# Battery to battery charger



## 4maddogs (May 4, 2010)

Hi
I am wondering whether this would be a useful addition? I have a 530lp 2010/1 model and I have added an additional battery already. I wild camp quite a lot but do not always move for any length of time between camps.
I think I am a fairly high user of power. In winter in Scotland when it is dark at 4 I tend to like the TV in the evenings. I have a sat dome and use a free sat decoder with a twin lab so I can record....the is only so long you can read. I camp alone. I also like my technology so I charge devices a lot.

As I mainly go to Scotland I don't think a solar panel would be the answer for me. I do not want a generator (noise, weight and having to leave it outside when wilding) so a b2b seemed a good choice, but I don't know too much about them.

Any suggestions would be appreciated , also where would be the best place to site it?
Thanks (also posted on Swift talk forum)


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## listerdiesel (Aug 3, 2012)

Although it gives you the option of using the vehicle battery and alternator as a power source, you have to run the engine to get that vehicle battery charged up, so you're no different to someone running a generator if you think about it.

If you are driving every day, that's a different matter, but you say you don't do that.

Solar is the way to go, or take the generator.

Peter


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## alshymer (Nov 4, 2007)

*B 2 B Charger*

Hi
I agree with the previous post. Although a B2B has its advantages, it would not suit your application. 
I have B2B, 120w solar, Sterling inverter Charger and an Efoy.
For winter if you can afford it buy the highest capacity Efoy you can afford.
Not cheap but great tool.
Best wishes
Alshymer


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## WildThingsKev (Dec 29, 2009)

You say that you don't move much but can you give an idea of just how much that is?

If it is more than an hour every second day a b2b may be worthwhile.

Kev


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## 4maddogs (May 4, 2010)

Thanks, guys. I said I do move, just not for very long so that does not charge the batteries enough. 

I really do not want a generator. I doubt I have the weight capacity and do not feel comfortable carrying petrol in a 6m van with no garage.

Yee gods efoys are expensive!!

Would a solar panel give enough charging power on a dingy December day in Scotland? I really have no experience of them, but my Swift is pre-wired for one (not sure of capacity though)


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## 4maddogs (May 4, 2010)

Hi Kev,

Yes I would probably move for an hour or so most days, but not all in one hit. So meandering around stopping and starting as the mood takes!


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## listerdiesel (Aug 3, 2012)

Whatever solar panel rating you look at, you'll get 1/4 to 1/3 of that in winter, probably even less in the shorter days in Scotland.

A small 800vA or 1kVA Chinese genny would be the way to go, despite your dislike of them, enough to run your onboard charger to recharge the batteries

Otherwise you'd end up with two flat batteries.

Peter


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## nicholsong (May 26, 2009)

4maddogs said:


> Hi Kev,
> 
> Yes I would probably move for an hour or so most days, but not all in one hit. So meandering around stopping and starting as the mood takes!


We have a Sterling B2B so I may be able to answer your question, but I also would like a bit more info so as not to misguide you.

You have told us how much you drive each day, but a bit more info on usage of electrics would help. You like you tele and you charge other devices. Are these other devices charged from 12v supplies without resorting to using an inverter? Most electronics can be charged from 12v even if needing to step up to say 19v using a multi-volt charger from Maplins. Inverters are heavy users of electrics and inefficient for charging say a 19v device.

What capacity are you batteries? did you match like for like when you added the second battery?

Are all you lights LED?

Sorry for so many questions but they all make a difference to what is suitable for you.

Look forward to hearing from you.

Geoff


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## daffodil (Aug 7, 2014)

WOW those efoys are amazing 
I want one so many applications
even for the house if there is a power cut 12 v lights and appliances brill


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## coppo (May 27, 2009)

If you have a couple of batteries I would say a B2B is ideal for you from what you have said.

Paul.


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## wobby (May 1, 2005)

You say your in Scotland, isn't it quite windy up there? Would you consider this as well as solar.

http://www.leturbines.com/products/le-v150-wind-turbine/

Wobby


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## erneboy (Feb 8, 2007)

That might be interesting. I tried a horizontal axis one some time ago but it wasn't great http://www.motorhomefacts.com/ftopic-68657.html
They need clean wind which isn't often found where motorhomers might like to park.

I understand vertical axis turbines do much better if the wind direction is a bit changeable which is usual in the places we want to park due to buildings trees etc.

It would be an interesting experiment. Turbines have moved on a bit, Alan.


