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Efest IMR 18650s (2500mah) only charging to 40% - Please help!

KillaB3E

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Hello All,

So my new (less than a month old) Efest IMR 18650s (3.7v / 35A) batteries have only been charging to around 40% for the last two charges. I also have a pair of Sony VCT4's and they charge to 100% on the same charger. I have a Nitecore D4.

Does anyone know what's going on? I have another pair of batteries (LG HE 2) on they way, but those won't be here until Friday at the earliest.

I have the Sony's and Efest batteries married, and have been trying to alternate when used in my Sig 100W Plus. I just don't know what's going on? I bought them from Lightning Vapes a few weeks ago along with my charger, so I'm pretty sure they aren't knock-offs.

Is there anyway to "reset" the batteries?

Also, while on the subject. Since these Efest are only @ 40% and dropping, while the Sony's are in the charger right now, is it okay to only partially charge the Sony's (so I can vape when these run out shortly), or should I always wait until the batts are fully charged before using.

As Always, thanks for your help!
 

KillaB3E

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Member For 4 Years
Thanks @BoomStick. The Sony's are at 3.96v, so I'm gonna start using them, while the Efest batts charge again.

I read on another forum that the Efest batts will lose charge if you don't use them for a day or two after charging. Has anyone had this problem?
 

KillaB3E

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Okay, so I charged the Elest batts again, let them sit for 30 minutes and put them to use. Working like a charm, so I guess the lesson learned is to use them ASAP.
 

Midniteoyl

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Thanks @BoomStick. The Sony's are at 3.96v, so I'm gonna start using them, while the Efest batts charge again.

I read on another forum that the Efest batts will lose charge if you don't use them for a day or two after charging. Has anyone had this problem?
I have 10 efests and dont have this problem.. They stay charged for weeks of non-use. I would suggest that either you got a bad batch, or something bad happened to them - such as internal shorting?. What is the charge amps set at?
 

KillaB3E

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I appreciate the reply. I charge them @ 750 amps, usually takes about 3 hours. I emailed the shop that I got them from but they are closed today, so I'll see what they say.
 

Midniteoyl

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Try the lowest the charger will go (in my case, .5amps) and see.. I would leave them in there longer too if you can.
 

KillaB3E

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Thanks, I'll try that next time. Is it a good rule of thumb to charge all batts slowly rather than ASAP?

BTW, they re holding up just fine right now, have been vaping for the last 2-3 hours.
 

Midniteoyl

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Thanks, I'll try that next time. Is it a good rule of thumb to charge all batts slowly rather than ASAP?

BTW, they re holding up just fine right now, have been vaping for the last 2-3 hours.
Each batt has a max charge rate, however, I find that slowly charging for a longer period, prolongs the batteries life as less heat is built up internally. Doesnt mean you always have to do a slow charge, but if I can, I do.
 

dr_rox

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The batteries could be new-old-stock and performing poorly.
However, if you do the math - assuming you missed a decimal point and meant .75 amps - .75 amps * 3 hrs= ~2.25 aHr or 2250 mAh. There is a ramp down on current on most chargers so that capacity is approx.
What are you using to test the battery to determine 40% charge?? If you look at battery curves for V vs capacity, it is not a linear relationship.
 

zaroba

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Member For 5 Years
I've got the same batts and charger, also a sigelei 100watt (standard, not plus). The D4 charges at 750mah, but if you hold in the bottom botten on the left side, it will switch to a 300mah charge, so could try that. I have 3 married pairs and they usually go 2-3 days before being used after being charged, never had a decrease in power.

How long are you letting them charge?
Is your sigelei saying they are 40% or the charger? If it is the sigelei, it could just be that 1 battery is 'bad'. Was one time I put a battery in my charger backwards. Was certain both said full when I took the pair out. Noticed something was wrong when my sigelei said 'check batteries' and reported 25% power after a half an hour or so. Recharged and all was fine so assume I had accidentally put the battery in the charger backwards.

Could be an issue with one terminal on the charger, like it wasn't making proper contact to charge the battery. Have you tried them in different slots on the charger?

Make sure the battery contacts on your sigelei are clean? Earlier today I noticed my sigelei kept turning off. Just had to tap the battery cover and it would shut off. Took the batteries out and wiped the contacts on my sigelei and all was fine. Think some juice had gotten on one of the contacts from a leak earlier in the day.
 

Xhalin

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Had a batt that wouldn't charge for my ipv mini... Took it out of the excellent Nitecore Digi- placed in box and fired her up a couple times and placed back in charger- charged fine after that... I don't trust that batt though... It was the one that came with the unit .
 

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