24V system in a 12V car

[bigegg]

I bought a 3000W vehicle mains inverter for a very small amount of money.
Trouble is, it's 24V.

To power it, can I just add a 12V battery in series with my vehicle battery?

It's basically to demonstrate some electrical gear is working when I sell it at the car boot, so won't be used whilst engine is running.

 

[gaz1]

yes you can

a solar inverter ?

if you view down solar installs they build via this way

though i am curious if it is an inverter may i ask how much?

 

[Porkypine]

Wouldn't putting another battery in series in the car's system blat the vehicles electrics with 24v though ?
if just demoing stuff at boot sales would a seperate pair of fully charged batteries in the back of the motor not run the inverter for the short time needed ?

 

[hotponyshoes]

Wouldn't putting another battery in series in the car's system blat the vehicles electrics with 24v though ?
if just demoing stuff at boot sales would a seperate pair of fully charged batteries in the back of the motor not run the inverter for the short time needed ?

Not if you wire it (correctly) in series with the car battery.

 

[Kram]

You can connect the extra batt in series but the car electrics must remain as they are, with only your mains inverter running at 24v.

However, expect to get very short life out (short term and long term) of the batteries at 3kw drain, thats 125A. What are you intending to power? Is it a one-off, single item? or a regular thing, that you sell?

 

[bigegg]

You can connect the extra batt in series but the car electrics must remain as they are, with only your mains inverter running at 24v.

However, expect to get very short life out (short term and long term) of the batteries at 3kw drain, thats 125A. What are you intending to power? Is it a one-off, single item? or a regular thing, that you sell?

3000W because that's what it was - not cos it was the size I thought I needed, if you see what I mean.
Bought it on the spur of the moment.


It's just to run a couple of tellies, and 5 or 6 Henry vacs; long enough to prove they work

And it's a "one-off" car boot. Then I'll probably be selling the inverter

 

[bigegg]

yes you can

a solar inverter ?

if you view down solar installs they build via this way

though i am curious if it is an inverter may i ask how much?

It's a 2nd hand "truck" inverter, cost me a tenner.

 

[Seadog]

Not if you wire it (correctly) in series with the car battery.

Assuming a negative earth vehicle, connect the negative of the extra battery to the positive of your car battery.

 

[bigegg]

Assuming a negative earth vehicle, connect the negative of the extra battery to the positive of your car battery.

That's my plan.

 

[Red'n'Black]

Find out what the no-load input current is, it should be in the back of the manual. Or get a DMM and measure it. An inverter that size, it could be a couple of amps, which will deplete the vehicle battery if you leave it connected all day.

If you disconnect the inverter from the batteries when you're not demo-ing anything, it should be fine.

 

[CompoSimmonite]

It's a 2nd hand "truck" inverter, cost me a tenner.

Unless you have a suitable second battery you might find it cheaper to simply buy a 12v inverter than a battery

 

[Pigeon_Droppings2]

Just buy/borrow X2 12v batteries and run it all independently of the car?

I wouldn't risk 24v running tho my car...enough seems to go wrong already!

 

[bricol]

Just buy/borrow X2 12v batteries and run it all independently of the car?

I wouldn't risk 24v running tho my car...enough seems to go wrong already!

Jump lead from +ve of car battery to -ve of spare battery. +ve of spare battery to inverter power in +ve. Inverter -ve back to car battery -ve.

Inverter has 24V
Car has 12V - and unless someone turns up with spanners, no chance of 24v to car.

Although last century, a quick connection of car batteries in series usually got a stubborn car to spin and fire up

 

[bigegg]

Unless you have a suitable second battery you might find it cheaper to simply buy a 12v inverter than a battery

I already have a 12V "accessory" battery - but only the one, otherwise I'd just build a separate 24V system.
As you say, too expensive to buy a second battery. Especially for what will be a "one off" use.

 

[Pigeon_Droppings2]

Jump lead from +ve of car battery to -ve of spare battery.

Agree...but I wouldn't trust myself to not have a moment where I do something stupid with the connectors...or I'd forget and drain the battery and then be stuck.

 

[Pete.]

Agree...but I wouldn't trust myself to not have a moment where I do something stupid with the connectors...or I'd forget and drain the battery and then be stuck.

Easily fixed - just buy a 240v car charger at the boot fair and plug it into the inverter, use it to charge up the car battery. Should work

 

[dave h 2]

Perpetual motion, now why didn't I thi............. thud

 

[hotponyshoes]

Perpetual motion, now why didn't I thi............. thud

Nope. It's running from the energy stored in the car battery.
Should work fine.
No fundamental laws broken here..

 

[dave h 2]

Sigh