Batteries off grid - my findings - my fix

eddievanbitz
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Great thread :)
(although I'm pleased my system is finished as was such a headache to get right)

One thing I have noticed in this thread is every time a B2B is mentioned it seems to be the Sterling. Nothing wrong with the Sterling at all but a few people have had problems with them conflicting with a solar MPPT.

For this reason I went with the CTEK D250S Dual which is a combined B2B and MPPT charger. I needed a lot of battery power in my van (400Ah), as I run a compressor fridge and an in-built PC all day long, so added the CTEK Smartpass which boosts the charging rate all the way up to 100a maximum per hour (although I also generally get around 40-50a on engine tick over, monitored by Nasa BM1).

The other advantage of the CTEK unit is, once the leisure batteries are full, the system switches itself over and charges the engine battery - great in the winter at stopping the alarm flattening the battery.

I know Sterling are going to bring out a combined B2B and MPPT called the Wildside but I don't think it's available yet.

I like Eddie's comment on cables.

I fitted 25mm cable runs between my batteries to reduce voltage drop. As this wire is nice and thick I was able to add an isolator to bypass the charger so if my starter battery is ever flat one morning I can flick the switch and start the van using the power of my leisure batteries. If this was tried through a smaller cable I think it would melt :)
 
Jim said:
Since installing the Sterling Battery to Battery charger, along with a , I have not had cause to run our Honda Generator at all. This year at some rallies the Funster band have been using power straight from our two 110 Banner batteries through the inverter. Should the band get too many encores (a common occurrence) I know all I have to do is run my engine a little while and the batteries are back to 85/90% very quickly (y) Who needs a genny, who needs the sun. You just need a B2B- for me its perfect.
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Sorry - just learning!!

Alan
 
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Jim said:
Since installing the Sterling Battery to Battery charger, along with a , I have not had cause to run our Honda Generator at all. This year at some rallies the Funster band have been using power straight from our two 110 Banner batteries through the inverter. Should the band get too many encores (a common occurrence) I know all I have to do is run my engine a little while and the batteries are back to 85/90% very quickly (y) Who needs a genny, who needs the sun. You just need a B2B- for me its perfect.
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Hi Jim

Do you mean you run your engine on idle?

I have heard/read that this is not a good idea with modern diesels. Something to do with the diesel particulate filter becoming blocked - apparently an expensive job to correct.

Anyone else heard of this - I would love to be reassured that I can run my B to B on idle.

Regards

Alan
 
Could you use cruise control and increase the tick over while charging ?

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Confused . Com ?
When a battery is fully charged what voltage should it read when tested ?
I have two 110 battery's that have been on charge for several days when I unplug the EHU they read 13.2 but drops to 12.6 in about 10 minutes under no load is this normal?
I also have a solar panel fitted by the dealer as part of the sale but no paperwork how do I test the output we allways seem to struggle to keep the batteries above 12v
 
Oh must be different on trucks then, if low on air you can put it on cruise to build up air while strapping your load or other jobs.
 
No it's the cruise control. Like if you get a motor that switches it's self off if you leave it on tick over to long to save fuel, you set the cruise for a faster tick over to over ride it. Handy when warming up the cab to clear the screen while you do your walk round.

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That isn't cruise ....all our lorries at work have that but it's not cruise control....they also have cruise control but they are entirely different things the cruise control can't be activated at less than 40mph it's controlled through the ecu
 
I just put my foot on the pedal , banged the button which works the cruise and it ticked over faster. Thought they all did it. Mind you have used the bit of wood in the past on the pedal, ha ha
 
LOL how can it control your cruising speed, when your stopped:LOL:;)

Don't forget that you can buy Alternator to Battery chargers and you can fit 220VAC alternator which do use "hand throttles" AKA Cruise control to some:)

Eddie
 
eddievanbitz said:
LOL how can it control your cruising speed, when your stopped:LOL:;)

Don't forget that you can buy Alternator to Battery chargers and you can fit 220VAC alternator which do use "hand throttles" AKA Cruise control to some:)

Eddie
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Eddie
That implies that you'r expected to leave the engine idling. Have you got any thoughts on this issue of the particulate filter getting blocked, as in my previous post.

