Improvements to leisure battery charging

[DavieR]

Alan.

 

I've emailed CBE in Italy about the possible PC380-DS and the DS520-AN incompatibility and the +3amps. I doubt that will be the problem though - the monitor and distribution box are in the same manual/instruction booklet. I'll report back if they reply.

 

My plan of action?

1. Fit the battery monitor so that I will know whether these +3 amps are for real or not.

2. Do as you suggest and move the charger +ve wire from +B2 to +OUT

 

Thanks for all you help, it's much appreciated

 

Dave

 

 

[Alanb]

Davie,

 

Please inform the forum as to the final outcome of this problem.

 

On browsing the CBE website last night, I could not find any reference to the DS520, but I agree that if it is in the same manual as the PC380 they should be compatible.

 

When you read the descriptions of the various CBE display units, it is claimed that the display unit performs most of the functions. Yes it has the various switches, but most if not all of the hardware is in the DS300 or DS520. The PC unit obviously handles the displays, but from visual inspection there is sufficient electronics in the DS to perform the simulated D+ and the 10.6V emergency cut off functions. (I fail to understand why the cut off is set so disasterously low.)

 

There was a post on this forum claiming that there was an emergency switch, allowing basic functions if the PC unit failed. Requested details were not given.

 

Alan

[weldted]

Re my set up, to give you some idea of what I have found. Yesterday results, we are 25 miles sw of Limoges clear sky no shading. Batteries at 83% at 11.00. On solar only 1.9 amps, started engine after 5 mins 7.6 amps, turned on inverter 16.3 amp but rapidly falling. After 5 mins 12.7 but still slowly falling. Drove for around 1 hour parked up engine still running, inverter on, clear sky no shading now down to 8.2 amps turned inverter of down to 3.7 amps, engine off down to 1.1 amp battery showing 97%. All reading taken from my solar controller via a shunt fitted to the negative terminal of the leisure batteries. This shows the net charge that is going into the batteries. SES fridge freezer was on 240 whilst inverter was on.

[DavieR]

Hi welted,

 

I'm envious of your results! Not only the the results but the precision. I have a battery monitor ordered and will hopefully fit this weekend.

 

Can I ask why you took the route you did? The invertor from the starting battery is unusual (in that I haven't seen it elsewhere) and I wonder why you chose that over a standard B2B. If you were starting again would you choose the invertor over the newer alternator boosters?

[weldted]

Hi, several reasons. Having previously used a B2B on my last van was not too impressed with the results, also found the large fridge freezer would consume around 17 amps on 12 volt. As we use the van over the winter and with shorter days for the solar and longer nights of tv I decided to look closer at going some way to overcome this.having both a microwave and needing to recharge our vacum cleaner and although battery technology has changed, my interpretation of batteries is leisure batteries were designed to supply small amounts of current over longer periods of time at say 10/15 % of their rated capacity, whilst a starter battery is designed to handle larger amounts of current. Given the wire sizes of Motorhomes habitation circuits I felt they would not cope too well in putting back the current required for heavy inverter use. Roughly you need 28 amps @ 12 volts d.c. To produce 1 amp @ 240 a.c. This allowing for inverter inefficiency voltage drop through cabling etc. Other advantages are running the fridge on 240 means it is temperature controlled so over the winter months it doesn't have to work so hard against using it on 12 volt which is not. Being able to use the microwave without flattening the leisure batteries. I can run it for around ten mins without effecting being able to start the engine, any longer if no near neibours I would just run the engine but as used normaly for reheating not found this is needed. Much faster charging of the leisure batteries did 67 nights over last Christmas with no hook up. Points to note! On my Elddis Aspire the ehu socket is recessed in the battery locker, this way I can plug the inverter into the socket without anything sticking outside the van. Using this method it is impossible for the mains and the inverter to be connected at the same time.

Cabling to the batteries from both the mains charger and solar system have been upgraded. Just to see how this system stands up to my previous set up I turned enough lights on at 5 pm last night to create a 3.5 amp load which is the same as the tv with the van not connected to ehu and at 11 this morning will turn off see what state of charge is left. The reason is I fitted two new Youasa L36- EFB batteries just prior to leaving the UK and we are at our cottage in France so not in the van. We will be leaving for warmer climes as the weather gets colder so wanted to see how they perform. Sorry if this reads like a novel but not the best at explaining. Will let you know how it turns out. ( that's local time!)

[DavieR]

Thanks weldted and apologies for the delayed response.

 

Our need for amps is somewhat less than yours but, now I have reread yours and Allan's posts, I think your inverter setup could work for us. The only snag I can think of at this stage is that our EHU point is on the side of the van so we would need some kind of switch to swap the 240v supply. That switch would need to be somewhere handy too.

