** Tokyo Marui MP7A1 CHARGER WARNING **
 

Hey Guys!

Will here from Specarms Airsoft.

I just wanna post this up as a heads up for everyone purchasing TM MP7A1's.

As far as I know not too many Retailers out there have these in stock yet, so most retailers haven't even touched / used one of these yet.


I had a friend call me today inregards to the TM Charger that is included in the package.

On the back of the charger it specifically states Input: AC100V 50/60HZ 7.5VA.

Now in North America our wall plugs are AC110V.


Yesterday, my buddy fried his charger already, only after a few hours of owning the item.

So, head to your local Radio Shack and buy a convertor for your MP7's.

I hope this hint helps out other retailers because i KNOW that some people will come back kickin' and screamin'

Thanks for the heads up! I'm sure people will benefit from this! :tup:

Reading on Arnie's you can just clip off the wires, figure out what's + and what's - and then shove it in the charger that you use for your normal AEG batteries (assumption that you aren't using a crap wall charger)

At least that's what the European people are doing to cope with the problem.

lol, thats no problem at all.

All AEP chargers are rated to 100v, and mine certainly hasn't either craped out or overcharged. Just read mine, word for word says AC100V 50/60HZ 7VA, and the output is DC7.5v 300mA. Maybe he got a bad charger.

That's excellent logic you're spinning there;

By the same reasoning, my car's gastank is "rated" for 40L, so I should be able to magically force 10% more gas in for 44L.

With the limited electrical background I have, I'd wager that the guy got a bad charger. They should be able to take the 110-120V we have here. It's surprising that this is the first report of this supposed "problem" we've heard so far. Anybody else with an MP7 wanna chime in?

My TM Glock 18c AEP 7.2V Micro Charger reads:

Input : AC100V 50/60Hz 7VA
Output: DC7.5V 300mA

And yes, mine works fine on 110/120vac.

Actually very true on the G18C AEP point.

Let me ask my battery supplier his opinion on this, he's much more knowledgable about batteries/chargers than I am.


There could be a possibility that he did receive a crapped out charger, in that case i scared all of you for no reason :smack:

This is the perspective from an electrician (me). The charger will take the 100-120 volts and step it down as ratio, lets say 12:1. that means if the charger gets 120 volts AC from your wall it will pass through a transformer and be stepped down by a multiplier of 12 (just an arbitrary number, but sufficient for this explanation) to give you 10 volts AC.

This 10 volts AC is rectified to give you 10 volts DC, which is now suitable to charge your battery (neglecting for now other electronic parts like voltage regulators, FETS, etc.)

If you input 110 volts to your charger, the ratio of step down remains the same (12:1) to give you a charge voltage (no load) of 9.167 volts. A little lower, but no biggie.

If you input 100 volts, the new charge voltage will be 8.33 volts.

The ratios I used are arbitrary and are not necessarily what Marui has designed for their charger. But you can see how varying input voltage will affect your output charge voltage.

The reverse however, is also true. If this charger was designed to give 9.6 volts at 100 volts input, increasing the input voltage will also increase the transformer output voltage. A smart charger will not usually be affected by this increase as they usually have some voltage regulation to counter these changes.

If you increase the voltage to the battery during charging, it MAY cause a problem such as increased heat generated during charging. Under really extreme circumstances, like high ambient temperature or excessively long charging time, damage MAY occur to the battery.

The case that Will brought up may be the result of a dud battery, or other conditions not mentioned.

So... if I use my Fuzzy Logic TLP charger on these batteries, I should be OK. Right?

Why yes, it is excellent logic, because I happen to be an electrical engineer. :-x
I will charge slighlty faster that rated, but by slightly I mean possible 2-3% and since it has peak detection you should have no worries.

That's what I was thinking as well. The diffrence from 100 to 110 shouldn't be enough to fry the guts of the charger. Quite strange.

I stand corrected! Just how much of a voltage difference would it be able to stand then?

As a rule of thumb, around 10% either way can be had with little change in the effect. Most households in the US and Canada don't have a perfect 110v system anyways. My house for instance was build ~40 years ago and uses an older, different wiring standard, and as such we get about 104-105v. Doesn't make too much of a difference. The charger system acts as a transformer to step down the voltage and then provide steady current at a rate of 300 mAh. The end result from starting with a higher voltage before stepping it down is that it will carge at a ever so slightly higher mAh. Its a 200mAh battery on my AEP and it charges in about 40 min, just like its supposed to.

The final answer is than I and many others have had AEPs for months with no major disasters, and even the retailers say its ok:
http://redwolfairsoft.com/redwolf/pr...p?prodID=16773

Ouch. That's a silly mistake for TM to make. Japanese mains are 100V. I would have thought that they would have manufactured product for the export market which could handle 240/120VAC.

The little "brick" charger that comes with the G18c appears to be a transformer type adaptor. Not one of the nice new switch mode power supplies which often include universal input circuitry. I would not recommend using it at North American mains voltage.

Transformer type adaptors rarely come with peak detection circuitry for cost effectiveness. I would guess that they use a timer instead. IRC, the output from transformers tends to be more noisy than high frequency switch mode regulated supplies which makes them less amenable to peak detection in the same package.

I don't know where you get 2-3% increase in charge rate. If the input voltage is increased by 20%, the subsequent open cct output voltage is also increased by 20%. IRC the ratio of the battery's internal resistance and the impedance of the transformer will not vary by charge rate at the beginning of charge. This means that you can expect 20% more current flow during the first half or so of battery charge.

