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| falkster Member Since: 12 Nov 2023 Location: Sutton Coldfield Posts: 9  
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Hi All,
I am currently looking into installing a dual battery setup plus solar for the summer and have a couple of questions. First, what am I trying to achieve: Fridge in the back, constantly on. Vehicle won't always be driving, hence the solar as back up (tricklecharge) for when it is either parked on the drive or stationary for a few days when on holiday camping. - For the additional load of multiple phones, couple of laptops, camera and camp-lights etc i want to be able to add external solar panels as well. I was thinking about ~100W fixed on the roof (basically for the fridge) and another ~100W as a foldable panel that I can put in the right direction when stationary and needed to support the appliances mentioned above. Sounds reasonable? - For the batteries I am currently considering 2 x 100Ah batteries. One as starter and one as leisure battery. For the leisure battery, Lithium sounds great but a bit expensive. for the use I want, would AGM work equally well? Ideally I would have both batteries under the passenger seat. - Ideally, i would have the leisure battery charged by the alternator when driving, and solar when stationary. I am also reading about using the leisure battery as a back-up starter battery (switchable) in case the starter battery dies. Does both work, when I am installing a cut-off switch for the starter battery as theft-delayer? Or would the leisure battery basically help starting the vehicle via the starter battery? Can solar trickle charge both batteries in the above scenario? - do compressor fridges actually work when parked on a bit of a slope?? - is there anything else I should consider? I am new to the topic, so any input would really help me get my head around this. Thanks so much.  |
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21st Mar 2024 1:29pm |
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| LR Nuts Member Since: 10 Aug 2022 Location: UK Posts: 835 
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try typing 'Dual Battery Solar' into the search engine above (in the dark blue bar)
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21st Mar 2024 2:11pm |
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| wyvern Member Since: 14 Dec 2009 Location: Cornwall Posts: 2071 
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hi and welcome to the forum !
lots of good info on here from those of us who have converted our defenders for overland trips so take a look at the many fab conversions undertaken on here - as mentioned above, the search function is your best tool to start with and then read as much as possible and ask questions as you go ! looking forward to seeing your conversion !
Batteries - I have x2 110 amphr normal style batteries under the passengers seat s which work really well for me - but we have no solar and no fridge, so the only draw on the aux battery is lights heater and water pump, with phone charging at times as well - we get about 3 days parking on a full charge. I can start the vehicle on the aux if needed but as the starter battery is only used for the vehicle then it has better charge most of the time than the Aux.. Phones laptops and cameras are normally charged when we are driving to save the Aux battery - my partner is a pro photographer and has a lot of batteries which I charge when driving via 240 inverter, the same for laptops - however my new mac air will charge from a usbC charger which is a big plus from the Mac Pro we had before. hope that helps Poppy - TDCI (Puma) 110XS 2.2 - Camper conversion - see the build here - https://www.defender2.net/forum/topic56530.html
Elgar -TDCI(Puma) 110XS Dormobile - now sold Devon & Cornwall 4x4 Response - DC126  |
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21st Mar 2024 3:14pm |
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| andy63 Member Since: 30 Jun 2023 Location: north east Posts: 250 
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Your electrical load is going to be considerable by the sounds.. Fridges and cool boxes are hungry and multiple phones and batteries all add up..
A 100 w (4.5 amps approx max) panel will support a 65l compressor fridge running through the day providing you have good sunshine all day.. At night you may find you would be best switching off when the door is not been opened so frequently.. The second portable is good but you possibly will not be able to use it if away from vehicle for security reasons, but it will be more effective than a flat panel if you are around and can track the sun👍 Charging a leisure battery from alternators is best done via a dc to dc charger…… but I've had success with good quality heavy duty dual sensing relays as well.. Heating in the form of diesel htrs which I know you haven't mentioned but most probably a good investment if out in cooler weather add further to your load.. |
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21st Mar 2024 6:37pm |
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| 34064 Member Since: 12 Dec 2023 Location: South Central Posts: 101 
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A DC DC charger would be a good idea as the solar could charge your start battery when it has charged your leisure battery.
Here's a handy calculator for working out your power consumption and what you need no affiliation just like using it! https://www.vunked.co.uk/campervan-off-grid-calculations/ 110 Td5 Ex Utilities slowly converting into a pop top camper one day Build thread:https://www.defender2.net/forum/post1024784.html#1024784 |
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21st Mar 2024 10:56pm |
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| bear100 Member Since: 22 Mar 2010 Location: South Wales Posts: 1871  
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Don’t discount a portable power station, I use an Ecoflow Delta 2 for all accessories like laptops, phones, lights, iPads, Bluetooth speakers etc
I also charge it from deployable solar panels but 90% of the time it’s not needed. My Engel fridge will run off my Optima yellow top for 2 days and then needs some help, if there’s no sun I simply plug the Ctek battery charger in to the Delta. I don’t recommend the Optima battery’s anymore mine is only 2 years old and already started degrading. Soon I will fit a lithium coupled with a Victron DC-DC charger 2016 Range Rover Autobiography 4.4 TDV8 2010 110 XS Utility 2.4TDCI 2010 Range Rover Sport TDV8 (gone) 2007 Discovery HSE TDV6 (gone) 1993 110 csw 200 tdi (gone) 1994 90 HT 300 tdi (gone) 1994 discovery 300tdi (gone) 90 hybrid 3.5 v8 (gone) Range rover bobtail 3.5 v8 (gone) |
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22nd Mar 2024 12:21am |
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| landy andy Member Since: 15 Feb 2009 Location: Ware, Herts Posts: 5424 
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If you get a good quality fridge, I don’t see your power consumption to be excessively high.
