New solar set up

[whitebeach]

Hi,

New to solar so need a bit of advice. Getting a 100W solar panel and also a new battery. What Amp battery is best? Mostly seems 100Ah but is it better to get a larger one 130, 150 ?

 

[MisterB]

Get the biggest lithium you can afford that will fit in the available space ...

 

[whitebeach]

Get the biggest lithium you can afford that will fit in the available space ...

Definitely worth getting lithium? Reasons?

 

[Guigsy]

Definitely worth getting lithium? Reasons?

Lead acid batteries generally only give you half their rated capacity. Discharging beyond damages them. They aren't that efficient, so every Ah you put in, you only get about 80% out. And they can only be trickle charged for about the top quarter of their capacity, so often you're throwing away solar energy because the battery can't take it. Lithium solves all these issues. You get more return on every watt of solar panel. And the batteries are smaller and lighter.

BUT the charge profile isn't the same as a lead acid battery. So technically all your chargers (DC charging from the alternator, AC charging from the mains and your solar charger) should use a lithium setting. That's the biggest obstacle for going to lithium now.

 

[ivorantony]

Lighter /smaller and twice the power but unfortunately more expensive,

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[Guigsy]

Lighter /smaller and twice the power but unfortunately more expensive,

The battery costs per usable Ah are now pretty close. Look at the price of a 100Ah leisure battery and the equivalent 50Ah LiFePO4 battery... it's about the same. The cost is switching over all your chargers.

 

[headlight]

Hi,

New to solar so need a bit of advice. Getting a 100W solar panel and also a new battery. What Amp battery is best? Mostly seems 100Ah but is it better to get a larger one 130, 150 ?

I'm assuming that, as you are only going to have 1 x 100 watt panel, that you are a light user of electric ?

 

[Jev88]

I find it helps to think of it this way,

More solar = more harvest
More AH in battery = more storage

There is no best AH to go for, just get the biggest that budget allows and will fit the space.

Lithium are a.bit more expensive but are smaller and lighter if you look at AH. You can also use almost all the AH in a lithium battery but only 50% of a lead acid leisure battery.

 

[LostInSpace]

New to solar so need a bit of advice.

Where are you going to be using it?

A 100W panel would be very useful in southern Spain. Not so, in northern Scotland.

 

[barryd]

Generally you match the panels to the battery power but if you have space go for the biggest panel that will fit. Yes lithium is better but its not as straight forward as some might tell you or as cheap. Lots of other stuff needs replacing / upgrading in most vans that are a few years old. If I was putting in a 100w panel I would put in a 120ah battery. In fact thats exactly what I had on my old van for about a decade and it worked fine. April to end of September it was really good in that van. I've found we need a bit more on our new one so now have 240w of solar and 240ah batteries (2 x 120ah).

Its also important to make sure whatever you buy (batteries) will fit in your battery box.

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[whitebeach]

Lead acid batteries generally only give you half their rated capacity. Discharging beyond damages them. They aren't that efficient, so every Ah you put in, you only get about 80% out. And they can only be trickle charged for about the top quarter of their capacity, so often you're throwing away solar energy because the battery can't take it. Lithium solves all these issues. You get more return on every watt of solar panel. And the batteries are smaller and lighter.

BUT the charge profile isn't the same as a lead acid battery. So technically all your chargers (DC charging from the alternator, AC charging from the mains and your solar charger) should use a lithium setting. That's the biggest obstacle for going to lithium now.

Thanks but...what does this entail? "DC charging from the alternator, AC charging from the mains and your solar charger"

 

[Jabstatt]

Take all advice carefully.
Lithium is a no brainier now. Cheaper than lead acid in terms of useable amp hours if you hunt around or even make your own.
Get loads of solar and a good controller. Don’t worry about chargers until you have a basic set up. Solar will do it.
Use a small separate panel to maintain the engine battery.

Build your system bit by bit.

Tony

 

[LostInSpace]

Don’t worry about chargers until you have a basic set up.

First job is disconnect the the split charge relay

Use a small separate panel to maintain the engine battery.

Why? A Battery Monitor will work fine with any leisure battery.

 

[whitebeach]

I'm assuming that, as you are only going to have 1 x 100 watt panel, that you are a light user of electric ?

It's all about cost for me. Is 100w useless? I do have a generator so if I want an espresso...

 

[LostInSpace]

I do have a generator so ......

Sell it and buy more lithium.

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[headlight]

It's all about cost for me. Is 100w useless? I do have a generator so if I want an espresso...

No not useless but a 100 watt panel will only produce 30-40 amps on a good sunny summers day to recharge your leisure battery.
My first year with solar I had a single 115 watt panel and 2 x 110AH lead acid leisure batteries, the batteries giving me a usable 110AH of power.
We managed fine over summer as our daily summer usage was only about 20-25 amps, so most days solar replenished our use.
It all depends on how you use your van and electricity.
After the first year I fitted a second 115 watt panel, and replaced the 2 lead acid batteries with a 230AH LifePo4 battery.
I already had a 60 amp B2B.
I haven't needed to plug into mains since.

