Member Since: 07 Aug 2015
Location: Perth WA
Posts: 264
Only very high end expensive solar controllers are waterproof. But you don’t need a waterproof one under the bonnet.
To keep both batteries charged you would need to connect the solar to the main battery, once that batteries voltage is above your dual battery isolator ‘link’ voltage it will then start to charge your second battery. In which case the solar controller will probably fit in the space between the main battery and the engine ECU. But depending on your dual battery isolators cut in and out voltages this may not allow the solar to reliably charge your second battery.
Solar controller size is determined by the solar panel maximum power and voltage ratings. This should be on a label on the solar panel. NOTE if you are using a house solar panel the output voltage will in the 50-100VDC mark, your cheap 12V solar controllers cannot handle a voltage that high. So you need to make sure the solar controller maximum input voltage is greater than your solar panel output voltage and the controllers current is rated greater than your solar panel maximum output current. Example of a solar panel label.
MY14 TDV6
24th Jul 2019 5:50 am
gstuart
Member Since: 21 Oct 2016
Location: kent
Posts: 14176
Many thks as that clears up so many questions
Sounds like it would be better to just connect to the aux battery as I can then at least use the t max controller to link them together if so req , inc making the system simpler
So with the engine off and just using the aux battery on days out etc at least the solar can keep that topped up and ensure the main battery isn’t drained
Thks so much once again and really am grateful for the information
24th Jul 2019 11:19 am
Andy Foster
Member Since: 27 Dec 2009
Location: Liverpool
Posts: 6551
Controller fitted. Will have an Anderson connector so it’s easy to just plug the panel in.
D4 MY15 SE TECH
D3 gone but never forgotten.
25th Jul 2019 7:06 am
gstuart
Member Since: 21 Oct 2016
Location: kent
Posts: 14176
25th Jul 2019 7:36 am
dadof7kids
Member Since: 23 Aug 2011
Location: sunny Doncaster
Posts: 1303
In our caravan off grid where 4 kids charging phones and iPads all the time and caravan battery if nearly flat at bed time a 80W solar panel is more than enough to recharge for next session of charging java Black D3 gone : (
Club Lux : ) GONE : (
25th Jul 2019 9:57 am
Narpy
Member Since: 18 Jul 2011
Location: Stockport
Posts: 7830
Andy, what size and type of battery do you have in that set up?
How big is the solar panel you've got to recharge it?Mods:
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Garmin Nuvi + D4 Surround + Reversing Camera.
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25th Jul 2019 4:06 pm
Andy Foster
Member Since: 27 Dec 2009
Location: Liverpool
Posts: 6551
@Narpy. Not got either yet, building it in stages. Will be fitting a 110ah battery and a 100w panel. At the minute I’ll only be running some LED lights and charging phones etc. A fridge is on the cards though D4 MY15 SE TECH
D3 gone but never forgotten.
25th Jul 2019 4:38 pm
gstuart
Member Since: 21 Oct 2016
Location: kent
Posts: 14176
Kelvo wrote:
Only very high end expensive solar controllers are waterproof. But you don’t need a waterproof one under the bonnet.
To keep both batteries charged you would need to connect the solar to the main battery, once that batteries voltage is above your dual battery isolator ‘link’ voltage it will then start to charge your second battery. In which case the solar controller will probably fit in the space between the main battery and the engine ECU. But depending on your dual battery isolators cut in and out voltages this may not allow the solar to reliably charge your second battery.
Solar controller size is determined by the solar panel maximum power and voltage ratings. This should be on a label on the solar panel. NOTE if you are using a house solar panel the output voltage will in the 50-100VDC mark, your cheap 12V solar controllers cannot handle a voltage that high. So you need to make sure the solar controller maximum input voltage is greater than your solar panel output voltage and the controllers current is rated greater than your solar panel maximum output current. Example of a solar panel label.
