Open to ideas - solar charging leisure battery and Jackery

[freeman3030]

Hi all,

I've been pondering on something as we're considering going off grid caravanning for a couple of days. We've got a Bailey D4-4, it doesn't have a solar panel and we don't have a Jackery (or similar power bank) with solar to keep the leisure battery topped. I'm concerned about running the leisure battery down too low and then not being able to use the motor mover to get the caravan back on the driveway when we return home. It would be impossible to get the caravan on our driveway without a motor mover and we're not strong enough to manoeuvre it by hand.

That led me to ponder... is there a system or how would you go about installing (if this is even possible) a solar panel or two on the roof of the caravan to charge a Jackery/Ecoflow style 1 or 2kw battery kept inside the caravan - maybe under the fixed bed and then plug the caravan into the Jackery/Ecoflow battery to charge the caravan leisure battery and be able to use 240v appliances in the caravan whilst off grid. We take laptops, TV, coffee machine etc on holiday that we wouldn't be able to use whilst off grid. I know we could get a Jackery + solar freestanding outside to feed the caravan with power the way I wish we could have it set up, but it would require setup each day. If it rained we'd have to get it all in and I would be concerned about it getting pinched. Particularly somewhere like the New Forest as when we used to camp in a tent, they warned us about spates in theft from the campsite. Do you think this is possible and has anyone managed this themselves already?

 

[JTQ]

I have the same concerns, and have had for decades [ since 1991]; it being paramount I get the caravan off our narrow lane when returning home. There is no practical way to tow it onto our property.

My solution is a small portable traction battery, that lives at home on a smart charger so is there always fully charged when we return.
I have a second pair of clip on battery connectors, and second battery isolator switch, but just one key. So I can use the mover when not at home with the key in the leisure battery's isolator, or my portable battery at home, with the key in its isolator.

I have used Varta 60 Ah traction batteries, they have a longevity of around 10 years in my application. Caravan is 1900 kgs, there is a dip to power out of climbing back up into the drive, one in 14 incline. Charger, CTEK 5 Amp, so auto corrects for power outages, a quite common issue with our rural overhead supply system. .

 

[Beardy]

Assuming that its wired correctly your leisure battery should be charging from your cars alternator on your drive home so you won't be arriving home with a completely flat battery.

My motor mover uses an average of 20 amps (according to the manual) so 15 minutes continuous use would need 5 amp hours, an hours drive should put that much in the battery. How long does it take you to move from the road onto your driveway?

 

[JTQ]

I am not convinced with the "puny" wiring our car and caravan makers employ in the caravan's battery powering circuits, now coupled to the widespread adoption of smart alternators, and further compounded with a general lack of voltage boosting caravan control systems, that a leisure battery gets much charge on route.
Plus the battery could start at a very low state of charge, and might be past its first flush of youth so not best placed to hold up the requisite voltage under peak motor current draw, its that not the average current that will trip the mover's low voltage feature.

In respect to gambling or not, a lot will depend on how vital moving the van off the highway is.

 

[Anseo]

Hi freeman3030,

You dont say what type of battery you have, the Ah capacity, and knowing age\condition of the battery would be helpful.

I assume that your car is capable of charging your caravan leisure battery, so having enough battery energy to operate the motor mover may not be a problem, how long does it take to drive from the New Forest to your home?

Personally I would forget the Jackery \ Ecoflow option.

JTQ's spare battery is a viable option.

Most lead acid batteries will suffer deterioration if discharged below 50% of capacity, you are normally looking at not having the battery going below 12.2 volts, your control panel or multimeter will keep you informed.

You may want to avoid using the coffee machine, power as much as you can using gas.
And using 12v DC coverted to 220\240 v AC is an inneficient use of your resources.

Is the TV able to be powered from the 12v supply? my TV is not particularly power hungry but still manages to draw 4 amps per hour.

The laptops can be powered using the 12v supply, and if your TV is not able to powered by 12v you can always use the laptops to watch TV, via tethering your smartphone.

I think we need more information to be able to provide some answers.

