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Refitting A Furnvo Unicharger


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I have had a Furnvo unicharger fitted to my current van for six years, and it has been an excellent way to charge the van battery from the car. I am picking up a new caravan on Wednesday which has the 13 pin socket {coachman Amara 550/5], has any one refitted these chagers to this type of van/socket.

Cheers Nigel

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I have had a Furnvo unicharger fitted to my current van for six years, and it has been an excellent way to charge the van battery from the car. I am picking up a new caravan on Wednesday which has the 13 pin socket {coachman Amara 550/5], has any one refitted these chagers to this type of van/socket.

Cheers Nigel

Hi Nigel

 

Sorry I have never heard of these devices, I have done a search,

but does not explain what they do ! unless I am missing the point.

 

But why do you want to add something else ?

just use the wiring on the car to charge the battery !

 

Radiotwo

Steve - Land Cruiser Amazon Auto + Pageant Series 5 Champagne

The match between car and caravan is perfect in accordance with a mix of European standards. However, according to the British Towing Code the percentage (loaded caravan / kerbweight tow car) is 49%.

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The unicharger is fitted close to van battery or charger/transformer, you then plug an extension cable between cars grey 12s and caravan lead. Leave connected over night, and the unicharger allows the car battery to charge the van battery. There is a cut out feature that stops the car battery from flattening. Drive the car the next day, or whenever and car battery is recharged. This allows extended use of van away from hook up, solar panels or generators.

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The unicharger is fitted close to van battery or charger/transformer, you then plug an extension cable between cars grey 12s and caravan lead. Leave connected over night, and the unicharger allows the car battery to charge the van battery. There is a cut out feature that stops the car battery from flattening. Drive the car the next day, or whenever and car battery is recharged. This allows extended use of van away from hook up, solar panels or generators.

 

Sorry Nigel

 

Still don't get what you are doing ! How can you charge a caravan battery from a car battery that is only at 12. 5 Volts ?

 

The only way is to have a voltage of 14. 5Volts (obtained when the engine is running) to charge the caravan battery.

Plus the fact you don't want any connection between the car battery and the caravan battery when you try and start

the car,as if the voltage in the caravan battery was higher, then the current would be drawn from there and you are

talking of quite high amps, much more than for the 7/13 core cable to handle

 

So the best way to do it is charge the van battery while you are driving, and when you stop (engine off) the habitaton

relay cuts out in the caravan and no current flow to the caravan, but when you start up the car and the voltage reaches

14(ish) volts the relay cuts in and charges the caravan battery, with no connection when you start the car

 

Radiotwo

Steve - Land Cruiser Amazon Auto + Pageant Series 5 Champagne

The match between car and caravan is perfect in accordance with a mix of European standards. However, according to the British Towing Code the percentage (loaded caravan / kerbweight tow car) is 49%.

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This seems to be the same type of device that allows one car to be started from another via a lead between the cigarette lighter sockets. If one battery is "flat" i. e. at a lower voltage than a charged one there will be an equalising voltage flow from high to low. This will, eventually, reduce the voltage in the good battery until the two batteries are balanced. However, it's not a good idea to connect two batteries together unless they are the same type and size.

It is not a device I would recommend using.

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I can't see the point of this at all.

 

Not allowing for any resistance in the connections, if the car battery is at 12. 8 volts (fully charged) and the van battery is at 12. 0 volts, the the voltage can only ever equal out at 12. 4 volts in both batteries - half discharged as far as I'm concerned. And these assumptions are made if the two batteries are of equal capacity - and I've yet to see a 110Ah car battery.

 

If the unit has circuitry to prevent discharge of car battery to a level where it won't crank the engine then I would consider van battery voltage would be even lower.

Far better to use the car to charge a second leisure battery as you drive around and then use this battery for van electrics.

Edited by MOG
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The Furnvo is an excellent piece of kit which takes the 12v from the car, passes it through an inverter and prduces a c13. 2v output which charges the van battery, but, as said, monitors the car battery and cuts off to leave enough power to start the car . . ahd one since 04 . . should be part of caravan equip from the manufacturer . . oh sorry . . we all have to use hook-ups now according to them . .

 

 

to fit to the new van, just use the same wires as before, but watch out . . some (all?) have a circuit that detects when the car is connected and uses the car battrey for the internal 12v . . (switches out the caravan battery . . I had to put a relay circuit in my Compass to allow it to work as intended

 

Can let you have a circuit if you wish

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cheers Taid, seems to be sorted by Broadlane service manager Steve. He refitted it for me and all seems to work, will give it a trial soon. Nice to hear from one of the "converted". I understand that these are used by services and on rescue vehicles at airports etc. Really give freedom from extra batteries, solar panels and generators, and I agree they should be standard fit from manufacturers. Even though the inventor has retired, I believe they are still made to order at Furnvo Design. {no connection, but very happy customer} Sorry to anyone who doesn't understand how they work, and thanks to Taid for some explanation.

