Now Shipping : Da Pimp : Battery Charger, Desulfator and Tester

Holy Scrap's latest widget is now shipping. Meet Da Pimp which can be used to recover, test and charge several types of batteries (Pb, NiCD, NiMH). The first video is up showing a dead power tool battery coming back from 0V after years of sitting in my office neglected. This charger is up to 60% more efficient than transformer based chargers. It uses capacitors to provide a constant current of .5A from 120V wall power. Combined with a bridge rectifier the AC voltage is converted into DC charging voltages. Unlike classic wall wart plugs Da Pimp is silent no noise, no heat and it fits in your pocket (awkwardly).

At Holy Scrap we use Da Pimp to charge our golf carts, car batteries, irobots and power tools. We also use Da Pimp as a tester when harvesting batteries from the local auto parts stores as it can tell us based on voltage reading which batteries have the least amount of sulfation.

This is a open source hardware project with all design files freely available.


Now Shipping : Da Pimp : Battery Charger, Desulfator and Tester #2

Now Shipping : Da Pimp : Battery Charger, Desulfator and Tester #4


ad3155d4-a1b8-11e1-8014-000bcdcb471e said...

I've ordered an assembled Da Pimp for the express purpose of testing and hopefully recovering part of a pile of power tool batteries. If we save two or three the device pays for itself.

I also notice you use one to charge your golf cart batteries. We have cart we use to get around locally and I'm thinking using this would be a lot handier than the standard charger. Two questions - 1 Do you just monitor the charge level and disconnect manually when you get to about 40v (36v EzGo)? and 2 How do you make the connection to the cart battery pack, adapt to the standard charging plug or just connect directly to the most positive and most negative terminals of the pack?

Thanks. This looks like a smooth piece of gear, looking forward to its arrival.

Mikey Sklar said...


Sorry for the delay. This post got lost in my comments for approval.

Hows has your charging been going?

I do use Da Pimp on our golf carts. Usually I plug into the most negative and positive ends of the cart and manually shut-off around 40V. Since Da Pimp only puts out 500mA it takes several days to fully charge and there isn't a lot of risk of overcharge if you are checking on the pack each day.

T said...

My PIMP arrived yesterday :) I have charged one Roomba battery so far. I am charging another one right now. I waited until the display consistently read over 16.1 before using the battery in my roomba. However, I didn't check the reading without the power going to it. I guess I was too excited. I only got about 1 minute of Roomba usage. But that was an exciting minute as that battery was totally dead (read 0.0 when I first plugged it in to Da PIMP).

Is there a guide for using the PIMP to charge these batteries? Or can you give me a little hand-holding on how to best charge these batteries with Da PIMP?

I think I heard I was supposed to charge 20% over the 14.4V - is that right? So when I see 17.2 on the display (after I turn off the main big black switch) then the battery is done charging?

The battery I'm charging now jumps from 16 to 21 when both switches are on. What does that mean (if anything)?

Mikey Sklar said...


I charge my roombas several times a week with Da Pimp. It is normal to see the voltage initially spike well over 20% on a battery that has sat for a long time. It's okay to let it charge for a hour or so at a time like that, just watch for heat. You will actually see the voltage drop when you check-in during charging which is a sign that the sulfation is being removed (lower resistance) so the voltage does not need to spike as much.

Great job getting a 0v battery to come back to life (even briefly). It will continue to improve.