"Jump-starting" 18v power tool battery...what else can I jumpstart with?


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Old 01-17-22, 11:41 AM
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"Jump-starting" 18v power tool battery...what else can I jumpstart with?

This weekend, I noticed that both of my Hitachi 18v batteries were dead. Actually, one is completely dead, the other will hold a charge for about 5 minutes. I see online there are suggestions to try and jumpstart the dead battery by connecting it to a good battery for a little while in order to get the voltage high enough to be recognized by the charger. Since I don't have a good battery, is there anything else I can substitute as a jumpstarter? I know I can just go buy a new battery/batteries, but wondering if there is another option.
 
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Old 01-17-22, 12:11 PM
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I've jump started the old nicad 19.2 volt batteries with my 12 volt battery charger before. Just a spark or two was enough to get it to start charging on the 19.2 drill charger.
 
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Old 01-17-22, 07:15 PM
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Thanks. I've seen some people say that the good and bad batteries need to have the same voltages. Any truth to that?
 
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Old 01-17-22, 09:42 PM
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You said one battery will hold the charge for 5 minutes. That means it will activate the charger and shouldn't need to be jumped for charging.

A completely dead battery will not turn a charger on. You need to be careful what you use to jump a dead battery pack. If it's lithium ion.... I wouldn't recommend jumping it all. You have to determine what the pins do on the pack in order to connect external voltage.
 
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Old 01-18-22, 05:56 AM
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You might want to check BISWAYE chargers. I took a chance a couple years ago and bought one for my old Craftsman drill that I just love, but the batteries were done and not worth buying new ones. The original batteries would no longer accept a charge from the original charger but were able to re-charge from the BISWAYE unit. The BISWAYE sent new lithium-ion batteries, but also were able to rejuvenate the dead original batteries enough that they are usable for a job completion. So, I now have 4 batteries, two lithium-ion and two originals. They all accept a charge.
 
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Old 01-18-22, 12:18 PM
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Thanks everyone. Yeah, I am a little nervous sticking wires into places and not knowing where battery acid may end up. But at the same time too, I kinda want to see if I can make it work.

Then, on the other hand, I have always wanted to make a switch to Dewalt as they seem to have better prices and options, and the prices of batteries are so high you can buy a new combo pack for about the same money.

But, I think I will try Norm201's suggestion. I don't see that Biswaye has Hitachi-compatible chargers, but there are other generics out there. Worth a shot, I guess.
 
 

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