Deep cycle batteries ( otherwise known as leisure batteries ) are expensive as we have found out to our cost and making sure they are constantly topped up is an essential part of Motorhome life especially when not on an electrical hookup. In this blog, 3 Steps to upgrading your off-grid power, I’m going to explain the three upgrades I have made to our system that has improved the overall recharging capabilities of my off grid system.
The old system
When we picked up our motorhome back in 2015, the first optional extra we chose was a 120W solar panel which was duly installed on the roof before it was shipped.
Energy generated by the solar panel has to pass through a solar controller before it can be sent to the batteries and our installation came with a standard controller such as the one in the picture. Having no knowledge of solar technology I just left the system to do its thing and for 12 months everything seemed fine. All the electrics worked when we needed them to and the batteries didn’t run flat. What I failed to realise, however, was that we were travelling during the summer and the sun was directly above us in the sky.
Being a complete novice and not really understanding off-grid systems I came unstuck when we arrived in southern Spain for the winter. Whilst we had plenty of sunshine the sun was so low in the sky as to render the roof solar panel almost powerless. It didn’t take very long to drain the batteries and pretty much kill them off. We limped along for a few months but when you’ve drained lead acid batteries once they need replacing so we had to take the hit and buy new ones and it was at this point that I realised I needed to buy a portable solar panel so I could point it directly at the sun wherever it was in the sky. Enter the Dokio 150W.
This proved to be an inspired purchase. Lay it up against the motorhome, across the windscreen and hook it onto the side and it provided a much needed boost to keeping the batteries charged up. There was only 1 problem. Even though for a few years our batteries didn’t ever drop to zero I had no idea what I was drawing from them or what state of charge they were in. Yes, the motorhome came with a volt meter although I didn’t find it terribly accurate and because it is not visible (you have to turn a dial to read the output) I could go for days without checking the readout.
However, on windy, cloudy and stormy days the portable solar panel had to stay in the garage and a prolonged spell of inclement weather soon had the batteries draining flat even though we could be on the move. It seemed that the on-board charging facilities weren’t enough unless we spent hours and hours travelling. It was time for an upgrade.
Step 1 – Victron MPPT Solar controller
The first upgrade I made was to install an MPPT solar controller. They are much more efficient than standard controllers by boosting the power received from the solar panel to give the batteries more amps per hour. All the information regarding the solar panel input and the output it sends to the batteries an be accessed by the Victron Connect bluetooth app.
If a standard controller received 3AMPS from the panel it will send 3AMPS to the batteries but an MPPT controller will boost the AMPS and sends over more than it receives. Also a standard controller offers very little in the way of information but with the Victron connect Bluetooth App you can obtain huge amounts of information as we can see below.
Here are two screenshots from the bluetooth app. On the left is the initial page showing the amount of watts being collected by the panel which is 18.8V and the AMPS being generated by the controller. Underneath is the state of the battery (13.14) and the AMPS being sent to the batteries. The controller is generating 2.9A and sending 4A to the batteries. On the right is the history page detailing the total watts being collected by the panel for the day (250W), the maximum amount of watts generated (90W) and the max and minimum Volts registered by the batteries. If we divide the max yield for the day ( 250W) by the Volts (18.8), we can calculate that 13.29AMPS has been generated by the panel for the day. All of a sudden I now have some useful information that I can use to manage my off-grid system.
Step 2 – Victron Battery to Battery Charger
Having installed my MPPT controller I noticed that even on a sunny day my 120W solar panel on the roof was only producing 70w of power. Being 9 years old I assumed that age had something to do with it so I investigated replacing it with a 200w alternative. However, after talking to a few people it was concluded that I only ever drain the batteries completely after a prolonged period of cloudy weather so adding extra solar panels on the roof would be a pointless exercise. If there’s no sun there’s no sun. A much better solution was to fit a battery to batter charger.
The Pilote 740C motorhome that we call home did come with leisure battery charging capability whilst driving along but a serious charge would take 3/4 hours of driving which when you are stationary is impossible to achieve so adding a Victron Orion B2B Charger helps with the process. In fact, you can get a full charge within half an hour which is far better than driving 3-4 hours. Its function is to take a charge directly from the engine battery, boost it and fast charge the leisure batteries. I can confirm it works a treat. It can also be controlled by the VictronConnect App just like the MPPT solar controller. Here is the screenshot from the App.
The information displayed is very simple to follow. Float means that the batteries are fully charged and only a trickle charge is being used to keep them topped up. The Input voltage is the voltage drawn from the engine battery and the output voltage is what the Battery 2 Battery charger is sending to the leisure batteries.
A WORD OF WARNING
These chargers will damage the alternator ( the device that charges the engine battery as you are driving) unless you have a Euro 5 engine (2015) or later. It is probably a good idea to check with a specialist regarding this matter before you go ahead and purchase a Battery to battery charger, just in case. I think you can replace your alternator for a more modern version to accommodate a B2B charger but don’t quote me on that. My suggestion would be to seek advice.
Step 3 – Victron Smartshunt
The Victron Smartshunt is an information gathering device that collects all the data from your batteries and allows you to monitor how much power is being drawn and how much power is being put back. It is designed to be installed in the battery compartment away from view and all the information it gathers can be accessed via the Victron Bluetooth app along with the MPPT controller and Battery to Battery charger. Here is the screenshot of what it looks like.
Again the details are nicely laid out and provides such in formation as state of charge, the current voltage, consumed amp hours and on the history page the deepest discharge, minimum and maximum battery voltage, last discharge and cumulative amp hours used. Combined with information from the MPPT solar controller and the Orion Smart battery to battery charger, the smartshunt allows me to understand everything I need to know to maintain and prolong the lifespan of my leisure batteries.
3 Steps to upgrading your offgrid power-Conclusion
I can confirm that we have been operating off-grid in the UK with predominantly overcast conditions for six weeks now and have had no problems keeping our leisure batteries topped up throughout. At a cost of approximately £450 for all three devices (I wired them in myself), I’m delighted with the results. It was suggested that we go all hog and upgrade the solar panel and swap the lead acid batteries for Lithium ones but it would seem that that expense can wait for the time being. All three devices I have installed work with lithium so if I do decide to upgrade in the future I haven’t wasted any money this time round. All in all a successful process.
Thanks for the post, a couple of questions:
What are the capacities of your leisure batteries?
Do you have an inverter?
Hi Norman, we have two 105AH Lead Acid Batteries and we have a 1000w pure sine wave inverter