Re battery and solar charging unit.

[Peter Waller]

Hi I have a Hobby 750 2000/01 the previous owner installed 3x 100 watt solar panels on the roof and a
Victron Energy Set - Blue Solar Charge Controller MPPT 100/30. There are 2 inverters under the bed and 2 new leisure batterys with an on/off red isolator switch between them to presumably turn off one of the battery's. When I am not using the van for long periods should i switch off one of the batterys to stop it being over charged by the solar panels or should I switch off the solar charge controller to stop the batterys being charged....if it is possible to do that.
Also there is a brand new 120amp battery under the bonnet for the engine and under the drivers seat is a toptron charge unit. I understand that when I am plugged into the house electrics that the little red rocker switch on this unit must be switched on so the switch is illuminated red. Exactly what does this do? I know it maintains the engine battery but does it do anything else..i see that a light on the control panel above the door glows re and eventually turns green. Just want to make sure that I am doing everything correctly and looking after my motorhome!

 

[Just smiffy]

Firstly I’m not sure why you have 2 inverters...?
Sounds like your solar system is a good one and if fitted correctly should charge your leisure batteries and possibly the cab battery.
You should not have to turn the solar off, the victron will not cook the batteries as it will only give a float charge once they are fully charged.
I don’t know about the charge unit under the seat, but I’m sure someone with far more knowledge then me will be along shortly.
@Badknee has this sort of van and may shed some light on it...

 

[Peter Waller]

I think one invertor is a spare and I also meant to ask should I turn the invertor off under the bed when the van is not being used. There is a switch inside the van to turn it on when using the tv etc but the actual invertor also has a switch saying , auto, on and off. Thx for the reply

 

[autorouter]

There are 2 inverters under the bed

This arrangement is unusual. Can you give the exact make and model of the two inverters, preferably with a photo of the labels?

If they are Victron, they make some very clever stuff that might have all kinds of functions that you wouldn't think of at first.

the actual invertor also has a switch saying , auto, on and off.

I think the auto/on/off function may be an automatic switchover for the sockets from mains hookup to battery-powered inverter. There are some situations where you might not want that to happen, so the on and off options are provided.

 

[Peter Waller]

Thx for your reply and here are pics of the invertors under the bed nxt to the leisure

battery box and then pic of the switch to switch on on the inside of the van and then pic of the solar charge unit and also the bluetooth part!

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[Stealaway]

The switch is for turning the Sterling inverter on. I imagine that you need to switch the inverter off when you are connected to the mains.
It could be that the inverter 240V power leads are also connected to the 13A sockets.
Ignore/disconnect the spare inverter.
Personally I would split the 240V sockets into two circuit sets - EHU and/or inverter power.

 

[autorouter]

The two inverters are both 1000 watts. The orange one is 'pure sinewave' and the silver one is 'modified sine wave'.

The silver one is Sterling, a good reliable brand. Its advantage seems to be that is has a remote switch, so it is easier to turn it on and off. In the picture there is no switch isolating it from the battery, and no fuse either. There should be one similar to the isolator for the orange inverter. A 200 amp Megafuse would be suitable I think.

Pure sine wave inverters are more expensive than modified sine wave (also called quasi-sine wave) inverters. Psw waveforms are more like the smooth waveform you get from hookup mains, and are better for delicate electronics like electric toothbrush chargers and laptop chargers.

Modified sine wave inverters are fine for dumb devices like lights or most power tools. The waveform is jagged with sharp breaks, that can cause problems for some precision electronics that is expecting a nice smooth sine wave. If it works on household mains but doesn't work on a MSW inerter then that's the reason. I have a Nespresso coffee machine (1000 watts) that refuses to even start on a MSW inverter. My microwave struggles a bit on MSW but is fine on PSW.

Where is this 'auto/on/off' switch that you mentioned? Or were you referring to the 'on/off/remote' switch on the silver inverter?

 

[El ETO]

One other thing to consider, and I'm going through exactly the same thing myself at the moment on a 2000/2001 Hobby 750 because I have 300W solar panels installed and am about to add an inverter as well. Potentially, when the inverter is on, if it's supplying mains 240v to the Toptron CH12MC then you are also charging the very same batteries you're operating from since I think when the shore power mains is plugged in, your batteries automatically get charged. This is obviously very inefficient and a waste of battery power. Someone please correct me if I'm wrong and perhaps your system has been modified. Maybe worth trying to get a wiring or input/output diagram of the Toptron. I'm presently looking for the same. (anyone have any ideas where I/we can locate one of these?)

I already have an inverter but this is a separate 3000W device for power to the roof top A/C unit but I only use it when the engine is running.

Also, you may have 2 inverters for different circuits. My Hobby 750 has both Euro and UK sockets onboard and I've found 4 RCD (breakers split between the two circuits) on the outside bulkhead in front of the water tank behind the left hand drivers seat.

I've attached a photo of the Toptron sticker with device details.

 

[autorouter]

Potentially, when the inverter is on, if it's supplying mains 240v to the Toptron CH12MC then you are also charging the very same batteries you're operating from since I think when the shore power mains is plugged in, your batteries automatically get charged. This is obviously very inefficient and a waste of battery power.

