Installing a 2nd leisure battery
Twenty five years ago, on our first motorhome, I installed another battery along side the existing one. Then I coupled the two batteries negative terminals together. using an appropriate jumping cable. Finally, I fitted a quality clip on terminal on the single positive cable. This + cable could then be alternated between the batteries. Okay, so the system did lengthen off grid camping opportunities but it called for careful management of the charging (either when driving or when available on EHU). I also had to ensure that on using neither battery was ever depleted to that critical point but that I already had to do when I had just the one battery anyway. This system worked for some 5 years wirhout issue until we bought our first brand new MH which came with a second battery 'permanently' wired in and had its own inbuilt charging management system with a low battery alarm. However, even with this I've still had to keep an eye out so as not to reach that critical discharge point on either battery. Now the question is, as I'm soon to swap our van for a new one should I go that one step further and install a solar panel? Part of me thinks though that I could return to that system I used all those years ago, afterall, it wasn't that much of a pain! Any thoughts on the above or alternative systems would be welcomed, also, if I go down the solar route, what size would folk recommend?
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I would fit a solar panel even if you only occasionally go off grid. Prices have fallen in recent years and they are not difficult to fit for any competent DIYer As to size, that will probably depend on your consumption when off grid. Down load >this solar panel calculator< and have a play around with the figures to see what might suit you. My requirements came out at a 150w panel but I could not physcally fit that on my roof so I had to downsize to a 120w panel with a more efficient MPPT controller. I bought and fitted a Kit from >Sunstore< That was three years ago and I have found it more than enough to keep us going and even in the winter months it keeps both my leisure and engine batteries fully charged. The latter via a battery to battery charging device.(Battery Master) My leisure battery is 200APH and it and the engine battery are 7 years old and both are still going strong. It pays to keep them topped up rather than discharge and re-charge.
peedee
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Thanks peedee, don't use 240v equipment so no need for an inverter and we are low 12v users, probably a hang over from those enforced frugal days. Thinking of solar just to keep topped up whilst in storage but clearly a larger panel will prolong off grid time.
Just for interest, I've always carried a multimeter and checked my batteries, even today with that management system on board.
I've always managed to stay above a reading of 12.2 volts (25%) with no damage to batteries over all these years.
With that 'primitive' system I described before, it was all about cost in those days, we had little and we had to find ways to make our passtime fit our wallet. The two batteries in this system did not have to be of the same type, same capacity or same age, they, in effect were two separate components in the circuit. It did work albeit with some management time spent by me.
That calculator you recommend looks both useful and interesting, cheers peedee.
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I used to do something similar although I carried the second battery in the boot of the car and had it charging from the 12N socket when driving around. Since I fitted my solar panel, I no longer use my EHU at home when the van is not in use.
peedee
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If you have not already done so, I would suggest that you take a look at the MMM motor home forum site, which has a lot of good information regarding a range of topics.
As I understand it, adding a second battery can cause damage to your charging system in some cases. Basically some charging units are built down to a economic (read cheap) price for use, whilst other are built and designed to accomodate a second battery. All to do with peak power and ability of circuits not to cook themselves.
Search MMM and if you cannot find the answer, ask the question as one contributor has in depth knowledge as a repairer and supplier of ehu charging units.
rgds
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Get the largest Solar panel you can afford, make sure there's enough roof space to fit it, good quality Leisure batteries and if you have on-board toilet facilities the World is your Lobster..
We have an 80W Solar panel, two 110amp Leisure batteries and a cheap (£20) B2B and do not need hook-up at home when the MH is stood on the drive or when we are away.
I wish we had originally fitted a bigger Solar panel but even at only 80W it has been adequate for our needs.
When in France, whatever time of year, we use Aires and don't use or need hook up and we can park up virtually anywhere without worrying about a power supply.
We only occasionally use a TV and run the fridge/freezer on the refillable gas system.
Solar really is the way forward to get freedom with a Motorhome.
Hope this helps.
Picture – Free Aire with toilets/shower/fresh water/waste disposal and peace and quiet.
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Mickey, I agree with the above posts, largest panel, two batteries (same type/size/age) permanently wired together.
what van are you getting? can't you do a deal with the seller?
id be looking to get plenty of stuff thrown in.....
negotiate really hard, you'd be amazed at what can be squeezed out...
