12V Inverter

MammaZita

Looking to buy a new inverter as our previous one fell and broke.

It would be used for watching tv/DVDs and ocassional emergency phone charging.

I've only become aware there are different sizes. Any recommendations for one strong enough for our usage yet won't unnecessarily drain the leisure battery? Pretty clueless on these things!

odds_on

MammaZita wrote: »

Looking to buy a new inverter as our previous one fell and broke.

It would be used for watching tv/DVDs and ocassional emergency phone charging.

I've only become aware there are different sizes. Any recommendations for one strong enough for our usage yet won't unnecessarily drain the leisure battery? Pretty clueless on these things!

A 300W inverter would dfo you - well, it does me. I run a 12 TV (actually a 240 v with a 12 v converter as it was manufactured to be a 12 volt set) and a 12v DVD player. I also run my laptop and can charge various things like phone, MP4 etc. using the laptop, I find the battery gets discharged less if I just run on the laptop battery and then recharge the laptop. Running the laptop directly off the inverter runs the leisure bank down to 80% (or something like that, the inverter has a volt detector which sounds a warning when Leisure bank is low) in about 5 hours.

I first tried to buy one in a Halfords store, but after waiting 5 minutes for someone to take the cash, I gave up and walked out. I then bought a 200w (which should have been good enough for my laptop) from Argos which cost about 45 euros but it wouldn't run my laptop so it went back. I then got one on Ebay 300w delivered within a week and cost about 21 euros delivered.

odds_on

odds_on wrote: »

I also run my laptop and can charge various things like phone, MP4 etc. using the laptop, I find the battery gets discharged less if I just run on the laptop battery and then recharge the laptop.

There's no way a lead acid runs down faster just powering a laptop than powering a laptop with a charging battery. Even it you turn off the laptop and let the laptop battery charge it'll still cost you more energy. Charging a battery from a battery compounds charge reluctance.
This is my breakdown last time I looked

Laptop rated current: 4.74A
(Consumption figures at the batteries not at the PSU)

600W MSW Inverter idle w/ laptop PSU: 600mA
Laptop on inverter: 2.8A
Laptop + charging laptop battery on inverter: 6.5A
Laptop battery charge only:4.3A

120W DC PSU idle : 50mA
Laptop on DC power: 1.5A
Laptop + charging laptop battery DC power: 4.5A
Laptop battery charge only:2.9A

Best economy is take out the laptop battery and just power direct off the lead acids.

There's a lot of motherboards developing USB problems due to people using them as chargers, the electronics for them aren't as durable as the cig. lighter to USB or 230v to USB versions.
...also charging a battery from a device charging a battery from a battery is a little more inefficient too.

I agree 300w would cover most things up to power tools, medium/large motors and appliances with heating elements.

The size of the inverter has to be greater than the total load you want to run off it. If in doubt have a look at the rating tags of your appliances and see what they add up to.

MammaZita

300W it is so. Thanks a million. This forum is great!

Macy0161

Just on phones - You can get cig lighter usb chargers for €1.50, plus the same again for a micro usb to usb lead in the likes of dealz. If you have android phones that might be an option?

Liamalot - am I right in assuming that doing these types of things, even with cheapo equipment is better and more efficient? Or should I be wary of them? We didn't really care about the phones (and I do use it in the car as well without issue), but now theres tablets and that coming into the mix which I don't want to risk. I believe that the cig chargers are a pretty slow charge on tablets anyway, but I don't think that's an issue more than an inconvenience!?.

moodrater

Macy0161 wrote: »

Just on phones - You can get cig lighter usb chargers for €1.50, plus the same again for a micro usb to usb lead in the likes of dealz. If you have android phones that might be an option?

Liamalot - am I right in assuming that doing these types of things, even with cheapo equipment is better and more efficient? Or should I be wary of them? We didn't really care about the phones (and I do use it in the car as well without issue), but now theres tablets and that coming into the mix which I don't want to risk. I believe that the cig chargers are a pretty slow charge on tablets anyway, but I don't think that's an issue more than an inconvenience!?.

The cheap chargers often have very rudimentary buck converter output can be totally off spec with load of radio noise. I'm not saying spend a fortune on one but get one from a reliable source.

Also a lot of the cheap ones don't provide enough current to operate a smart phone running gps and charge at the same time, also the 'high current' chargers will often just short the usb data lines which may work with some devices while other devices will expect a certain voltage on the data lines to switch to high current mode.

In my experience it's usually too thin wires that are the chief offenders voltage drop on 5v is a killer. USB leads shouldn't be longer than a meter.

Macy0161

Any recommendations of a reliable source - I've seen powergen ones recommended on Nexus7 forums? In fairness to the cheapo ones I've picked up in B&Q and Dealz, they've worked up to now (and they'd be used fairly regularly in the car), as have the metre usb cables.

MammaZita

We bought a cheap cigarette USB charger in Dealz and it broke the cigarette lighter. Possibly the fuse went which we haven't gotten fixed yet Are these easy to sort or do we need to take somewhere?

moodrater

MammaZita wrote: »

We bought a cheap cigarette USB charger in Dealz and it broke the cigarette lighter. Possibly the fuse went which we haven't gotten fixed yet Are these easy to sort or do we need to take somewhere?

Probably the fuse a lot of those cheap chargers are so narrow that you can put them in at an angle such that the center pin shorts the socket. In the highly unlikely event the wire is gone, its worth running a chunky wire with an inline fuse holder and tape a spare fuse to the cable. Then when the fuse goes just pop out the socket and change the fuse no rooting around. Allows you to run usefull things like 12v compressors without melting anything.

MammaZita

1m+ USB leads do work, just not very well. It'll be down around the 3.5v range at the end of it on most generic wire gauges which is why phone and pad-thingy batteries won't charge because it's lower than the acceptance voltage.

I've never had an issue with cheapo USB gubbins no brands worth mentioning.

MammaZita wrote: »

Possibly the fuse went which we haven't gotten fixed yet Are these easy to sort or do we need to take somewhere?

Generally they're quite easy get into with a small screwdriver.
Possibly vehicle fuse too.

moodrater

moodrater wrote: »

...you can put them in at an angle such that the center pin shorts the socket.

hahaha, I was very sceptical about that but I just managed to take out a 20A breaker there with one :pac:

moodrater

Sir Liamalot wrote: »

hahaha, I was very sceptical about that but I just managed to take out a 20A breaker there with one :pac:

Don't know whey they make them such a small diamater must be some oddball fitting in china.

The belkin ones with pill shaped contacts and the griffin ones are a nice snug fit. I found the cheap chargers would also flatten the battery over weeks if left plugged in. The belkin dual one draws almost nothing when not charging so I can just leave it plugged in.

'cos Chinese have small hands :pac: that's why they're so good at soldering. Also why the had to re-issue smaller Xbox controllers