Extra battery and/or solar panel? (1 Viewer)

[DangerMousy]

Looking for advice on what we actually need with regards to battery/solar....as opposed to what we'd like to have if money was no object LOL

We currently have one 110ah battery and there's space to fit another one in the battery locker next to it, we also like the idea of a solar panel. But considering the cost, we're not sure whether we actually need one - maybe we should just get the second battery and see how that goes? Or if we should bite the bullet and get a solar panel too?

In terms of our usage.....so far the most we have done consecutively off-grid is two nights and we were fine. But that was with 3 or 4 hours of driving in between, also we didn't have a TV then and we and didn't need the heating (Alde - which relies on 12v for the pump I believe). Next year we'll probably be looking at going to one or two touring car weekends and Fairford air tattoo (none of which I expect will have EHU available). For other holidays/weekends away we'll probably stay on a mixture of campsites/aire-type places depending on what looks nice and how much it costs.

 

[irnbru]

Depends on if you will be using your MOTORHOME in the winter. One 110 battery isn't going to last long. Solar is good for the summer but in winter very little gets put back in. More so in Scotland when daylight is short.

 

[Cal54]

IMO second battery should be the first priority. Solar can be added anytime once you have used the MH through all seasons and assessed your power needs.

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[peterc10]

Start with another battery. But if your existing battery is old it will be best to ditch that and get 2 new ones, otherwise it may drag the new one down to its level.

Before I got solar I found that in the summer (no heating) with 2 110Ah batteries we could last for about 3 or 4 nights without topping up with anything. Now with solar we can go for weeks without EHU, and we do.

 

[Gromett]

The rule of thumb I use and it has worked well is I try to have an equal number of watts in solar as I do AH in batteries.
So 2 x 110AH batteries would mean I would want 220Watts of solar. I eventually settled for 180Watts of solar.

However, there are obviously limits, weight and internal space for batteries and roof space for solar.

I will be shortly going back to to 500AH of batteries as this appeared to be my sweet spot. I can only squeeze on 2 extra solar panels and probably won't bother until I have monitored usage properly.

If you only have 1 solar panel and 1 battery and can only afford to add one more item. I would suggest a battery would be your first priority. 220Ah seems to be the level that covers the vast majority of peoples uses.

If you don't have a solar panel, then I would suggest a very cheap 80 watts solar panel with 2 x100Ah batteries would be best if you can push the budget out. It not only extends the time you can stay off hookup it helps keep the batteries maintained when you are not on hookup.

 

[DangerMousy]

Thanks all for your words of wisdom - battery first then!
We store the MH on the drive so its not a problem keeping the batteries topped up, also on the control panel you can set it to charge the vehicle battery from EHU too.

Our current battery is one of these: Link Removed and its only a few months old so its just a case of buying another one - I know the theory of how to connect them I just need to work out what bits I need to actually do it

Solar panel is really going to come down to £££ - I'm not confident on installing that myself so I guess its a case of getting a few quotes and seeing what they come out as. Any recommendations on brands to consider or avoid?

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[Camping Gaza]

You know you don't have to have fixed solar panels... you can get off e bay fold out panels that include a solar regulator built into the back, all you need to do to operate the is to clip the crocodile clips to your battery terminals.

http://www.ebay.co.uk/itm/100W-Port...050405?hash=item41b1fd6ea5:g:qwAAAOSw-kdXybdz

The way I am going to proceed is with flexible solar panels,

Link Removed

these weigh 2 kgs, are 1 meter long by 500 wide and 3 mm thick. They seem incredibly efficient, on a dull day INSIDE my van I was getting the correct voltage output as measured by multimeter. You can walk on them, so they are stored under the rear seat mattress and plug into my solar regulator when camped up, and can either work albeit reduced with the window blinds open and roof blinds open, one can sit up on the windscreen (inside) or when in during the day both can be sitting on top of the awning which can be open to 500mm and plonked on top of that. You can put a little cable lock or chain thru the fixing points to stop theft. On a calm day they can just sit up against the van sides looking at the sun.

