Old charger and Eneloop

edap617 · Jun 1, 2008

I just bought a 4-pack Eneloop without a charger. Can I use my old Sanyo NiCad charger without damage to the Eneloop? Here's the picture of the charger. Thank you.

Lynx_Arc · Jun 1, 2008

probably not, two problems with it... first the charging current would take almost a whole day at 140ma and second you would have to guess when to shut it off or overcharge your batteries most likely. I recomment getting a smart charger for nimh batteries.

Aluminous · Jun 1, 2008

Here's a general answer from http://michaelbluejay.com/batteries/charging-tips.html :

Old NiCd chargers handle only NiCd batteries. But most NiMH chargers handle both NiMH and NiCd. So if you have an old charger, you can charge only NiCd. If you have a new charger, you can probably charge either NiCD's or NiMH's.

Some chargers are dumb and just charge for a preset amount of time. As a result they almost always run too short (and don't fill up your batteries all the way) or they run too long and damage the batteries, shortening their useful life, meaning can't be recharged nearly as many times. These things are true even with charging NiCD batteries in a NiCD-only charger. But once you go sticking NiMH's in a NiCD-only charger it gets even worse:

If you put a discharged NiMH battery in a dumb NiCd-only charger then the charger will probably fail to fill up the battery, because NiCD's have a smaller capacity than NiMH's so the charger doesn't run as long as it needs to to fill up the NiMH. It won't hurt the battery, but you won't get a full charge either. In many cases you won't even get half of a full charge.

But what if you accidentally put a charged NiMH battery in a dumb NiCD-only charger? Then the charger charges it anyway, and since the battery is already charged then it gets overcharged, and probably damaged or ruined. It may even start a fire if it gets too hot.

There are also smart chargers which check to see when the battery is full and then stop charging. They can tell when the battery is full because the voltage actually starts to drop when more juice is pumped into an already full battery. The problem is that the voltage drop in a NiMH battery is harder to detect than with a NiCD battery, and most NiCD smart chargers can't detect the NiMH drop, so they keep charging anyway, damaging or ruining the battery, or maybe starting a fire.

Mr Happy · Jun 1, 2008

It looks like it can be used, but it is not ideal. From the pictures and description it charges batteries in pairs and I am guessing it uses a 140 mA charging current for AA size cells (50 mA for AAA cells). That is quite a low charging current, so I think it probably operates on a timer.

Although it is not normally advised to use NiCd chargers for NiMH, I think in this case you will be OK.

At 140 mA, it will take about 16 hours to fully charge a pair of Eneloop cells. If it stops charging before the 16 hours are up you may have to put the batteries back for a second charge.

If you can, you would do better to obtain a more modern charger specifically designed for NiMH cells, something like the Sanyo MQN05 for example, though there are many other chargers that are suitable.

Glasstream15 · Jun 1, 2008

I use the Energizer Family Charger for most of my batteries. Bottom left charger.

http://www.energizer.com/products/hightech-batteries/rechargeables/Pages/rechargeable-products.aspx

It is "smart" and each of its 4 bays is independent. Each bay will charge 1 or 2 AA/AAA batteries. $30 at Target. Charging and done readouts, but no "condition" settings. It does what I need on regular MiMH and LSD (Eneloop/Hybrid) and it also does a good job on some 4500 mAH D cells I have.

Handlobraesing · Jun 1, 2008

edap617 said:
I just bought a 4-pack Eneloop without a charger. Can I use my old Sanyo NiCad charger without damage to the Eneloop? Here's the picture of the charger. Thank you.

Not enough current. You want a minimum of 80mA / 200mA if you want to be able to charge in 16 hours.

An 120mA AAA/300mA AA charger should be able to charge fully drained eneloops in 8 hours.

edap617 · Jun 2, 2008

Thank you to all of you guys. I think I will get an intelligent charger as per your advice.

Old charger and Eneloop

edap617

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Lynx_Arc

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Aluminous

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Mr Happy

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