 

 

 

[weldted]

Rotary fully enclosed three pole change over switch will do it.

[Derek Uzzell]

DavieR - 2018-11-17 9:51 PM

 

Thanks weldted and apologies for the delayed response.

 

Our need for amps is somewhat less than yours but, now I have reread yours and Allan's posts, I think your inverter setup could work for us. The only snag I can think of at this stage is that our EHU point is on the side of the van so we would need some kind of switch to swap the 240v supply. That switch would need to be somewhere handy too.

 

 

It’s perhaps worth highlighting that weldted’s Elddis Aspire motorhome is a 2012 model and the unusual modifications he has made to his vehicle’s electrics were carried at the beginning of this year. So the changes will (presumably) have had no impact on any warranty his Elddis would have originally carried.

 

But your motorhome is a 2017 model and, consequently, may still be warranted by Shire. Consequently - if that’s the case - you might want to touch base with Shire to confirm that they would be comfortable with the sort of modifications weldted has made.

[plwsm2000]

weldted - 2018-11-17 11:37 PM

 

Rotary fully enclosed three pole change over switch will do it.

 

That should be 2 pole switch as you should only switch L and N, not the protective earth wire.

 

[DavieR]

Derek Uzzell - 2018-11-18 8:02 AM

 

It’s perhaps worth highlighting that weldted’s Elddis Aspire motorhome is a 2012 model and the unusual modifications he has made to his vehicle’s electrics were carried at the beginning of this year. So the changes will (presumably) have had no impact on any warranty his Elddis would have originally carried.

 

But your motorhome is a 2017 model and, consequently, may still be warranted by Shire. Consequently - if that’s the case - you might want to touch base with Shire to confirm that they would be comfortable with the sort of modifications weldted has made.

 

A valid point Derek, thank you. However, it's a risk I'm willing to take as having the upgrades for this winter and next year is more important to us than preserving the warranty.

[DavieR]

plwsm2000 - 2018-11-18 11:22 AM

 

weldted - 2018-11-17 11:37 PM

 

Rotary fully enclosed three pole change over switch will do it.

 

That should be 2 pole switch as you should only switch L and N, not the protective earth wire.

 

Something like this? https://www.amazon.co.uk/gp/product/B0057566WE/ref=ox_sc_act_title_1?smid=AIF4G7PLKBOZY&psc=1

[weldted]

I have the inverter fixed under the front passenger seat so to have a shorter run to the engine battery which is under the cab floor, a remote control switch for the inverter at the rear of the drivers seat frame, this can be reached safely whist driving and also from the habitation side. I have also fitted a mains switch in the same area and run the supply from the ring main to this switch then to the mains battery charger so it is easy to access. The point to remember is when parked up and need the inverter without the engine running you can turn the charger off. Re the warranty much as many dealers can't wait to fix all our warranty issues, all you are doing is fitting an alternative 240 supply from the engine/chassis side not the converters and using a psw inverter to produce clean electricity. But a worthy point made re warranty.

[weldted]

I appreciate the comment re 2 pole verses 3 pole, as you have to break into the mains cable fron the inlet socket to the consumer unit the only difference would be on 2 pole you have to make a separate connection to effectively continue a wire that at best is a couple of meters long that will do nothing when the mains hook up is not connected against a 3 pole that will still connect to the earth circuit but take all three wires back to the inverter with the Earth wire still doing nothing as there is no Earth at the inverter. Using the 3 pole means the whole electrical circuit is either to the inverter of to the mains. There is the potential that should the mains hook up be plugged in whilst the switch is set to the inverter although unlikely to cause any problems you have a potential earth through one system and supply through another

[plwsm2000]

weldted - 2018-11-18 7:46 PM

 

I appreciate the comment re 2 pole verses 3 pole, as you have to break into the mains cable fron the inlet socket to the consumer unit the only difference would be on 2 pole you have to make a separate connection to effectively continue a wire that at best is a couple of meters long that will do nothing when the mains hook up is not connected against a 3 pole that will still connect to the earth circuit but take all three wires back to the inverter with the Earth wire still doing nothing as there is no Earth at the inverter. Using the 3 pole means the whole electrical circuit is either to the inverter of to the mains. There is the potential that should the mains hook up be plugged in whilst the switch is set to the inverter although unlikely to cause any problems you have a potential earth through one system and supply through another

 

Switching the earth wire is mainly a problem when using EHU.

Mains plugs have a longer earth pin to ensure the earth connection makes first when you plug it in and breaks last when you unplug it. This won't happen with a 3 pole switch. This is a problem as many mains powered equipment contain filter capacitors connected to earth. If the earth is not made first, these capacitors can raise the vehicles metalwork to a high voltage for a fraction of a second.

