General Electrics advice/info

[DrewE127]

Hi all
I’m no good with electrics, I keep reading threads about overloading the system with things like eBikes, kettles, hair dryers etc but I must admit it makes no sense to me.

Does anyone know of any reading material around MH electrics? I don’t fancy ruining our new MH by just plugging something in

We might get a couple of eBikes eventually. Our Benimar Mileo 231 has a solar panel but I don’t know what sort it is.

Thank you

 

[Boris7]

I think your referring to overloading the power supply that you plug into on a site Or possibly an inverter if your MH has one.

The good news is in the worst case you’ll trip a fuse or circuit breaker and not damage the MH.

In the case of an inverter it will have 2 ratings a constant power and peak power value our inverter Has a peak rating of 3000watts and a continuous rating of 2000watts.

So add up the watts usage of ALL appliances you are going to run and make sure the total doesn’t exceed the inverters constant rating, if you over load it will have some type of overload protection and will protect itself bu either turning off, blowing a fuse or tripping a switch.

On mains hook up (MHU) the power supply will have a similar system (normally a trip switch) if you try to draw too much power it again will trip off.

The rating will almost certainly be in amps, so you need to have some idea of usage, as an example many mains kettles are 3000w to convert this to amps divide 3000W by 240v and you get 12.5amps

Many sites only provide 4 amps so in that case your kettle would trip the power out.

good site for leaning electrics https://www.powerstream.com/Amps-Watts.htm#watts-amps

None of this should harm your MH.

But be aware inverters are not battery friendly in the long term, and drain power in the short term.

Im lucky and get my batteries free (no before you ALL ask, yes Joy) but even so I tend to avoid the inverter.

 

[NorthernSands]

divide 3000W by 240v

Technically, haven't we been on 230v for many years now?

 

[Boris7]

I generally use to 220 for calcs as it gives a higher amp figure, and therefore a better safety net, but to OP didn’t need confusing in my opinion.

 

[DrewE127]

Thanks yes I’m very new to this. When we first starting looking my OH said oh there are normal plug sockets I can bring EVERYTHING lol.

I did have doubts but I’ll have a read of the link above, many thanks for that.

I think we will be fine but I’ve found a photo of the gtech eBike charger, which has the figures on it (below). I’m not sure what the Mileo has in terms of inverter etc, I’ll ask Marquis for a full spec sheet when I see them in the next few days and see what’s what.

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[poppycamper]

I appreciate your concerns over electricity... it is something a lot of us don't understand but modern day electrics really do look after them selves by using fuses/trips/cutouts etc to protect both the equipment and more importantly the users.
So by all means learn more about electrics but do not worry about it....IF fitted properly to your moho there is no difference to using at and home . The main thing is to understand your equipment limits

 

[SpeedyDux]

Watts divided by Volts = Amps

230v EHU on UK sites is 16 Amp (or sometimes 10 Amp) but on the continent it can be 6 Amp or less.

If you overload the EHU it will trip and cut the electricity supply. It may also cut the supply to a whole area of the site which makes you very unpopular with neighbours. Sometimes you can reset it yourself; other times you may need to call the wardens to do it, which may not happen outside their working hours.

You need to calculate your total amperage in use, therefore which 230v appliances can be used at any time, and in many cases never together at the same time. You need some allowance for the Amps that will be drawn by your 12 volt system via the battery charger. That 12v system powers the lights, fridge, TV, water pump, and other tech devices and chargers.

If you are off grid and relying on the solar + hab batteries and using an inverter, the need to calculate your 230v appliance usage before you flatten the hab batteries is even more crucial.

All in all it is unrealistic to expect the MH to allow you to replicate all the simultaneous 230v usage in your house, no matter how many 230v sockets there are in the MH.

We use a low wattage travel kettle, a 1 kw fan heater in case the Truma fails, and a 230v fan over the bed for hot weather. Never tripped the EHU, although several times we have been a victim of others who overloaded or shorted their EHU, cutting off our electricity supply as well until the site staff reset it.

