EHU - Simple (?) question from newbie

[Fellbound]

I'm still very new at this.

 

When on EHU is the base vehicle battery being charged as well as the leisure battery? If so would being on EHU occasionally on the drive at home help the base vehicle battery when MH not being used that much over winter?

 

MH is a Marquis Majestic 105 (ie based on an Eldiss Accordio 105).

 

[Charles]

I emailed Elddis when I got mine and the engine battery is not charged by the EHU.

I fitted a Lidl smart charger on a fused spur in mine.

[Caddies104]

Hi

Surprised that EHU does not charge up engine battery, are you sure it does not?,

 

[Charles]

Yes 100% sure I'm afraid. It's one of the ways they kept the cost down I suppose.

[davidmac]

Hi easy way to find out,put volt meter on battery should read about 12volts ,switch on ehu if charging should rise to 13-14 volts

regards david

[Charles]

Yes did that David and it just sits there at 12.5v. The reason I also emailed Elddis is I thought it might automatically charge the battery every so often.. not so :-(

[aka4ajax]

Yes i found out the same on EHU the charger only supplies the vehicle battery a float charge, which means it never gets fully charged around (80%) i believe.

 

Even the alternator does not fully charge the battery again i am told this is around (90%) the only way to fully charge a vehicle starter battery is by using a separate charger I am afraid,

 

Neil

[Fellbound]

Thanks for the suggestions, folks. I just sort of assumed the EHU would automatically charge both batteries.I don't have a volt meter to check so will also double check with Eldiss like one of those who kindly replied.

 

It seems that yet again a simple question doesn't have a simple answer...... :-(

[Matrix Meanderer]

I think that it is fairly normal for motorhome batteries not to be linked when NOT on EHU.

But it I would suggest that it is normal for them to be linked/charging when on EHU.

 

There is a simple (albeit costly) device from Vanbitz which will sort out all battery charging issues both on and off EHU. See: http://www.vanbitz.com/product/battery-master/

 

We have fitted this device to our last two vehicles and it works well. Excellent when fitted to a MH with a solar panel, no more flat batteries in storage.

 

Alternatively buy an Adria which does charge both batteries when on EHU (lol)

 

[Robinhood]

Matrix Meanderer - 2015-09-27 6:30 PM

 

There is a simple (albeit costly) device from Vanbitz which will sort out all battery charging issues both on and off EHU. See: http://www.vanbitz.com/product/battery-master/

 

 

...the cheaper (and very similar) option is one of these:

 

http://www.ebay.co.uk/itm/SPLIT-CHARGE-EASY-FIT-LEISURE-TO-ENGINE-BATTERY-CAMPER-MOTORHOME-BOAT-12V-SOLAR-/121767326651?hash=item1c59e5f3bb

 

 

 

[Steve Drew]

Just taken delivery of our new Benimar Mileo 202 which came with a solar panel as standard, and was pleased to find it came with a device called a CSB-2 which although it gives priority to the leisure battery once that is charged it then charges the vehicle battery on both mains or solar.

[Robinhood]

Steve Drew - 2015-09-27 7:46 PM

 

Just taken delivery of our new Benimar Mileo 202 which came with a solar panel as standard, and was pleased to find it came with a device called a CSB-2 which although it gives priority to the leisure battery once that is charged it then charges the vehicle battery on both mains or solar.

 

...see my link above ;-)

 

(note, made by CBE who supply the basic electrics for a great number of motorhome manufacturers.)

[Charles]

Fellbound - 2015-09-27 5:07 PM

 

Thanks for the suggestions, folks. I just sort of assumed the EHU would automatically charge both batteries.I don't have a volt meter to check so will also double check with Eldiss like one of those who kindly replied.

 

It seems that yet again a simple question doesn't have a simple answer...... :-(

 

Sorry fellbound I forgot to say my motor home is a prestige 105 (ie Accordo 105)

[peter21]

A friend with a new Eldiss was told he had to disconnect the engine battery before charging it with an external charger. This seemed very odd to me...I've always just clipped on leads from a charger and left everything else connected.....anyone else had this advice, or understand the reasoning?

