Solar watts for lithium amp hours

Joined
Jan 25, 2024
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Location
North Norfolk, UK
Funster No
100,876
MH
Bailey Approach 745
Exp
since 2012
What is the rule of thumb for solar watts and lithium leisure capacity?

Curios!

What do you think or have.

I’ve 460w Solar and 200 amp hours lithium.

My thoughts are that I should get leisure batteries up to 100% by sundown.

Any thoughts?

Tony
 
it also depends on what you are taking out of the batteries both when its dark and when the sun is shinning ;)
 
What is the rule of thumb for solar watts and lithium leisure capacity?

Curios!

What do you think or have.

I’ve 460w Solar and 200 amp hours lithium.

My thoughts are that I should get leisure batteries up to 100% by sundown.

Any thoughts?

Tony
Depends how good the weather is and how much battery you have used.
 
Sorry, not what I was asking.

What did funsters install?

Tony

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Yes, I’m in Spain, slough and not wales!!

General question!

Uk worst case, maybe.

Tony
 
Sorry, not what I was asking.

What did funsters install?

Tony
We have 520 watts solar and 640ah of lithium, we regularly make between 100ah and 200ah in a day but sometimes a lot less, we also use a lot of power so we are currently -146ah -and will be even lower in a minute when I switch the kettle on but we have the capacity for a few dark days and tomorrow should be sunny anyway.
 
I have the maximum that will fit on my small PVC's roof - 150W.
I have since added ability to attach a 200W foldout panel. But find I don't need that on sunnier summer days, it's cloudy weather when it makes a difference or the shorter days of early Spring and Autumn.

I only have 120Ah lithium. Typical use is 25-30Ah per day, if I don't charge the e-bike or switch on a laptop. Trying to find a way I can re-arrange tiny space and re-wire so I can squeeze a bigger battery in.

In summary, rule of how much solar per battery capacity to recharge is irrelevant to me. In both cases it's as much as I can get.
 
What is the rule of thumb for solar watts and lithium leisure capacity?

Curios!

What do you think or have.

I’ve 460w Solar and 200 amp hours lithium.

My thoughts are that I should get leisure batteries up to 100% by sundown.

Any thoughts?

Tony
460 W coming out of your solar panels and MPPT into your battery at a nominal system voltage of 12V is equivalent to around 40A. So if your solar panels work flat out they will take your battery from empty to full in 5 hours. Real life experience will definitely be different.
 
Over the last couple of weeks we have had a lot of lovely sunny days but my 350 watts of solar has not kept up with my usage.

Although the sky looks clear it has been a bit hazy not that noticeable to the eye but it really cuts down solar output.

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We had 250 watts of solar and 200 ah of lithium and charged 2 ebikes every day from nearly flat.
Absolutely shed loads for us and used this set up for March in Belgium/Germany a couple of times and Spain.

New van and even though that was enough, 300 ah and 350 watts was deemed by myself enough to enter the dick measuring competitions on solar and battery. to cover eventualities such as an air fryer which arrived today and anything as yet to be identified
 
The weather has been pretty good in Bristol/Newbury. Here is the yield from 3 x 175W panels (that probably need a clean.)

Screenshot_20240814_073416.jpg
 
Sorry, not what I was asking.

What did funsters install?

Tony
We have 230 watts of solar, which was the most that would fit on the roof.
Battery wise we have 230AH of LifePo4.
We generally use around 30-40 amps a day in the summer.
On a good day the solar can generate around 80 amps so we are fully charged early afternoon.
If the weather is poor so we dont fully replace our use we have the buffer of the 230AH LifePo4 to tide us over.
In winter we use around 50 -55amps a day.
Obviously our solar won't produce anything like what we use but even with no charge input what so ever we can do 3-4 days just on battery power alone.
Then when we move our 60amp B2B tops up the battery.
 
I have a one ended tape measure for such comparisons 😁
 
There is no rule of thumb. We all use different amounts of electricity. We all behave differently. Some rely on B2B charging. Some plug in more often. Some drive on regularly. Some have better solar regulators. Some have partial shading of their panels. Too many variables.