20% increased voltage and 20% increased current corresponds to 44% increased power (voltage*current). I would guess that TM wouldn't release a power supply with less than 100% safety margin, but 44% certainly does eat into that margin significantly. Extenuating circumstances like poor airflow or plugging into a power bar crowded with overheating bricks will reduce this margin further. I also note that the G18C brick is manufactured in China. I wonder if it is properly specified.

As a side note, we may be confusing Vp-p and Vrms in this discussion. In general Vp-p is used in discussions for appliance and accessory specifications. Actually I'm not sure if my calculations are correct. IRC I have to convert to Vrms if I want to work with power.

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

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.

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.

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

Can anyone translate this label?

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

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.

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

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.

*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.....

*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.

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

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

Wow, good thing I read this thread since my MP7 came to me today!

I found a fix for the charger I cut off the power adapter from the cable and put the cable ends for the cradle into my existing charger. Just let me try it overnight first if my battery explodes I'll let you know.

Well S.W.O.R.D. airsoft fixed the problem.

Basically it involves a little brain power, some common sense, wire cutters, a charger, japanese speaking friend and some luck.

The positive side or RED is the side with the japanese labeling.

We hooked ours up to the TLP charger and its working great.

See pictures and guide for our fix @ http://www.swordairsoft.com

Link to our fix with pictures!
http://www.swordairsoft.com/index.ph...opic&p=150#150

Nice, thanks a lot.

Direct "fix" from marui:

http://www.wgcshop.com/pcart/shopper...TM-CHR-500MAEX

thats the same charger I got with my MP7 I got it on march 17 and have charged probably 10 times, not a problem.

110-100
 

oh man I hope this isn't an old thread.. i dont need another warning...

but I believe it would be a bad charger, because i have brought back electronics from japan when I was there and vice versa, brought cell phone back and charged it a whole buncha times and it didn't fry in fact its still working, problem with it is it doesn't work on our networks i just charged it back to show people the pics I took on it. Brought back sony md player recorder thingy.. and that thing charges fine.. still works after 2 years of use. now this sounds stupid but i brought my OLD digi cam to japan and that changed fine and i got back and it still works. 100-110 shouldn't be that much of a difference. I brought back some other stuff like oh laptop... sony vaio..

yes by the same reasoning i guess your cars gas tank would be a problem.. but perhaps it defies logic lol.. ask david blaine... i becha he could do it.. =]

Most cell phones come with switch mode powersupplied chargers. They don't have the usual fixed ratio transformer which is designed for a particular voltage input. Switch mode supplies are often compatible with various input voltages and frequency.

Here's a better solution that I did as soon as I opened my MP7...

Chopped the battery connector end of the charger off the wall wart, soldered the leads, figured out which one was positive and which one was negative and now I just stick it in to my Systema battery charger for fuzzy logic computer controlled charging. Infinitely better than the wall-wart solution.

Charger is fine on mine no problem.

now that's what I wanted to hear :razz: I want to get one and I hope it will have the same results :-D

Hello People
 

Hi I am not exactly new with airsoft I am just new to this site Um I have been in airsoft for about 1 year and I just gor a Airmag M50 (mini uzi co2 cartridge powered 350 fps) do you think this is a good gun for a all time gun (not a back-up gun, I have a Walther P22 for a backup gun)? Thanks :)

yeah , that's a very good place to post. ( big sarcasm )

post in the correct section plz and be sure to know that we hate soft air cheap guns.

can somebody shove a multimeter and in their plug with nothing else in the room on? my electronics teacher from high school said something about the plugs and 112 or 117 constant volts. i can't remember if it was the plugs in the house or in the power lines.

A lot of Li-ion/poly battery electronic devices like cell phones, digital cameras, MP3 players, and laptops have switching power supplies with active power factor correction rated at 100-240V 50/60hz which I believe will work in every country with a simple physical connection adapter (no conversion circutry, just strictly the type of plug). On the other hand, a lot of cheaper AC/DC adapters, generally for less expensive products have specific power requirements. Clearly when they say 100V, they mean 100V. Because of electric standards and certifications, the power specification written on a product is correct. This way, they cannot be held liable for people putting 110V into a product rated at 100V input. Regardless of whether the charger works on 110V or not, that doesn't change the fact that it is designed for 100V and cannot be expected to perform optimally at voltages except 100V. Whether "optimally" means that some units fail at 110V or not, it is undoubtable that it is safer to NOT use this device on 110V outlets.

I've done about 3 full charges on my MP7 so far, and no problems

oh phew, thanks for posting this, i just bought one for my cousin, now i have to go buy a converter as well, Thanks Again For This Heads-Up! Saved Me!!!

hey can i order from hobbytron?

is this the same with the tm glock 18c aep?

yup

links dont work

Does this charger problem affect the TF7 clone? (Tactical Force 7 Clone with the same gearbox as the TM7)

Look at the charger description, see what the voltage is.

BTW you should invest in a better charger.

Lol, when I get the gun, I'll look for a better 7.2v battery. Heck, I'm buying this plastic beast instead of a kraken.

Okay... So do I get a converter to make the charger 100V? Am I reading this right?

I'm kinda sitting low here, just saw this today, a month AFTER my Tokyo Marui mp7 AND charger fried.


Kinda pissed off

Words cannot describe my confusion when I read the OP without checking the date.
"I know the TM MP7 is new and all, but it needs a charger now? What kind of GBB is this?"