[colin]

peter21 - 2015-10-01 9:43 AM

 

A friend with a new Eldiss was told he had to disconnect the engine battery before charging it with an external charger. This seemed very odd to me...I've always just clipped on leads from a charger and left everything else connected.....anyone else had this advice, or understand the reasoning?

 

Standard advise on most if not all vehicles is to disconnect if not remove battery for charging, standard practice seems to be to ignore this.

[Bulletguy]

 

From the op i didn't see anything to indicate his vehicle was on SORN over winter.......so why not take it out for a run every couple of weeks? Not only would the battery benefit, but the van too! Even a short run out is far better than leaving any vehicle standing for any length of time. I sold my car for this very reason.

[Cliffy]

Robinhood - 2015-09-27 7:13 PM

 

Matrix Meanderer - 2015-09-27 6:30 PM

 

There is a simple (albeit costly) device from Vanbitz which will sort out all battery charging issues both on and off EHU. See: http://www.vanbitz.com/product/battery-master/

 

 

...the cheaper (and very similar) option is one of these:

 

http://www.ebay.co.uk/itm/SPLIT-CHARGE-EASY-FIT-LEISURE-TO-ENGINE-BATTERY-CAMPER-MOTORHOME-BOAT-12V-SOLAR-/121767326651?hash=item1c59e5f3bb

 

 

We have a Van Bitz battery master fitted to our van, cost £95 six years plus ago. The above sounds like it does exactly the same job.

 

 

[aandncaravan]

The reason almost all Car battery charger manufacturers say you should not connect a charger with the battery connected to the vehicle is many have voltages greater than 15v which can damage ECU's, Fridge controllers, Power units, etc.

 

Our 'Battery Charging Faults' page shows a photo of one with a 17v output, see : http://www.aandncaravanservices.co.uk/battery-charging-faults.php

 

Some of the CTEK units can put out almost 17v.

Second reason is the risk of putting the leads on the wrong way around.

We would suggest you always remove the Earth lead before charging a battery.

 

Many Motorhome manufacturers have setups that don't charge the Starter battery from 230v when on EHU. Some have a switch to manually select the Starter battery, but these are quite rare.

Almost all Continental built vans from 2002 have auto charging of the Starter battery from Mains. It is a reduced current charge but up to 6 amps, so more than just the trickle suggested.

 

Please don't fit a 'charge theft' devices as recommended earlier, the Battery Master and the like.

 

They are not the best way of achieving what you suggest because they don't monitor the battery voltage, but the voltage at the battery which is quite different.

They also cause issues with some Charger/power distribution units.

There are much better mechanisms that are usually cheaper.

See our Solar Power page, items 1 and 15 for a full explanation on why they don't work as well as better arrangements.

 

 

[Charles]

Why is the battery voltage different from the voltage at the battery? It's like saying the tap pressure is different from the pressure at the tap. A typo I suspect.

[aandncaravan]

No not a typo.

You could have a battery that is at 9.1v, when you connect the EHU the charger will start putting 14.4v into the battery. If you then immediately measure the voltage at the battery it will show 14.4v, which is the voltage of the charger. The battery is still at 9v and will take many hours to slowly rise back up to 12.9v.

If you read the link it explains it more fully.

[Charles]

Ok, I know what you mean. You are technically wrong (voltage appears across, current flows) but I'm not going to be pedantic, in laymans terms you're right. ;-)

[Robinhood]

aandncaravan - 2015-10-03 9:29 PM

 

Please don't fit a 'charge theft' devices as recommended earlier, the Battery Master and the like.

 

They are not the best way of achieving what you suggest because they don't monitor the battery voltage, but the voltage at the battery which is quite different.

They also cause issues with some Charger/power distribution units.

There are much better mechanisms that are usually cheaper.

See our Solar Power page, items 1 and 15 for a full explanation on why they don't work as well as better arrangements.

 

 

...I have to say I find the (IMO) sweeping statements here (and in some of your other posts) somewhat odd, as they not only often go against conventional wisdom (which you do acknowledge), but also against empirical evidence widely observed elsewhere than in your quoted problem examples.

 

Both the Battery-Master and CSB-2 solutions patently DO work, and have successfully been used by thousands of motorhome users as a cheap and easily-installed solution to the exact issue that the OP wishes to address.

