12v generators (1 Viewer)

chrisgreen

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intresting :thumb:
same engine as im useing:thumb:



12 Volt Generators.
Link RemovedPetrol battery chargers (i.e.12 volt generators) are essentially a standard vehicle alternator attached to a small petrol motor. Many were initially home made and even the current wave of commercial ones are far from "consumer" products.
Most (all?) of the current ones seem to come from Australia although they may be assembled in the UK. Unlike mains generators you have to adjust the engine speed manually and if you suddenly apply an extra load the engine may stall.
Unless you are happy to use crocodile clips to connect to your battery each time you use the generator then you will need to do some serious heavy duty wiring and fit an external 12 volt high current socket. Note that disconnecting your generator whilst it is running may damage it.
The one illustrated above uses a Honda four stroke motor and a Bosch 55 amp alternator. It weighs 12kg and is only 410mm long.
Whilst significantly noisier (74dba @ 7 metres) than a top end mains generator (say 59dba @ 7 metres) it is considerably quieter than some no-name generators listed at an ear shattering 91dba! It will certainly charge your battery far faster than most battery chargers running from a mains generator and thus annoy your neighbours for less time! 12 volt 55 amp generators are available for around €775 at the end of 2008.
Because the current range of 12 volt generators do not incorporate a proper three stage battery charger they should only be used for bulk re-charging of a well discharged battery.
Unfortunately my testing of the generally well made 55 amp Christie generator (above) was cut short by an intermittent fault with the ammeter after a little over an hour of use. Whilst the generator itself was an interesting alternative to a mains generator my experience with the (only?) UK supplier was unsatisfactory (Trading Standards and my Credit Card company are currently involved and we may yet end up in the courts).
On balance I don't think the current range of 12 volt generators (petrol battery chargers) are yet ready for the overland campervan market. The need to manually adjust the engine speed, the absence of any current limiting electronics (so the engine does not stall when you switch on the inverter) as well as the need to add heavy duty 12 volt wiring together tip the balance in favour of a high quality (inverter) mains generator.
Note that many mains generators also provide 12 volts for battery charging at "up to 8 amps". My Honda EU10i will charge my campervan battery at around 6 amps but only if the "eco throttle switch" is set to off. This significantly increases the engine speed and noise level. With the "eco throttle switch" set to on, it charges at under 3 amps.
Stephen Stewart.
 

Terry

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Hi Chris :thumb: while I find your post interesting (after dragging it out for a long while) I too made the assumption that a alternator would be ideal to charge the batts only difference was mine is run by a 2.8 engine :ROFLMAO:
terry
 
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chrisgreen

chrisgreen

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Hi Chris :thumb: while I find your post interesting (after dragging it out for a long while) I too made the assumption that a alternator would be ideal to charge the batts only difference was mine is run by a 2.8 engine :ROFLMAO:
terry
but terry, do realy want to sit there with your 2.8 engine running for hours chargeing batteries with all the problems that it can cause,ie glazeing the bores,useing expensive diesel,and stinking out the van parked next to you?
and how would you start your 2.8 diesel if your battery is flat?

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scotjimland

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Well, as Terry said, they aren't new, .. but this sums them up rather well and why I believe they have never really caught on.. and unlikely to do so as they do not offer 230v mains without heavy cables and a large inverter..

On balance I don't think the current range of 12 volt generators (petrol battery chargers) are yet ready for the overland campervan market. The need to manually adjust the engine speed, the absence of any current limiting electronics (so the engine does not stall when you switch on the inverter) as well as the need to add heavy duty 12 volt wiring together tip the balance in favour of a high quality (inverter) mains generator.

With the RV, I had a EU20i Honda genny, a 70A four stage Victron charger/inverter .. and 4 x 85ah batteries.. When flat.. ie down to 50% or 12v it only took about 2 1/2 hours to fully recharge .. It did it fully automatically with no need for human intervention.

If I needed 230v the Victron provided 1.6kw of pure sine wave power..
 
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chrisgreen

chrisgreen

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Well, as Terry said, they aren't new, .. but this sums them up rather well and why I believe they have never really caught on.. and unlikely to do so as they do not offer 230v mains without heavy cables and a large inverter..



With the RV, I had a EU20i Honda genny, a 70A four stage Victron charger/inverter .. and 4 x 85ah batteries.. When flat.. ie down to 50% or 12v it only took about 2 1/2 hours to fully recharge .. It did it fully automatically with no need for human intervention.