Hi
Reading up more about this, is it better to have 2 x solar panels and 2 x controllers please for each battery ,
But have this T max split charge system fitted that has the link battery facility
However I’ve been reading some instructions so don’t know if I can do that
Or as mentioned is it a case u can only charge one battery at a time
Sorry bit confused , which doesn’t take much for me , just trying to understand it better
Or to get round it, would it be the case of removing the split charge t max system , plus if req can u still charge the batteries with a ctek having solar fitted
If the two batteries are connected to different systems with the same negative common ground (e.g. “engine” and “leisure” battery), but their positive terminals are also connected to a split charger or switch or another component which might link the batteries together, then the solar charge controller may not work properly. When the positive terminals of two batteries become linked, the controller will see both batteries as a mix, and it will not be able to treat batteries independently (e.g. even if you set the controller to 80%/20% it will still charge them as 50%/50%, and if one of the batteries is full it might continue charging anyway etc). You should avoid such situations when the positive terminals of two batteries become linked through another system component such as a split charger or a switch. If this is required in your system, use the solar charging kit to charge one battery at a time only, keeping the other pair of battery terminals of the solar charge controller unconnected.
• If your engine and leisure battery are connected to the positive common ground, you cannot use both Battery 1 and Battery 2 output of the solar charge controller at the same time either. You can only charge one battery at a time and keep the other pair of battery terminals of the controller unconnected. Remember: the solar panel cables should not be grounded in any case.
• If you only have one bank of two or more 12V leisure batteries to charge, and these batteries are connected in parallel (“+” to “+”, and “-“ to “-“), then you should treat them as a single battery and use only one pair of battery terminals of the solar charge controller to charge them. The other pair of battery terminals of the controller should remain unconnected.
Many thks and once again hope it’s ok to post it here and u don’t mind plse Ian and Andy , don’t want to be rude or disrespectful posting in ur thread in any way
26th Jul 2019 6:31 pm
Iguana
Member Since: 14 Oct 2013
Location: 'Sunny' Zomerset
Posts: 9424
Here's my trailer set-up
Click image to enlarge
240v hook up, charges battery, and runs mains sockets, then when not on hook-up switch to solar to run everything
Have a ctec solar controller
Only thing i havent got is inverter, but i do have a portable one that plugs into a 12v socket Iggy/Ieuan
Current LR =
2015 RR Sport Autobiography
&
1992 Land Rover Defender Camper
- Gone but not forgotten:
MY10 D4 GS
MY05 Disco 3 'S'
MY14 FL2 HSE manual in Blue
MY15 Disco 4 HSE Lux in Santorini Black
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1960 Series 2 88" (No idea why I sold it!)
26th Jul 2019 6:45 pm
gstuart
Member Since: 21 Oct 2016
Location: kent
Posts: 14176
Hi iguana
Great looking set up u have there
Also wished to say a massive thks as that CTEK I think will be perfect for what I’m looking for
To be able to charge both my batteries by alternator and solar , installing a solar panel on the roof and being able to leave it connected
Will have to remove my T max split charge system which isn’t any hardship , so that when I don’t use my disco for a while , or camping the solar will keep both topped up and basically the system will look after itself
Just got to see what size solar I need and what the controller will allow me to connect ref watts , amps etc , also if I can connect a ctek battery charger if needed
Have 100 ah main and 75 ah leisure batteries , so assume it needs to be around a 175 watt solar panel
Have the short roof rails so will have to see how to install the solar on the rails, also see the solar panel needs to be ground isolated from the vehicle
Brilliant and it was the eureka moment when I saw the installation you've got , thanks a million
Last edited by gstuart on 26th Jul 2019 8:50 pm. Edited 1 time in total
26th Jul 2019 8:13 pm
gstuart
Member Since: 21 Oct 2016
Location: kent
Posts: 14176
26th Jul 2019 8:19 pm
Iguana
Member Since: 14 Oct 2013
Location: 'Sunny' Zomerset
Posts: 9424
It's expensive, but 2nd hand ones do pop up on eBay on occasions
Ctek D250S Iggy/Ieuan
Current LR =
2015 RR Sport Autobiography
&
1992 Land Rover Defender Camper
- Gone but not forgotten:
MY10 D4 GS
MY05 Disco 3 'S'
