# Sterling battery to battery charger



## WINDYJOOLS (Jun 25, 2006)

has anyone had experience of these (rather expensive) units which claim to recharge your leisure battery quicker and more efficiently than a standard reay system? we have a compressor fridge which, even with a BIG solar panel gives the battery a hard time. we don't use hook up much so have struggled to keep the battery charged. we run 2 x 110a/h batteries, so any help or advice would be appreciated.

thanks to all who took the time to reply, i think we will try clives trick with the hefty wire & relay (at the moment we use a 70amp relay + 4mm wire) and see if that does the job. taking the cnnection direct from the alternator is one i have'nt heard of but makes sense.
happy days to you all.


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## DABurleigh (May 9, 2005)

Welcome to MHF.

Yes, I have one. The advantage over a thick wired split-charge system when the battery is low (50%) isn't that great. And similarly when the battery isn't far off full it won't do much either. In between it yields a substantial improvement. Whether it is for you depends on your electrical consumption in relation to driving time. Some would be better off with a third leisure battery. 

In sum, great technology; effectiveness depends on your envisaged circumstances. 

Dave


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## WINDYJOOLS (Jun 25, 2006)

cheers dave, we are pretty mean with our electrical consumption, led lights, no tv, no hot water system.... but the problem is that the compressor fridge is on all the time and if we have a few cloudy days, the batteries get down below 12.2 volts, which is toooooo low for comfort and does seem to take a long time for the 175watt solar panel to recharge them. the engine is reasonably modern so has a 90amp alternator but still takes a long drive (4-5hrs) to get the batteries back up again. 
the real question is ...... is it worth £200 for this b2b charger?


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## gnscloz (Oct 4, 2008)

i have one too, best mod have done to van fitted it alongside 2 independent 110 amp leisures batteries (wet lead type) can survive 5 days with out hook up easily using electric as would at home.


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## CliveMott (Mar 10, 2008)

Try replacing your existing split charging wiring with some significantly more substancial cable first. Bigger fuse and fatter relay as well and take the supply directly from the alternator B+ terminal. This may very well do all that you need and its low technology unlikely to fail!

C.


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## Jean-Luc (Jul 21, 2005)

Here is an example of how our B2B does the business.
Last December we spent 48 hours in the Aire at La Rochelle in freeeezing weather. The Truma was on constantly, lights, TV and Sat box were on for the long evenings. As we left, the voltage was showing 12.1v on the panel. After a four hour drive to Mayenne the batteries were fully recharged and ready for the coming night. 
We have two Varta Sem-traction 80ah batteries.


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## PeterandLinda (Feb 21, 2009)

Hi

It was explained to us that the Sterling would charge the leisure batteries from the vehicle battery much quicker once the engine was running, so that a relatively short journey between Aires would still leave the leisure batteries charged when we stopped - so far it seems to be working. If you want more detailed information We would recommend VanBitz. They know their subject.

P&L


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## Jean-Luc (Jul 21, 2005)

As P&L said the B2B will put charge back into the leisure batteries very quickly. That is because it will pump the power in at up to 50a/h and 14.8volts, which in fact, batteries like and it helps prolong their life.
The above figures only apply to ordinary wet lead acid batteries, which are best suited to the above charging regime and you need to keep an eye on the electrolyte levels, so the sealed type are best avoided. 
Gel, AGM and other 'exotic' batteries requires a 'softer' approach and will end the charging process with less 'power' stored (size for size obviously).


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## acctutor (Oct 3, 2009)

Hi

Maybe too late for the topic but we have fitted a SmartGuage system to our boat (1 engine battery/2 leisure batteries), and ther system works a treat.

They do lots of work with ambulance trusts

http://www.smartgauge.co.uk/index.html

No connection with the firm - but a very satified customer and will consider fitting one to our new Allegro 96 if the supplied system needs upgrading

Bill


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## rowley (May 14, 2005)

I would follow Clive's suggestion rather than pay out for an over-rated item.


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## dipsticks (Aug 2, 2007)

Has anyone fitted one of these Sterling battery to battery chargers to a Mk7 Transit ?

or

Does anyone know if they can be fitted to a Mk7 Transit with Ford fitted auxilliary battery ?