I used to run twin batteries, Odysseys, run a fridge constantly and charge all the camping kit. No solar panel and could easily last three days even in high heat such as the Sahara or Croatia. I kept things simple and could jump start myself by simply joining the positive terminal with one of the jump leads that I always carry. The batteries became joined/separated by a simple VSR. How long are you planning on being stationary whist fridge and other powered items are used? |
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22nd Mar 2024 8:20am |
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| Moo Member Since: 01 Oct 2021 Location: Bath Posts: 1043 
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I'm about to fit a Lensun solar panel on my Defender feeding a dual purpose battery under the bonnet which is linked to the main battery. I'm keen to ensure I have charged cranking power when camping. The new Defender does chew power opening and closing doors etc.
https://www.lensunsolar.com/index.php?rout...h=defender Click image to enlarge My debate now is whether to fit an additional Lithium battery in the rear on a DC-DC charger from the main battery for ancillaries like fridge and electronics or to use a power bank? The advantage of the fitted lithium battery is storage and space vs. the flexibility of a power bank.  Eiger Grey MY23 D250 SE with bits. Known as Noddy. |
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22nd Mar 2024 10:00am |
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| jst Member Since: 14 Jan 2008 Location: Taunton Posts: 7693 
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My 130 is currently running a similar setup that would fulfill your needs. My 110 also runs similar less the solar.
So i have an engel fridge 45L, webasto thermotop for heating coolant for heat exchanger for shower, plus two teenagers like to charge battery packs and phones constantly. We typically go away for a week ish. of which 4 or 5 days will be static no starts. i have 1 x CVX27 leisure battery numax under the passenger seat. (main battery) 1 x CVX31 numax in the rear (aux battery). 100W solar panel generic converter (?). perm wired in. solar panel semi rigid on the rooftent. Split charge Bluw Seas system See note at end but up until last year ran this setup since converting the 130 in covid. for our camping trip it worked well. Webasto would run 10mins to get shower to temp and then run shower for 4 x 5mins sessions. did this each day. Fridge was on duration of trip. i was really pleased with setup. The only time it struggled was summer 22 which was hot hot hot and the fridge took more grunt than usual maintaining temp. had an engine start on day 3. For summer 23, we did a ten day camping trip, no engine starts. Some significant changes: Setup as above but 3rd battery added (CVX27 as i had a spare kicking about) as 2nd Aux. so total 3 batteries. 180 W solar panel with Victron controller and BT management. (old 100w panel stopped working) 25L Wabco fridge compressor fridge Shower system not used, onsite showers provided. two older teenagers who along with their friends like to charge phones. i have 6 x usb ports and had an avg of 4 phones or battery packs plugged in for the duration of the trip. friends found out we had charging and that was it, there constantly! it worked a treat. Solar kept everything up to capacity (Late jul trip) vehicle aux and main battery would all be showing 13/13.1 at the end of the day as solar dropped off. charged most days around 13.8v according to BT log. my only stipluation was no phone charging at night. both fridges on the whole time. Hope this helps and gives food for thought. edited to add, as i have a roof tent i tent to park reasonably flat, slightly head up so cant specify on the fridge running but i know my engel has worked what ever i have thrown at it, off roading for a day then parking up. You can always chock the fridge with wedges if its not working. tends to be gas fridges that like to be really level from memory. Cheers James 110 XS Utility 130 Puma Station wagon/camper (in the making) 90 Puma Hardtop |
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22nd Mar 2024 2:04pm |
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| falkster Member Since: 12 Nov 2023 Location: Sutton Coldfield Posts: 9
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Thanks so much for all the input!! Looks like I came to the right place.
A lot food for thought provided. Absolutely brilliant. big |
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22nd Mar 2024 6:55pm |
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| pistonfields Member Since: 29 Mar 2022 Location: Zurich Posts: 65 
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see here https://www.defender2.net/forum/post1012078.html#1012078 for my setup. Definitely get a B2B charger to top up the second battery while driving. Trickle charge of the starter battery is in my opinion not needed if you connect all leisure loads including frigde to second battery. I had 200w solar and that was nice, but currently thinking about upgrading to more. at least one panel detachable is nice so you can park in the shade and have one panel in the sun.
Lifepo4: seems expensive at first but for what you get in terms of power AND lifespan it should be a no-brainer, honestly. Especially on a Defender where space is very limited. But your fridge won't consume less just because you have a small Defender and not a huge campervan. And when space for solar is limited again bigger battery and a powerfull b2b charger chan save the day / trip. All in all: try to calculate your average power need on a stationary day. Then calculate best and worst case solar conditions with a given setup, then you'll know how long a given battery will last and when you need to drive again in order to charger the second battery with your engine. That should give you an idea of what suits your needs. |
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26th Mar 2024 4:09pm |
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