charging/testing new AA NiMH LSD batteries

[scorman1]

Spent a lot of time on this site and with google search trying to find a conversation about LSD charging characteristics.
The advertising literature claims how long LSDs last in storage and having used AAA Tenergy Centura in TV remotes, I will agree.
Got a new Foxnovo FS-4 charger/tester and did a short writeup on Amazon mostly about Li-ion.

Just bought a set of (12) AA Tenergy Centura LSD rated at 2000mAh that were at a great sale price.
The charger runs in two modes ...when choosing 0.5 or 1.0 Amp rate for charging only, it will read out mAh to full charge at 1.42v.
When in test mode, it brings to full charge and then discharges at either 0.5A or 1.0A and measures discharge only under load, then brings to completely charged, and keeps the discharge measurements only.

So, although LSD are supposed to be delivered at full "pre-charge", most weren't. They varied from needing as much as 1200mAh to being nearly full.
First round of testing at 1.0A, produced measurements that were all over the map from 1100 to 2100..I was ready to send them back!
Second cycle saw significant improvement from >1500, while third cycle had all above 2100mAh and a few went to 2200mAh.
There is more than one review on Amazon that agrees with my measurements and some claimed readings of 2300mAh.
In conclusion...beat the specs and I am happy, but that isn't the point of this thread.

If these LSD are supposed to hold high % for long time, then why did I see such poor results as received?
Could the stock have been on the shelf for years?
Did the manufacturer not bother to precharge or cycle the new product at the factory?
In short, what conditions could enable such poor performance
Any comments would be appreciated.

So far so good and I will be field testing sets of four in scuba torches next week and will see how much drain after an hour or two at 0.70A rate (3.5 watt Q5 LEDs and they should last 3hrs) ...I will test them camping in the summer.

 

[SilverFox]

Hello Scorman1,

Welcome to CPF.

I believe most Low Self Discharge cells are delivered only partially charged. The idea is that they aren't totally discharged so you can use them (for awhile) right out of the package.

It usually takes a few cycles for cells to fall into shape. The Eneloop cells spoiled us by performing up to specifications right out of the package but that is not the norm.

Tom

 

[ChrisGarrett]

As Tom says, they're not charged up to 100%. When I started here the rumor was that the Gen.2 Eneloops/Duraloops were charged up to ~70% and by solar power, so they were greener to a degree.

It seems that the Eneloop XX/Pros/Duraloop Ion Cores are closer to 40-50%. Since we don't know the exact date of manufacture, it's tough to say.

I did a 1 year test on three popular LSD brands: Eneloop Gen.2 1500 cycles, GP ReCyKos and Imedions (Maha/PowerEx) and you can see the results here:

http://www.candlepowerforums.com/vb...ut-Eneloops-GP-ReCyKos-and-Imedions-it-s-done!

Here is a test for the Duracell 2000mAh DuraLoops (Gen.2 Eneloops?)

http://www.candlepowerforums.com/vb...year-and-one-day-Duraloop-AA-2000mAh-LSD-test

Eneloops lost ~13% after a year, the GPs ~17% and the Imedions ~32% and the DuraLoop 2000s ~14+%.

Chris

 

[MidnightDistortions]

They mass charge the cells quickly so they are not charged 100%, more like they are charged to 70% and they get weaker over time when sitting in the warehouse. Amazonbasics and Eneloops both put dates on their cells, i've noticed Energizer has done the same so it would give you some kind of idea how long they have been sitting. Eneloops after a year in storage has 90%, 3 years at 80%, 5 years at 70%. But that's only after you refreshed them a few times to get the battery working. I've seen some LSD cells low as 40% and your basic HSD cell at 0%. Precharged only means it's been charged at the factory and since they have to keep the production line moving they use the safest way of charging the cells, speedy but not too much to where they are overcharged/overheated. I think instead of them saying 'precharged' or whatever they should specify that they come in partially charged and should be cycled a few times if they have reduced performance.

 

[WalkIntoTheLight]

I think instead of them saying 'precharged' or whatever they should specify that they come in partially charged and should be cycled a few times if they have reduced performance.

Of course that would be a marketing disaster, so they'd never put that on the packaging.

In any case, from my testing with Eneloops, they don't really benefit from cycling to "break them in". They only gain about 2% capacity by cycling them once, and nothing from the second cycle. (I'm not including the first cycle or charge to bring them up from the partially charged state they ship in, which you should probably do but is optional if you don't care about a full charge.)

I don't know about other brands. Perhaps they do benefit from cycling a few times.

 

[MidnightDistortions]

Of course that would be a marketing disaster, so they'd never put that on the packaging.

In any case, from my testing with Eneloops, they don't really benefit from cycling to "break them in". They only gain about 2% capacity by cycling them once, and nothing from the second cycle. (I'm not including the first cycle or charge to bring them up from the partially charged state they ship in, which you should probably do but is optional if you don't care about a full charge.)

I don't know about other brands. Perhaps they do benefit from cycling a few times.

It's a double edged sword with that i think. People are going to think the company is false advertising because they say that the cells are precharged then they go back to using alkalines thinking that NiMH or other rechargeables are bad. Not to mention the 1.2 voltage cut off points for some devices that were designed to work with alkalines. There's some devices that say you should cycle the batteries a few times to get them working well which to me lets me know i should do that (even though already i know to do that anyway!). It's either that or the company will be getting a lot of defective batteries/products that are not really defective. I've seen reviews for Eneloops saying they don't come charged and they don't last very long when these people have no idea how to figure out what is really wrong with them and most of the time they don't care so they just write bad reviews and avoid the product.

Eneloops are high quality cells so i wouldn't imagine they needed refreshing when you first purchase them. I really don't know after several years in storage because i only have cells that are a year old. Other battery brands that are LSD tend to be weak and need to be refreshed several times upon purchase. I left some Eneloops i bought unused/untouched so i can perform a test on them when they're 3 years old to see for myself whether they need to be refreshed at all or they still have good performance on them. Other LSD cells like Energizer and the Goal Zero cells that came with the charger needed several refreshes before they at least had 92% or better capacity. Both sets were at least 2 years old already.