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Will do, looking at a couple, may opt for the Bourton which comes with a 80W SP. Might haggle for a larger capacity as part of the deal as I don't think that system they are fitting is built for or will cope with an additional leisure battery. The new automatic sprinter also has a canny spec and I really miss that auto box. The other possiblility is the Rapido V55 panel van as we wanted to downsize to something under 6.5m, they both fit this wish.
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yes, there have been many reported issues with AS solar systems when linked to particular Sargent PSU modules which are very power hungry, sometimes absorbing more power to sustain itself than it passes on from the panel to the battery.
there are simple workarounds for this.....bypass the Sargent PSU....for one.
im sure you'll find more room in the coachbuilt (full width I guess?) than in the PVC, but it depends where you put ease/drivability in the overall equation.
good luck, HTH.
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Thanks Tonylsh, your recommendation for further reading eventually took me here:
http://www.aandncaravanservices.co.uk/add-a-second-battery.php
What a mine field of confusion, compromise, differing opinions, disputes even dangers etc. this second battery issue brings with it. Particularly to someone like me who is now totally bamboozled by the technicalities and understanding.
Think I may just adopt that primative method I employed all those years ago. At least it gives me what in effect is some second battery advantages without the need or worries of having a second battery install into what in essence is a single battery system. What I will have to do however is continue to monitor both charge and discharge and swap over batteries at the most appropriate timing. I can see that trusty multimeter being invaluable once again.
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Micky, very many modern vans (certwinly the Comtinental ones) will be designed for twin leisure batteries, though it may only be one that's supplied.
theres usually a large storage tray for two batteries and fitting a second one can be arranged as a factory fit option or even a dealer fit prior to collection.
the dealer fitted twin batteries to both my Carthagos (amongst much, much more) as part of the deals.
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I think I'd agree, may just keep my second battery to use whilst in winter storage and just keep the other 'topped' up at home. As we visit our van in storage and occasionally use during the cold dark months we could swap them over then.
As for placing and using them side by side but as individual & independant units as described, it's not so much as swapping batteries, just swapping the + terminal clip from one to the other.
Who knows, depends what I decide on re MH and what I can barter for.
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if your storage facility is not enclosed, the solar panel will do the job for you..
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employing a solar panel to keep leisure and cab batteries fully charged is such a common place installation these days, especially if done as part of the original spec or by the dealer as part of a sales deal.
my own system is very straight forward....100w panel feeds simple twin channel regulator to split the charge to each set of batteries in line with a user programmable setting.
no passing through any third party PSU as our Swift did and some other brands do.
to me, the simpler the better.
along with the obvious advantage of keeping batteries up while in storage (or on the drive) it also opens up options for easily using sites that don't have EHU, for example the excellent C&CC THS network which get you close into many UK towns at a really good price.
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We have managed very well with our AS Merc 100w solar roof panel (space limited us to this size) and one battery. Charging up the engine and leisure battery is useful and we haven't found any need for extra equipment. We found some good LEDs recently so the lighting is much better than previously. I'd say look at the latest possibilities, don't look back!
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in some circumstances, the specific Sargent PSU fited by AS has caused issues with the success (or not....) of the SP installation. the Sargent PSU is being used as a regulator....and to split the charge.
I think it's the Sargent 500 (from reading their forum, worth a read Micky) that is so power hungry that it takes more solar power to support itself than its able to pass on to the batteries....ie often no charging despite favourable conditions...
this is a known (frustrating) issue, and on any after market install, I would definitely keep,the system simple as I posted earlier and avoid using the Sargent unit.
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Brue, it's a recurring theme on the ASOF.
The issue is (AFAIK) down to a particular model of the Sargent PSU...(the 500 series, I think) which is very power hungry, defeating the object of the solar set up.
instead of owners lobbying AS to get them to recognise the issue and find a way forward, suggestions are more along the lines of 'turn the PSU off' which, of course, then prevents it deciding where to send the charge, resulting in only the leisure batteries getting charged and the resultant flat cab batteries due to immobiliser/alarm current draw.
.....which is the recurring symptom that led to the posts identifying the issue.
how a 100w solar system can't maintain a couple of batteries in a van standing on the driveway is beyond me.
my old Bolero had a panel wired via the Sargent PSU system but it was a much earlier, low tech version which didn't have an impact on the solar output.
more complex technology has resulted in a larger power requirement to service the device if left on, so much so that cab batteries were going flat very quickly through lack of charge.
employ the suggested solution as above and it also stops the cab battery being charged......so the same problem exists....
other earlier PSU version don't seem to have the same issue.
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My solar panel goes to the regulator and thence to the batteries. No PSU involved. Why would it be?
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