Mygrid charger how does it work

If necessary he discharges Ni-Mh batteries to zero volts and then puts a dead short on them overnight before charging them back up to a full charge. Individual sticks of 6 cells that were in very weak condition were also brought back to life after sitting for long periods of time by cycling them. The IMA battery had self discharged to a total pack voltage of 0. After talking to the owner he allowed me to remove the battery and do rejuvenation at my house.

After two cycles the average stick voltage was The car is in very bad shape due to water leakage because the radio antenna base being sheared off in a hurricane, front bumper half ripped off and just general deteriation from sitting in the weather for many years. For that reason we couldn't actually drive the car to see how the battery would perform.

I would highly recommend reading this post of his and this one on how he sets his discharge current. When the battery pack voltage gets to 30 volts or lower during the discharge the current also be down in value. You may want to change the light bulbs to ones with a higher rated wattage when used at volts to raise the discharge current back up again. While eq1 discharges at quite a bit higher current than I use, I would shoot to keep the discharge at ma or so when going below 50 volts.

My idea is to give the chemical reactions within the batteries time to complete. Be careful when changing the bulbs. The bulbs may be dim at the lower voltages but they are still very hot if you change them without wearing work gloves.

I would turn the discharge off with the socket switch, wait awhile for the bulbs to cool off, change them to higher wattage bulbs and then start the discharge again to the final volt level for that cycle.

You will find the pack voltage rises quite a bit while waiting for the bulbs to cool off but the voltage will also go back down as soon as you resume the discharge. Storing a stick or a complete battery for a long time doesn't seem to be a problem. There is no danger of a cell becoming reverse charged by allowing a battery pack to self discharge for a long time with no load on it. Damage can occur by improperly charging a dead battery when starting to use it again.

IMPORTANT: When discharging the battery you must connect the grid charger to the charging harness so the IMA battery cooling fan can run while doing the rejuvenation since discharge cycles usually follow charging cycles. The battery will continue to rise in temperature for many hours after a charge so the cooling fan should be running even while doing a discharge.

The method I use to have an idea when it's time to stop the discharge is to record the battery voltage at the start and at each hour thereafter as the voltage drops to the voltage when you want to stop the discharge or discharge at. A weak battery may drop from to volts very quickly. So keep an eye on the voltage so you don't reverse charge many weak cells if you are discharging at high currents.

With a low current discharge the cells probably won't be damaged anyway with the fan running but why take a chance? By recording the volts per hour change as the battery goes below volts you can guesstimate how weak the battery is.

A quick voltage drop of 1 volt in 5 or 10 minutes is a sign of weak a cell s becoming completely discharged. Pay close attention to the battery voltage at that point if you are not discharging to zero volts. After you terminate a discharge the battery voltage will rise up to some higher value rather quickly with the load disconnected.

A weak battery discharged to volts will typically rise back to volts or more. A really good battery will not rise as much. It is permissible to start the discharge again to pull the battery back down to the goal voltage but keep an eye on the voltage because it will drop to your desired cutoff voltage in a shorter time after the initial discharge. I usually let the battery rest an hour with the IMA fan running to dissipate some of the battery heat before starting the next phase of a charge or discharge cycle.

Here in South Florida I usually don't have to worry about the temperature being too cool. The exact voltage will vary depending upon the battery temperature and charge current. A weak battery may show higher than volts due to higher than normal internal resistance IR of the cells. The higher the charge current, the higher IR voltage drop which will cause the total battery voltage to appear higher while charging.

As you can see there are a lot of variables when working with a cells in series battery. So it is important to not turn the cooling fan off while charging or discharging. If you use a 3 digit voltmeter you will not be able to see the slow 0. The typical charge time for a good battery may be 24 hours to 35 hours. The discharge time varies greatly and is determined by how much capacity the battery has etc.

A complete rejuvenation is going to take days to complete. But if you can get a year or two more life out of a weak battery it may be worth it. The money you save on gas can pay for a new better than OEM battery from one of the forum vendors. One Insight owner says he not only paid for the new battery by grid charging it but for the car too!

Return to Insight home page. This is an overall top view of the grid charger. The strip also is a mount for the 6. All the supplies are high efficiency switch mode type power supplies. The two LED driver supplies are mounted at an angle because that is the only way they would fit in the case.

This is a close up of the 6. The hold down strip also is used to mount the 12 volt, 2 amp power supply located in the lower left of this picture. One of the mounting screws for the supply is partially hidden and is located just above the small yellow voltage adjustment potentiometer.

There is a spacer located under each end of the LED supply hold down strip. This clamps the supplies in place and also helps to dissipate some of the heat they produce.

The hold down screw for the 12 volt supply is located on the right bottom of the supply below the green LED. The green and white heat shrink is used to protect the LED high voltage leads when the cover is placed on the case. This is the other end of the hold down strip showing the spacers and the screw that also mounts this end of the 12 volt, 2 amp supply.

The spacers are just hollow tubes that the mounting screw passes through. The PEM studs attached to the case are threaded for metric screws. The 12 volt supply has many holes in the cover for ventilation so it is OK to mount it against the case with its ventilation holes.

If your case doesn't have ventilation holes in that area space the 12 volt supply away from the case. The AC input wiring is on the left of this picture. Also shown is an end view of the 7 lug terminal strip I used.