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## 4maddogs (May 4, 2010)

We have a Sterling B2B so I may be able to answer your question, but I also would like a bit more info so as not to misguide you.

You have told us how much you drive each day, but a bit more info on usage of electrics would help. You like you tele and you charge other devices. Are these other devices charged from 12v supplies without resorting to using an inverter? Most electronics can be charged from 12v even if needing to step up to say 19v using a multi-volt charger from Maplins. Inverters are heavy users of electrics and inefficient for charging say a 19v device.

What capacity are you batteries? did you match like for like when you added the second battery?

Are all you lights LED?

Sorry for so many questions but they all make a difference to what is suitable for you.

Look forward to hearing from you.

Geoff[/quote
The batteries are both the same make and 110ah
The lights are partly LED I think. The main lights are, but I am not sure about the reading lights. They may be halogen.
I use an inverter (sterling 150w) to charge my MacBook air and to power the Humax freesat box....I suspect that this is quite power hungry as it is a very new model and records to. It also has a wifi receiver but I don't use that in the van.
I have not run out of power,yet, but I don't want to!!
Otherwise I use the 12v sockets for iPhone and iPad etc
The TV is an Avtex and runs off the 12v socket.
I suspect the biggest issue is the freesat box, but I rarely get a decent TV signal without using the satellite. I am loathe to change it as it does all I want when on hookup that a 12v box cannot.

Thanks for your advice
Julie


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## 4maddogs (May 4, 2010)

Love the wind turbine idea! 

I do want to be able to just drive off if there are any problems though! Not that there ever has been!


Those gassers can turn up anywhere though....duck!


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## 747 (Oct 2, 2009)

At £840 the LE v150 is very expensive and its output is poor at low wind speeds. Its only advantage is that it can handle higher wind speeds than a standard, bladed turbine.

Don't be fooled by output figures in watts, they seldom achieve anywhere near that. If you look at the performance chart, you need wind speeds in excess of 40 to 50 mph to look respectable.


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## TheFlups (Nov 9, 2012)

Warrior Generators have what seems to be a good deal on lpg genny's....this might be tempting.


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## WildThingsKev (Dec 29, 2009)

I think a b2b charger will work for you, the number of short runs won't matter. We have a similar van / leisure battery setup and since fitting the b2b I reckon we get 3 x the charge we did before on a normal 2 hour drive after a couple of days stationary.

You ideally need to fit a relay to isolate the leisure batteries from the existing charging system when the engine starts so the b2b can do its job properly.

Kev


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## nicholsong (May 26, 2009)

Julie

Let me first deal wth what you run off the inverter. I do not know in detail what the internal operating voltage of the particular items you are running but a lot of electronic equipment, including TVs 'step down' the 230v domestic electricity supply to 12-19v, which is why one can buy TVs which can run off 230v or 12v. So, try to establish whether you can dispense with the inverter which could save a lot of power and charge from the 12v system.

Having said that, even using the inverter and with 2 x 110ah batteries and driving about one hour a day I think the B2B would suit your needs. I would forget wind generators - they do not produce much and are noisy/vibrate and as you say do not permit just driving off at short notice. With a B2B if you were to get a bit low on power it would only take a few minutes of running the engine to top up - unlike a generator which would have to run for much longer.

For installation I suggest that the B2B is wired directly to the batteries and not through your existing system. As to location, position it as near to the leisure batteries as you can.

I hope this helps.

Geoff


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## 4maddogs (May 4, 2010)

Hi Geoff,

Well, I can buy a 12v charger for the macbook for about £25 which should work (just more slowly I expect). 

The freesat box I doubted would work over 12v.....well I just checked and it seems that there is a 3rd party lead. It is not expensive so worth a try. I always assumed it was a power hungry device (it certainly is powered via the inverter as you say.
The instruction manual states:
Power Supply
Power Type: External Adaptor
Power Consumption: 12V/4.0A (Standby: under 0.5W)
Input Voltage: AC 100~240, 50/60Hz

Makes little sense to me I am afraid!

I see that will make a difference to the power used. It also seems to make a lot of sense to go for a B2B as well.
Thanks for your help.


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## 4maddogs (May 4, 2010)

Update:
The 12v lead works fine so that cuts out the inverter for the freesat box. The 12 is powered using the 12v lead anyway.

The macbook air does not need much charging so I can plug it in sometimes (or go to a cafe!)

I think I will go the B2B route, but not before I go to Mull at the weekend.
Thanks all.


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## nicholsong (May 26, 2009)

So you are going to Mull it over :lol: 

Sorreeee :roll:


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