Also if the earth pole failed, you would not know about it until it is too late (nothing will be earthed).

A switch will also increase the earth fault loop impedance and limit the fault current in the event of a Live to Earth short somewhere.

 

The switch that DavieR linked to would work. I don't think you will find many 3 pole switches sutable for mains power. They are either 2 pole (L and N) or 4 pole for three phase (and Neutral)

[weldted]

Thank you for your detailed explanation.

[aandncaravan]

DaveR, We don't think there is a safer solution than the "2 sockets one plug" solution we documented in another thread. It is what Welted currently uses, but it describes how to create the set-up at the RCD in the typical motohome where the 230v inlet is in the outside wall, rather than the Caravan like battery box setup.

 

 

 

[Alanb]

Davie.

 

A few cautionary thoughts and some suggestions.

 

As Weldted suggested your mains switch will need to be enclosed.

 

Your 300W inverter may not be able to supply both the mains battery charge and the fridge.

 

Why the fridge? Weldted's system requires the split charge relay to be disabled in order to prevent a feedback loop to the inverter input. There is no simple way of disabling the CBE split charge relay. If you were to disconnect the ignition controlled input to the distribution board, you would also disable the fridge 12V supply and the simulated D+ output, which may be required for other functions.

 

When fitting a CTEK D250S B2B, I chose to use a separate fridge relay, controlled by the simulated D+ output. A changeover contact on the relay diverts the the connection from the starter battery, B1, to the fridge with a lower rated fuse. Mains charging of B1 and voltage indication are still available when the engine is stopped.

 

There is another feedback loop in the CBE system via the B1 mains charging relay. If using Wedted's system it would only be present if the inverter was run without the engine being started first.

 

A suggestion. You have stated that you only use your inverter to charge a laptop. If the laptop has an external charger, you may wish to consider a 12V powered charger. This would be more efficient than your current arrangement. I have used a 12v charger for many years.

 

Alan

 

 

[DavieR]

aandncaravan - 2018-11-19 11:58 AM

 

DaveR, We don't think there is a safer solution than the "2 sockets one plug" solution we documented in another thread. It is what Welted currently uses, but it describes how to create the set-up at the RCD in the typical motohome where the 230v inlet is in the outside wall, rather than the Caravan like battery box setup.

 

 

 

Thanks Allan. I found it. Here's the link for anyone interested - https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Euro-6-Ducatos-and-smart-alternators-/48494/

 

[DavieR]

Thanks for all the recent posts. It's all food for thought.

 

Alanb's point about the internal split relay of the CBE distribution box, feedback loop and fridge operation add a layer of complexity to Welted's inverter solution I think I am not willing to overcome. Also, the EHU/inverter - RCD plug solution will take up too much room in the limited space available. It's been interesting trying to figure it all out though.

 

I have returned to my original suggestion of the Scaudt WA121525 voltage booster/regulator. It wires into the existing system very easily. My only question at this stage is whether the existing built in relay is big enough for the job. The threading of cables through the van is no small task either!

 

But before fitting anything I will try to thread 16mmsq cables through the van to replace the present 6mm and see what I gain from that.

 

I'm still waiting on a few bits and pieces but this weekend I wired in a Votronic MPPT solar regulator, moving it to a position next to the distribution box. The 16mmsq cables have been laid between the leisure batteries, not under the cab floor matting but through a wooden extension to the cab floor integral to the original conversion. Two meter lengths were used.

 

I'm also planning to replace the starter - leisure battery -ve cable with 16mmsq.

 

 

[DavieR]

Alanb - 2018-11-19 12:06 PM

 

A suggestion. You have stated that you only use your inverter to charge a laptop. If the laptop has an external charger, you may wish to consider a 12V powered charger. This would be more efficient than your current arrangement. I have used a 12v charger for many years.

 

Alan

 

 

Oh, why didn't I think of that! Thank you.

[Alanb]

DavieR - 2018-11-19 8:22 PM

 

............................................................

I have returned to my original suggestion of the Scaudt WA121525 voltage booster/regulator. It wires into the existing system very easily. My only question at this stage is whether the existing built in relay is big enough for the job. The threading of cables through the van is no small task either!

................................................................

 

 

Davie,

 

May I again counsel caution as regards fitting the Schaudt WA121525. I have only glanced at the Schaudt installation instructions, but I think that my previous comments regarding a feedback loop, and fridge supply may also apply to your proposed course of action.

 

To elaborate, if the output of the Schaudt is connected to the CBE B1 terminal there will not be a feedback loop, except perhaps via the mains charging path for the starter battery B1. However the fridge will take about 50% of the Schaudts boosted output, which is not what you want.

