Sanyo NCR18650GA questions

Hi guys,

I recently purchased 6 Sanyo NCR18650GA cells, and an XTAR SV2 charger from IMRbatteries. I have two questions I'd love to hear your thoughts on:

1) The NCR18650GA cells fit my 47's MMX-360 really tightly. To put it in perspective, my current NCR18650B can easily slide in and out of it, but the NCR18650GA fits so tightly I have to fling the 47's MMX-360 to get it out. Is it safe for me to use the NCR18650GA in the MMX-360?

2) The XTAR SV2 charger can charge 2A x 2 slots. Can I charge both the NCR18650B and NCR18650GA at 2A?

Hope to hear from you soon.

QMT93 said:

Hi guys,

I recently purchased 6 Sanyo NCR18650GA cells, and an XTAR SV2 charger from IMRbatteries. I have two questions I'd love to hear your thoughts on:

1) The NCR18650GA cells fit my 47's MMX-360 really tightly. To put it in perspective, my current NCR18650B can easily slide in and out of it, but the NCR18650GA fits so tightly I have to fling the 47's MMX-360 to get it out. Is it safe for me to use the NCR18650GA in the MMX-360?

2) The XTAR SV2 charger can charge 2A x 2 slots. Can I charge both the NCR18650B and NCR18650GA at 2A?

Hope to hear from you soon.

Click to expand...

Without looking at HKJ's tests on those cells, 2A might be slightly high, more so for the NCR-B. I would just use 1A for both.

Are your NCR-GA cells protected? This could account for extra length. A slightly longer bare/naked cell shouldn't matter much.

Chris

Both types are button top protected, and the tight fit I was referring to is the width, not the length. In that case, is it safe still?

I bought the specific charger for the 2A charging capability. Guess I overspent

Sent from my PH-1 using Tapatalk

QMT93 said:

Both types are button top protected, and the tight fit I was referring to is the width, not the length. In that case, is it safe still?

I bought the specific charger for the 2A charging capability. Guess I overspent

Sent from my PH-1 using Tapatalk

Click to expand...

OK, 18650s come from their respective manufacturers in naked/bare form with flat top positive ends and no protection circuits, just to be clear. Third party vendors add the metal button tops and then possibly the PCB circuit at the negative end. After that, they usually add a clear shrink wrapper, which adds width to the cell proper. This is your problem, as there are no standards at that point.

If they fit and you don't bugger up the springs, or the wrappers, you're golden.

Chris

Yay, thanks!

Sent from my PH-1 using Tapatalk

Another question: I currently charged all 6 cells using 2A to 98% or 99%, and stored them in the plastic container. However, as I placed them back into the charger to check the capacity, the charger read at about 88%. Is this normal? Why is this happening?

QMT93 said:

Another question: I currently charged all 6 cells using 2A to 98% or 99%, and stored them in the plastic container. However, as I placed them back into the charger to check the capacity, the charger read at about 88%. Is this normal? Why is this happening?

Click to expand...

The charger is reading their resting voltage, and estimating capacity based on that. Charging lithium-ion cells generally occurs in two phases: a constant-current phase (in your case 2A), and then a constant-voltage phase.

When charging during the CC phase, the cell's voltage will be quite a bit higher than if you took the cell off the charger and let it rest. It's normal for the voltage to drop a bit, after a charging current is removed. That's because the charging voltage must be higher than the cell voltage, in order for current to flow into the cell. That's just the way electricity works.

When the charging voltage reaches 4.2v, the CV phase starts. At that point, current gradually drops, while the charging voltage is held at 4.2v. It will drop from 2A, to somewhere around 100mA after a half-hour or so. At that point, the charger says, "good enough", and ends the charging. The CV phase is used in order to fully-charge a cell. If you just stopped at the end of the CC phase, the cell would only be 80% or 90% charged.

You ended the charge before the cell was fully charged to 4.2v. When you removed the cell, its voltage dropped. Putting it back into the charger, made the charger report it as only partially charged. It is correct, although 88% is just a guess.