 

I will acknowledge that I have seen the odd problem reported in installing them with certain existing power set-ups (usually those that have subsequently been found to have the capability to charge the vehicle battery natively installed!)

 

I can see no issues raised in your referenced "explanation" that would cause one to question fitting one as a cheap and simple solution to the OP's issue - there may well be more sophisticated, but also more expensive solutions.

 

I will admit that, because of its mode of working in sensing (relatively small) voltage difference between leisure and vehicle batteries, I wouldn't by preference choose to fit a Battery-Master unless I were generally on hook-up or had solar installed, since it patently stands an outside-chance (largely in the case of a failing vehicle battery) of depleting the leisure battery (ies) in favour of that vehicle battery. There is little doubt, however, that thousands of 'vans have these successfully fitted.

 

Personally, to address the issues in the original post, I would prefer the CSB-2, where diversion to the vehicle battery of an element of the charge from a mains charger or solar panel only happens when one or the other of these are actually charging (determined by sensing a terminal voltage in excess of 13.6V). This solution thus doesn't steal from the leisure batteries, but is different from the Battery-Master in that it requires a charge to be available for the vehicle battery to be replenished.

 

You pays your money, you takes your choice (as to which basic function you need) - but the CSB-2 is (IMO) a good, cheap, safe and easy resolution of the OP's issue.

 

And, talking of money, you rather enigmatically mention "There are much better mechanisms that are usually cheaper". The CSB-2 costs £22 and a bit of wiring. Can you suggest a solution for the OP's issue and vehicle that would be much better and cheaper? I know that sounds rather confrontational, but it isn't meant to be, I genuinely would like to know (as, I suspect, would the OP).

 

(BTW I would exclude a secondary vehicle battery charger on the grounds of convenience. I'm assuming you would, too, given the comments about always detaching the terminals before charging with one of these).

 

 

 

[aandncaravan]

The Vanbitz battery Master device is around the £70 mark. Pair this with a single output Solar regulator at about £50 (one designed for a Motorhome, not a generic Solar regulator) and the total cost is about £90.

Compare this setup versus a dedicated Motorhome twin battery output Solar Regulator at £75.

 

A good twin battery output regulator will allocate the lions share of the power to either the Starter battery or Leisure battery as appropriate. It will charge up a Starter battery and cope with a big drain on it from 'extras'.

The wiring is less complex so quicker to install. It will be more reliable long term.

 

The CBE CSB-2 is a Battery Master style device. Like the Battery Master, it steals power from the Source battery whenever it's apparent voltage goes above a certain threshold, often around 13.5v. I think the other Battery Master units have a triggering voltage of about 13.3v?

So both work pretty much the same. Their very low trickle charge will help stop a Starter battery going completely flat, but won't always charge it up it or replace a big discharge, like from a Tracker device, etc

 

A typical Starter battery with a Battery Master may be only 75% charged, enough to start the engine but not enough to stop the battery deteriorating from Sulphation as a result of not being 100% charged. Just an hour ago I started an ACE Airstream showing just 12.2v on the Starter Battery without any issue. Showing just how discharged a Starter battery can be and still start an engine. Left in this discharged state for long and it will deteriorate very quickly.

Many owners may never know they have a deteriorating battery, so while they say it may have worked well for a long lime, the question is : Could it have worked a lot better?.

 

A lot of the sales blurb says these power theft devices only take power from the Donor battery when it is fully charged. This is misleading. They take power from the battery when the voltage at the battery goes above 13.5v. The battery itself could be at 10v, but the voltage at the battery from the Solar regulator charge might be 13.7v.

The voltage the Battery Master 'sees' will be the 13.7v so will start stealing power from the Leisure battery even though that is probably not what the Motorhome owner actually wants. That is why we call them power theft devices, as we think they often take power when they shouldn't.

 

I have never said the Battery Master style solutions don't work. But a typical dual battery Solar Reg setup will be more efficient, cheaper to professionally install, more reliable and not suffer the complications/issues when paired with more sophisticated power management systems.

 

8 years ago things were very different and Battery Master's were a cheaper option where the compromises were acceptable.

Solar regulators are now more sophisticated and much, much lower cost.