Bear in mind that assuming your car is capable of charging your leisure battery (it should be) then you have the option of using your car alternator to top up your leisure battery.

I typically use around 25amps for an evening of TV, evening laptop use, lighting, TV antenna booster, blown air heating, water pump, a small amount for when I am heating water for showers, my wife likes music so the radio can be on a lot if we are confined indoors, I am sure I have forgotten some other power requirements.

Not counting anything else I am very happy if I only use 25 amps per evening


I am feeling that solar panels etc. is not right for you at this time.
But I do think that you have viable options easily available to you for a couple of days off grid

 

[Beardy]

I am not convinced with the "puny" wiring our car and caravan makers employ in the caravan's battery powering circuits, now coupled to the widespread adoption of smart alternators, and further compounded with a general lack of voltage boosting caravan control systems, that a leisure battery gets much charge on route.

The alternator on my car is rated at 180 amps, typically they are 100 amp plus on modern cars. Pin 9 (12v power) should be 2.5mm flex rated at 25 amp.

I have no idea what the charging circuit is limited to, or how it's controlled, but the alternator and wiring are more than capable of charging a 100Ah leisure battery.

 

[freeman3030]

Thanks for the replies so far.

Our battery is 95Ah and I think it's 2 years old. It was fitted by the dealer when they installed the MM and gifted us the battery so I can only assume it was brand new. In terms of time to move the caravan between the driveway and car, it's probably takes 5-7 minutes. It's difficult to say exactly as I haven't timed it. It feels like longer. We have to move it off the road and once out in the road pirouette it 360° due to living on a dead end road with lots of cars parked on street, making it difficult at times, sometimes asking neighbours to move cars just to get the caravan out.

We have an external power supply that I use to keep the caravan battery charged at all times so the caravan has a full battery when motor moving from the driveway to the car. Every time I manoeuvre the caravan, when it's about half way (approx 3 minutes of using the motor mover) it slows down as though the battery is running low, so it takes longer to move the caravan towards the car as it's travelling at. About 50%-60% of initial speed. It's all on the flat so, it's not as though we're working on a gradient.

The new forest is about an hour and a half from home, so it would be a good opportunity to replenish charge. The idea would be for a long weekend to visit CLs within 30-40 min radius of home to make use of the caravan as we only get away it in for 3-4 weeks a year and we'd like to use it more. Plus we have the benefit of being able to work from home/from the caravan if we'd like to.

The additional leisure battery is a good solution that I hadn't considered. I just liked the idea of maintaining the charge on the leisure battery and being able to use 240v appliances. Re: the laptop charging, I thought it needed mains power to charge. I thought when using the leisure battery, the 3 pin sockets no longer worked.

Fortunately we have an AVTex 12v TV, so that would work.

 

[Beardy]

Re: the laptop charging, I thought it needed mains power to charge. I thought when using the leisure battery, the 3 pin sockets no longer worked.

The three pin sockets won't work unless you're connected to mains. Your options to charge your laptop are a dedicated 12v charger or an inverter.

I wouldn't expect the motormover to slow down after a few minutes use on a fully charged battery. Maybe the battery is on it's way out.

 

[JTQ]

The alternator on my car is rated at 180 amps, typically they are 100 amp plus on modern cars. Pin 9 (12v power) should be 2.5mm flex rated at 25 amp.

I have no idea what the charging circuit is limited to, or how it's controlled, but the alternator and wiring are more than capable of charging a 100Ah leisure battery.

The reality however is charge reaching the caravan's battery is related to what the whole systems cores sizes are, not what they "should be", plus what voltage the car's voltage system management decides the car needs rather than the current capabilities of the alternator that system manages.

Some caravan controller makers realise the reality and their units feature battery charging voltage boosting. In our Schaudt unit that is from 10 to 14.4 volts

 

[GUMPY]

The alternator on my car is rated at 180 amps, typically they are 100 amp plus on modern cars. Pin 9 (12v power) should be 2.5mm flex rated at 25 amp.

