150w Solar Panel enough for 2x Leisure Batteries? (1 Viewer)

[Jonny193]

Hi all,

Looking to get a bit of advice/guidance here. We'll be picking up our first motorhome soon and have opted to have an additional leisure battery installed, as we're wanting to camp off grid as much as possible. The factory battery is 95Ah and the additional battery will be 105Ah, I imagine we'll mainly be charging up batteries of laptops/camera/drone in the evenings (not all at once mind!). I've got absolutely zero experience with power and batteries so just wanted to check we'd be alright with this set up for what we'll be using power for.

Any hints or tips are greatly appreciated!

Thanks

 

[brynric]

We are not heavy power users. Our usage is mainly lighting, pumps, recharging phones, bikes etc. We have a single 105ah AGM battery and a 140w solar panel. At this time of year it’s a rare occasion when the battery’s not at 100% by late morning. We try to charge as much as possible during the day using “surplus” solar. We also have a couple of small power packs which adds a little back-up.

 

[Guigsy]

If you're mainly using the van in the summer and the fridge is 3-way, then you're probably ok. If you want to use the van in the spring and late autumn, and you've got a compressor and you don't move around much (so you aren't getting much from the alternator), then it might not be enough.

... It depends on a lot of factors...

If you currently rely on voltage to see your battery level, I'd recommend getting a shunt so you can more actually see how much juice you're using. Then decide if you need more.

 

[Jonny193]

We are not heavy power users. Our usage is mainly lighting, pumps, recharging phones, bikes etc. We have a single 105ah AGM battery and a 140w solar panel. At this time of year it’s a rare occasion when the battery’s not at 100% by late morning. We try to charge as much as possible during the day using “surplus” solar. We also have a couple of small power packs which adds a little back-up.

Thank you! It sounds like our usage is similar, we will be full-timing all year around so I'm just trying to work out whether 1 solar panel will be enough during the shorter days when winter rolls in!

 

[Jonny193]

If you're mainly using the van in the summer and the fridge is 3-way, then you're probably ok. If you want to use the van in the spring and late autumn, and you've got a compressor and you don't move around much (so you aren't getting much from the alternator), then it might not be enough.

... It depends on a lot of factors...

If you currently rely on voltage to see your battery level, I'd recommend getting a shunt so you can more actually see how much juice you're using. Then decide if you need more.

Cheers, we'll be full-timing (constantly moving around) and the fridge is 3-way. We'll have two 11kg gas cannisters (plus Gaslow for EU) in addition to the solar. It might be something we just have to go with and see how we get on, I guess it's not a huge issue to install an additional solar panel if we find ourselve struggling to charge the batteries in autumn/winter.

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[TrudeandDall]

Our VW T4 just had a single 80ah AGM and the only means of charging when off grid was from the split charge system. It always managed to cope with a similar load that you intend, that said all the chargers were 12v (no inverter involved).
Our new van has a compressor fridge drawing around 35 Ah per 24hours, so we doubled up the 95Ah AGM and fitted a 280w solar with Votronic mppt controller. In the summer that would keep us off grid for as long as we liked. The winter is a different matter, as far as solar charging is concerned. We've upgraded again to a 280 lithium (OPS - fellow funsters) and 50amp + 25amp B2B - simply because we need to recharge our two eBikes and this takes 50Ah each time.

So, given your equipment and requirements, I would give it a go. If it doesn't work you can then think about upgrading to lithium and B2B to manage the winter.

 

[MisterB]

Thank you! It sounds like our usage is similar, we will be full-timing all year around so I'm just trying to work out whether 1 solar panel will be enough during the shorter days when winter rolls in!

Full timing suggests to me that you're better off spending money upfront and having a single lithium battery fitted and a decent B2B for recharging it while on the road travelling.

What you should consider is how much power you're likely to use, then double it!! Then you can work out what size battery, though I would go for as big as you can afford that will fit. Next consideration is how are you going to recharge it, solar is good when it's available but if you're traveling often, and staying where the available solar is limited, then a decent B2B will work better for you than solar. You always add solar later or just carry a folding panel with you?

Just because you're looking to full time, it doesn't mean that you can't have gadgets to make your life easier. One months rent saved will buy you a decent lithium battery I reckon, and reduce your reliance on finding/buying lpg

 

[Nick and Mandy]

We've got 2 x standard 100ah batteries and three panels (100w +160w+160w), far too much for this season, but we use the TV for around 5 hours each evening, the cooker has a fan to cool it down (runs for ages and can't turn it off). Altogether we use around 31-39w of an evening. In a nutshell, we rarely go under 96%, and after a short journey in the morning, we're back to 100%. We have a 3000w inverter and when used, we can microwave on high for 10 minutes without the battery draining below 99%. Now that's in the summer season, winter is very different.