Regards

Alan
 
DPF (Diesel Particulate Filters) are designed to last for about 75,000 miles from what I have read. A Vehicle with a DPF will have a warning light on the dash to warn that it needs cleaning and of course there are many additives that you can add to clean the DPF

It's not my field, but I personally don't worry about it. Also, to be honest, I would never keep a vehicle any where near that mileage.

The depreciation in value that I suffer when I sell a vehicle on, absolves my conscience for what happens to a vehicle down the road, if that makes sense.

It's all about convenience.

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Don Quixote said:
Firstly 13.8 is FLOAT charge...... secondly all vehicle alternators charge at voltage of at least 14.2 is correct HOWEVER most charging systems fitted in motorhome these days DO NOT all 14.2 volts for a long period of time and step the voltage back to FLOAT charge of 13.8. If the voltage was allowed to stay at 14.2 or better the amps would be in the high 25/30/40 amps - if this was the case your batteries would charge in no time!!!!! BUT because it is stepped back this is why does it take 8+ hours of driving to charge the batteries.......

As I have stated already this is a "gray area that many do not understand" - why would Mr Sterling make the battery to battery charger if the system fitted in motorhome or boats for that matter have such a good system fitted already ??? - CBE or any other system fitted will only charge your batteries to 80% period. They DO NOT FULLY charge your batteries. it takes 2/3 days of charging with NO LOAD to fully charge batteries.
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I said that 13.8v is float? I did not say that MH charging systems hold 14.2v for a long period of time - I said for a period of time. Mine holds at 14.2v for around two hours IIRC. The vehicle alternator is (in many/most MHs and caravans) connected directly to both start and leisure batteries as long as the engine is running. Its output is preset at 14.2+V. It follows therefore that both batteries will be charging at this voltage for varying and quite lengthy periods. The charge current flowing at this time will be nowhere near even 10A after the first few minutes. Which is why it is almost impossible to fully charge a leisure battery using the vehicle engine and why a B2B charger needs to be (and is) a pretty clever device that raises the charge voltage well above 14.2v (probably in excess of 18v) and monitors the charge current (amongst other parameters) to safely "fast charge" the leisure battery.
 
eddievanbitz said:
.............. whereas motorhome manufacturers tend to locate the leisure battery(s) where there is a space and connect them together with a bit of wire no thicker than a boot lace!
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MH manufacturers connect everything together with wire no thicker than a boot lace. And always have. To compound the error they're now fitting charge / control panels with multi-plugs designed for boot laces.:)
 
tonyidle said:
I said that 13.8v is float? I did not say that MH charging systems hold 14.2v for a long period of time - I said for a period of time. Mine holds at 14.2v for around two hours IIRC. The vehicle alternator is (in many/most MHs and caravans) connected directly to both start and leisure batteries as long as the engine is running. Its output is preset at 14.2+V. It follows therefore that both batteries will be charging at this voltage for varying and quite lengthy periods. The charge current flowing at this time will be nowhere near even 10A after the first few minutes. Which is why it is almost impossible to fully charge a leisure battery using the vehicle engine and why a B2B charger needs to be (and is) a pretty clever device that raises the charge voltage well above 14.2v (probably in excess of 18v) and monitors the charge current (amongst other parameters) to safely "fast charge" the leisure battery.
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Not sure your comment is correct for all motorhomes. IIRC according to the manual the current from my alternator goes through my Schaudt Electrobloc and its voltage and size is changed depending upon the type of battery and its state. It certainly seems to get above 14.2V at the battery, but that must obviously be at the expense of current. For how long it holds at that state will depend upon the type of battery, because Gel batteries have a different charging regime to lead acid, all of which is controlled by the Electrobloc.

I also have solar panels regulated by a Schaudt regulator via the electrobloc and again, IIRC, the regime applied is supposed to be the same.