Edited by hvan
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cheers Taid, seems to be sorted by Broadlane service manager Steve. He refitted it for me and all seems to work, will give it a trial soon. Nice to hear from one of the "converted". I understand that these are used by services and on rescue vehicles at airports etc. Really give freedom from extra batteries, solar panels and generators, and I agree they should be standard fit from manufacturers. Even though the inventor has retired, I believe they are still made to order at Furnvo Design. {no connection, but very happy customer} Sorry to anyone who doesn't understand how they work, and thanks to Taid for some explanation.

 

Sorry again Nigel

 

But as a electrical engineer I still cannot see the point of taking a battery voltage of 12. 5 Volts up to 13. 2 Volts via an inverter.

 

You say there is a shut off, to protect the car battery, so lets say 12volts minimum the car battery starts at 12. 5volts, it takes

out a couple of amps and produces 13. 2 Volts, which will not fully charge a battery, then within a hour or so the system will cut out

and stop charging

 

So whats the point ?

 

At least when driving, you are giving 14. 8 Volts and poss 20/30 Amps which will charge the caravan battery

 

If it was such a good thing every one would fit them/use them !

 

Just a quick thought ! get a car battery and connect that to a inverter, then plug a battery charger into the inverter and then

connect the output to the battery Will it work?

 

Radiotwo

Steve - Land Cruiser Amazon Auto + Pageant Series 5 Champagne

The match between car and caravan is perfect in accordance with a mix of European standards. However, according to the British Towing Code the percentage (loaded caravan / kerbweight tow car) is 49%.

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You can count me in as another avid supporter of the Uni-charger.

Really is/was a good piece of kit for those not tied to EHU sites and wanting to stay at the site for three or more days. Unlike my solar cell I can rely on it in winter or late/early season.

Unfortunately they never were well marketed and were necessarily not a cheap item so only sold to those who understood its strengths.

I have made my own version by simply using a 120 watt inverter and Ctek smart charger. This has not the auto disconnect to retain a safe level in the vehicle battery so I limit the time its coupled. I also couple it to a second battery in the boot whilst out driving so effectively charge two leisure batteries when needed.

Edited by JTQ
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radiotwo, I am no electrical engineer, and have no detailed answer as to how this works. It was developed by a guy who lived away from power for an extended period. He would have to drive for water, and so would leave his car running to charge car battery. On his return, and at night, would connect his van electrics via this device to his car. The unicharger allows a flow to the van battery from car battery, and charges it. I have no idea how the cut off works etc, but having chatted to the guy after a recommendation from someone at Lowdhams, I was impressed.

 

We have used this a lot on our Hymer, and it has always charged the van battery, and never flattened the car; its the size of a pack of fags, no batteries to lift, no gens or panels and cost less than £100. We love it.

Nigel

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Sorry again Nigel

 

But as a electrical engineer I still cannot see the point of taking a battery voltage of 12. 5 Volts up to 13. 2 Volts via an inverter.

 

You say there is a shut off, to protect the car battery, so lets say 12volts minimum the car battery starts at 12. 5volts, it takes

out a couple of amps and produces 13. 2 Volts, which will not fully charge a battery, then within a hour or so the system will cut out

and stop charging

 

So whats the point ?

 

At least when driving, you are giving 14. 8 Volts and poss 20/30 Amps which will charge the caravan battery

 

If it was such a good thing every one would fit them/use them !

 

Just a quick thought ! get a car battery and connect that to a inverter, then plug a battery charger into the inverter and then

connect the output to the battery Will it work?

 

Radiotwo

 

my finger trouble 13. 2 should read 14. 2

 

don't knock it till you've tried it . .

 

it works . .

 

 

4 to 5 weeks away . . no hook-ups . . still got an adequately charged battery at the end . .( admit don't have tv)

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I can't see the point of this at all.

 

And these assumptions are made if the two batteries are of equal capacity - and I've yet to see a 110Ah car battery.

 

 

Although not many have, the Kia Sedona has a 110A battery. That 2. 9 diesel takes some turning over when its very cold. :D

Regards

SuperMike

together with

Management and Lady Faith Finesse, who is a Black & Tan Cavalier KCS - Gorgeous Girl, and my wife is as well.

Sedona 2. 9TDi - Swift Conqueror 645 LUX

CAVALIERS ARE LIKE SUNSHINE, THEY BRIGHTEN UP YOUR DAY.

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  • 2 years later...

Hi

 

Just to revive this thread I am a long time Unicharger fan, having had one for at least 10 years.

 

We have just bought a new Bailey Orion 430-4 and I want to refit my Unicharger to it but from this thread there is mention of fitting a relay. Does anyone know if the Orion needs one and if so how to go about fitting it. In layman's terms please as I am not an electrician although I successfully transferred it a number of times in the past.

 

Thanks

 

 

Den

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