 

[Jonny193]

Full timing suggests to me that you're better off spending money upfront and having a single lithium battery fitted and a decent B2B for recharging it while on the road travelling.

What you should consider is how much power you're likely to use, then double it!! Then you can work out what size battery, though I would go for as big as you can afford that will fit. Next consideration is how are you going to recharge it, solar is good when it's available but if you're traveling often, and staying where the available solar is limited, then a decent B2B will work better for you than solar. You always add solar later or just carry a folding panel with you?

Just because you're looking to full time, it doesn't mean that you can't have gadgets to make your life easier. One months rent saved will buy you a decent lithium battery I reckon, and reduce your reliance on finding/buying lpg

Thank you, I appreciate what you're saying and I'll keep it in mind. We've confirmed the solar/leisure battery setup with the dealer so for now we'll go with it and see how it fares. We're aiming to set off in February so it'll be a good test of how it handles winter weather and if we find we're struggling for power we'll be able to upgrade.

 

[Jonny193]

We've got 2 x standard 100ah batteries and three panels (100w +160w+160w), far too much for this season, but we use the TV for around 5 hours each evening, the cooker has a fan to cool it down (runs for ages and can't turn it off). Altogether we use around 31-39w of an evening. In a nutshell, we rarely go under 96%, and after a short journey in the morning, we're back to 100%. We have a 3000w inverter and when used, we can microwave on high for 10 minutes without the battery draining below 99%. Now that's in the summer season, winter is very different.

Thanks! I imagine in the evenings we'll be doing the same and I'm keen to see how much % of the battery this uses up! I was just curious as to whether the solar panel on it's own will be enough to charge both batteries but I suppose it'll be a wait-and-see kind of thing. We'll have LPG to run the central heating/water/cooker/fridge but it'll be interesting to see how the van copes during the colder months!

It's the first time we'll be branching out to motorhoming and we're excited and nervous in equal measures due to all the unknowns!

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[Guigsy]

Thank you, I appreciate what you're saying and I'll keep it in mind. We've confirmed the solar/leisure battery setup with the dealer so for now we'll go with it and see how it fares. We're aiming to set off in February so it'll be a good test of how it handles winter weather and if we find we're struggling for power we'll be able to upgrade.

In February, solar is pretty useless unless you head all the way to the Med. You only get a small fraction of the daily yield you'd get in summer. And it becomes even more dependent on weather and shade. Unless you're prepared to cover the whole roof and put out portable panels, solar is not dependable enough for winter use.

My tactic is, a large battery (280Ah lithium), move frequently (so I get a boost from the B2B) and go to campsites every 7-10 days to get hookup and refill the battery overnight... and wash my pants while I'm there.

 

[ChrisL]

Also remember in the winter you are likely to have the lights on a lot so make sure they are LED to ensure you minimise consumption where you can.

 

[Nick and Mandy]

Thanks! I imagine in the evenings we'll be doing the same and I'm keen to see how much % of the battery this uses up! I was just curious as to whether the solar panel on it's own will be enough to charge both batteries but I suppose it'll be a wait-and-see kind of thing. We'll have LPG to run the central heating/water/cooker/fridge but it'll be interesting to see how the van copes during the colder months!

It's the first time we'll be branching out to motorhoming and we're excited and nervous in equal measures due to all the unknowns!

We try NOT to use the heating system in winter as the fan uses a lot of power. When we switch the heat off, the fan continues for quite a while after too.

 

[Jonny193]

In February, solar is pretty useless unless you head all the way to the Med. You only get a small fraction of the daily yield you'd get in summer. And it becomes even more dependent on weather and shade. Unless you're prepared to cover the whole roof and put out portable panels, solar is not dependable enough for winter use.

My tactic is, a large battery (280Ah lithium), move frequently (so I get a boost from the B2B) and go to campsites every 7-10 days to get hookup and refill the battery overnight... and wash my pants while I'm there.

Thanks Guigsy I'll have a more detailed look into this, would you recommend anyone to install this if we did go down this route?

 

[Neil S]

If your using TV in the long winter evenings that's going to take a bit out of your batteries , our previous motorhome had
2 x 100 amp lead acid batteries and a single 120 watt solar panel routed through an upgraded solar controller (MPPT victron)
In the winter months we could manage 2 nights with heating and TV on in the evenings for 2-3 hours
On the 3rd Day the batteries were pretty well exhausted and down to 60-65% which meant starting the engine or going to a site with EHU

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[Langtoftlad]

2x 100ah leisure batteries, 120w solar has worked for me in the UK - but I don't use my van off grid during the peak winter months Dec-Feb.
My advice would be try it before making any expensive upgrades - just keep any eye on your battery resting voltages so you don't discharge them too deeply.