So yes what we say is, "against conventional wisdom but also against empirical evidence widely observed elsewhere", but only because that is out of date.

 

As for a solution to the OP's problem?

Why not connect a dual output Solar regulator to both batteries, then remove the 240v chargers 14.4v output from where it goes onto the Habitation battery and feed it into the Solar regulators input ?

 

Never tried it, but it might work ok with only a little loss in efficiency?

 

 

 

 

[Robinhood]

I think I may be losing the plot here a bit (but if so, I don't think I'm the only one ;-))

 

My question was:

 

"Can you suggest a solution for the OP's issue and vehicle that would be much better and cheaper?"

 

It would appear that the answer is a resounding NO.

 

The OP potentially wished, and the majority of the thread has revolved around that wish, to "maintain" his vehicle battery from EHU (given that the factory-installed charging system doesn't do that).

 

A Battery-Master or CBE CSB-2 has been suggested (not only by myself), and the cheapest of these is readily available at the princely sum of £22.

 

Whilst not being the most sophisticated of solutions, it is perfectly adequate for the purpose being queried, cheap to buy, and cheap to install (the main concern being the location of the leisure battery (ies) viz a viz the vehicle one) and should be fit-and-forget. Thousands of motorhomers have successfully used these devices for just such a purpose.

 

In response, you've instead suggested a "solar" solution, at a higher start price even excluding the cost of a (probably) non-existent panel and regardless of the fact that the question was about charging from EHU.

 

Plot, where are you? ;-)

 

I must admit that if I were installing solar (and thus had to source a regulator) then I would probably do as you suggest. It would probably be more sophisticated, but it would also cost a lot more than a CSB-2 and "a bit of wire", (and I note you're still having trouble coming to terms with your ambivalence about solar.)

 

===

 

Incidentally, I don't think the Battery Master and the CSB-2 function in the same way. I don't believe there is a threshold on the Battery Master at which it starts/stops working working (The Schaudt LR 03 seems to be similar), whereas I believe there is on the CSB-2. (see my post somewhere above). I can see different modes of use which might make one more appropriate than the other, though I think the CSB-2 is more appropriate for most users (and much cheaper). It's worth also noting that the CSB-2 is documented as having a maximum charge rate at the vehicle battery of 4A, which if true would be very useful, and is well in excess of the amperage generally available from a factory-installed system (which many people also find quite adequate).

 

aandncaravan - 2015-10-10 1:31 PM

 

As for a solution to the OP's problem?

Why not connect a dual output Solar regulator to both batteries, then remove the 240v chargers 14.4v output from where it goes onto the Habitation battery and feed it into the Solar regulators input ?

 

Never tried it, but it might work ok with only a little loss in efficiency?

 

 

...and what would you be posting when someone brought this lash-up (sorry.....improvised but sophisticated solution) to you to fix if (when) it didn't work? :-)

[aandncaravan]

Sorry how have I lost the plot? I did propose a solution to the OP's issue, using a dual battery Solar regulator.

 

A good Solar regulator already has the split priority charging system to allocate charge as required to different sized batteries that might also have very different requirements.

It is just DC to DC device that will take any input, then drop it down to 14.2 and distribute to the batteries.

 

It makes no difference if the input to it is from a Solar Panel, Alternator (so long as correctly current rated) or the 14.4v DC from a mains 230v charger. They tend to be very efficient, they have built in blocking diodes, good voltage control, good current regulation, etc. Very sophisticated chargers these days.

Putting the 14v from his mains charger into a good one should work really well. If he put a Power Meter, as shown on our Solar pages, he would have really good visibility of the charge rate, which probably won't be shown on the existing display.

 

Far from a lash up, it is a very clever, simple solution that makes good use of existing technology.

 

I started the reply the way I did because most people now only fit the Battery Master type devices when doing Solar. Very few new MH mains chargers now don't supply the Starter battery with charge.

Hence explaining the differences/disadvantages first.

 

You also asked for a solution as one of your last paragraphs, that is where I made my suggestion, at the end.

Not tried it but will have a go?

 

As for ambivalence about Solar, recently noticed a great comment from Mr Eddie Vanbitz saying he didn't rate Solar. Maybe there are more out there who have seen the Sun, er, sorry light.

 

(lol)