It's a "universal" size charger for NiCads and NiMHs with a switch for the type and it has slots for a 9V battery. The thing is it says 2.8 V 500 Mah and then like 15mh at 9.8 V. So okay that sounded normal. Yet both the 2.8 V slots and the 9.8 show ~14.60 Volts. It even charged a LiFePO when I had it in for like 2 mins. The question is why? Why would a company like Enegerizer make such a off spec thing? How bad is it for my NiMH's provided I don't overcharge them.? And the weird thing is even with all that voltage they don't get hot till they're almost done just like any other charger.
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Wtf is up with this Energizer battery charger?
- Thread starter joeyss
- Start date
Were there batteries in it when you measured? If not, you're measuring a no load voltage, which is basically a useless measurement. Don't charge lithium batteries in a NiCd/NiMh charger, they charge on a completely different process.
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I'm aware of that with the lithium. It needs 2 batteries and yes I did it when there wasn't one in a slot and I got 14 something. Doing it again while it was charging gave me the same maybe 14.3 instead of like 14.65. The fact that it's giving a 3.2 volt battery juice means it has to be more than 2.8. Very strange.
It's based around current limiting for NiCd and NiMh I believe. LiPo's I think like to be charged current first, followed by voltage. It's all based around total power really. Like you can run a 3V LED On 240V mains as long as you limit the current.
Fiddy
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As you load up the charger with a load (a discharged battery) the Open Circuit voltage of the charge will fall. What you want to do is measure the voltage across the battery while it is on charge and if you can measure the current as well.
Power lost as heat is given by: P=I^2R which means heat generated depends on voltage not current.
Fiddy's spot on.
Also, alot of these chargers pulse the current, sometimes 2x the rated charge current at ~50% duty, so measuring the just voltage can be very misleading.
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Putting 14V across a LiFePO will almost certainly blow something up or at least cause the current limit to kick in and drop the voltage down to the cell's voltage. You've measured something wrong. The LiFePO couldn't have been in the circuit.
Benm
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That is to be expected. This charger is intended to charge nimh cells mostly, and it will employ charge and perhaps even discharge pulses to gauge the internal resistance of the cells connected.
To see what its acutally doing would probably require a scope to observe.
Most importantly, however, is to note that these chargers are NOT suitable for lithium based cells at all. Doing so anyway could result in popping batteries and a fire hazard - use the proper charger instead!
To see what its acutally doing would probably require a scope to observe.
Most importantly, however, is to note that these chargers are NOT suitable for lithium based cells at all. Doing so anyway could result in popping batteries and a fire hazard - use the proper charger instead!
I decided to be brave and try and a small 400mah Lifepo4 , since those are much safer. I measured the charge voltage at 3.73 when the cell peaked at 3.63 and cut off ( it seems to be a protected one too since the charger led went dim.) I used a drill bit as the other battery. The cell was at 3.63 when i took it out and it dropped to 3.45. It's just a really weird charger. Does this mean I can charge Nimh and Nicad battery packs with it too then since it has some voltage detector?
