Ideas on best way to charge power tool batterys from truck?

What would be the best way to be able to charge power tool batterys from a vehicle,and continue to charge even with vehicle not running.

I assume I will need to add a second battery and some sort or solenoid? Just a plain inverter isn't going to work I dont think. As it would quit chargeing when key is turned off. Also I would need to protect the starting battery from going dead.

 

Yeah, inverter run off a second battery that's isolated is the best option.

 

Buy a really loud generator.

 

how many watts do you need?

 

A friend is a contractor. He has a whole section of his flatbed toolbox for charging about a dozen batteries, the chargers run off a converter.

 

Second battery, then put a splitter in from the alternator so both get charged when truck is running but the splitter is a 1 way valve that wont allow both batteries to drain. Then connect inverter directly to battery with a power switch. I did this for the stereo and lights on my ski boat. Worked great.

 

You should pick a deep draw battery.

If you want to go fancy (mindewe, you might have to do this) is to add a timer to protect your 2nd battery. The truck parked for a weekend will kill it over time.

 

Two batteries and a high current relay like this.

https://www.sonicelectronix.com/ite...MI9qbj94rm4AIV6h-tBh2dPgqPEAQYASABEgLBfPD_BwE

 

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Yes, I ride, and plan on doing an instructional trackday this season!

 

That's what I tell people all the time, if something needs fixed, I'll check the beeb because someone on there will know all about it.

 

1)Marine/Deep Cycle type battery
2)Battery Disconnect switch, to easily power down the system if needed.
3)Battery isolator to keep the starting battery and house battery seperate but charge both while engine is on, like this one
https://www.amazon.com/Smart-Battery-Isolator-Voltage-Sensitive/dp/B00400IYTK
4)Automatic low voltage disconnect switch (so you dont keep effing up your expensive deep cycle battery over the weekend) like this one
https://www.amazon.com/Galley-Power-LLC-Voltage-Disconnect/dp/B0147DYUN8
Edit..this one is probably to low in amps to run 120V chargers from, since its only 20Amps. Try something like this that has bluetooth control and 100amp continous rating
https://shop.pkys.com/Victron-Smart...7Q5aTkoNYLeOMtlIt9x1heTnR89LzDqAaAsaNEALw_wcB
5)Put a fuse here
6)120V inverter
7)plug in tool battery chargers

you now have an isolated deep cycle battery that will be charged when the engine is running, and the primary battery is full. It will power the 120V inverter thru a fuse and if it drops below the voltage you set on the disconnect, it will shutoff power to the inverter/tool batteries and not 'kill itself' by being repeatedly discharged too low.

if needed you can add a battery tender type plug in for charging from 120V if the engine cant keep the house bat full

 

I just finished such a project on my van. I used a simple 'bosch' style relay that powers on with the ignition to join the batteries. A diode will work to isolate, but diminishes your charging voltage by 0.7 volts. I used 14 gauge wire to join and put a 30 amp fuse on both ends immediately after the positive posts. Most any cheap 300 - 500 watt inverter should work. A deep cycle battery is best but a true red neck will not be able to resist the biggest, cheapest ($49) battery Walmart has in stock.

 

Some inverters, especially the higher end ones, have automatic low-voltage cutoffs built in.

 

You would think there would be an off-the-shelf solution, being that there are many folks probably looking for the same.

Vehicle battery? DC. Tool battery? DC, but maybe at different voltage. Avoid, if possible, DC-AC-DC conversions; very inefficient.

Let me ask some EE nerd friends that are familiar with low voltage components and see if something cost friendly can be built.

 

Dewalt has a 12 volt charger;
https://www.amazon.com/DEWALT-DCB11...walt+charger&qid=1551642856&s=gateway&sr=8-16

 

Can you draw me up an simple wiring diag. on how I would wire all this up?

 

This place is great!

 

I aint Toe.....

So I cant draw maps like Toe...and I dont have draw software...so ill describe it.

The battery isolator I linked is super simple. You dont have to run alternator wiring are stuff thru it. You run a cable from the positive of the main (starting) battery to where you mount the isolator. You connect this cable to Side 1 and ground it to the chassis. You then run a cable from Side 2 to the positive side of the house battery. Ground the house battery to the chassis. This switch senses how much voltage is between the main bat and the ground. If its below 13.4V (no charging) the switch stays open and you cant drain the house battery. If the voltage is 13.4V it can connect the 2 bats and charge both.

So now we have a way to charge and separate the 2 bats.

Like Beac said, if you buy a nicer inverter it will have a LVD. This shuts down the inverter if the bat goes too low.
If you have a cheaper inverter you run wire from the positive side of the house bat thru a seperate LVD. Then hook up inverter.

Now if you can find 12V chargers for your tool batteries, you can omit the inverter and be more efficient.

Plug in tool chargers and go to town...

How many chargers do you want to run? Any idea how many amps they run? This is needed to size the inverter or inverters.

More than likely you will need 4-6 AWG copper for this. Get solder on lugs if you can. Make sure the grounds are very good.

if you search for people adding second batts you can see pics of how people mount these things.

 

the remote control world have a gazillion chargers that will run directly of 12V lighter outlets for all kinds of batteries, save your inverter cost and complication, just attach a bunch of 12V outlets to plug them into, you will want the isolated aux battery though to avoid run your starting battery down.