 

[cyberyacht]

" You can never be too rich, too thin or have too much solar" Wallis Simpson

 

[Jabstatt]

I would run a mile from a dealer who suggests putting two different spec batteries in parallel!!

Tony

 

[Bessy765]

As stated consider lithium as they are well down in price to what I paid four years ago. We have 700 watts of solar but in the winter it does not produce much, even down in Portugal the sun is low daylight hours short and lights on much earlier. If you are on the move regularly it will help but full time and parked up a loot means you may struggle a bit. On our system a B2B is not required but. We can get over 90 amps from the alternator but with respect the system was not cheap, the more solar you can install or even a portable one (they can be better in the low sun s you can point them whereas roof ones are just flat.

 

[Jonny193]

I would run a mile from a dealer who suggests putting two different spec batteries in parallel!!

Tony

Hey Tony, how come?

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[Neil S]

Hey Tony, how come?

they should really be the same amperage and preferably same brand

 

[ChrisL]

Hey Tony, how come?

A couple of things that I can think of, different chemistries require different charge profiles, a small and a large battery in parallel may lead to the smaller battery being over charged once it's full which will happen before the larger battery.

 

[Jabstatt]

Ideally identical, same batch even.
Any difference could lead to imbalance, circulating currents, self discharge of the bank.
Internal resistance is the key.

The indicator is that they are wired in parallel correctly.
Feeds taken negative on battery one and positive on two.

With a heavy load, such as inverter, things get worse.

Tony

 

[Bessy765]

Also if one battery is much older it will pull the new one down to its level

 

[TheBig1]

It is not set in stone, but a guideline is have as many watts of solar as you have amps of batteries or better. So 2x 100ah batteries = 2x 100watt solar panels etc and use MPPT to ensure you are harvesting all the power you can

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[sfrain145]

We are not heavy power users. Our usage is mainly lighting, pumps, recharging phones, bikes etc. We have a single 105ah AGM battery and a 140w solar panel. At this time of year it’s a rare occasion when the battery’s not at 100% by late morning. We try to charge as much as possible during the day using “surplus” solar. We also have a couple of small power packs which adds a little back-up.

If it’s a new vehicle I would opt for a power box like a BLUETTI ac200 this will keep you going but the issue will be getting it recharged.
You can use a fold up set of solar panels or get as much solar as you can fit on your roof straight into the power box. Then tap into your main 240input and this way you can use your van like it was on hook up mine is hard wired in and it lasts indefinitely but I do have a few other ways of recharging it

 

[Tude]

Hi all,

Looking to get a bit of advice/guidance here. We'll be picking up our first motorhome soon and have opted to have an additional leisure battery installed, as we're wanting to camp off grid as much as possible. The factory battery is 95Ah and the additional battery will be 105Ah, I imagine we'll mainly be charging up batteries of laptops/camera/drone in the evenings (not all at once mind!). I've got absolutely zero experience with power and batteries so just wanted to check we'd be alright with this set up for what we'll be using power for.

Any hints or tips are greatly appreciated!

Thanks

Your batteries should be matching otherwise one battery will fully charge the other won’t.

 

[Trackman]

Solar power at that level is highly unlikely to be sufficient in winter. Short days, low sun & weak light mean the 4kW of panels on my house deliver very little power in winter, so 150 W (25 times less) will deliver next to nothing.

 

[Jonny193]

Appreciate everyone's advice so far. I called Vanbitz and spoke to a brilliant chap who was very knowledgeable and gave me 5 minutes of his time. He confirmed that having two batteries of different capacities would mean the larger battery is hamstrung but it was more important to ensure they're the same type (AGL, Gel, Lithium, etc.). So rather than have 95Ah + 105Ah it'll act as 2x 95Ah... fine. His advice was to go out and experiment and see if/where it falls short and to give him a call again after where he can give more accurate suggestions on what to look at upgrading or adding. Really helpful advice and it was refreshing not to have a company try and shove products down your throat at their first opportunity!

 

[Emmit]

Solar power at that level is highly unlikely to be sufficient in winter. Short days, low sun & weak light mean the 4kW of panels on my house deliver very little power in winter, so 150 W (25 times less) will deliver next to nothing.

And your 4kw is angled towards the Sun. The OP's panel is likely to be horizontal.

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