Yet another battery question

[aandncaravan]

spirou - 2018-09-15 1:20 PM

 

While on the subject... Where can I conveniently get D+ on an x250?

 

Spirou, I think you said you had a Schaudt Elektroblock EBL208 installed, if so you will find D+ at pin 22 which is set aside for technicians to use for driving the retraction of Satelite systems and such like.

 

 

 

Keith, Yes I like the Merc 'option' setup, but it is usually under the right hand seat, with the disadvantage of extra connectors and 'thin' cable and a longer run than straight from the Starter Battery.

The Merc option is not that different to the UK built vans that have a takeoff from the right hand dashboard down and across to the right hand door pillar.

But the cable run actually begins at the Starter Battery under the passenger feet on the left hand side, up to the Dash, along to the right hand dash side. Back down to the floor by the door Pillar, etc. Probably a wasted 2.5 metre cable run in 'thin' cable with about 5 different connectors?

 

To make it worse a UK Sargent Power Controller/charger often sits up high in an overhead cupboard, so the battery feed then runs back up from the base of the door pillar to the roof and then back down again to the batteries at ground level. You couldn't create a poorer design if you tried.

 

 

The best we have seen was a Burstner with the 12v electronics/power controller under the passenger seat just 2 feet from the starter battery with the habitation batteries under the Drivers seat, everything that is cable length critical was in close proximity.

 

 

 

I don't think the battery industry is aware just how bad some of these installations are or the impact they will have in destroying batteries that are not super tolerant of poor charging, etc.

 

One thing AGM's are not, is tolerant, but Wet acid batteries have a long history of proving that tolerance is one thing they have in spadefuls.

 

[spirou]

That's just the thing... whoever did our van wiring was an idiot who couldn''t read the wiring diagrams supplied with the EBL208. He wired the "D+" pin from the starter battery (via VSR) which meant the EBL was nearly always drawing 0.4A in standby mode. We've since replaced it with a somewhat crude solution of wiring it off the rear light cluster. Since lights are on when the engine is running it works. But if I do get to work on rewiring the cables to leisure batteries and installing a B2B I would like to use a real D+ wherever it's needed.

 

Now that I think about it, I never checked how he wired the stairs to retract with ignition on.

 

The electrician in question got fired within months if not weeks. Our van was one of the few he worked on and I'm surprised he lasted as long as he did. When we took the van back a few times the new electricians did fix a few things but these were again just improvised solutions that didn't resolve the core issues. I've looked at several of their newer vans, also this week at the show, and I did notice improvements but still not as good as it could/should be. The conversations there prompted my question regarding educating companies rather than buyers. They simply didn't see any issues even when I pointed them out. Granted they probably weren't electricians but sales people however the designs and solutions suggest this is an industry wide lack of understanding.

[aandncaravan]

Spirou, It is a wide spread issue across many vehicles from around the World, but some manufacturers pay more attention to detail than others.

 

While poor Alternator charging design will clearly have a major impact on the end result, this has come to a 'serious' head because a change in the loadings placed on those systems, which while not even vaguely efficient in many cases, have at least been safe while wet batteries are being used.

 

Fitting AGM batteries in motorhomes can be like installing an exploding bomb on a timer, literally, which I don't think many fully appreciate.

 

We have established the charging systems are worse than average on UK built motorhomes, so unsuitable for AGM batteries.

Veletron, for whom I have huge respect for his electrical and motorhome knowledge, yourself and many others have established that as fact.

By moving from Wet batteries that are super tolerant of any old Alternator charge rate above 13.5v to intolerant AGM batteries has introduced an element of danger that I think might be better not side tracked by manufacturers installs?

 

Now we have seemingly broad acceptance that the charging systems are severely flawed, may I now reiterate the danger aspect, because in all the replies, both on here and the Swift forum, it doesn't seem to have been acknowledged?

 

 

Why are AGM's more dangerous?

AGM batteries are from a group called Valve Regulated Lead Acid batteries where a valve is inserted into the 'Vent' at the top of the battery to keep them pressurised internally. One industrial AGM battery we are aware of has a vent pressure close to 30 PSI, but the norm is only a few PSI.

