** Tokyo Marui MP7A1 CHARGER WARNING **

[MadMax]

Nope, I'm wrong. I mean I was right...

120VAC is a RMS specification so my power calculation should be correct. However I was wrong in stating that appliance specs are supposed to be in Vp-p. 120VAC(rms) is 170Vp-p

[Syphen]

Well, it shouldn't be TOO bad to use that charger, but it depends on the type of transformer that it uses. You can tell by lifting the brick part (the part that plugs in) and its weight. The heavy bricks are transformer based, all they are, is a set of coils changing 120vac into 12vac and then into DC through a rectifier. There is 'smart transformers' too, these power bricks are usually light weight and contain little circuit boards with voltage regulation. If its a smart transformer, it would probably not be an issue at all to use it. If its a transformer then you could have some issues depending on the power at your house that your plugging into because your output will always be a direct ratio to your input.

The BEST solution, if your worried, is to look at the output of that power brick and go get a 120/240 power brick with the same output specs and just cut off the old one and replace it with the new one. I don't see why people are working this out to be a HUGE issue, hell just cut off the wires to the adapter and use your regular charger, thats what I would do. Just lop off the charger brick and strip the two ends of the wires and throw on a large tamiya connector so I could charge with me fancy smart peak charger.

[JourneyMan]

That 2-3% is a conservative estimation of what you would observe when using this charger. I did zero math to find that number, I just used what I see to guesstimate. My guess is that since it has peak detection(I have tested it), it also has some form of voltage regulation, since when I charge my dead batt to full, the charger is very warm and the batt is a normal room temperature. Doing the math says that at 300mAh, you will charge your 200mA batt in 40min; since sometimes I charge in a little less than that I guessed it charges a little faster, but that could be an observational error, since I don't precisly dicharge the thing.
Bottom line, the charger is fine, as time has shown. Nothing to fret about.

[Blastyman]

Well when I get mine i will use the charger till it craps out so you guys will have more data to work with. =p

[MadMax]

Can anyone translate this label?

I have a feeling that the third line doesn't mean: "Happily eats hairy Gaijin non 100VAC without harming".

[MadMax]

Well, I'm pretty sure the G18c charger is not designed for 120VAC input. I opened mine rather non reversibly. Initially I imported this for retail, but realized that I couldn't because it does not have CSA or UL approval. The 100V warning is also an indication of non compliance.

What I find inside is not very surprising. A step down transformer connected to a timer circuit. The timer IC is CD451be which is a fairly simple timer IC branded by Texas Instruments. It controls a PNP transistor to start and end the charge cycle. There is NO voltage measurement circuitry to be found (hence no peak detection). Furthermore, I see no evidence of voltage regulation downstream of the transformer which means no ability to regulate input voltage to the charge circuit. I see some thermal overload protection on the transformer core, but I don't know if it's resettable or single use.

Journeyman: you made some pretty broad claims without observations or calculation. Engineers cannot make justifiable claims without good backing.

[Blastyman]

Originally Posted by MadMax

Well, I'm pretty sure the G18c charger is not designed for 120VAC input. I opened mine rather non reversibly. Initially I imported this for retail, but realized that I couldn't because it does not have CSA or UL approval. The 100V warning is also an indication of non compliance.

What I find inside is not very surprising. A step down transformer connected to a timer circuit. The timer IC is CD451be which is a fairly simple timer IC branded by Texas Instruments. It controls a PNP transistor to start and end the charge cycle. There is NO voltage measurement circuitry to be found (hence no peak detection). Furthermore, I see no evidence of voltage regulation downstream of the transformer which means no ability to regulate input voltage to the charge circuit. I see some thermal overload protection on the transformer core, but I don't know if it's resettable or single use.

Journeyman: you made some pretty broad claims without observations or calculation. Engineers cannot make justifiable claims without good backing.

ok in this case I will just use my regular charger instead as it will be better for the battery.

[ILLusion]

I have an insanely expensive Systema charger. I think I'll use that instead and not worry about this silly fried charger/battery nonsense.

[MadMax]

I'm tempted to unwrap a bunch of winds from the secondary coil to adjust it to the necessary ratio. Not that I like timer based chargers. It's just a shame to throw away something which made for a nice integrated electric pistol package.

[JourneyMan]

*coughelectricalengieerstudentcough*

Well if its your day to day job, I sure will trust you experiance over my inexperiance. I never really pulled anything about, just took for granted that after 6 months the thing was probably fine. Now I feel the need to look more closely at these things.....

[Mulitkikr]

*cough not an electrical engineer, just a student.* Oh ya *cough*

[JourneyMan]

Originally Posted by Mulitkikr

*cough not an electrical engineer, just a student.* Oh ya *cough*

Lets see you do electrical field problems :-x

Alright, so I've learned to get off my lazy ass and pull the damn piece of equipment apart before I try to guess whats its doing, I won't this mistake twice.

My charger has not malfuntioned in 6 months. End of my contribution.

[nic_s]

I'm still confused. Is it safe for me to use my TLP charger on the MP7 battery?

[Blastyman]

Originally Posted by nic_s

I'm still confused. Is it safe for me to use my TLP charger on the MP7 battery?

yes. I am pretty sure the TLP is capable of 7.2v

[nic_s]

Sweet, this will simplify things a lot. Plus, I figurea a charge should only take 20 mins or so with the TLP.