 

[Kannon Fodda]

If you try and connect too much stuff at once, you risk overloading the circuit. A fuse may blow or trip.
On the battery powered circuits these will be little replaceable plastic plug in things. These can be in a couple of locations - in my ducato based van there is a small fusebox in the floor behind the drivers seat, and then as part of the main habitation power supply controller. Have a look at those and then take a trip to Halfords to get a selection of spares.

On the mains supply in your MH, with the main power supply controller, fuses will look like those in your house, usually resettable trip switches. Outside where you connect your hook up lead to the blue hook up point there will normally be another master trip circuit breaker. It's that one that will need resetting when you try to plug in more than the campsite allows you to use. But as that supply point is also shared with others, if you all use too much you might be waiting on campsite staff to do a big reset at their master fuseboard.

On a campsite you won't have anywhere near as much mains power as you would in your house. You are effectively doing everything off an extension lead. Some sites give you very little power, perhaps only 6A. You won't be able to run much other than keeping an electric fridge going and recharging the leisure battery. At that rating you may be able to plug in your e-bike charger, but it might not be happy if your leisure battery was also drained. At 10A you may be able to run a small heater, or boil a basic powered kettle (don't buy the fast boil type that have the higher rated elements), but not together. The best supply will be 16A, which become generous so you should have enough to run your heating systems, charge bike batteries from mains and all sorts, but plug in your heater, kettle, microwave, hairdrier all at once and you'll go to far. A bit of experimentation will soon tell you how much you can do at once, and realistically, if you are getting stuff for motorhome buy lesser power hungry stuff accepting it may take a bit longer to use.

Your next challenge is the leisure battery and how much it can store and supply. There are many different sizes. My MH has a feeble 75Ah (Ah is the battery capacity), but there will be some here who have over 300Ah and more over a combination of batteries. For most there is not a problem if you are on hook up to the mains, as you should be able to recharge faster than your power drain from lighting, radio, water pump and stuff. When out and about you'll need to be more considerate. It may depend on how long you stay in one spot before you get a recharge whilst driving, or if you have solar to give some recharge during the day. When driving, your leisure battery gets the spare capacity from your engine's alternator, but for most MH's it can take a good while to fully recharge if you'd used the battery heavily and a 10 minute drive to get a pint of milk isn't going to cut it.

Most MHs will allow you to monitor your leisure battery, voltage is key. It will depend on the battery type, but the most common leisure batteries are lead acid based and for these it is good practice to discharge to around 50%. Although our systems are rated at 12V, in practice a fully charged battery voltage is above that. Lead-acid will be completely flat (and probably irreversibly damaged so it won't hold a charge) at around 10V, at 50% it may be around the 12V mark, 100% charge could be 13.5V. Normally battery voltages take a few minutes to settle after charging, or after discharge. Certainly when I'm using stuff in my MH, the voltage displayed is lower whilst the battery is being worked, than once I've turned off.

To compound this all batteries have a maximum discharge rate, beyond which you again risk damaging it. Your standard MH kit won't be a real problem to be using most of the lights, water pump radio and things. Fridges can be a problem as if battery powered they will need a lot of energy that your battery may not have.

Inverters which take the 12V stored battery power and uprate the voltage to 230V mains add complexity. A small inverter say 500W at 230V will draw a lot of power from the 12V system. That will be pushing the capabilities of a single lead-acid to the limits and perhaps more of it's discharge rate. The energy has to come from somewhere so you will also be emptying that leisure battery. Those who are claiming to operate 2-3000W inverters, effectively equivalent to a decent electric mains hook up capability, should have a setup of multiple leisure batteries to provide the storage and discharge capacity. Inverters should ideally be switched off when not in use (if permanently wired usually there is an isolator between the battery and inverter) as even in idle they do draw some current from the battery. Inverters for all but the tiniest ratings should be connected with short leads from the battery with a fuse protection. If all you want to do is top off your e-bike battery then a 500W inverter should be more than sufficient, and you may well get away with a good 300W version. But if your OH want's to use a hairdryer, that 500W isn't going to do the job. Finally if you are getting an inverter, there are various types. Pure Sine Wave is usually recommended since that simulates mains power Alternating Current, and is most compatible with more sensitive electronic circuitry found in chargers and other devices that today have microchips embedded.