This raised internal pressure helps to recombine any Hydrogen/Oxygen back into water which then drips back into the battery cells.

 

It is universally acknowledged that AGM batteries are more prone to 'Thermal Runaway' explosion than any other Lead Acid battery type.

As the battery tires it runs hotter, this promotes battery breakdown, producing more heat. This extra heat promotes faster breakdown, that produces even more heat and faster breakdown again until, BOOM.

In some instances Fire is a greater risk.

 

So obvously an AGM battery in a Swift motorhome, which clearly won't get anything like the correct charging voltages/charging, is going to fail fairly quickly. But this won't be expected by the motorhome owner who 'knows' he has spent double the money on an "8 year life battery", so uses it well past it's safe best.

 

You can also see that if the battery breaks up internally debris can block the valve potentially making the explosion more serious. it is also obvious that if you install the battery on it's side or inverted, how debris will be more likely to block the valve increasing both the risk and consequences of the explosion?

 

We saw AGM battery explosions when Hymer/Banner rolled out AGM's in 2014, and that was on Alternator charging systems and chargers that HAD close on 14.4v, not the mid 13v we see in Swift built "AGM" motorhomes.

 

 

 

 

But they are safe in a Car, what's the difference?

 

Having an AGM battery in the boot of a car that is constantly monitored for temperature, capacity, efficiency, etc will have it's degraded nature reported by the ECU long before it is even 80% used. So it gets replaced well before risk of explosion.

Even if explosion occurs in a Car, the hazard to life is low as it is not in the passenger compartment.

 

 

Long term unattended, unmonitored use on EHU/Solar of an AGM battery that we KNOW will fail early in a motorhome is quite different.

 

Even if the risk of explosion was minuscule, is an exploding battery something you want under your seat?

 

 

One other question : are these Golf Buggy batteries low pressure VRLA's with just a few PSI or 30PSI style industrial batteries, as that may impact safety?

 

 

 

Spirou, you say above about fitting a B2B, which is the way most technicians address this issue, but do you realise that is 'bodge' not a fix?

 

What some B2B's do, like the old Sterling units is just raise the charging voltage at the habitation battery to a higher, preset output voltage. But increasing the voltage is done at the expense of less current. Additionally the units often run at about 85% efficiency, so you can see that this isn't the best option.

 

If you further add into the mix that the Fridge runs from the habitation area battery, it can still drop even the 'boosted' voltage.

Some newer B2B's will try and compensate for this voltage drop, but again at the expense of current.

The overall benefit from the average B2B, even those that some have spent thousands on, can be less than 75% so won't be as efficient as taking the Fridge feed direct from the Alternator/Starter battery and using proper sized cabling where good practice and common sense can yield 100% efficiency.

 

Like I wrote above in an earlier post,

 

"It is a shame they (B2B's) actually address the wrong issue, boosting the voltage when all that is needed is sensible Fridge cabling, wiring, etc. not a £600 expenditure. Another example of the products in the market place not understanding the issues?".

 

 

But now we are getting back to the hardware when I would rather inform on the danger for now.................

 

 

 

 

 

 

[spirou]

Fully aware I'd be trading voltage for current but, as our consumption is quite low and the battery not very large, I'd be inclined to such trade in. When I measured the voltage at starter battery under alternator charging it wasn't much above 14V, highest I saw was 14.2, albeit at idle and after only about a minute.

 

So even if I upgrade cables to 6mm2 (reasonably largest I might be able to pull through) it still won't get me to 14.4 or so.

But, as I haven't really had a chance to explore the viability of these mods, I just might end up doing nothing. It's not entirely up to me anyway as the van belongs to my parents and I just use it whenever available. They are inclined towards improvements and we keep working on various bits (not many things left from original state) but if the electrics turn out to be too complicated to sort out they might just say it's good enough as it is.

[aandncaravan]

Spirou, Almost 98% of the benefit of the usual Motorhome B2B install comes from the cabling that they dictate is used as part of the installation, not the B2B itself.