MY14 FL2 HSE manual in Blue
MY15 Disco 4 HSE Lux in Santorini Black
MY08 Disco 3 SE manual in Buck Blue
1960 Series 2 88" (No idea why I sold it!)
26th Jul 2019 9:58 pm
gstuart
Member Since: 21 Oct 2016
Location: kent
Posts: 14176
Many thks, see they are around £230 but it’s really 2 x items in one
Also wondering if I can plug my ordinary ctek battery charger in like I’m doing now
Haven’t seen anything else that will work in the same way
Even using separate controllers they say about issues with there linked via the t max dual battery set up
Many thks and will keep an eye out for a second hand one
Other option would be to remove the split charge system, can then get a dual battery controller and panel, think I would prefer 2 x panels so if one fails have the other as a back up
It’s only the link button I wouldn't have but having the solar hooked up it would at least keep both topped up and eliminate the need to link the batteries if the main one got low , along with it being cheaper and an easier setup
Thks again
26th Jul 2019 10:12 pm
Kelvo
Member Since: 07 Aug 2015
Location: Perth WA
Posts: 264
Gstuart you are over thinking it.
IMHO fitting the CTEC instead of the T Max isolator would be a backward step. The solar input into the CTEC is only used to charge the second/aux battery, so no different to how the T Max would work, you lose the ability to manually join the two batteries , and it is then a 20A DC-DC charger so will increase the time it takes the alternator to charge the second/aux battery.
You only want one solar controller, as the other manual said having multiple solar controllers connected to the same batteries (IE when the split charge links them) will confuse the solar controllers and you will best case only have the charge from one panel actually charging or worse case neither will charge the batteries.
If I was doing it I would be using the T Max, one solar controller connected to the second/aux battery and as much solar power as I had space for. If the main battery is low when you want to start the engine link the batteries. If the second/aux battery voltage is above 13.3V and you actually have solar charging happening you can manually link the batteries to then charge both from the solar. When the main battery voltage drops below the ‘isolate’ voltage of the T Max (I can’t see what this is in the manual, but would guess it’s 12.7V) the isolator will seperate both the batteries.
This is essentially what I do when my camper trailer is attached with my Traxide USI-160 battery isolator, and have never had any issue.
The biggest mistake people make is under sizing the wiring. I use a minimum 8mm2 cabling for solar panels to solar charger, and solar charger to battery. I’m then using 13.5mm2 cables from my trailer battery to my D4 second/aux battery, and then 70mm2 from my main battery to my second/aux battery. The 70mm2 is overkill, but I was able to get it for a good price.MY14 TDV6
26th Jul 2019 11:52 pm
gstuart
Member Since: 21 Oct 2016
Location: kent
Posts: 14176
Hi Kelvo
Think ur spot on because I do tend to over think things and always good when it’s pointed out
Don’t know how I missed that diagram with the T max, perfect idea and thanks a million for pointing it out and indeed does make it a lot simpler and cheaper that’s for sure
Will have to find space and where to fit the controller , also think the wire can come through the rubber grommet of the upper tailgate
Did once see solar panels fitted inside to each side of the boots side window , don’t think u would get much output
Wondering if it’s possible to fit 2 x solar panels into one controller so that if one panel fails the other can still be used
Currently have 16 mm cable between both batteries and t max relay , do u think it would be better to also fit 16mm from the roof to the front of the disco where my aux battery is plse
Can’t thank u enough and so grateful for putting my head back in gear and not freewheeling
Will also see what I need for my short roof rails in order to mount the folding solar panel
I’ll also see what the max wattage solar panel I can fit
Thks again for this
Last edited by gstuart on 27th Jul 2019 8:03 am. Edited 1 time in total
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