Spare leisure battery in Nuevo

With the double clanger of the Hull and Whitby events coming up, and the weather being what it is, Janet and I have been giving some thought to how to keep the TV and the lights going for 10 days with only a 50 mile drive to recharge in the middle.

Various methods are available, and all are either expensive or bulky. The cheapest solution is to drive around for two hours on the second day at Whitby, but that method lacks elegance and style. Another way is to persuade someone using their generator to charge up to let us plug into the spare socket, but that sounds a bit too much like cadging.

The cheapest way seems to be to buy a 40AH battery and charge it before we go, and supply the TV directly from it. But what I would like to ask is would it be possible and wise to just connect another battery, stored say, behind the drivers seat, directly to the fitted leisure battery and use them in parallel, even if they were different capacity batteries? I am loath to buy and fit a solar panel, good though they appear to be.

Thanks

Peter

It's not generally recommended to connect lead acid batteries in parallel. It can work Ok with batteries that are the same age/condition, but as they age their voltage when fully charged tends to drop, so an older battery will tend to partially discharge a newer one when they are connected together.

Also, bear in mind that trying to charge two batteries in parallel will present a lower resistance to the charging circuit, which may be damaged as a result. And if you do decide to go ahead, be careful to ventilate both batteries well before making connections close to either one.

Inelegant and style-less works well for me - in your position I'd just drive it round for a bit!

Peter, Will pm you with bulldog01s phone number he has a little used Generator for sale - cheap, I have used it once and whilst it isnt mega watts it will do what you are asking and you are only 30mins away

Why not do without the telly and use fewer lights?
Cheapest solution yet

Frank

boxerman wrote:Why not do without the telly and use fewer lights?
Cheapest solution yet

You only have to look around any campsite in the evening to realise that a lot of people like their tellies!

If it's an older Nuevo then I'd guess it may have halogen downlighters - converting those to LEDs would save a significant amount of power, and you can buy both MR11 and G4 versions for only a few quid - particularly if you have them shipped from HK/China. At around a tenth the power consumption - or less - of halogen, it's well worth doing...

Hi Peter,
One of the first things I did when we bought this van was to fit an extra leisure battery under the passenger seat, mounted in a screwed down plastic crate and connected to the origional by heavy gauge wires down through the floor and up again, if you decide to take this route check the physical size of several makes of battery as capacities and physical size vary considerably. I was lucky or unlucky depending how you look at it, that my origional leisure battery as fitted by AS was on its last legs and had to be replaced shortly afterwards so I had 2 batteries of similar age. I have also altered most of the lights to LED to reduce power consumption. I would definatly advise against carrying a loose battery in the van as this could become a missile, or spill acid, in the event of an accident. Our setup lasted us 4 very wet days at the Peterborough show when the tele was on far more than usual.

Brian2

Hi Peter,

I have a spare leisure battery in my Nuevo and it sits almost next to the original one under the seat, albeit my Nuevo has the seatbelted version so seats are either single or bench. However, I use this battery solely for my TV as I am often away at weekends competing with no hook ups. I find this set up great as I can watch the telly all weekend if I wanted....:0)

Thank you one and all. I have bought a new LB specially for the TV, which i will charge up before i go, as I am not sure how to connect the As charger.

Thanks again

Peter M

Hi Peter,
If you connect your new battery to your existing leisure battery, positive to positive and negative to negative this will give you the larger capacity that you require at 12 volts and charge it through your vehicle charger though at a slower rate than with only one battery connected.

Brian2

Thanks for the advice people.

My spare leisure battery worked fine running the TV in isolation from the rest of the van.

Next question. OK, I could connect both leisure batteries in parallel to save messing about with a separate charger for the TV battery. However I am unsure as to whether the AS charger would cope with what would be virtually a 170AH battery.

Secondly, as the old leisure battery seems to have lost some capacity with age, as has been said, the old battery will take charge from the new battery, possibly causing it to sulphate. Now, could I prevent this by connecting a rectifier in the charging wire between the old and new batteries that would that stop the fully charged new battery discharging back into the old battery?

Any guesses?

Hi Peter,
We have 2 x 75amp hour batteries fitted over 2 years ago and we have never had a flat leisure battery, the second battery is mounted under the passenger seat, in a plastic crate screwed to the floor.
I would say that the AS charger will cope fine with yours.

Brian2

Peterm wrote: OK, I could connect both leisure batteries in parallel to save messing about with a separate charger for the TV battery. However I am unsure as to whether the AS charger would cope with what would be virtually a 170AH battery.

I personally wouldn't risk it if you think you might deeply discharge both. As I said in another thread, the charger will not have been designed to deliver current into that sort of load, and if it blows, a replacement will cost a lot of money.

Peterm wrote:Secondly, as the old leisure battery seems to have lost some capacity with age, as has been said, the old battery will take charge from the new battery, possibly causing it to sulphate. Now, could I prevent this by connecting a rectifier in the charging wire between the old and new batteries that would that stop the fully charged new battery discharging back into the old battery?

You could, but unfortunately all rectifiers have a forward voltage drop, which would cause it to see the battery as fully charged when it is not. It's hard to say how much the capacity would be reduced, though. It may be better to just add a changeover switch - but make sure that the back of the switch is not located in any battery compartment, or it will represent a small but real risk of causing a hydrogen gas explosion.

'Confused' from Barnsley here, Why would you want a rectifier in the battery lines? Its not AC, but already DC, so what are you 'rectifying'????

Also, 2 leisure batteries CAN be paralleled together, ok so one may well drop slightly to level out with the other, but then the on board charger will

Whack them both up together, & it WILL charge them, but just take longer.