Just look at a Sterling B2B installation manual on the web and you can see that the minimum 16mm cabling they specify is going to make THE difference.

 

They also stipulate single cable runs, so losing the usual zillions of connectors that many motorhome builders/converters use.

 

While I would like Motorhome Builders to use much fatter cabling than 10mm in their installations, when improving existing ones, the cabling does not need to be as large because it's in addition to whats already there.

So just adding an additional 6mm (50amp) rated thin wall cabling with a decent Split charge relay will make a massive difference to your setup. Especially if you take both the Positive feed and Negative directly from the Alternator B+/Body.

 

 

The work involved is half the labour of fitting the usual Sterling B2B, with costs that are not quite in their 'pennies' but are low.

About £1.69 a metre for the cable (12v Planet) and less than £4 for our 'B2B equivalent' Split charge relay from several suppliers on ebay.

 

The Split charge relay is a key component, it should be rated to at least 100amps, not because it will pass that much current, but because the contacts will be huge so voltage drop across them will be low and more resistant to burning as they age.

 

See our web page for more info on how to do it yourself, how to diagnose issues, etc : http://www.aandncaravanservices.co.uk/add-a-second-battery.php

Look for the section at the bottom of the page titled, "Things You Might Want to Think About If Increasing The Battery Bank Size, Even Slightly", just above a picture of a Split Charge Relay.

 

 

You don't need to disable the existing arrangement, this will work in parallel with what you already have. Don't forget the 60A fuse.

 

 

Cable supplier :

https://www.12voltplanet.co.uk/50-amp-single-core-thin-wall-auto-cable.html

 

Split charger relay supplier £3.99 :

https://www.ebay.co.uk/itm/Car-Motor-Boat-Split-Charge-Relay-DC-12V-100A-ON-OFF-4-Pin-Heavy-Duty-New/151867130466?epid=601221192&hash=item235bfc8262:g:feAAAOSwFIVayblW

 

Note these are not recommended suppliers, just examples.

 

[arthur49]

aandncaravan - 2018-09-17 10:00 AM

 

See our web page for more info on how to do it yourself, how to diagnose issues, etc : http://www.aandncaravanservices.co.uk/add-a-second-battery.php

Look for the section at the bottom of the page titled, "Things You Might Want to Think About If Increasing The Battery Bank Size, Even Slightly", just above a picture of a Split Charge Relay.

 

 

Sorry for being 10 days late on this one, but as I said in a previous thread, I installed Allan's recommendation. DIY. I found it easy. With engine running and fridge off I'm getting 14,34v at leisure batteries

[arthur49]

aandncaravan - 2018-09-17 10:00 AM

 

You don't need to disable the existing arrangement, this will work in parallel with what you already have. Don't forget the 60A fuse.

 

So sorry Allan for resurrecting this thread and your statement above - we've been away from home!

 

As I said in post above I've installed your wiring/split charge suggestion and achieved a big improvement in charging whilst engine running (14.34v at LBs, tick over, fridge off)

 

But I DID disable existing arrangement. I can see now there is no need to do that as 'existing' and 'improved' will simply complement each other. Or am I misunderstanding your statement above?

 

Thank you Allan

 

[aandncaravan]

Arthur, it depends on what the set-up is already. The response above was specifically aimed at Spirou's vehicle, but generally, the improved 'new' cabling will effectively provide a 'wider' pipe through which the electricity will flow.

Just like Water through larger sized pipework, electricity will take the path of least resistance, through the thick, low voltage drop cable.

 

However, because the current in the old 'existing cable' is reduced, because a second cable is carrying much of the load, the voltage drop in the old cable is also less than it would have been. So even the old wiring delivers better overall power with a raised voltage as a result.

 

Reducing the current in a wire by half, has a similar effect (well nearly) to doubling the wires thickness in terms of voltage drop.

So just adding a second cable the same size can have a dramatic effect, making the new cable slightly thicker again to 6mm/50amp is better still.

 

 

That is one of the reasons why we like to use the existing split charge relay to drive the new 100+ amp relay.