All the output voltage wiring connects to the terminal strip or the green stand off which is the high voltage positive output terminal. This is a close up of the terminal strip with the high voltage HV wiring on the 4 left end lugs and the two 12 volt wires on the 2 right end lugs. The 5th lug is the mounting grounded lug. It is located under the green stand off terminal in this picture. A normal computer power cord is used. After these pictures were taken I installed a female 4 pin Molex connector on the "front" side of the case for the charging harness to plug into the charger.

A discharge 2 pin connector is also mounted on the front panel. The case is made of steel so you will have to find a way to cut the two rectangular holes for the LED meters. It took quite a bit of careful measuring to make sure the larger meter clears the fan. The fan fits into the clear area above the meter and to the left of the switches in this picture. The two calibration pots can be seen on the multi-meter.

The two white connectors and wires came with the meters. Return to top of this page Bill Of Materials. Description Vendor 1N, silicon diode 1amp, Vr Various suppliers 2 amp fuse, volt and holder Various suppliers, fuse holder bgmicro. Part of power supply case NE-2, neon pilot lamp Various suppliers Not absolutely required but nice to have Male line cord plug Part of power supply case Molex male 4 pin Any 2 pin connector rated for Vdc for discharger cable volt, ma LED current limited power supply Various suppliers Any tolerance value will work.

The difference is subtle but most constant current supplies wired in series will not track properly. Use whatever combination is cheaper at the time you buy the parts.

How to mount them is left up to the student. Sorry 'bout that. Use the pictures of the parts to find current vendors. The dual meter I used is also hard to now find on eBay. I have linked to another eBay vendor that seems to have the same volt drivers I used. Do not buy similar looking units that do not output volts DC. There seems to be many more drivers now that have either too high or too low a voltage range.

The total no load output voltage of the series connected supplies should be volts to volts.. With luck you can probably find the resistors and other small parts in the computer supply that you can use for the case.

I used a male 4 pin Molex white computer power supply connector cut from a cable adapter on the end of the grid charger cable. I used a normal Molex 4 pin female connector from a computer power supply cable on the charging harness from the IPU.

You can make a cable with 4 AWG 22 insulated wires and place them in insulated tubing instead of a dedicated cable. Use stranded wire, not solid wire. My charging cable comes out of a gap at the bottom of the rear right corner of the IPU case next to the floor of the car body. The multimeter reads current when the push button is released OUT and voltage when it is pressed and holds IN.

When that LED is lit, it means that there is contact with an adapter. Unfortunately, I had almost no luck using the adapter tips with the devices I tested them with.

The Slacker G2 would show that it was charging only every so often like there might have been a bad connection.

I also tried the USB tips both of them with a couple different Motorola phones that I have laying around. No luck with them either. That said, they all are using mini USB connectors to charge and they charge fine with my computer. So go figure…. But the sleeve did! These are flexible Black rubber type sleeves with a built in connection to the charging pins on the phone. You can see the iPhone sleeve above on the Right. It has a stand dock connector built into it.

The back of the sleeves have the same spring-loaded contacts as the Power adapter that stick out and touch the myGrid charging pad surface. The iPhone sleeve fit my iPhone 3GS just fine. The only down side is the somewhat ugly lump on the bottom that houses the built-in dock connector.

As soon as I dropped my iPhone on the base, it began charging. Charging seemed just as fast as when using a USB docking cable with my computer. An advantage of the myGrid is that you can charge up to 5 devices at one time. You might have a hard time fitting them all on the base though. I see the Duracell myGrid as a definite step in the right direction as far as wireless charging is concerned. But until that happens, the myGrid is a cool alternative if the adapter tips work.

Please keep your additional bulk cases out of my already limited carrying space. But I love your rechargable batteries and charge docks. More tiny parts to lose and more parts to buy to get the thing to work. Will it charge my Garmin? Has nobody here heard of Powermat? The initial tech is more expensive and does not inlcude tips, and only supports 3 devices, but it has much more device support in terms of jackets many smartphones and even the DS lite and DSi and the jackets cost less.

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Novel, Holborn, London. The cases aren't too bulky, but they're not particularly attractive compared to many of the cases designed just to protect your phone and look good. The iPhone Power Sleeve. You attach this to a clip with the charging adapter on; we were able to fit these onto all the devices we tried, including Android, BlackBerry and Windows Phone 7 devices, and even the ViewPad 7 tablet, although you may need to take off any case you're using.

You can attach the clip permanently to the back of your phone with the sticky pad supplied or just balance in place. We're not keen on sticking something onto a phone for good and if you do that you'll have to have one clip per device - but if you don't, you have to balance things carefully so the inductive connection between adapter and clip stays in place even when the weight of the device pulls against it. Magnets help and stop devices getting jarred off the mat but it's a little more fiddly, especially if you're trying to fit four devices onto the myGrid.

You can get four devices on if they're small enough we couldn't fit much alongside the ViewPad 7 because you don't need the whole phone on the pad, just the charging connector - but the connector does need to be flat on the pad. Power Clips: both mini and micro USB clips come in both orientations - and they fit snugly enough to keep on your phone if they don't get in the way of your case. Once you've dealt with the complexity of plugging in the adapter for a system that's supposed to stop you having to plug things in , the charging part is hugely convenient.

The reflective strips of metal on the pad make a connection with your device almost instantly and the blue charging light comes on and stay on until your phone is charged.