We used to regularly charge up 2 ton 72v traction batteries, that's 36 separate cells & there were ALWAYS a couple that were down on the others, but

they all 'equalled-out' during the charge process.

Peterm is referring to a diode (aka a rectifier), with the intention that current will flow into the battery from the charger, but cannot flow back out and into the other battery.

Please believe the point being made on this: The van charger will ~not~ have been designed to charge 2 batteries connected in parallel across one of its outputs. It may survive perfectly well, but then again, it may not.

Just a thought... have you considered a solar panel. I had the same dilemma when we first ventured out off hookup. I eventually had an 85w panel fitted, for considerably less than you see at the shows, after trawling the web for a decent deal. I have made no changes to the lighting and we can stop anywhere indefinitely without worrying about the battery. I also use a smaller panel on the dashboard via the ciggy lighter to keep the van battery topped up. You could use a portable (briefcase) panel or if confident with tools install your own.
Rich..

As far as the charger is concerned it doesn’t matter if one or two batteries are connected. With two batteries the charger just sees one large capacity battery so the question becomes can the charger charge a battery of that capacity? I think the answer is probably “yes”.
When you connect a single very flat battery the potential charging current is enormous. The actual charging current is limited by the charger and so will not be any higher for a large capacity (i.e. double) battery. It will just flow for longer. I’d be tempted to try it but check the temperature of the charger every now and then. If it overheats change it for a properly designed one!
There is more likely to be problem with a modern “intelligent” charger in that if the terminal voltage is not rising as fast as expected the charger may decide the battery is faulty and switch off. No damage in this case - just a flat battery.
As mentioned before diode idea will work but the second battery will never fully charge (not in any sensible time frame anyway). In fact it will not charge at all unless the terminal voltage of the first battery is about a volt higher. Never the less the extra battery will still give useful extra capacity.

brodco wrote:As far as the charger is concerned it doesn’t matter if one or two batteries are connected.

From an electrical point of view, this is not true. Every battery has an internal resistance, and in the case of a lead-acid battery this is typically a fraction of an ohm.

If you connect two batteries in parallel you effectively halve the resistance that the charger "sees" across one of its outputs. Will the design be able to cope with this? I don't know, and there isn't really any way of knowing without studying the charger's circuitry, to see how well the current limiting part of the design has been implemented.

As I've said previously, I doubt it will cause a problem with partially-discharged batteries, but the charger is put under most load (obviously) when charging from flat, and if you make it do that into a lower resistance than normal, you are likely to find out the hard way if its design and/or components have any weaknesses.

And you should consider yourself lucky that you are able to check your built-in charger's component temperatures - I suspect many will be like mine, which is stuffed away in an unventilated space under the screwed-down floor of the wardrobe! In that situation most people won't know until it's too late.

Thanks RML.

I have considered a solar panel, but went for the extra battery solution for the following reasons.

1. The existing battery is 6 years old, so it will have to changed soon anyway. So now I have it's replacement sitting under the bed seats at this years sale price.
2. Solar is still expensive and comparatively messy for someone with a decreasing attention span. The battery option gave me the opportunity to evaluate how much need I might have for solar.
3. I don't need the extra capacity very often as we prefer to camp in places with hook ups.
4. I can use the extra battery as a stand alone for the TV, so I can in effect prioritise the available capacity if there is larger than planned battery use.

As it happened the weather was fine at Whitby and Hull, plus Janet persuaded a fishery owner to let us charge the van from his kettle socket whilst I fished. So, I have come to think that the whole extra capacity problem has just seen me behaving like a headless chicken.

Knowing the parlous state of every subsystem in my Friday afternoon built van I think I will not risk cooking the AS fitted charger - it has already been changed once under guarantee because of mysterious flat batteries.

Thanks for all of the advice, everyone. A marvellous site .

Peter

I think the solar panel is a great idea. My van came with one fitted on the roof and I never have a problem with the leisure or van battery, even when using the tv etc on a site with no electricity, the longest being for 5 days but I would think it would go on indefinitely. I think it's fairly easy to fit too, the wires connecting into the existing charger unit. Oh, and no noisy generator!

I also think that mine would go on forever as well, think about it, constantly charging during daylight hours, whilst travelling AND when on site, you'll

get something even if overcast, also, with a couple of hundred ah. to play with, I can use 240v with the 2kw inverter, & even then, its only for a few

hours at night & it'll whack the leckie right back in the next day

All I need now is a solar gas generator

I think the solar panel is a great idea.

All ok if you are rich. In winter one needs at least 6 hours worth of lighting, say three lights at 1ah each, plus 4 hours tv at 1ah, plus 24 hours of fridge, pump etc, say 3AH. That is about 25 ah. If its cloudy and the charger is working at about 50% for 5 hours, then it needs to provide 5ah, alowing for losses. To do that I would need to buy a 10amp system, that is 120w. Now those with leds may use less lighting, but replacing my tubes would be a further expense.

Perhaps someone can tell me how much such a solar system, with all the connections and chargers might cost after good bargaining, and why it would be cheaper then just carrying a spare battery - or even two.

You are correct, it all comes down to cost in the end. The correct solution is the one that suits you best. Personally I would not relish the task of managing extra batteries that are not fitted to the van. Also, you have the added workload of monitoring the charging in the van and possilby at home, and then lugging them about. We are at opposite ends of the country but our panel was fitted by http://www.caravanmotorhomesolutions.co.uk/ based in Chard, Somerset.
Rich..