 

 

 

 

[arthur49]

aandncaravan - 2018-10-04 11:52 PM

 

Arthur, it depends on what the set-up is already. The response above was specifically aimed at Spirou's vehicle, but generally, the improved 'new' cabling will effectively provide a 'wider' pipe through which the electricity will flow.

Just like Water through larger sized pipework, electricity will take the path of least resistance, through the thick, low voltage drop cable.

 

However, because the current in the old 'existing cable' is reduced, because a second cable is carrying much of the load, the voltage drop in the old cable is also less than it would have been. So even the old wiring delivers better overall power with a raised voltage as a result.

 

Reducing the current in a wire by half, has a similar effect (well nearly) to doubling the wires thickness in terms of voltage drop.

So just adding a second cable the same size can have a dramatic effect, making the new cable slightly thicker again to 6mm/50amp is better still.

 

 

That is one of the reasons why we like to use the existing split charge relay to drive the new 100+ amp relay.

 

 

Thanks Allan. I'm starting another thread about an article in C&MC magazine and I'll see if I can scan it and send it to you. All about L-ion, with some staggering statements eg 100Ah lead acid battery weighs about 35kg (25kg?) and costs about £300 (£110) .....

[Earthmover]

Hi Allan,

You mention a 40mm/30amps earth strap (Grey), where would I try get one from?. What size cable do you recommend for running from the chassis to the battery Negative. Can you do a sketch!. thankyou.

 

Regards Em.

 

Ps, thankyou for your comments on my wind turbine question. I have been trying to visualise the size of your Motorhome, which requires a wind turbine with 90ft blades!!.

 

[Derek Uzzell]

This March 2018 discussion may help regarding the earth strap

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Ducato-X250-2-3-Multijet-Earth-Strap/48885/

 

 

[spirou]

Did some more testing this weekend both on the road and at home. Results below are with the vehicle stationary. I'll save the driving results for another thread.

 

With the alternator (at idle speed) charging only the engine battery: 14.0-1V (lights on/off didn't make a difference)

 

With the existing 6mm2 wiring, fridge on max power, radio on: 13.7-8V (measured at leisure battery)

 

With additional 10 (maybe 16mm2, can't tell as there is no exposed core to measure) ancient jumper leads with tiny crocodile clips (so possibly not ideal conduction), fridge ON, radio ON: 13.8-9V

 

So I decided that I'll do some minor rewiring and use dual 6mm2 wires (already in place) which will aparently get me an improvement of 0.1V at best. Not much but as the work involved is not that difficult I'll do it anyway.

 

The second pair of wires that I will repurpose is currently used for the radio and I'll just wire it to the starter battery. We hardly ever use it without the engine on and it can be turned completely off so no phantom drain on engine battery. And it comes with the added bonus of saving 2-3A load from the leisure battery.

 

The question then becomes, what can be done to improve alternator charging further? I don't know if x250 2.2 EURO5 engine has a "smart" alternator or not. Probably not? Is B2B the only viable next step? That would probably be one of the Schaudt units to keep things in the family. I definitely won't go for the major job and do what weldted did.

[aandncaravan]

Spirouu, Yes take the charging feed from the Alternator B+ and the Alternator body.

It can especially make a huge difference on a vehicle 4+ years old.

 

See our webpage : http://www.aandncaravanservices.co.uk/add-a-second-battery.php

See about 3/4 down the page starting from the image of the giant relay.

 

 

No, X250's don't have any sort of Alternator smart charging,not even the 2018 model/Euro6 we have just worked on. Just a fixed 14.4v output.

I suggest you should be focusing on resolving the wiring issue first. Fix that and you won't need a B2B.