 

The alternative of connecting the Schaudt to either to OUT +ve, or directly to B2 +ve, will have feedback loop problems, and result in the fridge taking a large chunk of the Schaudt output.

 

I hope for simplicity that I am wrong in the above, as I have not done more than glance through the Schaudt instructions.

 

Probably the simplest method of increasing battery charge current is that recommended by Allan of AandN Caravan Services, using thicker cables, as you are already proposing, and a larger external split charge relay. This approach has been used by Arthur49, and Velotron. They may be prepared to comment.

 

I fully appreciate your problems encounterd when threading larger cables into the confines of a PVC. Probably mine a 5.6m is smaller than yours!

 

Rerouting the fridge supply was not that difficult, and I could give further info if required.

 

Alan

[Alanb]

Davie,

 

The split charge relay fitted to my CBE DS520AN ia a Tyco V23134 series relay.

 

Maximum continuous current is 70A at 23C, downrating to 50A at 85C.

 

However a larger external relay could be expected to have a lower contact resistance. As a first stage a larger relay could be wired with its contacts connected to the CBE B1 +ve, and OUT +ve terminals. Coil energisation should be from the CBE FA4 terminal and a convenient negative.

 

Alan

 

[aandncaravan]

If the Schaudt WA121xx unit is installed between the Starter battery and the CBE 'Starter Battery Input' terminal, then all the CBE system sees is a decent voltage, it won't be 'aware' of any other change or where that voltage has come from. That is the beauty of the WA and wiring it this way.

 

But you are right, the WA's current will be used to drive the Fridge, which is no bad thing as it will at least get a decent voltage and be more efficient.

There should not be any 'Feedback' issue and the WA should ramp up it's output to suit but it would require the 40 amp version to work well..

 

 

DaveR, My concern with all of this is that the talked about changes will make improvements, but they are likely to be relatively small benefits when you need big improvements for Winter Wild camping in Scotland.

 

For example, in Winter the improved Solar set-up will probably improve things by up to 40%, but 40% of 5 Ah a day is very little.

Likewise you said you don't drive a great deal between stops so even if the WA improves things by 25%, that is 25% of maybe an hours drive, so again only a few amp hours, possible every three days?.

 

.

A motorhome in Scotland in mid Winter will need about 30Ah a day, and these changes won't achieve anything like that, unless you drive about 3 hours a day?.

 

My other concern is that in between stops the 220Ah batteries will regularly get run down very low and a trip to a campsite with EHU will result in the poor CB516 mains charger, which supports a 160Ah battery bank, getting a hard time that will eventually lead to it's expiry.

 

 

[arthur49]

Alanb - 2018-11-20 3:52 PM

 

Probably the simplest method of increasing battery charge current is that recommended by Allan of AandN Caravan Services, using thicker cables, as you are already proposing, and a larger external split charge relay. This approach has been used by Arthur49, and Velotron. They may be prepared to comment.

 

I fully appreciate your problems encounterd when threading larger cables into the confines of a PVC. Probably mine a 5.6m is smaller than yours!

 

Alan

 

Just picked this up.

 

I did exactly as Allan recommended towards the bottom of this page http://www.aandncaravanservices.co.uk/add-a-second-battery.php

 

I disabled the existing split charge relay. I then used 25sqmm cable + and - from leisure batteries to starter battery. The worst bit was getting under the van to route the cables. I put the + cable in spiral conduit for added protection. I managed to get the cables out under the floor through existing vents but I had to drill through the plastic starter battery box, as high on the wall of the box as I could. Big fuses at starter battery and leisure battery to protect the + cable.(I had gold fuses and holder in my spares box so I used them)

 

The result is 14.34v at the leisure batteries, with engine at tickover and fridge off. Very pleased with the result and at a fraction of the cost of a B2B

 

I've now traded in that van and will probably adopt Allan's recommendation in new van which has CBE equipment ........ and a smart alternator!

 

 

 

[arthur49]

aandncaravan - 2018-11-20 7:05 PM

 

If the Schaudt WA121xx unit is installed between the Starter battery and the CBE 'Starter Battery Input' terminal, then all the CBE system sees is a decent voltage, it won't be 'aware' of any other change or where that voltage has come from. That is the beauty of the WA and wiring it this way.

 

 

Allan

 

But does this approach still mean there could be undue strain on the power distribution unit as it tries to pass higher current?

 

I recall your photos of burned out boards and relays. If a non-Schaudt distribution board is used isn't there a tendency for high current issues? My previous van had a pretty puny Sargent EC155 for example

 

Every day's a school day :-D :-D :-D