invertors .what size

[chriswilliams29]

we are thinking about buying an invertor to run a microwave also a portable telivision . what size is suitable and is it best to wire the invertor direct to the battery. thanks

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[tr7v8]

Err, inverters consume huge amounts of electric most are around the 60-800 watts mark and require a fair bit more than that to startup. Say a 600W one you'd need roughly 800-1000W to get it started which at 12V equates to circa 80 amps at 100% efficiency. Hence to answer the other question inverters of this size need siting near the batteries to stop excessive voltage drop. Much easier to pipe 240Vrount the boat. Portable tele much less dependant on size but typically around 150-300W, agan require more to start up but most inverters allow a surge at start up.

Jim
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[Oldhand]

I think Jim has covered the problem for the Microwave - too high a power consumption for most battery systems. On the portable TV front, doesn't your set run off 12v as well as mains? If it is a true portable, it should. I have used a 5" screen colour portable which only drew 1 Amp off the 12v supply and a 10" colour portable which draws abour 3 Amps off the 12v supply. If you need to use mains, check the power consumption of the set on the data plate on the back and use a pure sine wave inverter with at least 1.5 times the set's specified consumption.

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[ballena]

Be careful with inverters, they have very little hold up capacitance and do not cope well with the inrush current surge of most devices starting up.

I have a 150W inverter for running laptop etc, and will not start up an 83 watt TV.

You need to specify one at about double the required power. For your needs I would go for a 1500W unit, remember it will only draw a small current running the TV(around 8A), however it will pull around 80A whilst microwave is running.

Most invereters will not run at 100% power continuously.

Paul R

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[alastair]

Agree with all thats been said.
The start up current can indeed be a problem with domestic spec TVs and it will sometimes trip the inverter.
Start up current can be minimised by disconnecting De-Gausing coils which are placed around the CRT (tube). The purpose of these coils is to neutralise magnetic fields which the TV has been subjected to eg a loudspeaker placed closeby. The effect is colours in the wrong places (Blue grass and Green sky)
Doesn't often happen on a boat.
This is a simple job - disconnect from mains, take back off TV, locate and disconnect small plug which feeds the coils. BEWARE there can be high voltages from capacatance in TV, even when switched off. Please DO NOT do this unless you know what your doing!!.
Mine has been disconnected for the past 3 years with no problems

Hope this helps

Regards

Alastair

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[petery]

Samsung do a 12v microwave for about £200 - it still uses a massive current but
there's less to go wrong as it goes direct to the battery

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[tr7v8]

All the Samsung microwave is is a mains microwave with it's own inverter built in, looked at it a little while ago, it's current consumption @ 12V is horrific! This will give a problem as it'll need to be close to the battery so problem returns.


Jim
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[chriswilliams29]

where can i buy one of these 12v samsung microwaves. the cheapest i have seen
is £380

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[tr7v8]

Too late now but just found this on E Bay <A target="_blank" HREF=http://cgi.ebay.co.uk/ws/eBayISAPI.dll?viewItem&category=36798&item=2406126803>http://cgi.ebay.co.uk/ws/eBayISAPI.dll?viewItem&category=36798&item=2406126803</A>

Shows 65Amps at 12Volts serious consumption!


<hr width=100% size=1>Jim

Draco 2500