and/or ruin your whole project. On top of that, it generally costs more to buy the cells, the protection circuit, the charger, switch, plug, and the battery indicator than to just buy a prebuilt pack. It may be slightly less efficient because you're not handpicking each component, but as a rule it's significantly safer and can get the job done almost as well. If you put $100-300 and a bunch of time into a project, you don't want it exploding or the batteries dying. And you definitely don't want it setting a fire while you're charging it overnight.
Important Note! We suggest that you should never use lithium ion/polymer batteries without protection cells. Without the protection, a slight mistake in their use could destroy the battery and they have a much higher risk of exploding or catching on fire."
The protection circuit has over charge and over discharge protection. So yes, it will significantly extend the life of your battery, but it will also stop it from blowing up or setting a fire when they're fully charged. Lithium Ion batteries are known to be temperamental and it's extremely important that they are treated properly.
I'm sorry this post was so long, but I really wanted to impress on everyone how serious it can be if the batteries aren't set up properly. Extensive research is needed to understand everything that is needed to get a stable battery circuit, and even then I'd recommend not building one unless you're really sure you know what you're doing. Lithium Ion cells can really be dangerous.
You definitely should not be using those cells without a charge protection circuit. Here's a quote from the Adafruit Li Ion info page about protection cells.
- "Do not charge them above their maximum safe voltage (say 4.2V) - usually taken care of by any on-cell protection circuit
- Do not discharge them below their minimum safe voltage (say 3.0V) - usually taken care of by any on-cell protection circuit
Important Note! We suggest that you should never use lithium ion/polymer batteries without protection cells. Without the protection, a slight mistake in their use could destroy the battery and they have a much higher risk of exploding or catching on fire."
The protection circuit has over charge and over discharge protection. So yes, it will significantly extend the life of your battery, but it will also stop it from blowing up or setting a fire when they're fully charged. Lithium Ion batteries are known to be temperamental and it's extremely important that they are treated properly.
I'm sorry this post was so long, but I really wanted to impress on everyone how serious it can be if the batteries aren't set up properly. Extensive research is needed to understand everything that is needed to get a stable battery circuit, and even then I'd recommend not building one unless you're really sure you know what you're doing. Lithium Ion cells can really be dangerous.
Carb0
.
- Joined
- Aug 24, 2016
- Messages
- 8
- Likes
- 2
Even if it seems to work correctly, you risk an explosion of the batteries if you over-charge or over-discharge them, or if you short them out. A protection circuit is an absolute must in any device that uses lithium ion batteries. A low battery indicator is not enough since there is still room for user error.
A battery protection circuit only costs a few dollars. If you buy one, make sure to get one that has voltage cutoffs that are compatible with your batteries. You also need a 16.8V smart charger to take advantage of the over-charge protection of the protection circuit. Your current smart charger doesn't work with a battery protection circuit. If the charger malfunctions, it can over-charge your batteries.
They may work fine for a few charge cycles but nevertheless they may be damaged. It's better if you just replace them, even if it costs you a few bucks.
I totally agree.
- Joined
- Nov 10, 2016
- Messages
- 606
- Likes
- 1,625
There's a reason why I've stuck with the same camcorder battery packs and chargers for all my projects so far. They're dead simple to work with, the protection circuits are built into the packs, and I do no modification aside from opening the packs to rearrange the cells inside my project case.
One of my future projects will require me to branch out and use li-po batteries, but you can be sure I'm going to do all my research before that day comes.
One of my future projects will require me to branch out and use li-po batteries, but you can be sure I'm going to do all my research before that day comes.
Mumble
.
- Joined
- Jan 28, 2017
- Messages
- 174
- Likes
- 82
- Portables
- 0
Okay...In response to this, I really. REALLY don't want to take off all this hot glue (I broke the famous words of Ben Heck RIP).
Could I order batteries with a built in protection circuit like @fibbef is saying? It would obviously be a lot more money than $15, but if it has built in protection like you guys are saying, it would make me feel better about myself.
http://www.ebay.com/itm/ATK-3-7v-18...059345?hash=item1eb8f4a3d1:g:WrsAAOSw8w1X6c1j
Could I order batteries with a built in protection circuit like @fibbef is saying? It would obviously be a lot more money than $15, but if it has built in protection like you guys are saying, it would make me feel better about myself.
http://www.ebay.com/itm/ATK-3-7v-18...059345?hash=item1eb8f4a3d1:g:WrsAAOSw8w1X6c1j
I can't find it now, but I seem to remember reading somewhere that the protection on individual cells doesn't work when you have them in a pack. Can anybody confirm?
For that price, you could just order a whole battery pack with a charger and protection and everything. Also, protected cells are larger than unprotected ones so they may or may not fit in your holder.
Mumble
.
- Joined
- Jan 28, 2017
- Messages
- 174
- Likes
- 82
- Portables
- 0
Maybe it is an overkill of a price. But it's still better than opening the portable.
As if size, that would suck...But let's hope for the best of the luck. They also allow you to get refunds within 30 days, so if they don't work I can get my money back.
