This review is from: DEWALT DCB090 12V/20V Max USB Power Source (Tools & Home Improvement)
The current drain can be a problem. I measured the current drain with a meter. The charger draws 2mA when connected to the battery pack and not in use. With this current drain it will take forty-days to drain half of the charge from a 4AH battery. The charger has a microprocessor that will protect the lithium battery from full discharge damage by reducing the drain current to nearly zero when the battery voltage drops below a safe level.
Despite this shortcoming I love the Dewalt 20V lithium family of tools and this charger. I bought a couple more chargers after buying and dissecting the first one. I bought one for my wife so that she can share my passion for Dewalt battery powered tools. However, I did modify the internal circuit so that the current draw drops to zero when the charger’s output current drops to near zero. The modification includes a circuit (brassboard) that senses when the switching regulator goes into low power mode and then fools the microprocessor with a false low battery voltage signal thus bringing the current to zero. With this arrangement the charger goes to ‘sleep’ after the phone/pad is completely charged. I also boosted the output current to about 2 Amps and added a LED to indicate that the charger is on and providing power through the USB port.
I would be glad to share this modification information free of charge to Dewalt or an interested Dewalt fanatic that is handy with electronic circuit construction. The modification requires electronic components such as a transistor, a diode array, a LED, capacitors and resistors. Surface mount components are preferred due to space limitations. Leave a comment if interested and I’ll check for posts periodically over the next few months.
Help other customers find the most helpful reviews
This review is from: DEWALT DCB090 12V/20V Max USB Power Source (Tools & Home Improvement)
I expected a two-port USB power supply powered by a huge Li-Ion battery pack to have the ability to charge at a high rate.
However, once you get the product, you find that it is limited to 1.5A for BOTH of the ports. You can’t even charge a single iPad at full 2.1A rate, let alone two modern cellphones at 1.0A each.
1.5A simply isn’t enough current for this kind of device. Other than basically being a 1-port worth of power device, it does do its job. The power LEDs indicate state of charge of the battery pack when you first connect it, then shut off to save power after a few minutes.
Help other customers find the most helpful reviews
This review is from: DEWALT DCB090 12V/20V Max USB Power Source (Tools & Home Improvement)
I really like this product it’s a really good idea it’s very convenient on the job-site or when traveling to have them in a backpack.
I would love to give this product given 5 start but it’s not an excellent idea it need some improvement. Well the problem with this product is that when it remains locked in to the battery it’s draining the battery even if you do not have any device connected to it.
It would be great if they would add a on and off button feature onto the device.
Help other customers find the most helpful reviews
An electrical engineer’s opinion,
Despite this shortcoming I love the Dewalt 20V lithium family of tools and this charger. I bought a couple more chargers after buying and dissecting the first one. I bought one for my wife so that she can share my passion for Dewalt battery powered tools. However, I did modify the internal circuit so that the current draw drops to zero when the charger’s output current drops to near zero. The modification includes a circuit (brassboard) that senses when the switching regulator goes into low power mode and then fools the microprocessor with a false low battery voltage signal thus bringing the current to zero. With this arrangement the charger goes to ‘sleep’ after the phone/pad is completely charged. I also boosted the output current to about 2 Amps and added a LED to indicate that the charger is on and providing power through the USB port.
I would be glad to share this modification information free of charge to Dewalt or an interested Dewalt fanatic that is handy with electronic circuit construction. The modification requires electronic components such as a transistor, a diode array, a LED, capacitors and resistors. Surface mount components are preferred due to space limitations. Leave a comment if interested and I’ll check for posts periodically over the next few months.
Was this review helpful to you?




Provides basic USB power, but at limited current,
However, once you get the product, you find that it is limited to 1.5A for BOTH of the ports. You can’t even charge a single iPad at full 2.1A rate, let alone two modern cellphones at 1.0A each.
1.5A simply isn’t enough current for this kind of device. Other than basically being a 1-port worth of power device, it does do its job. The power LEDs indicate state of charge of the battery pack when you first connect it, then shut off to save power after a few minutes.
Was this review helpful to you?







Good idea but not excellent.,
I would love to give this product given 5 start but it’s not an excellent idea it need some improvement. Well the problem with this product is that when it remains locked in to the battery it’s draining the battery even if you do not have any device connected to it.
It would be great if they would add a on and off button feature onto the device.
Was this review helpful to you?






