18650 question

[Mnementh]

I have an Ace-G that I want to use 2x 18650s with.I bought the UltraFire 3000mAh 3.7V batteries for it from Battery Junction. Everywhere I've read says not to use batteries of mixed charge status, or devastation will surely follow. How much difference in voltage is allowed?

One battery charges to 4.16V on my multimeter before the charging light goes green, the other only goes to 4.03V. I feel like I'm being too cautious just asking this, as it doesn't seem like that much of a difference.

 

[TooManyGizmos]

No , I don't thing you're being too cautious.
I personally think that is a wide gap , and I would not use them together.

Before using them , wait for someone here to give you a guideline on what the acceptable gap should be.

They need to be pretty close.
The one at 4.03 is quite low.

You should use protected cells when using multiple cells together ... IMO .

 

[old4570]

Lots of other batteries to chose from ..

Do a little research on CPF , and head on over to Flea bay or DX or one of the other vendors , and buy some better batteries .

When you run 2 x Li-ion , you want two well matched cells , not only for capacity / Voltage level but discharge rate as well .

 

[Mnementh]

I've taken the extender tube off of the Ace-G and am running it on 2x CR123A's for now. I'll buy some more 18650's later when the credit cards have cooled off a bit and try again.

For now, I'm using the 'good' 18650 in my Olight M21. Would you consider the lower voltage 18650 to be good to use as a backup, since the M21 is a single cell for 18650s?

 

[old4570]

I've taken the extender tube off of the Ace-G and am running it on 2x CR123A's for now. I'll buy some more 18650's later when the credit cards have cooled off a bit and try again.

For now, I'm using the 'good' 18650 in my Olight M21. Would you consider the lower voltage 18650 to be good to use as a backup, since the M21 is a single cell for 18650s?

For single battery use , charge state makes no never mind , except it just may store less charge .. I would suggest running the lower charge battery first ..

Often new batteries may need a little running in so to speak , and it may actually improve with some use ..

Ive had a few that toped out at 4.18v and after use came off the charger @ 4.21v and settled to 4.2v after 30 minutes of rest ..

4.03v is very low , but try using it some , and then put it back on the charger and see if it goes higher .

 

[Mnementh]

After doing some reading, I may have a theory:

I have the DSD charger, which charges in parallel, so (as I understand it) when one battery hits the cutoff, both will cut off. So the 'good' battery hits the cutoff, and the lower voltage battery doesn't charge all the way. I haven't tried it, but can I charge just one battery in this charger? I don't see why not, but with as finicky as these things apparently are I thought I'd ask.

 

[old4570]

After doing some reading, I may have a theory:

I have the DSD charger, which charges in parallel, so (as I understand it) when one battery hits the cutoff, both will cut off. So the 'good' battery hits the cutoff, and the lower voltage battery doesn't charge all the way. I haven't tried it, but can I charge just one battery in this charger? I don't see why not, but with as finicky as these things apparently are I thought I'd ask.

Sweet Lord ! , DSD charger , yes , it will charge one battery at a time .
You might consider almost any other charger :
WF-139
Trustfire TR-001
Shekor
Soshine

 

[unit311]

Sweet Lord ! , DSD charger , yes , it will charge one battery at a time .
You might consider almost any other charger :
WF-139
Trustfire TR-001
Shekor
Soshine

Is this really good advice? Everything I have read about cheap chargers lately makes it sound like the DSD is one of the safest. Certainly safer than the wf-139.

 

[old4570]

I own the :

DSD
WF-139
TR-001
Shekor

I would rate the Shekor as the safest ... [ Turns off on completion ]

As for the rest , the Wf-139 and TR-001 use independent channels for charging , and as long as you monitor the chargers , there safe enough ..

I have left my TR-001 charging overnight by accident , and the battery was 4.21v right out of the charger and 4.2v after 30 minutes . This was a unprotected Green Ultrafire 2600 , so no protection circuit kicking in .

The UF-139 ?? I would not want to leave it overnight , but its still a great charger , and as long as its used correctly , a fantastic product .

Im buying a Soshine charger shortly as it charges faster :
So far my Wf-139 is the fastest .. But I want more power !!!

I dont think the chargers are dangerous , I think people are dangerous , but having said that , I dont like single channel chargers for dual battery charging .

if the batteries are not carefully monitored , you could end up with a situation where one battery has more voltage than another , and one battery is stressed to much , and becomes unstable .... [ Dual batt flashy ]

 

[Mnementh]

I think it is definately the battery, after all. I put the higher voltage battery into my M21 and ran it till it matched the lower voltage, then recharged. When the light turned green I tested the batteries again. (I had put a piece of tape on the lower voltage to keep them seperate in case the battery was bad.) The higher voltage battery charged to 4.16, the lower voltage to 4.09. Getting better, but still the gap. What I'm going to do:

Discharge the higher voltage battery to the lower level batteries level, then charge again, this time switching the batteries position in the charger. This will determine if it's the charger or the battery.

Buy a new charger regardless, as I want one that will charge the batteries in separate circuits.

Buy a new set of batteries for the ACE-G

Keep the current set of batteries for the M21.

The only question I'd still like some more feedback on is the safety of continued usage of the lower voltage battery. If switching the battery positions doesn't work, is this battery safe to use even as a single cell?

 

[mfm]

What I'm going to do:

What you should do is to charge only the "low" battery and see how high it goes.

 

[Mnementh]

Charging it by itself brings it to 4.09.

 

[mfm]

Charging it by itself brings it to 4.09.

You should return that to battery junction as faulty.

 

[old4570]

You should return that to battery junction as faulty.

Yep , see if they will replace it , some thing is amiss .
Its safe to use as long as you dont see any unusual heat generated by the cell .
It could be as simple as the battery having just a little more internal resistance than the other cell , and the charger is terminating earlier as it senses the resistance to charging ...

Having said that , it could also be the charger being overly sensitive to the battery , I have found that chargers that push more current are less sensitive to the internal resistance of individual cells ..
And if I have a battery that terminates early , I just throw it into my WF-139 and its then taken all the way to 4.2v ..

I just ordered the Soshine SC-S2 , its supposedly 1000mA per channel , while most others are 500mA or less , either way Im looking forward to halving charge times .

 

[Mnementh]

I've been using them in my M21 separately, and it's starting to even out. The lower one now charges to 4.12 and the high one to 4.15.

I've purchases some AW 2600s and a WF139 charger, as well. I'll put the AWs in the ACE-G, keep using the UltraFires in the M21, and use the 139 charger exclusively.