- Joined
- Nov 10, 2016
- Messages
- 606
- Likes
- 1,625
Does anyone have the diameter of those unprotected cells off hand? They look like they're about the same as an alkaline AA, which is ~13.5mm (just measured an Energizer). The protected cells I use are noticeably thicker. I'm estimating 15 or 16 mm, but I'm not at home to confirm at the moment.
Mumble
.
- Joined
- Jan 28, 2017
- Messages
- 174
- Likes
- 82
- Portables
- 0
Dimensions: Height: 65.0mm±0.5mm. Diameter: 18.0mm±0.5mm
Maybe it is an overkill of a price. But it's still better than opening the portable.
As if size, that would suck...But let's hope for the best of the luck. They also allow you to get refunds within 30 days, so if they don't work I can get my money back.
http://www.candlepowerforums.com/vb...ow-do-you-protect-li-ion-batteries-for-a-pack
This might be the place where I read that. Like I said earlier, you need to do extensive research before attempting to build your own pack. I've read and read and read and still don't know even close to everything. Please spend some time looking around and reading about Li Ion cells before attempting to add or remove any components. These are finnicky and dangerous if not handled properly.
18650s are about 18.3mm in diameter. Protected cells are slightly longer for sure, idk about thicker. Maybe only on the end that has the circuit.
- Joined
- Nov 10, 2016
- Messages
- 606
- Likes
- 1,625
My estimate is probably off by a couple of millimeters. I could find out for sure when I get home.
The packs I use have the protection circuit welded to the cells, not actually built into them. But for sure, don't know if they would work in your battery holder, Mumble. Especially since you would have to figure out what to do with the circuit.
pipbug
.
Overdischarging won't make the battery explode, but it will render them useless. Overcharging however, CAN cause the battery to catch fire. Using safety circuits are a MUST with Lithium cells.
Mumble
.
- Joined
- Jan 28, 2017
- Messages
- 174
- Likes
- 82
- Portables
- 0
I found a better price, and a seller who I have had a good purchase from. (Same one where I bought my unprotected cells that worked out really well)
http://www.ebay.com/itm/2x-Keeppowe...469527?hash=item1c798e8c97:g:TO0AAOSwA3dYbSTw
The description for these cells says this:
Dimensions: Height: 68.9mm±0.5mm. Diameter: 18.6mm±0.5mm
which is slightly bigger than:
Dimensions: Height: 65.0mm±0.5mm. Diameter: 18.0mm±0.5mm
I feel like that can fit in my battery holders, at least the height, fingers crossed with the diameter / width. I think I'm going to order them and try them out. If they don't work, everything I know has failed me
http://www.ebay.com/itm/2x-Keeppowe...469527?hash=item1c798e8c97:g:TO0AAOSwA3dYbSTw
The description for these cells says this:
Dimensions: Height: 68.9mm±0.5mm. Diameter: 18.6mm±0.5mm
which is slightly bigger than:
Dimensions: Height: 65.0mm±0.5mm. Diameter: 18.0mm±0.5mm
I feel like that can fit in my battery holders, at least the height, fingers crossed with the diameter / width. I think I'm going to order them and try them out. If they don't work, everything I know has failed me
pipbug
.
I can't stress this enough
Mumble
.
- Joined
- Jan 28, 2017
- Messages
- 174
- Likes
- 82
- Portables
- 0
So, correct me if I'm wrong, but they're just saying that a protected battery with another PCB is not a good thing?
Yes. Protected batteries are for individual cells (like single battery projects). I believe they are also okay if they're only in parallel, but definitely mess things up when in series. Yours are in series, so you have the right batteries. You just need a protection circuit and a smart charger. You're going to have to research all of that yourself though because I can't do it for you. All the info is out there.
All this mess is why I won't build my own pack. It saves maybe a tiny bit of space, and is good for voltages where there is no prebuilt battery pack, but it costs more, is time consuming, confusing, and difficult. And I would always worry about leaving mine to charge overnight. The last thing you'd want is a fire in your house because you skipped a step or misinterpreted something.
Mumble
.
- Joined
- Jan 28, 2017
- Messages
- 174
- Likes
- 82
- Portables
- 0
Alright so based on what I've read in about 35 minutes, I've found that you can actually use batteries in series
(source: http://www.candlepowerforums.com/vb/showthread.php?197823-protected-18650-in-series-safe )
The only thing that I am confused with is how if it's actually safe to simultaneously charge them.
I bought a charger that will charge them simultaneously, and it should be here in the next two weeks or less (you know how China shipping is)
http://www.ebay.com/itm/112103853541?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT
Some people say it's safe, other's say to charge individually.
Anyone know anything about this?
Edit: I also asked the guy who sales the protected cells, and he said using them as a battery pack will work.
(source: http://www.candlepowerforums.com/vb/showthread.php?197823-protected-18650-in-series-safe )
The only thing that I am confused with is how if it's actually safe to simultaneously charge them.
I bought a charger that will charge them simultaneously, and it should be here in the next two weeks or less (you know how China shipping is)
http://www.ebay.com/itm/112103853541?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT
Some people say it's safe, other's say to charge individually.
Anyone know anything about this?
Edit: I also asked the guy who sales the protected cells, and he said using them as a battery pack will work.
Last edited: