Solar panel wattage ?

[headlight]

I have never "off gridded" before, always had EHU.
However this year I will be without EHU a few times for 1 or 2 nights max at a time.
With this in mind I have I replaced my single 100AH lead acid leisure battery with a twin 100AH lead acid set up.
I will be running a mains 24" TV (sticker says it uses 45 watts) from an inverter for say 3 hours a day, plus 12v lighting for say 3 hours a day, phone charger from the inverter and the water pump when required.
Roughly what wattage solar would I need to replace the amperage used ?
Also as my solar needs will be infrequent I was wondering if a suitcase "type" panel would suffice rather than permanently attaching a panel to the roof.
Obviously if I was going to be off grid regularly then permanently fixed panels, lithium batteries and a B2B would be the way to go but as my needs are limited I don"t see the point and will stick with lead acids and split charger.

 

[Kannon Fodda]

If you are without EHU one or two nights max, your pair of 100Ah lead-acids should be sufficient alone. This assumes you arrive with them fully charged. For that type of use you are probably going to do 30-40Ah per day, with lead- acid you can use 50% so that should be 2 days use. This assumes lights are LED type for efficiency. Your TV is the key, not so much the TV itself but that you are being a bit inefficient powering through an inverter, rather than a 12V TV, and the inverter loses something from inefficiency.

Your batteries would be fully charged if you had previously been on EHU for a couple of days, or you had driven a very lengthy period (a standard relay based charger - at least the pathetic one in my van - managed a max of 12A, so the 50% use of your setup could mean some 8 hours of driving!) If starting from home go on EHU there for a day or so to pre-charge it all.

Solar is great when the sun shines. a 100W panel flat on the roof in summer would put most of your daily use back. But cloudy, and Spring / Autumn it get's less predictable. The suitcase type solar, again 100W can be more efficient that a flat roof panel, as normally it is angled at the sun. But there may be a risk of theft, and are you there to keep moving it to point the right way?

 

[Stealaway]

I have a similar usage as you also with a 230v 28" TV through an inverter. We also watch TV in the evenings for around three hours.
We never use sites or EHU.
We have 250watts of solar but simply fill the gaps with the biggest panels that will fit.
We have a duel battery solar controller to charge the engine battery.
I monitor the batteries condition with a pair of voltmeters

 

[Richard n Ann]

We have a similar use, inverter and TV is on for 4+ hours at night, LED lights, water pump & phones charging.

We have one 80ah Gel battery and a 150w solar panel and manage easily off grid for 8 weeks in Benidorm. The battery typically drops to 70% but it's recharged by lunchtime.

 

[headlight]

The suitcase panel comes with crocodile clips to attach to the batteries.
I would like to hardwire from the batteries under the floor to a plug, cut the crocodile clips off and replace them with the other plug end.
Any suggestions for a suitable waterproof plug ?
Amperage is only low, less than 10 amps.

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[Phill D]

The suitcase panel comes with crocodile clips to attach to the batteries.
I would like to hardwire from the batteries under the floor to a plug, cut the crocodile clips off and replace them with the other plug end.
Any suggestions for a suitable waterproof plug ?
Amperage is only low, less than 10 amps.

Mc4 connectors.

 

[Phill D]

Ah, just realised you will want them waterproof when not connected...
I guess.

 

[headlight]

Yes.

 

[Richard n Ann]

I've put these on our battery maintainers, they are waterproof when connected but when I disconnect the scooter one I've made a blank plug out of another plug which I just sealed up with silicone.

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[headlight]

Would a 10amp plug be high enough amperage ?
Theoretically the solar can deliver just over 8 amps although from what I've read in full strong sunlight 6 amps max is more realistic.

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[Richard n Ann]

Should be OK as long as the cables aren't too thick to crimp in.

You might be better off with MC4 connectors and make some blanks up for them.

Are you connecting the solar panel to a controller?

 

[Phill D]

could you bring the plug ends out into the gas locker, they would be protected from the elements and there is the vent at the bottom of the locker that the portable unit cables could be fed in through when needed.

 

[Phill D]

Should be OK as long as the cables aren't too thick to crimp in.

You might be better off with MC4 connectors and make some blanks up for them.

Are you connecting the solar panel to a controller?

excellent solution.

 

[headlight]

Should be OK as long as the cables aren't too thick to crimp in.

You might be better off with MC4 connectors and make some blanks up for them.

Are you connecting the solar panel to a controller?

The controller is attached to the back of one of the panels.

 

[Richard n Ann]

The controller is attached to the back of one of the panels.

You're supposed to connect the batteries first but it should be OK if supplied like that. It would be better installed next to the batteries though because of the slight voltage drop... Unless it's been compensated for

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[headlight]

These

 

[headlight]

 

[Lenny HB]

I wouldn't use MC4 connectors for anything that needs to be plugged in and unplugged regualy. They are a pig to get together & get apart that's why they are such a good waterproof connector.
Andason plugs & sockets would be better.

 

[headlight]

I'd thought of Anderson plugs but are they waterproof ?

 

[Richard n Ann]

I wouldn't use MC4 connectors for anything that needs to be plugged in and unplugged regualy. They are a pig to get together & get apart that's why they are such a good waterproof connector.
Andason plugs & sockets would be better.

I didn't used to click them together fully when we used the free standing panel, it only made 2.5 amps though.

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[Phill D]

while i agree with Lenny that without the tool they are very difficult to disconnect. if you use the correct tool for Mc4 they are easy to take apart and the tool costs pennies.

i purchased 5 Mc4 connectors and 2 tools from amazon for around £7.


the other point i would make is that you plug in to the batteries before opening the solar panel out.

 

[headlight]

 

[mitzimad]

if your worried about the anderson plug being waterproof buy a spaer plug to insert when not in use

 

[Silver-Fox]

I’m not sure why you would use an inverter when lots of tv are 12v.
They normally step the voltage back down from the mains.

Or I may be wrong

 

[DumfriesDik]

We have one solar panel (130w?) and two 100amp lead acid batteries. I swapped the controller from pwm to mttp.
I use a CPAP through the night and a siesta in the afternoon.
I’m near Andorra and the batteries have gone from 80% to 100% today, which has been very sunny.
We shower, charge iPhone and iPads use lights and listen to the radio. Watching the 12 volt telly is an option, via Netflix, I am not worried by it.
I also use a Bluetooth monitor to check what is happening. Well worth considering.

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[Off da Grid]

The suitcase panel comes with crocodile clips to attach to the batteries.
I would like to hardwire from the batteries under the floor to a plug, cut the crocodile clips off and replace them with the other plug end.
Any suggestions for a suitable waterproof plug ?
Amperage is only low, less than 10 amps.

Anderson plugs will be best.
Charge phones from 12v not inverter way too wasteful.

 

[headlight]

Say my phone needs 2 amps to charge it then roughly how many amps would the inverter need to draw from my leisure batteries to put 2 amps into my phone ?