You will need a solar regulator with these, but I have a Battery To Battery Charger as well that you hook the solar panels up to that has one built in, so that's a big plus.

The point is at least you are getting a bit of charge into your batteries. I just bought one 100w and will try it out before getting another.

To connect your batteries together as one big bank you'll need at least 25mm SQUARE cables, like jump lead thickness only bigger, its not cheap, but safe and fuses of at least 170amp connect in parallel not series or you get 24 volts and can damage your van.

Yes 2nd battery first, then add solar of your choice. If you are serious about keeping up your batteries health, and power requirements, I would add a battery to battery charger too, that way even a short drive will charge your now much larger battery bank.

 

[tonka]

Def Battery first,, It instantly doubles your capacity..
Then add solar, it does not have to be expensive. If you can do some DIY, Drill a hole, use a sealant gun and connect wires then there is lots of info already on here and plenty of people who can give advise..
I buy most of my kit via ebay, never had any issues.. 120w panel £80 ish..

 

[peterc10]

I agree with Tonka. Solar prices are falling all the time as the technology becomes mainstream. But now may be the best time to buy because I suspect the week pound will put prices up.

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[DangerMousy]

If you can do some DIY, Drill a hole, use a sealant gun and connect wires then there is lots of info already on here and plenty of people who can give advise..

I don't mind a bit of DIY but my skill level is more amateur than pro, so self-install of solar panels is definitely outside my comfort-zone. I'm ok with the theory of connecting up the batteries - I know how to do it in parallel rather than series, but I am struggling to work out exactly what bits I actually need to connect them. Might just buy the battery and get a mobile engineer to install it for me.

I don't think standalone panels will work for us coz one of the compromises of our MH is a lack of storage for large items so we'd want roof-mounted ones.

 

[peterc10]

I don't mind a bit of DIY but my skill level is more amateur than pro, so self-install of solar panels is definitely outside my comfort-zone. I'm ok with the theory of connecting up the batteries - I know how to do it in parallel rather than series, but I am struggling to work out exactly what bits I actually need to connect them. Might just buy the battery and get a mobile engineer to install it for me.

Why not ask other motorhomers to show you how they have done it. Never had anybody say no to that!!

There should be people local to you in Hampshire. In fact there will be 40 of us meeting in the New Forest the weekend after next so you could pop down there for the day and ask one or more of us to show you what we have got!!. Most of it bought on line, if they are anything like me.

 

[two]

A battery is an ‘electricity tank’. The bigger your tank, the longer you’ll last, but you’ll need to ‘refill’ it sometime and there are many ways to do so: use the mains; use the engine; use solar; then Efoy, generator or even wind…

Many people have strong views about the effectiveness of different methods (especially solar) but with little evidence of accurate measurement to support their claim, so take care if heeding such advice.

It may be that the capacity of your existing battery is low and affecting performance. If you upgrade to a bank of batteries, get identical ones from the same source at the same time. Then, if capacity remains an issue, look for ways to improve the topping-up regime. The most effective method will depend on your pattern of use. Split charge or battery-to-battery (B2B) charger may be best if you move on regularly. Solar is less use in Winter, especially in snow, and Winter is when you need more juice. Whatever you do, avoid letting your battery(ies) go flat and always recharge as soon as possible.

I’d suggest investigating B2B chargers. I do lots of off-grid camping and only once became stuck at the end of a long winter rally (in spite of 150W solar panels). Running the engine for 20mins got me going again but I don’t think a split charger would’ve been as effective for that. B2B is said to be 5 times faster, they are easy to fit and less expensive than solar. Food for thought?

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[Abacist]

Installing solar panels is not as daunting as you might think. I followed @Techno's thread with great step by step pictures and he usually shows where he has bought all the major bits and pieces. Obviously drilling the hole in the roof is the most worrying bit but do it with care so you are drilling from outside into a cupboard making sure that you will avoid cupboard joins etc. having planned your cable routes in advance to give you where to drill your hole. There are special waterproof connectors to use outside on the roof and use cable channel to stick to the roof to carry the cables along the roof to contain them. Sikaflex is your waterproof mastic/glue and they also sell a clear cleaning fluid to clean the roof patches before you apply the glue and use the clear fluid to tidy up the mastic once the panels are pressed onto the roof. Connect your batteries to your solar controller first so that it recognises it as a 12 volt system and not 24 volt, then cover the panels so that they cannot be generating current and connect them to your solar controller and away you go.

Just don't be afraid to ask on here anything that you are unsure of and you will find people ready to help and advise.

 

[DangerMousy]

Sadly I don't think we'll be able to make it down to the New Forest as we already have plans for that weekend. Shame because that would have been ideal

I found a really useful picture of someone's battery setup which shows what cables and clamps they've used (from the labels it looks like they've these battery cables from Halfords Link Removed) so I should easily be able to replicate that

I've been reading a few threads on solar - its starting to look do-able though I think a lot more research is needed if I'm going to start drilling holes! One thread makes me wonder whether we actually need it though - received wisdom seems to be that over winter in the UK they won't do much good and in the summer, unless you're stationary for a few days, the battery should last ok.

 

[peterc10]

Sadly I don't think we'll be able to make it down to the New Forest as we already have plans for that weekend. Shame because that would have been ideal
.

Many of us will be there Friday afternoon, if that helps.

Or start a new thread headed something like "help with Solar in the xxxxx area". May well get somebody willing to help.

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[two]

Sadly I don't think we'll be able to make it down to the New Forest as we already have plans for that weekend. Shame because that would have been ideal

I found a really useful picture of someone's battery setup which shows what cables and clamps they've used (from the labels it looks like they've these battery cables from Halfords Link Removed) so I should easily be able to replicate that

I've been reading a few threads on solar - its starting to look do-able though I think a lot more research is needed if I'm going to start drilling holes! One thread makes me wonder whether we actually need it though - received wisdom seems to be that over winter in the UK they won't do much good and in the summer, unless you're stationary for a few days, the battery should last ok.

You won’t need such a long lead to connect two batteries. I got a boat chandler to make up two lengths for me (blue & brown, I think) with the right connections on. I’m sure other trades may provide a similar service. Wires need be no thicker than those leaving your existing battery.


I think you’re absolutely right about solar. I’ve bought a panel and am measuring the output from a flat panel by time of year. I’m also trying to determine the effect of different angles of incidence to the sun and different degrees of dappled shade. Theory says that horizontal panels are very inefficient in Winter, although some users believe otherwise. Practice may prove the case.

 

[Abacist]

Wires need be no thicker than those leaving your existing battery.

I would not be happy with this as my standard Autotrail wiring is woefully inadequate to connect two or more batteries to run anything that draws a lot of power and certainly not an inverter not that you said you wanted to use an inverter. I prefer to over engineer DIY solutions but that's me!

 

[two]

It does depend on how the second battery is connected but, if the supply wires are the same size or smaller, they will fail (or fuse) first.

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[peterc10]

I connect my batteries using 25mm starter cables. You can buy them ready made including different types of connectors to the battery, or you can buy it by the metre and add your own connectors. They do it in black (negative) and red (positive). All bought from ebay.

You will need that size if you have a large inverter - mine is 2000W.

 

[ukdw]

A battery monitor is also a very useful and fairly easy to fit £100 addition. My van came with a solar panel and 1x90ah battery. I added a victron battery monitor first, then replaced the single 90ah battery with 2x100ah.