Thanks

Pete D


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## time-traveller (Apr 23, 2007)

rowley said:


> I would follow Clive's suggestion rather than pay out for an over-rated item.


That's interesting. Presumably you have had a Sterling BTB charger, then, and base your comment that they're 'over-rated' on practical experience? What is it about them that you found you didn't like?


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## Jean-Luc (Jul 21, 2005)

I must say my B2B does exactly what it says on the pack, for example, after 48 hours on an Aire in December in La Rochell in freeeezing weather, with heating on permanently plus lights, tv, sat, etc. my batteries (2 X Varta Semi Traction 80Ah) recovered from 12.1v back to full after only c.300Km/about 4 hours driving.


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## blondy (Aug 23, 2007)

I don't believe its over rated as I am on my third M/H, all with twin leisure batts, and at last with my BtoB we have never had a low battery, even in the winter. As has been said, it charges very fast while travelling, and pos could be used instead of genny on site. We bought a new genny just before we got this M/H, and have never used it since BtoB charger.


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## time-traveller (Apr 23, 2007)

time-traveller said:


> rowley said:
> 
> 
> > I would follow Clive's suggestion rather than pay out for an over-rated item.
> ...


Bump for Rowley

I'm really interested why you think they're over rated and to hear of your experience of one ...... :?


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## Lunarvictim (Aug 15, 2009)

dipsticks said:


> Has anyone fitted one of these Sterling battery to battery chargers to a Mk7 Transit ?
> 
> or
> 
> ...


They can be fitted to any vehicle as long as you have room for it but as the unit is quite small you shouldnt have a problem.The wiring is vey simple the only thing i would say is use the thickest wire you can to cut down resistance.They are an excellent product and just make the alternator work at full capacity.I even used my towcar engine to charge the MH batteries by using jump leads when we were stationary for a while instead of using the Mh engine.


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## Mike48 (May 1, 2005)

These things must play havoc with the vehicle's alternator. Is there evidence of early alternator failure I wonder.


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## CliveMott (Mar 10, 2008)

The two battery system fitted to the latest Transits is a tad different.
The two batteries are both wired in substancial "starter current" sized cable. The second battery is connected to the first battery with a high current bi-stable relay. This relay includes a permanent magnet inside it so that once energised to close it it will remain closed. It has 3 coil connections, one is energised momentarilly to close the relay and another energised momentarilly to open the relay. The associated fuse is very substancial.

When the engine is being started the relay is closed so that both batteries supply starting current.

When the vehicle ignition is turned OFF the the relay is opened so that any accessories that are used only discharge one battery.

It could be a tad complicated to integrate a B2B system between this pair without compromising Fords basic design phylosophy.


(We took the seat out of a new Transit and crawled all over it with a multimeter to work out how the heck it worked, the seat belt was a pain!)

C.


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## Lunarvictim (Aug 15, 2009)

gelathae said:


> These things must play havoc with the vehicle's alternator. Is there evidence of early alternator failure I wonder.


The unit has sensors that attach to the Alternator and batteries.If the Alternator or batteries get to hot the unit cuts out until the temperature comes down again.


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## Lunarvictim (Aug 15, 2009)

CliveMott said:


> The two battery system fitted to the latest Transits is a tad different.
> The two batteries are both wired in substancial "starter current" sized cable. The second battery is connected to the first battery with a high current bi-stable relay. This relay includes a permanent magnet inside it so that once energised to close it it will remain closed. It has 3 coil connections, one is energised momentarilly to close the relay and another energised momentarilly to open the relay. The associated fuse is very substancial.
> 
> When the engine is being started the relay is closed so that both batteries supply starting current.
> ...


Would be worth contacting sterling for compatability with this system as the Aux battery becomes a start battery while the engine is running.


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## time-traveller (Apr 23, 2007)

Lunarvictim said:


> gelathae said:
> 
> 
> > These things must play havoc with the vehicle's alternator. Is there evidence of early alternator failure I wonder.
> ...


That sounds pretty sophisticated to me - was it easy to fit then? Did you fit one yourself?


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## Lunarvictim (Aug 15, 2009)

time-traveller said:


> Lunarvictim said:
> 
> 
> > gelathae said:
> ...


