Calculating load from power tool batteries

[Iristocratmusic]

Hi all
I am calculating the expected ac load for our cabin ( off grid ) in country Nsw Australia.
Somethings are easy like
10 x 10w led lights= 100w

How about recharging tool batteries?
For example
1 x 4amp battery (18v)
How many watts will that draw to fully charge from depleted.?

 

[Iristocratmusic]

Also : how do you calculate iPhone and laptop loads?

 

[Rednecktek]

The bottom of the charger should list what it draws and the bottom of the battery will list the total Wh of the battery. iPhone wall warts are usually 10w unless you have the fancy fast charger and the laptop power brick will list input and output on the bottom of the power brick.

 

[SamDeleted]

Reduction Revolution Plug-in Power Meter

A must-have gadget. User-friendly power usage meter. Easy to read numbers and letters. - Geoff A. (Verified Buyer) Uncover Your Energy Guzzlers The Reduction Revolution Power Meter measures the energy usage and running cost of any standard plug-in appliance. Here's what it measures: Watts (W) -...

reductionrevolution.com.au

Get something like this and measure their kwh consumption in the real world , that's the best way

 

[SamDeleted]

the laptop power brick will list input and output on the bottom of the power brick

True but it doesn't show you real terms power use, my laptop power brick is 250w+ , but a full 8hr day uses less than a 1kwh

 

[Rednecktek]

True but it doesn't show you real terms power use, my laptop power brick is 250w+ , but a full 8hr day uses less than a 1kwh

Yes, but it gets you a number for calculations. If you estimate high it just means your batteries last longer.

 

[SamDeleted]

Yes, but it gets you a number for calculations. If you estimate high it just means your batteries last longer.

Haha yes that is a good point

 

[dcg9381]

I was wondering the same question the other day, wondering if I could use one of our car's factory inverters to run a Makita charger. I didn't see any good information on the draw of the tool charger. I'm estimating in the range of 200-300 watts peak.

It's going to vary depending on battery type and charger capacity/rate...

 

[HRTKD]

I was wondering the same question the other day, wondering if I could use one of our car's factory inverters to run a Makita charger. I didn't see any good information on the draw of the tool charger. I'm estimating in the range of 200-300 watts peak.

It's going to vary depending on battery type and charger capacity/rate...

The inverter in a car may or may not work with a battery charger. Some do, some don't. The inverter is usually a modified sine wave, not pure sine wave. So delicate electronics should not be used on it.

 

[Iristocratmusic]

The bottom of the charger should list what it draws and the bottom of the battery will list the total Wh of the battery. iPhone wall warts are usually 10w unless you have the fancy fast charger and the laptop power brick will list input and output on the bottom of the power brick.

Thanks … much appreciated

The bottom of the charger should list what it draws and the bottom of the battery will list the total Wh of the battery. iPhone wall warts are usually 10w unless you have the fancy fast charger and the laptop power brick will list input and output on the bottom of the power brick.

are you in Australia as well?

 

[Iristocratmusic]

Reduction Revolution Plug-in Power Meter

A must-have gadget. User-friendly power usage meter. Easy to read numbers and letters. - Geoff A. (Verified Buyer) Uncover Your Energy Guzzlers The Reduction Revolution Power Meter measures the energy usage and running cost of any standard plug-in appliance. Here's what it measures: Watts (W) -...

reductionrevolution.com.au

Get something like this and measure their kwh consumption in the real world , that's the best way

Thx… looked these up… v handy and correct plug for Australian. Have you used one of these.?
I’ll check what my appliances say as a rough guide… but one if these will precisely let me know.

 

[Iristocratmusic]

Reduction Revolution Plug-in Power Meter

A must-have gadget. User-friendly power usage meter. Easy to read numbers and letters. - Geoff A. (Verified Buyer) Uncover Your Energy Guzzlers The Reduction Revolution Power Meter measures the energy usage and running cost of any standard plug-in appliance. Here's what it measures: Watts (W) -...

reductionrevolution.com.au

Get something like this and measure their kwh consumption in the real world , that's the best way

Thx
To calculate my modem draw…
The 240v adaptor has 1.5v 1500mA
On it..
The modem has 15vac 1.0 amps
How do I calculate this? Per hour?

 

[SamDeleted]

Thx
To calculate my modem draw…
The 240v adaptor has 1.5v 1500mA
On it..
The modem has 15vac 1.0 amps
How do I calculate this? Per hour?

Volts x amps= watts

1.5v x 1.5a = 2.25w

15v x 1a = 15w

Then times 24 for a days consumption:
15w x 24hrs = 360wh

 

[SamDeleted]

Thx… looked these up… v handy and correct plug for Australian. Have you used one of these.?
I’ll check what my appliances say as a rough guide… but one if these will precisely let me know.

Yes I have one, the UK version. Takes out the guess work

 

[pollenface]

Best tool is an inline power meter. Like this

When I used it with an 18w LED bar it turned out to be 9.8w

1 x 4amp battery (18v)
How many watts will that draw to fully charge from depleted.?

Short of not having a plug in meter, rule of thumb is to calculate for 85% efficiency. 4*18/.85=84.7wh