BTW, it's better to use 1A or 1.5A for those GA cells. They can take 2A charge, but it will slightly shorten their lifespan.

That was a great explanation WITL, thank you.
P

Thank you so much for the explanation! I read on Battery University, but wasn't able to to understand.

Sent from my PH-1 using Tapatalk

I might add if the cell width is snug while loading into tube this is not recommended as once it heats up and expands you're going jump up and down all day long and that cell won't budge. Make sure you have wiggle room so cells can breathe a little in the tube

Is there anything bad if I use it this way? The tight fit bothers me, but I'm not sure what else to buy.

Sent from my PH-1 using Tapatalk

Check out Zebralight dot com site. ZL advertises the smallest size 18650 (protected cell) Not sure how width specs compares.. You can try re-skin the GA, factory casing covers are thicker than the heat shrink wraps offered from battery suppliers. That will help a little.

I see. Thanks for the input! I'll look into that. The "re-skin" sounds risky. If the fit doesn't affect the function of the battery or the light, and that it's ok to use it so, I'd prefer to keep it that way. Is it safe though? What risks am I gambling against, if any?

QMT93 said:

I see. Thanks for the input! I'll look into that. The "re-skin" sounds risky. If the fit doesn't affect the function of the battery or the light, and that it's ok to use it so, I'd prefer to keep it that way. Is it safe though? What risks am I gambling against, if any?

Click to expand...

In single cell lights, with low voltage cutoff, or with low voltage warning (step downs,) you can run naked cells if you're comfortable and if your lights have springs at both ends of the light.

You're running quality cells and a quality charger, so you've just eliminated 95% of potential problems and protection circuits can and do fail.

Buy a digital multi-meter to measure things, if you don't already have one.

Chris

Many have suggested that I charge the 18650GA cells at 1A, instead of 2A, which defeats the purpose of getting the XTAR SV2. However, I understand their reasoning, and am considering picking up a 4x1A bay charger, probably the XTAR VP4 Plus Dragon, or the GyrFalcon All-44. Thanks for your input!

QMT93 said:

Many have suggested that I charge the 18650GA cells at 1A, instead of 2A, which defeats the purpose of getting the XTAR SV2. However, I understand their reasoning, and am considering picking up a 4x1A bay charger, probably the XTAR VP4 Plus Dragon, or the GyrFalcon All-44. Thanks for your input!

Click to expand...

If you really, really need to charge up a 18650 cell at 2A, you really, really need to have a couple/few spares.

26650s like 2A and perhaps the newer 21700s and some 18650s can stand it, but 2A isn't ideal, IMO, especially if you're wanting to maximize cell life.

Chris

Got it! I should have done some more research. Anyway, the 2A can be the backup, so I guess I should be good. Thanks for the input Chris!

Sent from my PH-1 using Tapatalk

Yeah, I definitely recommend 1A charging for the GA cells, rather than 2A. But, don't get too hung up on it. They'll handle 2A okay, you'll just get a few less cycles out of them.

The GA cells are rated for 500 cycles (to 60% of original capacity), when charged at 1.65A and discharged at 6A. That's quite heavy power-usage, so they're pretty tough cells.

If you charge them at 2A, you might get 400 cycles? Are you even going to use the cell for 400 full discharge cycles? If you drain the cell every few days, then yes, stick to 1 amp so you'll get 5 years out of it rather than just 4 years. Probably worth it.

But if 2A is more convenient, and you only charge it once every week or two, then you'll get 10 years out of the cell either way.

Newer chargers do 3A or 4A charging. I'd certainly avoid those rates, except for high-drain cells like the Samsung 30Q, Sony VTC6, or better.

Got it! Thanks for the input! That's really informative and reassuring.

Sent from my PH-1 using Tapatalk

Will the GA fit and work well in Lumintop fw1a or would a Sony vtc6 be better?