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## DABurleigh (May 9, 2005)

Ease of fitting. Probably the trickiest thing is choosing where physically to put it. Electrically it fits in place of a standard split-charge relay. If you know you have one and where it is you can fit a B2B.

Over-rated or not depends ENTIRELY upon one's MH pattern of use, understanding and expectations and not upon the design, which is excellent (it got Sterling the Queen's Award to Industry). Where it adds effectiveness and where it doesn't I have covered before on MHF; just search.

Dave


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## CliveMott (Mar 10, 2008)

I would have thought that the viewpoint of Ford would have been more important?

Anything can be made to work but what if ...... etc.

You would be safer having a totally seperate set of Leisure batteries if you want to use a B2B to charge them. Then nothing is compromised.

Alternatively just double up on Fords second battery and use it for leisure as well leaving the charging regime unchanged.

C.


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## emmbeedee (Oct 31, 2008)

CliveMott said:


> The two battery system fitted to the latest Transits is a tad different.
> The two batteries are both wired in substancial "starter current" sized cable. The second battery is connected to the first battery with a high current bi-stable relay. This relay includes a permanent magnet inside it so that once energised to close it it will remain closed. It has 3 coil connections, one is energised momentarilly to close the relay and another energised momentarilly to open the relay. The associated fuse is very substancial.
> 
> When the engine is being started the relay is closed so that both batteries supply starting current.
> ...


Clive, what you are describing is, I think, the standard Transit commercial van two battery system. However, mine only has one vehicle battery. Under the passenger seat is a leisure (only) battery whilst the vehicle battery lives under the driver's seat.
This hasn't caused any problems so far but we haven't been able to use it much lately.  
The only mod. I've done in this area is to make up a (fused) lead to connect the two positive terminals when on hook-up. The van had been standing on our driveway & after about six weeks of non-use, when the batteries started to go down, I plugged in our hook-up cable. But of course this only charged the leisure battery. Using my new lead both are charged.
I think I saw this idea mentioned by you on another thread, it works very well, so thanks for that.
I haven't checked any other similar Transit MHs so don't know if it's just Roller Teams that have the more traditional separate battery system or whether it applies across other MH also.


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## DABurleigh (May 9, 2005)

Here:
http://www.motts.org/BRIDGING FUSE.htm


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## emmbeedee (Oct 31, 2008)

Yes, DAB, that's the one. I did mine a little differently to make use of items I already had in stock, or, as the rest of the family put it, "in that pile of junk you have in the garage".
I used Lucar clips (remember them?) & an in-line fuse holder. Couldn't find my stack of fuses but salvaged one from a redundant 13 amp plug.
I fixed a Lucar blade to each battery positive terminal (suitable bolts already there) so I can just unclip each end when not in use.
Simple, cheap, (free in my case) & effective.


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## rowley (May 14, 2005)

Sorry Time Traveller, my choice of word was perhaps unfortunate for I know that the item works. However, I consider that it is certainly overpriced for what it is, and I would prefer to follow Clive's advice which is simple, cheap and effective.


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## time-traveller (Apr 23, 2007)

rowley said:


> Sorry Time Traveller, my choice of word was perhaps unfortunate for I know that the item works. However, I consider that it is certainly overpriced for what it is, and I would prefer to follow Clive's advice which is simple, cheap and effective.


Have you carried out Clive's mod on your motorhome, then? And you find it charges up the habitation battery to its full capacity without the alternator 'knocking off' at around 60% full charge?


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## Tinyk (Mar 18, 2009)

We have just had this battery to battery system fitted to our Renault by VanBitz along with a sterling 50amp mains charger and 2500 inverter.

First time out since fitting, been fantastic used it flat out the first night and a short 60 min drive brought the batteies back up to full again. So much power with the new 220 ah batterie that first night on site we stuck the immersion, kettle and fan heater on without thinking and tripped the mains fead, batteries kicked in and it was two days before we noticed that everything was running on batterie and not mains LOL.

I would certainly say although we had the mains system fitted to run with our genny to cut down the charging time that we had to keep genny on for, we will no prob do away with genny all together as we can just run the van engine to charge batteries just as quick, no wires no getting wet no messing just lean over and turn key  thats my type of job.


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