Having said all that the wire between the alternator and the Electrobloc seems pretty thin on my motorhome, so it is not going to move large amounts of energy about! Although the wire from the Electrobloc to the adjacent battery is a lot thicker, and certainly a lot thicker than a shoe lace! But still nowhere near the size of the starter lead I used to connect the second leisure battery to the first with.

Eddie - will you be at Lincoln, because I would like to discuss with you the advantage (or not) and cost of me getting a B2B system fitted.
 
Hi Peter, No sorry we don't do the Lincoln show, we tried it a couple of times and it doesn't work for us.

Please also bear in mind that if your motorhome has an Electrobloc with an ammeter that fitting a B2B will "confuse" the system. The ammeter counts amps in and amps out and tells you what is happening.

The B2B has to be connected directly to the batteries and will be charging the batteries, without the ammeter knowing.

That's not a problem until you discharge the batteries when off hook up and the system thinks that you've used more than you have put in and starts to panic, erroneously!

The only solution to this is to fit a separate battery computer that will keep tabs on "everything" in, and out. We use the Victron unit which will handle 500Amps on the shunt so will allow for inverter discharge to me measured accurately. The Electroblok couldn't handle these levels of charge/discharge so have to be by-passed.

This is in no way any reflection on the equipment, but as I have said before, the average motorhome is designed for the average user to do "average things" So moderate use, normally on hook up when possible, mainy relatively short runs at weekends with a couple of longer runs/trips a year. Based on this, water tanks, grey and loo, battery capacity and charging regimes all tend to do the job, but can be enhanced/improved with specialist attention or equipment.
 
Has anybody seen the article on batteries/charging by Alan of A&Ncaravan services, the hymer electrobloc specialists, he doesn't rate B2B chargers or solar, instead recommending a generator? He also raves about Bosch S5 batteries as the bees knees.

Paul.
 
CazPaul said:
Has anybody seen the article on batteries/charging by Alan of A&Ncaravan services, the hymer electrobloc specialists, he doesn't rate B2B chargers or solar, instead recommending a generator? He also raves about Bosch S5 batteries as the bees knees.

Paul.
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Nop not seen that one do you have a link?
 
Hi John. I,m crap at links, just google the firm and click on batteries.

Paul.
 
CazPaul said:
Hi John. I,m crap at links, just google the firm and click on batteries.

Paul.
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Paul, I did and it's a minefield, however I'm convinced the way ahead is B2B regardless of what he has written because if the boating fraternity swear by them and many MH owners have them fitted and are very pleased I'm sure I will. I get home around the 14 September and when I have got hold of some + /- cable I will fit it and then post on here my findings. All being well I will have a Honda 10i for sale that I have dragged around for past 2 years and used a handful of times.........
 
That's like saying that mains hook up is better! If we are talking generators, then there are infinitely better mains chargers than the Electroblok, which is, by definition a "jack of all trades" charger, split charger, distribution block and fuse board

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Addenton said:
Confused . Com ?
When a battery is fully charged what voltage should it read when tested ?
I have two 110 battery's that have been on charge for several days when I unplug the EHU they read 13.2 but drops to 12.6 in about 10 minutes under no load is this normal?
I also have a solar panel fitted by the dealer as part of the sale but no paperwork how do I test the output we allways seem to struggle to keep the batteries above 12v
Click to expand...

any answers on this ?

interested as my set up is similar but do see higher voltages
 
Ivory55 said:
Am following this as it's interesting. One thing I have always wondered, on trucks I drive they hang a battery pack on the chassis behind the cab out in the open. Why do they not have similar on motorhomes . They make beany boxes to use space under the vans, why not have a cage for battery's under the van instead of sticking a battery under the drivers seat etc.
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Had that on my minibus. Fine in the summer but not in the winter. In winter I had to carry a spare battery to jump start the beast.
 
eddievanbitz said:
Hi Peter, No sorry we don't do the Lincoln show, we tried it a couple of times and it doesn't work for us.

Please also bear in mind that if your motorhome has an Electrobloc with an ammeter that fitting a B2B will "confuse" the system. The ammeter counts amps in and amps out and tells you what is happening.

The B2B has to be connected directly to the batteries and will be charging the batteries, without the ammeter knowing.