If I needed 230v the Victron provided 1.6kw of pure sine wave power..
so how much payload does that that lot take up remembering not all motorhomes have the same payload as an rv,roughly 70 kg i recon?, and cost?£1000 i recon?
and if you needed 240 why not pull it off the genny at 1800kw of pure sine wave??
 

scotjimland

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so how much payload does that that lot take up remembering not all motorhomes have the same payload as an rv,roughly 70 kg i recon?, and cost?£1000 i recon?

Cost .. yes, not cheap, about £800 for the genny, ( but of course you could buy a Kipor :ROFLMAO: )
Charger .. again not cheap a 50A 4 stage will set you back £350 -£400

payload.. I guess about 30kg

I know where you are coming from Chris, a 12v 70A genny is cheaper and lighter but comes with the associated problems of being unregulated and requires some technical knowledge to use safely ..

When it has a voltage regulator for battery charging and a governor on the engine to maintain the speed irrespective of the load when coupled to an inverter .. it may become a serious contender ..

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chrisgreen

chrisgreen

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just looked on ebay cheapest 2000 honda new is just over a grand:Eeek:
dry weight 21kg.
i had a problem with it not adjusting the throttle when a load is applied,but can get over this by just running it at high rev's to start with:thumb:
most altenators have built in voltage regulators.
but i did not build it as a direct replacement for a 230 volt genny,but as a fast battery charger:thumb:
and im in the proccess of sorting out the noise,by changing the air intake:thumb:
 
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Road Runner

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TBO I rely on 12 volt so a way of rapid charging the battery via an alternator is a brilliant concept:thumb:
 
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chrisgreen

chrisgreen

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TBO I rely on 12 volt so a way of rapid charging the battery via an alternator is a brilliant concept:thumb:
see thats all it takes, a comment from an itteligent(sp) and good looking buddy,and my spirits are well and truly lifted:thumb:
i thank you kind sir:thumb:

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Road Runner

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see thats all it takes, a comment from an itteligent(sp) and good looking buddy,and my spirits are well and truly lifted:thumb:
i thank you kind sir:thumb:

A good idea deserved good feedback::bigsmile:

It does all our solar panels do but far more rapidly and worth a bit of petrol, miles better than running a genny all day to achieve the same outcome.

Couldn't think of anything rude to say:winky::roflmto:
 
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chrisgreen

chrisgreen

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A good idea deserved good feedback::bigsmile:

It does all our solar panels do but far more rapidly and worth a bit of petrol, miles better than running a genny all day to achieve the same outcome.

Couldn't think of anything rude to say
:winky::roflmto:
not like you john:ROFLMAO::ROFLMAO:
do you want to be my marketing manager?:ROFLMAO:
 

Terry

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but terry, do realy want to sit there with your 2.8 engine running for hours chargeing batteries with all the problems that it can cause,ie glazeing the bores,useing expensive diesel,and stinking out the van parked next to you?
and how would you start your 2.8 diesel if your battery is flat?

No Chris you have the wrong idea :ROFLMAO: I go to the shops or pub etc, so the van charges the batts :thumb: As to starting the van -I make sure the starter batt is a good un :thumb: but if it let me down then the L/Btt takes less than a few mins to swop over to the starter one :ROFLMAO::winky: I used to carry long jump leads but after abiut 3 yrs decided a adjustable spanner could do the same job :thumb: all be it with a little more effort :Eeek::ROFLMAO::winky:

Probably a lot better solution than carrying a engine/alternator and spare can of fuel :winky:
each to there own :thumb:
terry
 
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chrisgreen

chrisgreen

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No Chris you have the wrong idea :ROFLMAO: I go to the shops or pub etc, so the van charges the batts :thumb: As to starting the van -I make sure the starter batt is a good un :thumb: but if it let me down then the L/Btt takes less than a few mins to swop over to the starter one :ROFLMAO::winky: I used to carry long jump leads but after abiut 3 yrs decided a adjustable spanner could do the same job :thumb: all be it with a little more effort :Eeek::ROFLMAO::winky:

Probably a lot better solution than carrying a engine/alternator and spare can of fuel :winky:
each to there own :thumb:
terry
so running to the shop's is the best you can come up with,once i park my motorhome up it's there for the duration.and useing the water pump,for showering and the wife useing a hair dryer every day and telly on every night needs power so i need to put back that power quick,and dont need big bank's of batteries to run all that ,just needs a small 12v genny capable of chargeing fast,job done:thumb:
i suppose it a bit like building your own motorhome when it's cheaper to buy one on the open market,but each to there own:thumb: i know, i build one and if i took my labour into account i would have been better off buying one:thumb:but you got the satisfaction of building yours,as i got the satisfaction building a little genny:thumb:
 

haganap

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As some-one that uses 12v more than 240 hook up, I think its a great concept. But, here is the adjustments I want on it before I let you trial it in my van.
I want to be able to have it installed in a locker, an automatic start.