So far I am really pleased, especially with the battery monitor. Wife always used to insist on having hookup - which restricts sites, pitches as well as costing quite a lot sometimes. Now it is a pleasure to no have hookup - saved £12 over 2 nights last week by not needing hookup. Also and knowing how much power you are drawing and what your reserve levels are makes us feel much less guilty about using too many lights, chargers or TVs etc.

I find the solar doesn't usually keep up with my 12v compressor fridge power requirement, but certainly helps, and I also like the fact that when at home it always tops you back up to 100% capacity after you have use the fridge or tv for a few days,

The biggest surprise to me was how quickly the batteries get topped up by the alternator when driving - at least 20-30x quicker than solar panel - so moving an even quite short distance every 2 to 4 days gets us back up to 100% capacity. Even driving around a large campsite (like shell island) to try to find a better pitch after lots have people have left on Sunday adds an amazing amount to the battery levels.

Only changes I might want to make in the future are 1. Finding a way to make use of the relatively new 90ah battery as a reserve tank somehow, 2. Adding some sort of home made sun tracking to the existing solar panel, combined with a better solar charge controller. 3. Getting the bluetooth addon to the battery monitor - so that I can see what level we have reached when driving along.

 

[Daz n Tina]

I have a Bailey 740. I added a solar panel last week,. In the battery box I came through the same hole as the battery cables, and then followed these up back though the floor by the fuse box. The cable then will go behind the sink under the cooker and into the cupboard. I have set my controller up at a low level below the first shelf.

The only thing is the controller states to use approximately 2 metres of cable between the battery and the controller mine us about 3.2 meters but currently does not seem to be a problem. I have used a Meter and there seems to be no voltage drop.

The entry point is to the left of the aerial and drops neatly in the cupboard next to the existing trunking the aerial cables is in.

I used a short length of self adhesive trunking running next to this.

If you decide to fit yourself make sure you connect the controller to the batteries first then the solar panel to the controller.

I purchased my panel from the Lincoln show from solar energy alliance the complete kit cost £200 ish this was with a 130 amp panel and a standard controller not a mppt.

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[DangerMousy]

You won’t need such a long lead to connect two batteries. I got a boat chandler to make up two lengths for me (blue & brown, I think) with the right connections on. I’m sure other trades may provide a similar service. Wires need be no thicker than those leaving your existing battery

I would not be happy with this as my standard Autotrail wiring is woefully inadequate to connect two or more batteries to run anything that draws a lot of power and certainly not an inverter not that you said you wanted to use an inverter. I prefer to over engineer DIY solutions but that's me!

I connect my batteries using 25mm starter cables. You can buy them ready made including different types of connectors to the battery, or you can buy it by the metre and add your own connectors. They do it in black (negative) and red (positive). All bought from ebay.

You will need that size if you have a large inverter - mine is 2000W.

So there seems to be some debate over what size cables to use to connect the batteries

I've been looking at these ones: Link Removed which come in 16mm/110a, 25mm/170a or 35mm/240a options.

We don't have an inverter (and don't plan to get one) - what are the pros & cons of using using higher rated cables?

 

[two]

Don’t get leads any longer than you need. The thicker the better in general.

Short + Thick = Less voltage drop, which is important when you have only 12V to start with.

For joining two batteries, and assuming that the existing wires have been suitably sized, the wires need have no more cross-sectional area than the sum of all those leaving the bank.

 

[Jaws]

Don’t get leads any longer than you need. The thicker the better in general.

Short + Thick = Less voltage drop, which is important when you have only 12V to start with.

For joining two batteries, and assuming that the existing wires have been suitably sized, the wires need have no more cross-sectional area than the sum of all those leaving the bank.

Unless you intend using an inverter wired to the battery bank.. In which case the cross section should be at least equal to the cables on the inverter

We have three 110aH batteries and 300w of solar power.
BUT.. We use the tv a lot ( 22" Cello ).. The morning news is watched for at least a couple of hours and then it usually goes on again about 6pm and stays on until gone midnight..
We have yet to run out of power even if staying in one spot for a couple of weeks

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