That's not a problem until you discharge the batteries when off hook up and the system thinks that you've used more than you have put in and starts to panic, erroneously!

The only solution to this is to fit a separate battery computer that will keep tabs on "everything" in, and out. We use the Victron unit which will handle 500Amps on the shunt so will allow for inverter discharge to me measured accurately. The Electroblok couldn't handle these levels of charge/discharge so have to be by-passed.

This is in no way any reflection on the equipment, but as I have said before, the average motorhome is designed for the average user to do "average things" So moderate use, normally on hook up when possible, mainy relatively short runs at weekends with a couple of longer runs/trips a year. Based on this, water tanks, grey and loo, battery capacity and charging regimes all tend to do the job, but can be enhanced/improved with specialist attention or equipment.
Click to expand...
Eddie

Thanks for that info. Shame you won't be there, but I can understand why.

I guessed putting a B2B in my system was not as simple as others. The Electrobloc has an ammeter, or at least the display shows me the amps going in (or out) as well as the volts and % charge of the batteries (I have 2 x 110Ah). At the moment I am not sure I need the added sophistication. I have installed 200W of solar (using a Schaudt controller and going through the Electrobloc) over the summer and I want to see how we get on with that before deciding what more (if any) to do. We do not use a lot of energy and that might be enough for us. We will see at Lincoln maybe with 4 days with no EHU in the autumn.

One thing you said has got the alarm bells ringing. I installed a 2000W/4000W inverter and it is obviously wired directly to the batteries. We do not use it much - really for wife's hair dryer about once every 3 days or so. I wonder if that is going to confuse the Electrobloc when I use it.
 
peterc10 said:
Not sure your comment is correct for all motorhomes. IIRC according to the manual the current from my alternator goes through my Schaudt Electrobloc and its voltage and size is changed depending upon the type of battery and its state. It certainly seems to get above 14.2V at the battery, but that must obviously be at the expense of current. For how long it holds at that state will depend upon the type of battery, because Gel batteries have a different charging regime to lead acid, all of which is controlled by the Electrobloc.

I also have solar panels regulated by a Schaudt regulator via the electrobloc and again, IIRC, the regime applied is supposed to be the same.

Having said all that the wire between the alternator and the Electrobloc seems pretty thin on my motorhome, so it is not going to move large amounts of energy about! Although the wire from the Electrobloc to the adjacent battery is a lot thicker, and certainly a lot thicker than a shoe lace! But still nowhere near the size of the starter lead I used to connect the second leisure battery to the first with.

Eddie - will you be at Lincoln, because I would like to discuss with you the advantage (or not) and cost of me getting a B2B system fitted.
Click to expand...

All true. My van (Hymer B584) uses the Electrobloc. Without investigating it further I noticed that the charge level with the leisure battery well discharged and the engine running is well in excess of what I'd expect (approaching 30A for the first half hour and still over 10A after an hour) which is why I said earlier that the EBL incorporates elements of the B2B technology. My EBL is charging 3 x 110Ah conventional leisure batteries (with the little switch on top set accordingly).

I was generalising (and exaggerating a little!) when I mentioned wiring. Wiring size can be determined in two ways: firstly by ensuring that it is capable of carrying the current required without over-heating and is therefore safe. Surprisingly 'thin' wire can carry substantial currents if sized by this method (0.5 sq mm - 11 amps, 3 sq mm - over 30 amps). And secondly by considering voltage drop. This relates to the resistance of the cable which, although very low, rapidly becomes significant as the length of the cable run increases. It's very significant when considering low voltage circuits. For example a wire resistance of 0.02 ohms will cause a voltage drop of 1V when carrying 20 Amps. This is true whether the circuit voltage is 230V or 12V. At mains voltage it represents less than 0.5% drop: at 12v it represents a quite significant 8%. Hence when considering low voltage cable runs "keep it fat, keep it short" becomes a useful rule of thumb.
 
It would be great if there was an educational meet with one of you knowledgeable people being teacher. I would love to learn more but it just seems a lot to try and understand in a thread. Fantastic thread though.

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