Surely a power surge wouldn't matter if it was running 12v any way? or how would you load it?

Until you update your plans, Im out :thumb:

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chrisgreen

chrisgreen

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As some-one that uses 12v more than 240 hook up, I think its a great concept. But, here is the adjustments I want on it before I let you trial it in my van.
I want to be able to have it installed in a locker, an automatic start.

Surely a power surge wouldn't matter if it was running 12v any way? or how would you load it?

Until you update your plans, Im out :thumb:
the auto start is an easy bit:thumb:
installing it in a locker easy:thumb:
no trial needed as it work's and does exactly what its suppose to:thumb:
power surge.???
i think people cant get their head around the fact that it is a battery charger and not a genny:Sad:
the way it can be loaded is when its running and the wife decides to use a 1000w 230v hair dryer through the inverter as it will try to replace the power being used out the battery:thumb:
must be something good about it, i have five more to build for other people:thumb:
and the new ones will be lighter as i will be useing ally for the frame work:thumb:
 
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chrisgreen

chrisgreen

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indeed, but how will you control the charge rate and auto stop when battery is full . ?

I alluded to this in a previous post.. it needs to be used by someone who has half a brain .. it isn't press button and forget ..
it controll's its own charge rate-it wont just chuck out 70 amps it will only put out what it needs to:thumb:
on a slightly disgarged battery it will bring that battery back up to charge(14.8) on tickover,on a fully discharged battery say 11v it has to work harder but once the battery goes over 12v the alternator will work less right up untiil the bat is fully charged.
jim!! just 1 Q do you know how an alternator works?

if a running alternator is connected to a fully charged battery all day it will not try and charge it it will sit there doing nothing.

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scotjimland

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it controll's its own charge rate-it wont just chuck out 70 amps it will only put out what it needs to:thumb:
on a slightly disgarged battery it will bring that battery back up to charge(14.8) on tickover,on a fully discharged battery say 11v it has to work harder but once the battery goes over 12v the alternator will work less right up untiil the bat is fully charged.
jim!! just 1 Q do you know how an alternator works?

if a running alternator is connected to a fully charged battery all day it will not try and charge it it will sit there doing nothing.

Yes I do understand how they work and appreciate they are now self regulating .. when I asked about regulation I was thinking of the older types that had an external regulator.. my mistake.. :Blush:

just one point, when the battery is fully charged , the voltage from the alternator will still be 14.4v across the battery .. yes ? Will this not boil the battery if left too long ?

hence my question about auto off ..

As an aside, what do you estimate the build cost is ?
 

Snowbird

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Am sure I have seen these at ex military sales years ago.
Am not saying they were exactly the same,but the concept sertainly was.
If my memory serves me right they used to be built into a small frame.
 
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So now they're in production, how much are you charging (£ not Amps) for one ?

Wonder if I could fit one in my empty gas locker once the fixed gas tank is fitted. I also need to leave space for a spare toilet cassette in there as we find this is the limiting factor on how long we can be independent.

Forget the knockers, this is a great idea.

Thought some of the Australian ones were a bit odd, what's the point of electric start on a battery charger for a flat battery :roflmto:

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chrisgreen

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So now they're in production, how much are you charging (£ not Amps) for one ?

Wonder if I could fit one in my empty gas locker once the fixed gas tank is fitted. I also need to leave space for a spare toilet cassette in there as we find this is the limiting factor on how long we can be independent.

Forget the knockers, this is a great idea.

Thought some of the Australian ones were a bit odd, what's the point of electric start on a battery charger for a flat battery :roflmto:
i will be building more for those that want them but at the moment trying to source engines at a good price to push the cost down,will let peeps know when i can fix a firm price:thumb:
 

Terry

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so running to the shop's is the best you can come up with,once i park my motorhome up it's there for the duration.and useing the water pump,for showering and the wife useing a hair dryer every day and telly on every night needs power so i need to put back that power quick,and dont need big bank's of batteries to run all that ,just needs a small 12v genny capable of chargeing fast,job done:thumb:
i suppose it a bit like building your own motorhome when it's cheaper to buy one on the open market,but each to there own:thumb: i know, i build one and if i took my labour into account i would have been better off buying one:thumb:but you got the satisfaction of building yours,as i got the satisfaction building a little genny:thumb:

