12VDC to 18VDC Hard wire tools through the charger

I am working off grid and I want to run 18V tools directly off my deep cycles I have powered by solar. I have a few dead ryobi one batt. laying around that I could open up to use. My question is can I use a 12V DC charger for the 18v batts to power an 18v grinder? I would gut the batteries and wire the two together put one in the charger one in the grinder. Too much amperage for the charger?  

Comments

[Jack A Lopez]

Have you tried simply connecting one of your 18V tools to your 12V deep cycle battery? If you have not tried this, you should. Then see if the motor still turns at a speed fast enough for you do any useful work with it.

Regarding the question of how much current does your tool draw when loaded:   Why don't you put an ammeter in series with it, and measure the current, with the tool under load? 

Then you'll know how much current it draws, and you'll have some idea of how beefy of a DC-to-DC converter you'd need.  That is if you actually want/need to convert up to 18V.  Like I said before, the performance from just a stiff 12V supply, like a large deep-cycle battery, may be adequate.

[clow57]

Can anyone tell me the max amp draw I am looking at for say a 18v drill under heavy load?

[steveastrouk]

20-30A quite likely

[seandogue]

(removed by author or community request)

[clow57]

What about using a dc to dc step-up converter? If at all possible I would like to do this without having to switch between series and parallel on my batteries all the time.

[steveastrouk]

No way to use your charger, it can't produce enough current to run your tools. I'd use your deep cycle batteries, though you'll have to tap one of the internal bus bars to do it.

Steve

[Re-design]

I8 volt tools need 18 volts. The 12 volt charger won't run them with any power if at all.

[clow57]

Sorry let me clarify, the charger is for 18 volt batteries but it runs off a 12 volt battery through a cigarette lighter. I want to find a way to jump up from 12 VDC to 18 VDC to power the tools. I want to do it on the cheap, and I figured the charger should be putting out a little more than 18 volts to charge up the batteries.