1.Extra battery and then 2. Inverter

Clemmo

Clemmo

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McLouis
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Guys...
I know this has been discussed before but Im getting contradictory advice on the net!!

1. I want to install a second leisure battery

2. Then add an Inverter

Linking the batteries brings mixed messages.

Can anyone provide me a definitive diagram?.. The one below confuses me as I thought the second diagram was correct? ( the 24V bit confuses me I am getting a 12VInverter)

Thank you..Clemmo (y)
 

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Stick to the 12v one wiring to 24v will destroy your normal 12v system
 
The second diagram will only be correct if you have a 24v inverter. Which is very doubtful in a vehicle.

Use the top diagram with 2 x 12v batteries but your technically supposed to take the feed to the inverter from the positive of one battery and the negative of the other to balance the batteries. Doesn't really matter with just 2 batteries though. ?
 
like this?
 

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The other thing to consider is size of inverter and usage regarding size of battery bank .
 
As above, understand the type and power required for your inverter.

Wiring for battery connection and connection to Inverter. Make sure you put a suitable fuse near the battery.

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Thank you!

Not a huge Inverter.. we only want to charge our ElectricBike Batteries when off grid. ( Leisure batteries supported by Solar Panel)

Whats an RCCD?

Clemmo

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Clemmo said:
Thank you!

Not a huge Inverter.. we only want to charge our ElectricBike Batteries when off grid. ( Leisure batteries supported by Solar Panel)

Whats an RCCD?

Clemmo
Click to expand...
There are two types of inverter one is a pure sign wave inverter the other is not. You will need a P.S.W. inverter if your charging deleicate devices like phones, Lap tops etc and you should check out what you need for your bike battery. A RCCD is a circuit breaker.
 
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I’d suggest keeping the inverter and the extra leisure battery separate from the main battery, that would protect the other hab battery from being drained by the inverter
 
Yeah... I can do that ?

anybody help on the fuse/ breaker calculation?

cheers
 
For a 1000 watt inverter, that will in theory take 1000/12 = 83 amps at full power. Add about 10% for inefficiencies, so that's about 90 amps. You could get away with a 100 amp breaker, especially if you rarely intend to be pulling the full 1000 watts from the inverter. Otherwise go for a 120 amp breaker.

The wiring is sized by 'cross-sectional area' in square millimetres, rather than the diameter. The size required depends on the length of the cable run. I'd guess 25 mm squared is suitable. That's quite beefy, like jump start cable. I've found that the cable size is often listed on web sites simply as 25mm when they mean 25mm2.

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1000w inverter should pull about 80amps so 100 amp fuse OK and I would go 50mmsq cable.

Martin
 
The thicker the cable the less the voltage drop, don’t know of a downside other than weight and cost, I ran our 2kw on 80mmsq.

Martin
 
eddievanbitz said:
Don't forget to add an RCCD on the AC output of the inverter before the load (y) (y) (y)
Click to expand...
I believe a 2 pole RCD is needed with some inverters because they don’t distinguish between positive and negative. In other words don’t rely on the cheapie single pole plug in ones.
 
Pausim said:
I believe a 2 pole RCD is needed with some inverters because they don’t distinguish between positive and negative. In other words don’t rely on the cheapie single pole plug in ones.
Click to expand...
Yes your right, (y) but can get double pole plug in jobbies, but they don't normally latch which is a pain having to re-set them every time the inverter is used
 
Superb answers...thank you!
I only want to charge Ebike batteries so 1000w is over specified...but best that way.
Im going for 100amp breaker as that seems safe too.

Cable... to be decided...seems 25mm or 50mm

Now RCD... (dual pole has thrown me).
i was going to buy a plug in device and plug it into inverter before my charger?

Im thinking this is not good now?

clemmo?

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Clemmo said:
Superb answers...thank you!
I only want to charge Ebike batteries so 1000w is over specified...but best that way.
Im going for 100amp breaker as that seems safe too.

Cable... to be decided...seems 25mm or 50mm

Now RCD... (dual pole has thrown me).
i was going to buy a plug in device and plug it into inverter before my charger?

Im thinking this is not good now?

clemmo?
Click to expand...
The single pole ones will pick up the difference between the two connections but only switch off the one it thinks should be the positive. This is probably ok in UK domestic use because we are fussy about polarity. However many inverters do not have a single identified positive, some deliberately use both lines but out of phase. This means that the voltage in each wire is much reduced, you only get the full 230v where the two meet at the appliance. This means that you need a device that turns off both wires, which is known as double pole or 2 pole. As eddievanbitz says you may also want a latching type of RCD, otherwise you have to reset the RCD every time you turn your inverter on.

I use one of these with a short wire and plug going directly to the inverter.
www.screwfix.com

PowerBreaker 13A 2-Gang Unswitched Metal Clad Passive RCD Socket with Neon with White Inserts - Screwfix

Order online at Screwfix.com. Robust, easy to install RCD with neon indicator and power cut-out for added protection. 13A max load, trips under 20ms at 30mA. Double pole. Passive operation. FREE next day delivery available, free collection in 1 minute.
www.screwfix.com www.screwfix.com
It looks very similar to one of these which is half the price but only single pole so best not to get them mixed up.
www.screwfix.com

British General 13A 2-Gang SP Switched Metal Clad Passive RCD Socket with White Inserts - Screwfix

Order online at Screwfix.com. 13A max. load. Trips at 30mA. Passive operation. Heavy duty, metal-clad moulded safety RCD switched socket that protects against the risk of a fatal shock. Latched with no need to reset after a loss of power. FREE next day delivery available, free collection in 1...
www.screwfix.com www.screwfix.com
 
Superb..
Thank you!

Feels like Im getting a better understanding now :giggle:

Many Thanks again

Clemmo
 
I'm no expert of 240v but sure I read some time ago that RCD will not work on a centre tapped inverter, any experts.

Martin
 
I am not an expert either but I think that there is no basic reason why a RCD should not work with a centre tapped inverter but there can be issues if there is not proper isolation of the DC and AC sides of the inverter. Canal boaters seem to have some experience in this area, including this one who proved the need for double pole switching by giving himself a 115V shock off the neutral wire.

Inverter surprise - rcd advice.

WARNING! Much to my surprise, having switched off the inverter-supplied 'mains' wall socket by its switch, I got a shock from the appliance on which I was working. I was wondering how many folks know that many inverters make both the 'live' and the 'neutral' wires live, but with both registering ...
www.canalworld.net

The explanation given in post #6 of this thread was one that seemed to make sense.

Inverter Earth

Have moved my inverter and used it last week proper, notice there is no earth connected to earth point on the device.. Should this be earthed to the earth point on the socket, it has a kettle like cable coming out the inverter to a 240v plug socket but only black and red cables. Should it also be...
www.canalworld.net

He refers to “Mickey Mouse Isolated” inverters and I am left wondering if some of the cheaper ones that lack detailed technical information might fall into this category? When it comes to something working at mains voltage I prefer to buy from a known manufacturer with technical support.

Edit. I think it may be Earth Leakage Circuit Breakers that do not work with centre tapped inverters. Better get some expert advice.
 
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