Inverters and truma - techies please (1 Viewer)

Jul 5, 2013
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Tunbridge Wells, Tunbridge Wells, UK
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It is an inverter charger.

When your on hook up it is an 80 amp Multi stage battery charger
When there is no hook up it is an inverter
When there is hook up and you require more power than the hook up can give you, it "makes up the difference"

Simple! ;) (y)
But shouldn't it be wired in such a way that when it is working as an inverter it will not feed the 240v side of the Truma heater? That will knacker the batteries in no time whether lead or Lithium..
 

funflair

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Dec 11, 2013
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But shouldn't it be wired in such a way that when it is working as an inverter it will not feed the 240v side of the Truma heater? That will knacker the batteries in no time whether lead or Lithium..
On our Flair we could run the heating on the inverter, not for long though as you say so we didn’t do it but never it as a problem that it was wired that way, I think the ability to run the fridge from the inverter is a positive.
 

eddie

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Oct 4, 2007
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Not good.
:doh: As in this type of installation the original mains charger is disabled as it’s not suitable for Lithium, which is why the ‘inverter’ ‘charger’ is recommended as a replacement, why is it ‘not good’ not to tell a customer to turn off a disabled charger?:LOL:;)

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Lenny HB

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Oct 18, 2007
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:doh: As in this type of installation the original mains charger is disabled as it’s not suitable for Lithium, which is why the ‘inverter’ ‘charger’ is recommended as a replacement, why is it ‘not good’ not to tell a customer to turn off a disabled charger?:LOL:;)
I was referring to the customer not being told to not run fridge and charger on mains when the inverter is on.
 
Apr 27, 2016
6,852
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Manchester
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I was referring to the customer not being told to not run fridge and charger on mains when the inverter is on.
It's an inverter/charger. The switchover relays work automatically. The charger does not charge the batteries unless there is mains hookup. It's a 2kVA inverter, so it is quite capable of running the fridge on mains if required. As you imply, it's not a good idea because it's very easy to forget, leave it on for hours and flatten the leisure batteries.

There is a manual override switch, so it can be in charger-only, inverter-only or inverter-charger mode if you want.

The Truma heater should work on gas only, and should go into 'boost' mode with higher speed blower fan whenever it has a 12V supply from the leisure batteries, if the measured temperature is a lot less than the set temperature. This is regardless of any mains heater elements. If it doesn't do boost mode on 12V with gas, there's something wrong with it.
 
Dec 2, 2019
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Amersham
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Oh dear so much confusion, the op has a professional inverter charger, that works everything automatically as it should. These inverter chargers have been specifically built and designed for this very purpose and niche application.
What I can only repeat, is what I already mentioned in my previous post. Make sure in the inverter settings the ground relay is activated. It needs this for the boilers to recognise a true neutral that is bonded to the ground. These physical bond is done internally by a relay, but you need to set it to do it. When you are on ehu, it detects power in and deactivates the relay to allow shore earth to protect.
Simples.
The user should use the inverter as it likes, it’s the only user to decide its time of use as its sees fit. Not us. It can be used on Truma on electric for a limited time if necessary. Lithium can and so the inverter. No issues there.

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busbuddy

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Oct 2, 2018
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swift suntor 630G
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I bit the bullet, have decided to go with replacement of element and motherboard but to leave the wiring as is. They’d planned to put in a separate circuit for the truma that would only allow electric bit to work off mains only Thus bypassing the inverter. the mechanic seemed to think that the inverter wasn’t pure sine wave. I’ve had clarification by the installer that it is.
After you get that done I would book it back into vanbitz for them to check what they fitted, sometimes stuff fails internally, and also get them to check how it's been bypassed
I'd rather pay Eddie to give it a clean bill of health than lay awake at night worrying if it's been done right

Just noticed you not having it bypassed, I'd still get eddie to give it the once over 👍
 
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Caggsie1

Caggsie1

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Sep 2, 2013
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busbuddy We’re heading down to Cornwall in May subject to all the lockdowns being lifted as expected. I’ll get it booked in for return journey. Thanks
Raul - thanks for your advise, as above I’ll get Eddie to lookie see, or he’ll tell me it was done at installation.
thanks to all who gave an input
 
May 7, 2016
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I am no expert on electronics but I know that my Victron inverter copes with excessive surge loads by temporarily reducing the voltage. I understand that low voltages can damage sensitive electronics, less likely than over voltage damage but still a possibility. An 1800W heating element could well cause a significant initial surge load, if the inverter responds to this by reducing the voltage could this be the cause of the damage to the Truma?

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Dec 2, 2019
3,579
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Amersham
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van conversion
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I am no expert on electronics but I know that my Victron inverter copes with excessive surge loads by temporarily reducing the voltage. I understand that low voltages can damage sensitive electronics, less likely than over voltage damage but still a possibility. An 1800W heating element could well cause a significant initial surge load, if the inverter responds to this by reducing the voltage could this be the cause of the damage to the Truma?
Very unlikely, the surge can be double the power for few seconds, down to 120-130% overload for 30 mins. Depends on the overload, the duration of being sustained. Also the 1,8kw resistive load of the element, will be well within parameters of the inverters capability of 2kva, without overload. The resistive loadsare not surging like the inductive loads, ie compressor motor of a fridge.
I have never seen a overload with reduced voltage output so far, but if really happens, the 240v equipment can work fine down to 180-190v. The inverter outputs 230v exactly, at 49,9-50,1Hz unless you change that in the settings.
The low voltage scenario, can be from local grid overload more likely, than inverter. The inverter parameters on stand alone mode are microprocessor controlled to a very high accuracy. But, If you plug into EHU, the inverter copies those parameters by synchronising to it, and allows the power to pass through. It has no control over grid parameters but copying what’s coming in. In this scenario, if you have a local overload or surge, it will come in as that. On off grid stand alone mode, you get the cleanest power possible, because it has full control over it and being a very small it’s own micro grid, it can respond and adjust very fast in milliseconds.
 

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