Battery charger and charging

therog1

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Joined
Sep 14, 2017
Messages
4
Hi all,


I've got a couple of questions about charging rechargeable batteries, and the best charger to use for them.


1. I've got the Nitecore D4 charger, and wonder if this is the best charger for my needs? At present I only charge NiMH's but like the option to be able to charge Li-Ions if need be later (got a torch that can take 14500's, but no cells yet). I've been looking at the Opus BT – C3100 V2.2, but wonder if the benefit of it is worth the cost? I estimate it would have to increase the life of my cells by ~50% (I don't have that many), to be worth the cost (assuming I didn't resell the D4 or anything). I like the idea of having an analysing charger, but don't know that it's worth the cost. Anyone have suggestions? (Opus is ~$50AUD for me)

2. When I charge the cells in the D4, I usually set them going overnight on the "low" setting (I think 375mAh for AA, 150mAh for AAA with all slots full), because I'm not in a hurry, and thought this would help extend the life of them. However, reading this page and other threads I've read here suggest this current is too low, and I should just use the "high" setting as that is between 0.3C-1C (can't remember what it is exactly off the top of my head, maybe ~500mAh?). Is this correct? Should I just use the high current setting? And how quickly should I be taking them out of the charger once finished? All of my cells are standard eneloops/fujitsu NiMH.


Thanks!
 

ChrisGarrett

Flashlight Enthusiast
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Feb 2, 2012
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5,725
Location
Miami, Florida
I have a lot of chargers and own an Opus BT-3400 v.2.2 and it's a good charger.

With a couple of minor differences (can turn the display off and 'better' fan), it's the same as the BT-3100 v. 2.2. You can find the 3100 v. 2.2/v. 3.1 for $30-$35 at some of the Asian vendors, like GearBest.

I just got done with hurricane IRMA here in Miami (82 hours w/o power) and you can never have too many chargers in an emergency. Get chargers that work off of 12vdc AND chargers that work off of 5vdc USB and then get a decent 40w-80w 12vdc solar panel w/digital charge controller and finally get a small 14w-21w 5vdc USB solar panel, to charge everything back up with, in case you lose power.

Chris
 

Keitho

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Jun 7, 2017
Messages
781
Location
CO, USA
The best source I've found, by a lot, for info on chargers and cells/batteries is lygte-info.de. The review he did of your charger is here: http://lygte-info.dk/review/Review Charger Nitecore Digicharger D4 UK.html

It seems that there is no trickle charge, so there probably isn't a rush to take cells out of the charger once they are done. However, I'm in the habit of taking cells out pretty soon after they are done, mostly because being in that that habit over the long term might get me a little extra life out of my cells. Even though my chargers mostly do not have trickle charge functions, they will re-start charging once a cell self-discharges below some set voltage; repeated cycling "wears out" cells. See, for example, this explanation for NiMH chemistry charging: http://lygte-info.dk/info/batteryChargingNiMH UK.html

Have fun!
 

terjee

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Joined
Jul 24, 2016
Messages
729
Location
Bergen, Norway
The D4 is fine, and you don't *need* to upgrade from it. I would however recommend having another as backup. The Opus you mentioned is one of the typical recommendations.

In your shoes, if you're not in a hurry, I'd wait until the review is in for the SC4, unless you really want an analyzing charger.

Also, lower isn't always better with NiMHs, like you mentioned. All else being equal, it's better, but if charge current is too low, some chargers can miss the termination indicators, and overcharge the cell. It'd be better to charge a bit faster and terminate correctly, than charge slower and not terminate when they should.

Charging at 500mA to 1A isn't much of a problem for an AA Eneloop, and there's not much need to go below it.

C-rates are based on battery capacity, so C/1 for a 2000mAh battery is 2000mA (2A), and C/2 is 1000mAh (1A), and so if goes.

For Eneloop NiMHs, I'd agree on the 0.3C to 1C, but stay on the low side, so about 500mA to 1A for AA cells.
 

therog1

Newly Enlightened
Joined
Sep 14, 2017
Messages
4
I have a lot of chargers and own an Opus BT-3400 v.2.2 and it's a good charger.

I just got done with hurricane IRMA here in Miami (82 hours w/o power) and you can never have too many chargers in an emergency. Get chargers that work off of 12vdc AND chargers that work off of 5vdc USB and then get a decent 40w-80w 12vdc solar panel w/digital charge controller and finally get a small 14w-21w 5vdc USB solar panel, to charge everything back up with, in case you lose power.

Chris

Thanks for your input Chris. This is something I'm actually really interested in (being able to keep things charged in an emergency, or for camping trips), and working towards, so would appreciate some thoughts about what I need from here.

I've got 2x Klarus CH1's because they charge from 5V DC USB, and my D4. I've also got 1x 10000mAh (Anker) and 1x 20000mAh (Xiaomi) power banks which I can use to charge all my eneloops (via the CH1s) and phones etc off grid.

I've been wondering about an alternative charging method to top up the power banks off grid though. Are solar panels the way to go, or is there something else?

All this has to meet the wife test though... (Why do we need that, and how much did you spend on it?!) ;)
 

therog1

Newly Enlightened
Joined
Sep 14, 2017
Messages
4
The best source I've found, by a lot, for info on chargers and cells/batteries is lygte-info.de. The review he did of your charger is here: http://lygte-info.dk/review/Review Charger Nitecore Digicharger D4 UK.html

It seems that there is no trickle charge, so there probably isn't a rush to take cells out of the charger once they are done. However, I'm in the habit of taking cells out pretty soon after they are done, mostly because being in that that habit over the long term might get me a little extra life out of my cells. Even though my chargers mostly do not have trickle charge functions, they will re-start charging once a cell self-discharges below some set voltage; repeated cycling "wears out" cells. See, for example, this explanation for NiMH chemistry charging: http://lygte-info.dk/info/batteryChargingNiMH UK.html

Have fun!

Thanks Keitho. Yes, been pouring over that page and the reviews of various chargers. Will have a look at the link about NiMH charging, cheers.
 

therog1

Newly Enlightened
Joined
Sep 14, 2017
Messages
4
The D4 is fine, and you don't *need* to upgrade from it. I would however recommend having another as backup. The Opus you mentioned is one of the typical recommendations.

In your shoes, if you're not in a hurry, I'd wait until the review is in for the SC4, unless you really want an analyzing charger.

Also, lower isn't always better with NiMHs, like you mentioned. All else being equal, it's better, but if charge current is too low, some chargers can miss the termination indicators, and overcharge the cell. It'd be better to charge a bit faster and terminate correctly, than charge slower and not terminate when they should.

Charging at 500mA to 1A isn't much of a problem for an AA Eneloop, and there's not much need to go below it.

C-rates are based on battery capacity, so C/1 for a 2000mAh battery is 2000mA (2A), and C/2 is 1000mAh (1A), and so if goes.

For Eneloop NiMHs, I'd agree on the 0.3C to 1C, but stay on the low side, so about 500mA to 1A for AA cells.

Thanks for this info terjee. I have the Klarus CH1 (x2) for charging from USB, and the D4 seems to be going fine so probably worth going for an analysing charger if I'm going to get another?
 
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