Charging a portable drill battery from 12 vdc system

[Tom&Shelly]

Nothing wrong with a charger that plugs into the cigarette lighter socket. I have been using them for about 3 years. Both milwauke and dewalt tools. I use the batteries to power my lights and roof fan , untill I can afford to get my battery set up in my cargo trailer.

Just saw this was an old thread. My bad

Your experience and thoughts are still relevant to me, thank you!

The only problem with resurrecting old threads is when it's done by spammers, since they don't have anything relevant to say, but merely offer well known (and possible wrong) advice (probably obtained via some AI tool searching the internet).

Tom

[Tom&Shelly]

You're correct that using an inverter to convert DC to AC for a proprietary charger isn't the most efficient way to go. Inverters themselves can lose around 5-15% of the power in the conversion process.
While there might not be a plethora of options for proprietary DC-DC chargers for drill batteries, there are some XXX available that can fit your needs. These are often designed to handle lithium-ion batteries, which you mentioned you have.

Another serial spammer who has managed to evade the admins so far. (No mention of DC-DC chargers on the site he links to.)

Tom

[bullchuck1]

To make things work I purchased a 20 volt - 12 volt reducer from Amazon for about $30.