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sizeyuk

Having read an article in Which Motorhome Mag. about generators I emailed Hymer about using a generator on my Hymer Motorohome and they strongly advised against it, I have recently emailed Marquis on behalf of a friend and they also advise against using generators, they can damage the charging units and in some instances the switching relays between cab and habitation have been damaged. They say that an added safety issue as the generator has a 'floating' earth so any rcd units fitted to the mains input may not operate effectively, they also have experience of generators damamging rcd's and mcbs. Has anyone else heard of this, if it is gernerally know why is there not more information around.[color=red:6e67eba95d][/color:6e67eba95d] Sad

Anonymous

Hi

the information you have been given is correct. Small generators can damage sensitive electronics.
The problem is controlling the voltage when the generator is loaded and unloaded. The governor on the engine tends to lag behind the demand. For example, when you plug in an electric kettle the voltage drops for a second or so as the engine takes the extra load, no problem for the kettle or the electronics but when you switch off the kettle the opposite happens. A voltage surge ensues which can damage chargers and other electronics.
The only safe way to use it is to charge your on board battery directly from the generator with it disconnected from all other circuits, a lot of hassle.
Or use the mains directly from the generator, again not very convienient.
I hope this makes sense, have you noticed how many second hand generators are for sale ? Crying or Very sad

Jim

EOR

Use the 240volt output of the generator, but make sure you have good bonding between your generator and your vehicle as its possible to have them at different potentials.

I would be cautious of using the geny to charge leisure batteries as their output is too low. Leisure batteries require a higher charge voltage to normal starter batteries, so its best to charge then via the mains.

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[b:2bda 1712c6]Steve
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Anonymous

Hi Steve,

Good point, you are correct about charging from a genny, I should have added that a generator should be used in conjunction with a proper battery charger. The 12v output from a genset is usually very ineffective for charging batteries.

Typical charging voltage for a deep cycle battery is 14.8 volts but as most onboard chargers/power supply units only push out 13.8 volts it is impossible to fully charge a deep cycle battery. The reason for this is to prevent overcharging when connected to the mains hook-up for long periods.
When you charge from the vehicle alternator the voltage should be up around 14.4 -.6 which will fully charge the battery if you are driving all day.
During the winter or any other time when I am are not using the MH for a while I remove the battery and put it on a long slow charge, checking the SG with a hydrometer until it is fully charged. This is much better than a fast "boost" charge.

Your point about good bonding is also true, this is a safety issue but it does not prevent damage as I described.

Jim

EOR

In actual fact vehicle alternators don’t actually charge leisure batteries to capacity, let alone starter batteries. People think they have a fully charged starter battery on the basis that it starts the vehicle or turns it over for quite a while, but if it was fully charged it would go on a lot longer. Leisure batteries need a higher charge voltage to charge them to somewhere near capacity. You’ll never charge a batter to 100% capacity.

f your looking for a more efficient charge to you leisure battery you will have to make changes to your alternators regulator. There are some simple circuits on the web to do this, however there are a number of companies who now market such a device. The best I have come across is from a company in Worcester called Sterling Power. Their product is called an advanced regulator which requires fitting inside the alternator which lead to the new regulator. On the regulator you need to set links to let the device know what sort of batteries its dealing with and it adjusts its rate of charge accordingly. You can get extra displays etc. but I prefer to let it get on with it.
___________________________________________________
[b:0934a30 2fa]Steve
aka A very wild....wild camper[/b:0934a302fa]
.
[URL=http://tinyurl.co.uk/lpak]Click here for my van website![/URL]
.
[img:0934a302fa]http://www.motorhomefacts.com/alb ums/PostingPhotos-1/VanThumbnail01.gif[/img:0934a302fa]

[i:0934a302fa]I do like a bit of feed back to my posts please[/i:0934a302fa]
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Anonymous

We live full time and have been using a Honda EU20i daily for months with no problems whatsoever. If you get a decent generator with an inverter output, you will get mains as smooth as if you were at home which will not damage your charger.

The Honda generators are expensive, granted, but we feel they're worth every penny. Our EU20i has already given us hundred of hours of quiet and reliable power.

(We sell them at very reasonable prices by the way)