 

[Miggs]

Your questions suggest limited knowledge and it would be unwise to undertake a conversion by yourself. Best bet would be to get quotes and advice from reputable auto electricians. Offgrid Power Solutions are one but there are many others.

 

[barryd]

It's all about cost for me. Is 100w useless? I do have a generator so if I want an espresso...

Why not tell us a bit more about your usage? How long do you spend off grid? What are you running 12v wise in the van etc? Where do you tour and for how long do you stay off grid or want to stay off grid for without moving the van? A simple low cost set up might be enough.

This is what I did. Last summer I got very frustrated with my solar setup on my new van. Despite it being a bigger panel than the 100w one on my old van it just didnt seem up to the job. I was about to sign up for one of the top Solar installers to fit a £3k Lithium system. Thats about what it costs for a couple of decent panels, a good Fogstar Lithium 280ah battery and then all the changes to the van which include the B2B from the alternator, MPPT Controller, cabling and a Lithium profile 240v charger.

Long story short I was talked out of it after one of my pals who really is a bit of an expert inspected my set up and declared it rubbish but not beyond "improving". The cables were pathetically thin (important) and the solar controller was not up to scratch. So we fitted an extra 100w panel to join the 140w in place, replaced all the cables with proper thick ones, stuck in a second identical 120ah lead acid battery (the other one was new last year) and a Victron smart solar controller. We did the work together to be fair but the total cost was about £350 and its all compatible with all the charging stuff already in my van. Ill see how it goes this summer but early tests suggest it will be more than enough for our needs.

 

[oldiesontour]

Put as much solar as space/budget will allow,not for the bright days but for the many with cloud...the extra cost is not that great at around 50p per watt..buy a mppt controller there are plenty of decent ones for not a lot of money.. preferably one with a lipo charge as well as lead acid..may be get a cheap sub £100 battery (110/130ah)try it for a while if you want more capacity later you can add another lead acid or go lipo and add a B2B.

 

[herald_400rl]

I've just got a 415w panel off eBay (new) for just under 50 notes. Need to collect it yet. I was about to order a 200w one for over double that!!

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[oldiesontour]

£1 per watt was a good price more recently 50p per watt are we now going to 25p per watt...where next,same with lipo4 now cheaper than lead acid and sodium on the way for even less..but still manufacturers class lipo and solar a premium upgrade on new vehicles!

 

[headlight]

£1 per watt was a good price more recently 50p per watt are we now going to 25p per watt...where next,same with lipo4 now cheaper than lead acid and sodium on the way for even less..but still manufacturers class lipo and solar a premium upgrade on new vehicles!

Yes, having an 'offgrid' set up is much more affordable now.

 

[TheMobileWanderer]

I find it helps to think of it this way,

More solar = more harvest
More AH in battery = more storage

There is no best AH to go for, just get the biggest that budget allows and will fit the space.

Lithium are a.bit more expensive but are smaller and lighter if you look at AH. You can also use almost all the AH in a lithium battery but only 50% of a lead acid leisure battery.

Nice and succinct.

I would add that installing more than is needed by current owner might be a good thing if factoring in potential increased resale value. The next owner may be prepared to pay more if there already is a power system that will suit their needs.

 

[oldiesontour]

Nice and succinct.

I would add that installing more than is needed by current owner might be a good thing if factoring in potential increased resale value. The next owner may be prepared to pay more if there already is a power system that will suit their needs.

The difference in a 100w panelled 100ah system and a 400w 300ah system is not that great but the results are worlds apart and as you say more and more will affect future saleability if not value...buyers are less interested in brand names than performance in not all but certainly many if not most cases

 

[Stevie-b]

The battery costs per usable Ah are now pretty close. Look at the price of a 100Ah leisure battery and the equivalent 50Ah LiFePO4 battery... it's about the same. The cost is switching over all your chargers.

Seems to be about £200 for a good agm battery, 100ah capacity 50ah useable. Ive seen eco worth, 280ah as low as £360 with vouchers

Making the agm £4 an AH and the lifepo4 £1.28

On average lithium now seems to be half the price

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[herald_400rl]

Seems to be about £200 for a good agm battery, 100ah capacity 50ah useable. Ive seen eco worth, 280ah as low as £360 with vouchers

Making the agm £4 an AH and the lifepo4 £1.28

On average lithium now seems to be half the price

I'm going down the route of self build with the advice of oldiesontour, just bought 4 315ah cells for £160 delivered. Bms, sheets, connection bars, etc. Be another £100 to make at least 300ah useable for £260.

 

[LostInSpace]

No not useless but a 100 watt panel will only produce 30-40 amps on a good sunny summers day

More like 3 amps.

 

[headlight]

More like 3 amps.

I meant over the course of a good sunny summers day.

 

[Jabstatt]

The absolute max you will get is(100 divided by 12) and is in amps.
And that is in the best sunlight you can imagine.

Tony

 

[LostInSpace]

I meant over the course of a good sunny summers day.

Still only max of 3 amps all day.

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