I have no idea what the charging circuit is limited to, or how it's controlled, but the alternator and wiring are more than capable of charging a 100Ah leisure battery.

Charging from the car into my LifPo4 battery is at 5amps, on my drive home today that will be 25-30Ah. A lead acid battery will take a lot less. The charge rate is set by the car/wiring I have added nothing to the circuit.

 

[JTQ]

Charging from the car into my LifPo4 battery is at 5amps, on my drive home today that will be 25-30Ah. A lead acid battery will take a lot less. The charge rate is set by the car/wiring I have added nothing to the circuit.

The LifPo4 will feature its BMS [battery management system] that will address how it exploits what voltage actually reaches it, unless a LA battery benefits from the voltage boosting circuitry as Schaudt controller's feature, it will have no such assistance.

 

[Beardy]

The reality however is charge reaching the caravan's battery is related to what the whole systems cores sizes are, not what they "should be", plus what voltage the car's voltage system management decides the car needs rather than the current capabilities of the alternator that system manages.

Some caravan controller makers realise the reality and their units feature battery charging voltage boosting. In our Schaudt unit that is from 10 to 14.4 volts

So this magical voltage boosting increases the 'whole systems core sizes' does it? Does it communicate with the car's voltage system management as well?

If you draw power from a car battery the voltage drops. Try putting a meter on the battery and switch your headlights on. Unless pin 9 is completely isolated from the battery it will drop the voltage when the caravan is connected and the management system will compensate via the smart alternator.

I can see the point of voltage boosting on solar panel controllers but on an alternator delivering 13.5 - 14.5 v it isn't necessary.

 

[trevormonty]

Hi all,

I've been pondering on something as we're considering going off grid caravanning for a couple of days. We've got a Bailey D4-4, it doesn't have a solar panel and we don't have a Jackery (or similar power bank) with solar to keep the leisure battery topped. I'm concerned about running the leisure battery down too low and then not being able to use the motor mover to get the caravan back on the driveway when we return home. It would be impossible to get the caravan on our driveway without a motor mover and we're not strong enough to manoeuvre it by hand.

That led me to ponder... is there a system or how would you go about installing (if this is even possible) a solar panel or two on the roof of the caravan to charge a Jackery/Ecoflow style 1 or 2kw battery kept inside the caravan - maybe under the fixed bed and then plug the caravan into the Jackery/Ecoflow battery to charge the caravan leisure battery and be able to use 240v appliances in the caravan whilst off grid. We take laptops, TV, coffee machine etc on holiday that we wouldn't be able to use whilst off grid. I know we could get a Jackery + solar freestanding outside to feed the caravan with power the way I wish we could have it set up, but it would require setup each day. If it rained we'd have to get it all in and I would be concerned about it getting pinched. Particularly somewhere like the New Forest as when we used to camp in a tent, they warned us about spates in theft from the campsite. Do you think this is possible and has anyone managed this themselves already?

In theory you could use Ecoflow (power to charge caravan battery via caravans 240V input. As others said not most efficient way to do it but should work. Just need to make sure all systems are operating on gas not 240V.

Alternative just use separate battery charger and plug it into Ecoflow 240V outlet. The advantage of this is charger and Ecoflow could stay inside caravan.

It maybe possible to disconnect caravan battery (save it for MM) and power caravan 12V system from Ecoflow. They can only deliver 10A from their 12V output so will have to watch what you turn on in caravan. Ecoflow displays current draw so should be able to figure out what you can and can't use and in what combination.
Charge all your USB device straight off Ecoflow not from USB outlets in caravan.

Plus side of Ecoflow is you get lot for your money, LiFePo4 battery, inbuilt Inverter, solar charger, USB outlets, DC-DC charger( charge from car), 12V 10A outlet.

 

[JTQ]

So this magical voltage boosting increases the 'whole systems core sizes' does it? Does it communicate with the car's voltage system management as well?

If you draw power from a car battery the voltage drops. Try putting a meter on the battery and switch your headlights on. Unless pin 9 is completely isolated from the battery it will drop the voltage when the caravan is connected and the management system will compensate via the smart alternator.

