1. Wizard Universal Charger

Maha MH-C777Plus-II Universal Battery Charger & Analyzer© Brooke Clarke 2007usingclip leadsusingpogo pins to contact batteryBackgroundOne of my early battery chargers was the C777Plus. It looksverysimilar to the Plus-II. The Plus-II has a recessed RESETbuttonon the front panel that wasn't on the Plus and also behavesdifferentlyin how it works.The reason I got the C777 was that it could charge packs containingdifferent numbers of cells. Most chargers are made to chargeonly one pack configuration.

1. Used: Maha MH-C777-Plus-II Universal Charger. This is a charger that can be set up to charge and condition both the NiCAD and NiMH batteries for.
2. Maha MH-C777 Universal Charger Conditioner Instruction Manual. Maha Communications, Inc. And will be seen Bureau Philadelphia Regional Office thomas kerrigan artist stats injuries transactions TX. All your work via of the OSIGenentechRoche alliance. The two fan bases next time you want a tasty filet mignon.

User Manual - MH-C777 Universal Charger User Manual - MH-C777PLUS-II Universal Charger User Manual - MH-PBL52 Lantern User Manual - MH-C980 Turbo Charger-Analyzer.

Another feature of the C777chargersis that they can discharge. You can just let the C777automatically go into Quick Charge mode. The charge currentiscontrolled only by the Chemistry switch (800 ma for Ni and 400 maforLi) so the number of cells is not a factor in the current.Thecharge will be terminated when any of a number of things happen,eitherthe -dV/dt hits a trip point or there is a zero delta V or the maxtemperature is reached. (There may also be a peak voltagetermination).

This was a problem with the C777Plus andNi-MH, it always terminated with Err3 High Temp, not warm but hot. The -dV/dt charge determinationvaluedepends on the number of cells in the battery and the Peak Voltagecharge termination depends on the number of cells.When using Peak Voltage for termination the number of cells is afirstorder (major) factor. For example a 4 cell pack of Ni-MHcellswould be fully charged when the peak voltage was about 5.6 with nocharge or load and maybe a little higher, say 5.8 V while undercharge.When trying to understand the problem charging 4 eneloopcells held in a 10 AA battery holder where the discharge wasstoppedtoo soon and where the charge was stopped too soon and the 777firstgeneration unit was showing a voltage that was higher than itshouldhave been the effect of estimating the number of cells at 5instead of4 would be to over charge or over discharge. Maybe theproblemwas with resistance added by the battery holder?Do NOT charge9 V batteries! The charge current is 800 mA!Note three cells have poped open expanding the size of the packand blowing off the top.Battery ChargedThere is a soft beeping when the charger is finished and the LCDshows:BATT MODE NiFull05.6 V3450 mAh alternating with 238 minQUICKThe battery is warm but no hot and there's no error message.This is a big improvement over the first generation charger.These cells are rated 4500 mAh and had some charge in them so thedisplay is about right. Note that you need to put inmoremAh than the battery rating.

The normal C/10 charge for 16hoursputs in 60% more than the rating. So in terms of efficiencybatteries are not that good.Discharge then ChargeTo discharge just press the Discharge button, but it's good to waitforthe battery to reach room temperature first if it's hot. TheFull icon turnsoff and in the lower left of the LCD DISCHG is blinking.Discharge is about 300 ma for either battery chemistry so if thesecells are near 4500 mAh it will take 15 hours or 7 am tomorrow.I just pressed Discharge until the C777Plus-II started the dischargeand DISCHG was blinking.

This is the Discharge then Chargemodewhich was the only mode in the first generation unit. So thismorning the LCD is showing QUICK CHARGE and CHARGE isblinking.So I missed the discharge capacity.Analyze FunctionThis is new with the C777Plus-II. To enter Analyze you mustPRESSAND HOLD down DISCHARGE until the display stops blinking, about 3 or4seconds. You can recognize an analyze discharge since theDISCHGicon will NOT be blinking. When the analyze function gets toendof charge the LCD just stays in a state showing the capacity andtimeand does NOT automatically start charging the battery.TheLCD will continue to display the capacity even after the battery hasbeen removed.

This is a good thing because you may remove thebattery then realize that you haven't recorded the data. Toclearthe LCD and start another charge or discharge you need to press theRESET button on the front panel using a small screw driver or othertool. It's a good idea to recharge a battery after it's beenanalyzed.

It's not a good idea to put a discharged battery ontheshelf.14 Dec 2007 Noon - the charger beeped at the end of a chargewitha dispaly of: 5.7 volts, 476 min, 6,900 mAh. Pressing andholding Discharge for a few seconds resulted in a discharge icon ontheLCD that was not blinking and the voltage changed to 5.5 Volts. Observation: 476 minutes is close to8hours which would be 4 am instead of the 7 am I hadestimated.That's short by 3 hours which times 300 ma is 900 mAh.Sothe capacity was about 4500 - 900 = 3,600 mAh.Observation: the change in voltage is because of the totalresistancein the circuit which includes the short wires and alligator clips,contact resistances at all the contacts, the resistance of thebatteryholder and the internal resistance of the cells. So: (5.7 V-5.5V) = R. (300 ma + 70 ma) or R is 0.54 Ohms. 300 ma becausethat's the charging current and 70 ma because that's the tricklechargecurrent that's applied after a charge has ended. The twocurrentsare added because they have opposite polarity.

