Invertor Install

S

steveh57

Joined
May 19, 2020
Posts
205
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Funster No
70,901
MH
Knaus Sun Ti 650 MEG
Exp
Since 2020
Looking for some advice please

Background.

We're new to the pastime/passion , purchased an unmolested 2016 Knaus Sun Ti 650 MEG in March 2020. Now keen to get off grid!

Current electrical set up as I understand it

Leisure batteries 2 x 100Ah Yuasa L36 EFB both under a year old

Toptron - 12v distribution board

Weaco Perfectcharge 1225 - mains battery charge to hab and cab

Fridge Dometic - 3 way manual

Hot Air Truma 6.

240v distribution box - current breaker x2 and RCD -40/2/30

Last week - I added 350 watts (2x175) of solar power via Victron MPPT 100/20 48v Controller and a VanBitz battery master, thankfully despite my complete inexperience and the inclement weather both seem to be working as they should.

I would like now to add an Invertor- if I can top up charge one Bosch electric bike battery first thing in the morning I will be happy- yes it's terribly inefficent and I guess my battery capacity is somewhat limited . I will probably end up with Lithium but may wait until the current ones expire.

So the current thought is a 1000w Invertor

The service locker seems to me a suitable place to site this- the DC cable run from the batteries will be short, I will fit the relevant sized cables, fuse and a DC isolation switch. Now the tricky bit for me, I need to keep the two potential 240v supplies separate and avoid using the Invertor for the charger, fridge, heating and hot water. I think fitting an automatic change over relay and some rewiring to avoid the heavy duty loads whilst on the invertor is beyond me?

Therefore is it safe and hopefully possible to wire a hookup plug to the Invertor output cable, the EHU socket exists in the same service locker as well. To remind me also a legible label/sticker which states something like Invertor On - Charger OFF Fridge,Heater,Hot water - GAS Invertor OFF DC Isolate OFF

Lastly do I need to add an additional 2 pole RCD for the invertor output as I'm uncertain whether the one installed will suffice?
 
1000w is enough to charge 5 bikes simultaneously, you'd need some thick wire to do it justice. I charge 2 Raleigh bikes on a 300w pure sine wave, no problem.
 
I would just add a new socket somewhere or use the socket on the inverter if your main use is going to be charging a bike battery. This would be by far the safest way to do it. You will want a pure sine inverter I think.

I described my fitting in this thread: https://tinyurl.com/y5gjksrm
 
You should use a pure sine wave inverter. I’ve done similar for a Bosch 500 battery with the compact 2A 240 v input. and also a powerful computer with a Victron 375 inverter and even that is heavy. But do consider the power draw off your gab battery, with your lead acid you have 50% of the total capacity useable to avoid potential damage or shortening of battery life. A Bosch battery can take 7 hours on that compact charger if emptied.

it was easier just to add another socket in the gab area direct wired to the inverter than mess with other existing circuits. Inverter also fitted with a remote switch to power on /off from the hab area rather than fiddling under seats when not needed as the inverter even idle has some background current draw
 
We decided to have separate sockets for the inverter one in the garage and one in the main hab area, remote switch in hab area. Works very well, was easy to install and if needed take out or change.

Bought a 1000w pure sine wave, EDECOA😱 Power Inverter, so far it has been brilliant😁, we tend to top batteries up they rarely get below 60%.

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Thanks everyone, very helpful. Sorry I should have said it would be a pure sine wave invertor. It does seem that just wiring in a couple of dedicated sockets wins the vote so far. However was my original idea of inputting via the EHU socket un safe? I'm pretty obsessive usually when beer free and would ensure the heavy loads where either off or switched to gas. It doesn't however prevent someone else who will be nameless cocking it all up.
 
We use a 1000 watt Inver for our Bosch powered bikes with 400 watt batteries.
It can charge both at the same time but I have to plug one in, wait a couple of minutes for it to stabilise then plug the other one in otherwise the inverter trips out due to the initial startup of the charger.
With only two 100ah batteries I wouldn't charge both at once unless really necessary.
 
steveh57 said:
Thanks everyone, very helpful. Sorry I should have said it would be a pure sine wave invertor. It does seem that just wiring in a couple of dedicated sockets wins the vote so far. However was my original idea of inputting via the EHU socket un safe? I'm pretty obsessive usually when beer free and would ensure the heavy loads where either off or switched to gas. It doesn't however prevent someone else who will be nameless cocking it all up.
Click to expand...
The problem with plugging into the EHU socket is turning off everything like the battery charger, which will otherwise be feeding off the leisure batteries. It isn't unsafe using this method, assuming the inverter is turned off when you plug into the EHU socket, but it lacks "elegance" as a solution. :)

You asked earlier about RCDs, this isn't easily answered because the answer may vary between different models of inverter. For the vast majority, possibly all, but I'm not 100% sure, plugging an RCD into the socket won't do anything as there is no link between the inverter output and earth, or in the case of a MH the chassis. The solution is to create the link by connecting one side of the inverter output to the vehicle chassis, which sounds outlandish but will create the link to earth. It is actually not massively different to how many modern houses are wired where there is no actual earth connection coming into the house and the neutral line is used instead. However, it is possible some inverter models, using a centre tapped winding, may create an earth connection that way, but I wouldn't know how to identify, if indeed there are any, which models these are. If you do fit an RCD use a "latching" one. This will avoid the need to reset it every time you turn it on.
 
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Thanks Lenny HB, the advice to start one after the other is taken on board. I thought charging both at once would be marginal for me with the Bosch bike batteries, but from experience of our typical bike battery usage we could probably alternate each day or charge both when moving perhaps.

Thanks DBK , I agree it's not an elegant solution, I becoming more convinced by the dedicated socket solution. When it comes to centre tapped winding and neutral earth bonding etc it makes me think I need a professional install. However I currently have 6 mains sockets supplied by the EHU. I'm wondering whether I could repurpose a couple for sole use of the invertor, certainly I've noticed one that is on a single feed from the mains distribution box, there may be another.
 
Very surprised by this. My Bosch engined Kube draws over 3A for the first part of charging. My 300W inverter would immediately trip out. 1500W does happily charge two of them though.

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domf said:
Very surprised by this. My Bosch engined Kube draws over 3A for the first part of charging. My 300W inverter would immediately trip out. 1500W does happily charge two of them though.
Click to expand...
I think you mean 30amps that's what ours thaks when charging a 400 watt battery.
 

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