There's basically two solutions to this problem.
1. Keep inverter and hookup 240 volts circuits separate.You could have some sockets from the inverter, and some sockets from the mains that are never powered by the inverter. For example, you may want the inverter to power the TV, phone charger and maybe a couple of electric bike chargers. The hookup can supply electric elements in the water heater and space heater, and the battery charger. You can manually plug the devices into whichever sockets you want.

2. In my setup, I have some appliances like the water heater and battery charger permanently connected to the hookup mains and are never powered from the inverter. Other circuits are on a 2-way switch, to switch between hookup and inverter. My switch is manual, but others have a relay that switches automatically to hookup as soon as it's plugged in.

 

[Peter Waller]

Oh dear I am lost! But thank you for the comprehensive replies. The on off switch I was referring too was the one on the sterling inverter so do you think I should switch it off when the van is stood up on my drive for long periods and not the van is not plugged into the house electrics? Sorry but I do not understand and also should I use the isolator switch after the orange invertor to isolate one of the battery's to save if from being charged all the time (Again when the van is not in use) I do hope I am not asking again what you have already told me!
But thx anyway

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[El ETO]

Oh dear I am lost! But thank you for the comprehensive replies. The on off switch I was referring too was the one on the sterling inverter so do you think I should switch it off when the van is stood up on my drive for long periods and not the van is not plugged into the house electrics? Sorry but I do not understand and also should I use the isolator switch after the orange invertor to isolate one of the battery's to save if from being charged all the time (Again when the van is not in use) I do hope I am not asking again what you have already told me!
But thx anyway

Yes, if you're not using it then switch it off. Inverters use a small amount of voltage when they are switched on, even when they are not supplying power. Also make sure the battery or batteries supplying power to the inverter also have an inline fuse or at a minimum a cut off device as someone else has mentioned. The DC power from batteries is not to be underestimated if you get a short circuit or any other issue. If in doubt, ask a specialist. I know I'm always mentioning Phil at Rhino Installs but he's very good and will check, advise or install whatever you may need if you're unsure how to do it yourself. I'd call him for an informal talk first and take it from there and you'll feel more confident about your setup afterwards. Otherwise if you're fully aware and confident in doing/checking yourself then fine. Just my two pennies worth.

 

[El ETO]

There's basically two solutions to this problem.
1. Keep inverter and hookup 240 volts circuits separate.You could have some sockets from the inverter, and some sockets from the mains that are never powered by the inverter. For example, you may want the inverter to power the TV, phone charger and maybe a couple of electric bike chargers. The hookup can supply electric elements in the water heater and space heater, and the battery charger. You can manually plug the devices into whichever sockets you want.

2. In my setup, I have some appliances like the water heater and battery charger permanently connected to the hookup mains and are never powered from the inverter. Other circuits are on a 2-way switch, to switch between hookup and inverter. My switch is manual, but others have a relay that switches automatically to hookup as soon as it's plugged in.

Agree with the above BUT I'd like to find the Toptron circuits that charges the batteries when I'm on mains shore power. I'll then wire in a switch that stops power going to the batteries when the inverter is in use and not shore power. I also have a 50W panel just for the start battery and separate 300W panels to the house batteries.

So if anyone knows how to get ahold of the Toptron diagram I'd love to know. I keep searching the web but no luck so far. I'm sure Pete would find it useful as well.

 

[autorouter]

I can't see the batteries so I don't know how they are connected. The usual arrangement is to connect them both together, positive to positive, negative to negative, which makes the pair act like one big battery.

In the picture there is no switch isolating it from the battery, and no fuse either.

The big switch by the orange inverter is an isolator. Looking at the picture again, does the red wire go from the orange inverter to the silver inverter? It's not very clear in the picture. If it does, then the isolator switch cuts off both inverters from the batteries. That is satisfactory for safety.

Turn the isolator off if the inverters are not being used, and especially if the MH is in storage. If it's on, the inverters will take a small amount of power even when nothing is plugged into it.

The same for the on/off/remote switch of the silver inverter. This switch is on the output side (not the input like the orange inverter). It doesn't quite stop the current drain completely, however, so switching off at the isolator switch is a good idea when the MH is in storage.

 

[Ivory55]

Oh dear I am lost! But thank you for the comprehensive replies. The on off switch I was referring too was the one on the sterling inverter so do you think I should switch it off when the van is stood up on my drive for long periods and not the van is not plugged into the house electrics? Sorry but I do not understand and also should I use the isolator switch after the orange invertor to isolate one of the battery's to save if from being charged all the time (Again when the van is not in use) I do hope I am not asking again what you have already told me!
But thx anyway

Welcome to the mysterious world of the 12 volt supply in motorhome. Haha

 

[Peter Waller]

Thank you............received and finally understood! THANK YOU

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[pappajohn]

Any switches built into the inverters only switch off the 230v supply, the same as switching off a socket at home.
the 12v supply is still connected and using battery power even with the 230v switch off.
To turn off the 12v supply would need a switch and 200+ amp relay.