If you werewatching the voltage when a charge ended the voltage should dropbecause the charge current changes from 800 ma to 70 ma.At 20 minutes past midnight the 777 beeped a fewtimes. The LCD shows:BATT MODE Ni0 4.5 V0759 minutes alternating with 4377 mAhDISCHG is on solid and QUICK is blinking.Why the zero space then 4.5 Volts?759 minutes is 12.65 hours.3 amps = 3.8 Ah, yet the 777 says4.377 AH, why?Also the analyze was started at 12:20 and exactly 12 hourslater it beeped. 12 hrs.3 amps = 3.6 AH.12:30 pressed reset, removed a clip lead to clear error, resetagain and it's not on quick charge.15 Dec 2007 7:45 - FULL 5.4 Volts, 188 min 2743 mAhIt may be that the 777P2 is using some kind of pulse during charge,discharge or both and it that's the case the duty cycle would effectaclock time analysis.The Plus 2 version is much better at terminating the charge than thefirst oneRelated-LinksBack to Brooke's,an error occurred while processing this directive page created Dec 13,2007.

Maha MH-C777 Universal Charger /Conditioner Frequently Asked Questions:Primary SensorFunction-dV (NegativeDelta V) & dT(Delta Temp.)RapidCharge Rate650mAhTrickleCharge Rate40mADischargeRate400mAVoltageSupported4.8V, 6V, 7.2V,8.4V, 9.6V, 12VAuto voltage sensing.OverchargeProtectionSafetyTimerCharge TimeChargelisted battery packs with-in 1hour to 3hoursFrequently Asked QuestionsQ:I amhaving trouble conditioning/discharging mybattery pack. The green LED only shows for a fewseconds and then goes back to the charging mode.Is there something wrong with the charger?No.

This is a very common difficulty. Some modernbattery packs feature a diode protection at the'charging contacts', the metal contactsusually located at the bottom or back of thebattery pack for drop-in chargers.

The diodeprotection will prevent the drawing of power andthus hinder the conditioning sequence. To solvethis problem, simply switch to the 'radiocontacts' (the metal contacts locatedusually at the top or front of the battery packfor radio use). The radio contact can be used forboth charging and discharging.Q: My battery pack features more than twosets of contacts.

How do I distinguish thepositive from the ground?First, check the 'scale system diagram'at the back of your manual. It tells you the pinposition relative to the scale behind. If yourbattery pack is not listed, then sometrial-and-error is required. The best tool to dothis is a digital multimeter. When you get ahigh, positive voltage, then you have found theright contacts. However, if you cannot find anysignificant voltage, then your battery packsvoltage reading is blocked the one-way diode.

Wizard Universal Charger

Thecharger, on the other hand, has the ability todetermine contacts, even though your meter cannotread it. Simply try different combination ofcontacts on your battery pack with the chargingpins. When the appropriate contacts are located,the charger would initiate the charging sequence.Q: The charger seems to charge in a fewminutes, and the initial voltage indication showsa lower voltage Is something wrong with thecharger?This problem is usually caused by the batterypack. This situation occurs when your batterypack is 'over-discharged', meaning youhave drawn power from the battery pack too long.To temporarily solve this problem, you can chargefirst for about 10 minutes.

Then, remove thebattery pack and put is back again. To solve thesource of the problem, observe the following.Most modern radios have low voltage protection.When the proper indication shows on the radio,remove the battery pack immediately in order tocharge and preserve long life for your batterypack.Q: I have a 'battery case' thatconsists of 4 to 6 rechargeable AA NiCD/NiMHbattery cells. Can I charge via the MH-C777?Although the MH-C777 is not designed particularlyfor charging individual battery cells, this canbe accomplished. First of all, it is recommendedthat you obtain a clip-lead, part number MHS-CW4,that can interface with the charger and yourbattery case. When charging, make sure allbatteries are in equal state.

This means theymust be the same model, brand, capacity,chemistry, and voltage. A mix cell may causeextreme damage. In addition, in order to prolongthe life of your battery cells, charge batteriesfrom the same electronic device. Another words,do not mix two batteries from your remotecontrol, another two from a toy, and another twofrom your radio. They must be in equal state. Inaddition, the conditioning feature is suggestedin this arrangement.Q: Is there anyway, using the MH-C777, toanalyze the capacity of the battery pack?Yes!

Although the MH-C777 does not feature acapacity display feature, you can find itmathematically. The charger's discharge currentis about 400mA +/- 50mA. So measure the dischargecurrent first. Then, count the total hoursrequired to discharge the battery pack. Finally,multiply that by the initial charging current.For example, you discharged a battery pack at400mA for 3 hours. This would indicate a capacityof 1200mA.Basic FeaturesQ: The MH-C777 beeps continuously whenever Iinsert my battery pack.

What should I do?The continuous beep indicates a reverse polarityon the charger. Simply flip the 'polarityswitch' and reinsert battery pack toreinitialize charging sequence.Q: What particular lighting arrangementwould indicate a full charge?When the charge is completed, you will hear along beep. In addition, the indicator should onlyshow the rightmost red LED.Q: When I discharge my battery pack, thecharger becomes very hot. Is this normal?Yes. While discharging the internal load isabsorbing all energies and eventually released asheat. Between discharge / charge cycles, allowsufficient time for cooling.Q: What is the warranty?This product is covered by Maha's One YearLimited Warranty.'

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