460W of panels sounds like a good size for 200Ah but…………

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440 w solar,340lithium,plenty in good weather ,3day comfortable in poor, but 200 amps is circa 4 hours drive or on suitcase Genny...no amount of solar will hold its own when no sun,rule of thumb as much solar as you can fit and enough battery to stay still for as long as you need...balanced against cost,weight and space
 
630 watts of solar, to 560ah of Lithium. we are heavy uses so i’m getting a 200 watt portable panel
What panel you going for, I'm looking for one to use in Spain in winter.
 
What panel you going for, I'm looking for one to use in Spain in winter.

not sure yet Michael

I did have a Renogy 200w folding solid panel which tbh looked great but very heavy, i’d struggle with it so sold it on still brand new

I’m looking at a flexible folding panel, possibly not as robust but a 3rd of the weight

maybe an Allpowers one i’m not sure yet

if you make any progress please lmk if you wouldn’t mind

Al 👍

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550w (100w tiltable) solar 100Ah ( batteries were expensive,) still not needed to extend. 30A b2b.
 
This looks like a good solution but the sellers I’ve found call it 200W, 20v and 5 amp!

Is it 200w or 20v, 5a hence 100w???

Tony
 
This looks like a good solution but the sellers I’ve found call it 200W, 20v and 5 amp!

Is it 200w or 20v, 5a hence 100w???

Tony
I just looked at it and was slightly confused by the description, it also seems to be able to be plugged directly into devices so must have some sort of regulator.
 
In our 6m Panel van we have 600AH of Lithium with 320watts of panel installed on the roof. A further 400w can be used in the shape of a Renogy folding array which we can quickly deploy if we go under 200AH and start to panic.

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I’ve ordered this one MichaelT and got it 50% off for £115

View attachment 946248

This looks like a good solution but the sellers I’ve found call it 200W, 20v and 5 amp!

Is it 200w or 20v, 5a hence 100w???

Tony
I have this panel and it is 200W. Obviously you will only see that in full sun. But converted to the battery charging it means if it maxes out you will see almost 15A at your charger voltages of around 14V.
I just looked at it and was slightly confused by the description, it also seems to be able to be plugged directly into devices so must have some sort of regulator.
I have this panel. It was discussed in another thread. There is no controller provided but there is a USB power outlet whilst the fly lead has connectors that would plug into some of the portable power pack boxes that combine battery/charger/inverter, and also the Anderson 30 type plugs and XT60 plug. I route the Anderson connector to Victron Smartsolar 75/15 controller.
In our 6m Panel van we have 600AH of Lithium with 320watts of panel installed on the roof. A further 400w can be used in the shape of a Renogy folding array which we can quickly deploy if we go under 200AH and start to panic.
Some people are just greedy :)
 
I have this panel and it is 200W. Obviously you will only see that in full sun. But converted to the battery charging it means if it maxes out you will see almost 15A at your charger voltages of around 14V.

I have this panel. It was discussed in another thread. There is no controller provided but there is a USB power outlet whilst the fly lead has connectors that would plug into some of the portable power pack boxes that combine battery/charger/inverter, and also the Anderson 30 type plugs and XT60 plug. I route the Anderson connector to Victron Smartsolar 75/15 controller.

Some people are just greedy :)

thanks for this info, it was your posts in the other thread that prompted me to order this panel which hopefully arrives tomorrow


I’ve got an Anderson connector already wired to a spare Victron 75/15 Smart controller so will be interested to see how to wire this panel to the Anderson connector.

This btw will give me 830w to play with so i’m also in the greedy club 😜👍
 
not sure yet Michael

I did have a Renogy 200w folding solid panel which tbh looked great but very heavy, i’d struggle with it so sold it on still brand new

I’m looking at a flexible folding panel, possibly not as robust but a 3rd of the weight

maybe an Allpowers one i’m not sure yet

if you make any progress please lmk if you wouldn’t mind

Al 👍
I use Allpowers 200w panel it's very efficient...but it's not lightweight...
A dedicated Victron MPPT also..
 
We have a 440w panel (£68 from here in Cambridge) and have been getting up to 200ah on a good sunny day. Fitted on tilting bracket which made much more of a difference than i thought. Got up to 429w when tilted. Using with a victron 100 30 controller.



Screenshot_20240907_190526_com.victronenergy.victronconnect.jpg

tilt.jpeg
 

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