Battery Revamp

As mentioned in other pages on here I had decided some 4+ years ago to add 3x 160AH AGM’s to help bolster the existing leisure batteries.  At the time convenience and space dictated where these batteries were located.  Again for convenience I decided to keep these AGM’s on a separate circuit to the existing factory standard circuit.   This also allowed us to keep within the terms of our warranty and this set up has worked extremely well for over 4 years.  When planning our next winter break it worried me that the engine battery and the original leisure batteries were coming up to 7 years old by January 2012  and it was possible that anyone of them could fail.  The engine battery would cause the most inconvenience but the original leisure bank would also be a nuisance.   During the summer it would be unlikely that the batteries would let me down as with 434W of solar panels any problems would be masked.  Not so in winter as that is when you need most power but get less time to draw energy from the sun.  I took the decision to replace the engine battery and then started looking around to see what I could replace the old leisure batteries with.  The AGM’s were still under warranty and with a 10 year life cycle they should be good for a few more years.  The Flair battery box is the main limiting factor as it really is too small to fit anything other than a couple of 75AH Gels and I really would have liked to increase that capacity.

In the Flair garage there is a cubby hole extending forwards under the bathroom area, that while useful for storing items it is of little use in practice as when our MP3 and cycles are loaded the cubby hole is virtually inaccessible.  After checking on the cubby hole dimensions it occurred to me that it would be relatively easy to fit the new battery(s) in there.  I had decided on a 270AH Elecsol carbon fibre battery but discovered that the height given on the technical sheets was only to the top of the battery casing not the top of the terminals – making it too high.  I then looked at the 220Ah Elecsol that was approximately 30mm lower.  That got me  thinking, particularly when I rang Elecsol direct and they mentioned they could do a special deal on the 220Ah’s to include delivery, giving me a saving of over £300 over any other supplier.  Doing the sums it would work out that the cost of 3 Elecsol 220AH would cost around £150 more than replacing 2 x 75AH Gels so I made the decision to revamp the electrics.

I removed the AGM’s, removed the GEL’s removed the two Sterling Pro Digital chargers, removed the Inverter and all relevant wiring and fuses and fitted the Elecsols in the cubby hole along with the inverter.  Morningstar were very good and advised me that by using battery one position on the Sunsaver Duo all power would go through there if battery two position was disconnected.  The inverter remote cable was also long enough to allow me to  leave the remote in the same position.  I then placed the AGM’s on eBay and sold them for £150.  I made a partition to protect the wiring and inverter from accidental damage and fitted a battery isolator to the whole system.

I sold the chargers again on eBay making the total cost of changing over around £50 other than the cost of a few bits of wire and terminal that I had in stock anyway.  Here is an interesting outcome:-

By replacing the AGM’s with Elecsol’s and removing the GEL’s, chargers and excess wiring it works out that I have reduced the overall weight by a massive 120kgs.  Now the weight wasn’t an issue for us as we don’t use our full  allocation of 1475kgs payload.  What the real benefit is that we now have full use and access to the large side locker giving us room to store large items if needs be.  In reality it means we can re-jig some items such as the chairs and table making it much easier to get them out or put them away.  Previously they were stored in the garage but we had to move things around to get at them and technically it meant we were using the full payload of the garage loading limit so moving around 20kgs of table/chairs and loungers to the locker brings us safely inside our margin

By reverting back to one leisure circuit for all our power, meaning our 240 volt supply will also come off the leisure circuit;  it does present another thought.  Will I need the generator at all?  Now we have the engine alternator charging as well as the solar panels and given we move around every few days we may not even need to take the generator with us thus freeing up another locker.

We have recently got back from a 5 week trip to the south of France and here are our conclusions regarding the upgrade.  First of all it was very revealing to see exactly how much power the basic habitation systems take.  We had not been able to accurately monitor the 12 volt side of things as the Sterling Battery Management System will only monitor fully one circuit (even though it keeps an eye on up to 4) and had been monitoring the 240 volt circuit.  The basic habitation systems took far more than we imagined and saw up to 20 amps per day coming out purely for lighting, heater pumps and water etc.  Of course the alarm, central locking took its share.  We we left the heating on all night this figure would rise to around 30 amps per day. ** Now if we only had the 2 x 75 AH batteries (total of 150 AH) and no solar panels then we would be suffering flat batteries every 3 or 4 days. or with 240 volt usage added they would be flat every day or so.

Another surprise was that the engine alternator output must have a blocking diode or resistor or some such thing fitted as the maximum output was limited to 18 or 19 amps and not the 100 amps plus that it can whack into the engine battery.

When you add in the 240 volt usage via our inverter then our total daily consumption rose to around 70 amps so with 660AH available we theoretically could have lasted for up to 6 or 7 days without solar.  Now 70 amps per day is a worst case scenario and in reality it averaged out to around 50 AH.  Thankfully the solar panels took care of everything and we were completely recharged by mid afternoon each day.  We didn’t even get close to needing the generator so the conclusion is that we don’t believe we will need to carry it along with us any more.

** We experienced severe weather of minus 12 centigrade with constant gales of 55mph so had to keep the heating on to prevent us and the water tanks from freezing up.

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