Plugging In Charger BEFORE Inserting Cells?

[AFAustin]

So, I am the proud owner of a new Maha PowerEx MH-C401FS charger for my AA and AAA NiMH cells, and I appreciate the good advice I received on this forum in deciding on it.

The online manual states: "Do not place batteries in the charger before powering it up."

Could someone please explain to me, as an electronics challenged person, why this is important?

Thanks.

Andrew

 

[välineurheilija]

I would also like to know this for lion chargers because i have seen on youtube that rewievers just put batteries in and out of the charger while its plugged in :thinking:

 

[Arm and Leg]

It differs on some chargers.
In my experience with almost all chargers, they don't work unless the battery is already inside.

 

[Kick]

My Maha MH-C9000 seems to go through a quick cycle of some sort when I plug it in. It displays all of the text and counts from 11.11 to 99.99 then turns the backlight off. I takes about 10 seconds. I just read the manual and it states to plug it in before inserting the cells.

 

[PhotonWrangler]

I can envision two possibilities -

1) The charger cannot control the voltage present on the charging terminals until it's fully booted up. This could be a precaution to protect your batteries.

2) Certain designs of semiconductor circuits are vulnerable to having voltage placed on the "user interface" terminals before the circuit itself is powered up. If voltage is present before the circuit has it's main power applied, it can cause damage to the transistor or chip that feeds the charging terminals.

 

[Mr Happy]

The online manual states: "Do not place batteries in the charger before powering it up."

Could someone please explain to me, as an electronics challenged person, why this is important?

I don't own that charger, but I do own other chargers with much the same instruction. I believe what happens is that when the charger powers up it goes through its test cycle where it looks at what cells are in the slots and decides what to do. I don't know what happens if you ignore that instruction, but for me it just seems convenient to put the cells in the charger and plug it in. There seems to be no need to fight what the manual says.

Follow instructions: everything works. Ignore instructions: maybe not. Why trust to luck?

 

[HotWire]

I have 2 different Maha chargers. I pretty much leave them plugged in and insert the batteries when I want to charge them. If you have a button that selects charge>rate of charge, I would not set that until the battery is in the charger.

 

[lightcycle1]

I was eyeballing a C9000 today. UI seems to be a PITA compared to the similar Lacrosse unit. And it doesn'T accept 18650's???
Cant understand all the love for the C9000.

The UI looks like a nightmare. Readout for only 1 cell at a time? The Lacrosse charger UI looks much more advanced. I dont understand the lack of 18650 capability .

Sent from my SCH-S720C using Tapatalk 2

 

[Kick]

The UI is actually real easy, you can just place the cells in, without pushing any buttons, and after 10 seconds the charger will start charging at 1000 mA . The readout will scroll through mAh, ma, time and voltage twice, then move to the next cell. You can also manually scroll to the next cell info just by hitting the button. The reviews on Amazon make it seem harder than it really is. I am very happy I bought this charger. As for 18650 cells, I have a Xstar VP1 on order.

 

[Russel]

I was eyeballing a C9000 today. UI seems to be a PITA compared to the similar Lacrosse unit. And it doesn'T accept 18650's???
Cant understand all the love for the C9000. [...]

The MH-C9000 is very easy to use, just install the AA cells and let it charge at the default rate. If you are charging AAA cells, you do need to adjust the charge rate down.

The MH-C9000 is a NiMH charger, it can't be used to charge Lithium Ion cells. I've never seen an 18650 NiMH cell.

 

[digitor]

You're right - the thing's totally useless - I tried charging my 12V 300Ah deep cycle lead acid battery with it today, and the charger exploded. I'm sending it back to Maha.

I was eyeballing a C9000 today. UI seems to be a PITA compared to the similar Lacrosse unit. And it doesn'T accept 18650's???
Cant understand all the love for the C9000.

The UI looks like a nightmare. Readout for only 1 cell at a time? The Lacrosse charger UI looks much more advanced. I dont understand the lack of 18650 capability .

Sent from my SCH-S720C using Tapatalk 2

 

[AFAustin]

Thank you, gentlemen, for your replies. I also sent an e-mail inquiry to Maha and if they reply I will post their answer.

Andrew

 

[TEEJ]

So, I am the proud owner of a new Maha PowerEx MH-C401FS charger for my AA and AAA NiMH cells, and I appreciate the good advice I received on this forum in deciding on it.

The online manual states: "Do not place batteries in the charger before powering it up."

Could someone please explain to me, as an electronics challenged person, why this is important?

Thanks.

Andrew

Hmmm, its sounds like you should merely be plugging it the charger before inserting cells to charge?

IE: "Power it up" = plug it in?

1) Plug in charger

2) Insert cells to charge

Its possible that reversing that would discharge the cells if there's no circuit to prevent it?

IE: A cell in a dead charger has its +/- on terminals, and, potentially, current could flow, draining the cell?

 

[Kick]

You're right - the thing's totally useless - I tried charging my 12V 300Ah deep cycle lead acid battery with it today, and the charger exploded. I'm sending it back to Maha.

I had to re-read that a few times, because I couldn't find a "sarcasm to english" translator on google. That was funny.

 

[donn_]

I've never seen an 18650 NiMH cell.

They exist.

 

[donn_]

Here's an 18670 NiMH.

 

[Mr Happy]

The online manual states: "Do not place batteries in the charger before powering it up."

Could someone please explain to me, as an electronics challenged person, why this is important?

Oh, I totally misread that before. Various chargers I have say to put the batteries in the charger and then plug it into the wall. The instruction above is the opposite. In which case I have no idea...

 

[Illum]

So, I am the proud owner of a new Maha PowerEx MH-C401FS charger for my AA and AAA NiMH cells, and I appreciate the good advice I received on this forum in deciding on it.


The online manual states: "Do not place batteries in the charger before powering it up."

My guess is that some chargers may require a reference voltage in comparing where the cell's SOC lies, and the reference voltage is biased by a regulator that is feeding off the input supply. If the battery is connected before the reference voltage, somewhere along the way the battery voltage is fed back into the circuit giving it an incorrect reading. From there the charger goes into a dead-reckoning mode that proceeds to charge the cell until the "correct" reading is reached. Years ago when I still had the DSD charger, I noticed that when charging moderately depleted li-ions [Vrest = 4.0V] the DSD behaves differently depending on when I put the battery in. If the charger is plugged in before I put the batteries in, the indicator light will read green indicating bulk charge completed. However, if I installed the batteries before plugging it in, the red light will light and the charger will "bulk charge" the li-ion until the protection circuit [thankfully AWs] cuts it off.
This doesn't occur for all the DSDs I've bought, but of the three I had, two exhibited this behavior. Now I don't use DSDs at all, I don't know if my DSDs were lemons or what?

 

[lightcycle1]

My Nitecore i4 charger says to plug in before loading cells. It runs through a brief cycle when powering up.
I'm no expert but powering the chargers up before putting batteries in makes sense to me. Id say the reference voltage theory sounds belivable. Voltage sensors need to be powered and in a ready state to read the installed battery voltages.

Sent from my SCH-S720C using Tapatalk 2

 

[välineurheilija]

My Nitecore i4 charger says to plug in before loading cells. It runs through a brief cycle when powering up.
I'm no expert but powering the chargers up before putting batteries in makes sense to me. Id say the reference voltage theory sounds belivable. Voltage sensors need to be powered and in a ready state to read the installed battery voltages.

Sent from my SCH-S720C using Tapatalk 2

Damn i have used it the other way putting the batteries in first oops :) but i havent had any problems.


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