 

 

[fesspark]

I have a 5 month old Burstner 680G only used it for 700 miles so far has a 150 w solar Panel fitted on roof that seems to be charging fine, How ever the Bty has stopped holding its charge. 2 questions as the bty is a Varta dry cell 95Ah 850A can I replace it Temporary with a Varta LFD 90Ah wet cell that I kept from my last Burstner fully charged and nearly new until I take it to the dealer on Warranty? I have connected it up and not put the fuses back yet. Fesspark

[aandncaravan]

Fesspark, It is not abnormal for the AGM Varta to fail prematurely, so not surprised yours has also gone, see our web page on AGM batteries : http://www.aandncaravanservices.co.uk/agm-batteries.php

 

Yes the Varta LFD90 is the best option on that vehicle and will tolerate the Elektroblock EBL chargers higher AGM charge voltage of 14.7v quite well short term, but we recommend using the Lead/Gel setting on the EBL unit in the longer term..

Only change the switch setting with the mains disconnected. The slide switch is easily damaged so gently does it and use a Ball Point pen.

 

 

The Solar regulator must also be changed to a wet acid setting in the longer term, but ok short term, that is assuming it is the correct Schaudt LRM1218?.

 

 

Suggest you ask for a cheaper but more motorhome appropriate LFD90 or Yuasa L36-EFB under the warranty claim rather than get another AGM?.

 

 

 

 

[spirou]

Just took a look at the installation instructions for EBL208 and their B2B WA 121525 and one thing stands out immediately. Whereas the EBL suggests use of 6mm2 cables between both batteries, the B2B has them at 16mm2 (10 possible). Quite a difference. :-D

 

As I was thinking about it I might try to pull a bigger cable through rather than use doubled 6. Not sure if 2x16mm2 fits in the same space as 4x6 though. Have to go find some cable to measure first. I only find core diameters online.

[fesspark]

Thanks Al,have put the 90Ah on the EBL setting as you suggest, not sure I need to alter the Solar reg? all seems well at the moment, put the 95 on electric Bty Charger for the day and I will disconnect later and see tomorrow if its held its Charge,feespark

[fesspark]

Alan, just checked the battery in the m,home, My 90Ah was showing 13.5 ,V ie fully charged at 2 pm, now at 5.45, and getting dark, dropped to 12.5,by tomorrow I suspect it will be even lower, It looks as if something is draining the battery, the engine bty; is still good.Maybe its good news ,not the 95 gone but something within the m,home, any ideas what to do? fesspark

[spirou]

First I'd put the multimeter to current mode and see if there is actually any drain present. Then go through devices one by one (or fuses if available) to see if there's any change

[aandncaravan]

13.5v at 2 pm is not the battery voltage, but the voltage at the battery raised by the Solar charger. The actual battery voltage might have been only 12.4v.

It can't have been 13.5v because an LFD90 has maximum 13v.

 

 

I think you need to put the LFD 90 on EHU for 24 hours to be sure it is fully charged??

 

When you then check the SOC, the battery needs to have been off charge and off load for a few hours.

[fesspark]

Thankyou again all of the people who helped me, Getting there fesspark

[fesspark]

Alan,any ideas? Put battery on EHU for 24hours switched off and left it, strong sun all day,still showing fully charged? tonight 9pm dark,dropped to just over 12. engine Bty; reading 12.75. the leisure bty; is obviously loosing its charge? How can I find out what is causing the discharge? fesspark

[Alanb]

spirou - 2018-10-17 1:18 PM

 

 

..........As I was thinking about it I might try to pull a bigger cable through rather than use doubled 6. Not sure if 2x16mm2 fits in the same space as 4x6 though. Have to go find some cable to measure first. I only find core diameters online.

 

Spirou,

 

On 12voltplanet website & in Vehicle Wiring Products catalogue, thinwall 16mm cables OD 7.9 mm & 7.5mm are quoted. Hope that this helps.

 

Alan

[spirou]

fesspark - 2018-10-19 10:17

How can I find out what is causing the discharge? fesspark

 

If the same behaviour doesn't happen with the battery completely disconnected then do as I mentioned earlier. Take a multimeter on current mode and start pulling fuses/wires. But if this is recent development it is probably more likely to be a dead battery so charge, disconnect and measure after a day or more. Remember to pull the fuse from the solar regulator before disconnecting the battery.

[fesspark]

Thanks, Its not the Battery has I have tried 2 and both went from fully charged to almost flat,it is obvious the circuit, I will do as you suggest,fesspark