 

[mb567]

Apologies if I'm being particularly dense - also new to this and don't want to trip out any campsites!

The e-bike charger above says "Input: 100-240VAC 1.8A 50/60Hz 90W" and "Output 42.0V 2.0A"

Does that mean the charger requires 90W of power? So dividing 90W by 240V supply = 0.375A being drawn? What does the Input 1.8A figure mean?

 

[DrewE127]

Thank you all for such useful information, I know that there are failsafes in this modern equipment and a lot of people just put their faith in it all working but I’ve been a total pedant since I was a kid

The hairdryer situation isn’t that important tbh and we can use campsite facilities if needed.
I think the hab fuse box in mine is in a cupboard under the non-travelling seat behind the front passenger seat. I saw some familiar looking consumer-unit style fuses there.

Still interested in eBikes so going to try and find out if we have an inverter as standard (not sure if that is uncommon) and what sort of batteries/solar we have.

I’m glad you mentioned the blackout scenario - knowing my luck we’d have been “those people” who turned up, plugged everything in and then ruined everybody’s evening.

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[pappajohn]

Technically, haven't we been on 230v for many years now?

Only to bring us in line with Europe, the actual voltage never changed.
It's something like 236v to 254v tolerance.

 

[Kannon Fodda]

A majority of Motorhomes won't be fitted with an inverter as standard equipment. They are usually an owner addition. So initially think of just your 12V leisure battery capability, or what you might have if on a campsite and you've paid to use their hook up.

If you are looking at e-bikes, but don't have yet, be aware that the e-bike battery capacity and charger sizes vary widely. That g-tech charger linked above has a low power draw (wattage at mains power), but probably the g-tech battery is also quite small. Other manufacturers such as Bosch will need a bigger charger to cope with their 500Wh or even 625Wh batteries, and that would also make quite a dent in your leisure battery. Many will only try and recharge their e-bike batteries whilst on hook up or on the move. There are a few threads on here on e-bike battery charging options.

 

[DrewE127]

Thanks yes I think our style of touring will mean that we are driving and using solar more than EHU so I’ll have to take that into consideration.

Marquis are fitting the TV and roll out awning for us, I might see what they’d charge to fit a decent inverter too.

If we do get eBikes they’ll most likely be the gtech ones but want to do a few trips first just getting used to the MH itself plus they are out of stock, probably due to the governments new eBike commuting grant

 

[dr1uk]

I posted this a few days ago with regards to electrical items....

Might be of use?

Power (Watts) = voltage (Volts) x current (Amps)

Although we refer to 240v the UK now has 230v (EU regs).

Campsites that supply 16 amp, will give you (16a x 230v) 3680 Watts (3.68 kW).

A site providing 10amp will provide 2300watts (2.3kW).

Some UK sites provide 5 amp supply, and France for example 6 amps. Check with your campsite before using electrical items.

Electrical items will have the power rating somewhere on the device measured in watts.

Also, circuit breakers in motorhomes may have 10amp rating (check first) and with 230v you have a maximum 2300 watts available.

For sites with 6 amps you have a maximum of 1380 watts so a domestic kettle at 3000 watts cannot be used, whereas a travel kettle at 1kW (1000 watts) will be ok.

 

[DrewE127]

Thanks dr1uk that’s a really helpful reference

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[autorouter]

Although we refer to 240v the UK now has 230v (EU regs).

It's still 240V if you stick a meter into the socket. The EU spec changed to 230V plus or minus 10%, so technically we are well within that band, as is the commonly used 220V value in some parts of Europe. It doesn't make a great deal of difference.