Behavior of charger with non-independent charging ports

I'm sure I don't even have the terminology right. If I have a charger that has non-independent ports (e.g., the default Eneloop charger, which has two pairs of 2 ports), what is the behavior if I put in two batteries that aren't discharged to the same level? So I discharged one battery much lower than the other, and put both batteries side by side in one of the dual ports. Will the charger charge both batteries until either one is charged, and then shut off charging, leaving the other battery only partly charged? I know the right answer here is "get a Maha" or something like that, but until I do, I have a single Eneloop that I want to charge, but can't guarantee any other battery I charge it with will be discharged to the same level. I have exactly the same problem with two Tenergy Lifepo 16340s, which I run singly in separate devices, but (I think) I need to charge as a pair in the little Tenergy recharger.

Joe

One battery will reach full charge first, and it will be overcharged until the other battery is fully charged.

LiFePO4 batteries generally aren't charged in series...are you sure the charger won't charge one battery? What's the rated output on the charger's sticker?

Robin24k said:

One battery will reach full charge first, and it will be overcharged until the other battery is fully charged.

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Ouch. Just ordered a Maha.

LiFePO4 batteries generally aren't charged in series...are you sure the charger won't charge one battery? What's the rated output on the charger's sticker?

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Actually, you may be right, up until now I've always used my two lifepo4's together and charged them together. I am just about to split them up, and just assumed it was a dual charger. The charger's sticker says output is 3.6v 360ma. I guess I can always put just one battery in and see if the light turns green... It's tenergy's ph-123a-3.0 that I think battery junction used to bundle with the tenergy lifepo4s

It's normal for lithium ion chargers with slots to have independent channels for each cell, or to charge the cells in parallel (which is OK for lithium ion).

Robin24k said:

One battery will reach full charge first, and it will be overcharged until the other battery is fully charged.

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The reason this is OK with eneloop chargers like the MQN06 is that eneloops are very tolerant of being overcharged. Even if you overcharge them for hours at 300 mA they will be OK. Sanyo knows this and designed the charger accordingly.

Thanks, I've been laboring my way through the Maha thread, and am slowly coming up to speed...

I know the OP already bought a Maha, but I had the same issue (single-cell EDC light, series charger) and finally solved it with $7. It's the Rayovac PS19 charger from WalMart. It's a dumb, slow charger but can charge a single cell.

Eneloops might handle overcharging, but most of my cells are Rayovac 4.0 so I need to baby them.

Thanks ... I have no buyer's regret on the Maha, I'd planned to buy one for quite a while, to tinker around with all the modes and get my battery nerd on. That said, I'm quite certain that if straightforward charging of a single cell is the entire goal, I'm sure your solution is more cost effective