I can see the point of voltage boosting on solar panel controllers but on an alternator delivering 13.5 - 14.5 v it isn't necessary.

Whilst the alternator might be delivering 14.5 or higher volts, it is what volts are seen by the remote caravan battery under a charger load that dictates charging.
The Schaudt "booster" is effectively a DC to DC unit specified to out put 14.4 volts, with inputs from as low as 10.
Schaudt clearly understand there is a problem and have solved it.

 

[GaryB]

Every time I manoeuvre the caravan, when it's about half way (approx 3 minutes of using the motor mover) it slows down as though the battery is running low, so it takes longer to move the caravan towards the car as it's travelling at. About 50%-60% of initial speed. It's all on the flat so, it's not as though we're working on a gradient.

Next time you use the mover (carefully) feel the terminals where it connects to the battery, if they are warm or hot the connections are poor. I have worked in the cable connector industry for many years and a poor connection will cause a high resistance joint (showing itself as heat). Every time I have a mover swapped when changing the caravan I re-do the battery connections from the moving by using a soldered ferrule onto the ends of the conductor strands, simply trying to successfully clamp all of the strands using the standard battery terminal screws is very hit & miss.

 

[GUMPY]

Whilst the alternator might be delivering 14.5 or higher volts, it is what volts are seen by the remote caravan battery under a charger load that dictates charging.
The Schaudt "booster" is effectively a DC to DC unit specified to out put 14.4 volts, with inputs from as low as 10.
Schaudt clearly understand there is a problem and have solved it.

A Schaudt is unnecessary on my Skoda and probably many other VAG cars as well.
Voltage at battery terminals* with the van connected and engine running is a constant 14.2v, charge current into the battery is 5amps.
This charged the battery from 79% easily today on my return to Devon and would charge a LA battery just the same although the charge rate would drop on an LA battery as it gets near fully charged even though the voltage would remain at 14.2v.

* Readings taken from Victron Smart Shunt and battery BMS both meters read within 0.01v of my calibrated DVM 😉

When I was living on board my boat it was always about getting the maximum charge with minimum engine run time, not something that I need to worry about with the van.

 

[GUMPY]

For those that are worried about having enough charge left in a battery when arriving I would suggest changing to a LifP04 battery and fitting decent amount of solar.
After 2 days away from EHU running TV etc my battery was still at 75% this morning when I left site and was at 100% after just over 100miles on the way home charged from the engine and solar.

Battery

Lithium Leisure Battery - Fogstar Drift 12v 105Ah

105ah 12v Fogstar Drift Lithium Leisure Battery | Grade A LiFePO4 cells, JBD BMS, Bluetooth, Heating | Lowest Prices in the UK. 10 Year Warranty.

www.fogstar.co.uk

MPPT
Victron Energy SmartSolar MPPT 75V 10 amp 12/24-Volt Solar Charge Controller (Bluetooth) https://amzn.eu/d/eb503yi

Solar Panel
ECO-WORTHY 120 Watts Monocrystalline Solar Panel https://amzn.eu/d/adXfF8q

I am considering adding a second panel even though I am managing well with one.
If I do this I might well add an inverter as well🤔

Oh and just to add doing a 50metre move spin and park with the motor mover used less than 2% of the battery

 

[Mr Grumpy]

Just buy a 100 or 150 watt suitcase solar panel and connect directly onto the battery.
If you're going to a site with EHU just leave it at home.

 

[Anseo]

As Mr Grumpy said.

I bought a 100w portable solar from kit from Alpha Batteries last year, just very recently my friend bought the 150w kit, both excellent and recommended.

My recommendation would be this and it is excellent value for money:
150w portabel solar kit bargain.

 

[Anseo]

Regarding powering laptops from 12v DC:

I have bought a couple different sets like those linked to below (change of laptop required the second purchase as the first set did not have a suitable adapter for my new laptop).

Both sets work perfectly.

Your user laptop manual or google search should identify the 12v plug in adaptor size\dimensions required.

e.g.