Whoa Chris I am not knocking the idea at all :thumb: I posted a few months back asking the question on how long would it take the alternator to charge a battery- especially mine as it is a heavy duty one (ambulance) I think it was PPJ (not sure) who came back with the answer that mine would charge at around double the normal 55 amp hr rate :thumb:
As to parking the van up for the duration :ROFLMAO: not a chance :thumb: we use ours just like I would use the car and get out and about in it :thumb:
You may as well become a tugger if your van never moves once sited :Eeek:
I have a couple of leaf blowers in the garage and if I dare go into a couple of dark corners in there,it may well have an alternator in it :thumb: so it would be a easy job to knock one of your chargers up.That is assuming I ever felt the need for one :thumb: at the moment it is in the pending bin along side extra battery's and solar panels which all would be nice but do not need ::bigsmile:
terry
 
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chrisgreen

chrisgreen

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Whoa Chris I am not knocking the idea at all :thumb: I posted a few months back asking the question on how long would it take the alternator to charge a battery- especially mine as it is a heavy duty one (ambulance) I think it was PPJ (not sure) who came back with the answer that mine would charge at around double the normal 55 amp hr rate :thumb:
As to parking the van up for the duration :ROFLMAO: not a chance :thumb: we use ours just like I would use the car and get out and about in it :thumb:
You may as well become a tugger if your van never moves once sited :Eeek:
I have a couple of leaf blowers in the garage and if I dare go into a couple of dark corners in there,it may well have an alternator in it :thumb: so it would be a easy job to knock one of your chargers up.That is assuming I ever felt the need for one :thumb: at the moment it is in the pending bin along side extra battery's and solar panels which all would be nice but do not need ::bigsmile:
terry
first thing a leaf blower engine is not powerfull enough and 2 stroke.:Doh:
my van is 8mt, long from the front to the rear of the bike rack which carries a 125 enduro bike for popping down the shop's:thumb: so useing the van for a shopping trip's not an option as parking becomes difficult:RollEyes:,as for being a tugger been there done that:thumb:,but you could also say the same for people that pull a toad:Doh::RollEyes:.but i also wild in mine so its the perfect set up.as every thing is geared up for 12v, apart from wifes hair dryer:shout:
as i said if my previous thread every man and his dog will start building them,and they will:thumb:
as for your altanator being double the normal 55ah(110ah) rate,that is not uncommon on a lot of cars, a landy disco has a 150 ah altanator
the altanator im useing came off a 1200cc car and rated at 70ah.:thumb:

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Terry

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first thing a leaf blower engine is not powerfull enough and 2 stroke.:Doh:
my van is 8mt, long from the front to the rear of the bike rack which carries a 125 enduro bike for popping down the shop's:thumb: so useing the van for a shopping trip's not an option as parking becomes difficult:RollEyes:,as for being a tugger been there done that:thumb:,but you could also say the same for people that pull a toad:Doh::RollEyes:.but i also wild in mine so its the perfect set up.as every thing is geared up for 12v, apart from wifes hair dryer:shout:
as i said if my previous thread every man and his dog will start building them,and they will:thumb:
as for your altanator being double the normal 55ah(110ah) rate,that is not uncommon on a lot of cars, a landy disco has a 150 ah altanator
the altanator im useing came off a 1200cc car and rated at 70ah.:thumb:
OK the leaf blowers out of it :ROFLMAO:-HOW ABOUT A BRIGGS AND STRATTON 4 stroke lawn mower engine then? -got one of them lurking in a dark cnr :thumb: at least it tells me not to give it away :Doh::ROFLMAO:
No idea what the ambulance alt, amp rating is just know it is fitted with a H/D one :winky:We also run everything off 12v :thumb: but the wife's hair dryer is solely for hook up unless she uses the old fashioned way called a towel :ROFLMAO::thumb:At under 20ft I can get just about anywhere with the exception of height barriers :winky:
terry
 

JJ

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Definitely interested in one Chris... I will watch out for your updates...

This device reminds me of a self build I saw on an old, old bus on the continent over twenty years ago.

The guy had an old lawn mower engine fitted under the bonnet and a series of belt tensioners. He could slacken off the usual fan belt and tighten a belt from the mower engine to the van alternator. He fired up the engine (cord pull) and it charged up both the van engine battery and the habitation one with out using the van engine.

Brilliant.

JJ :Cool:
 

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