Jump to content

Parked on driveway


Recommended Posts

It depends on many factors like the charger profile, the batteries installed, current being drawn, etc.

Have a look at why we, Yuasa and Victron Energy think long term EHU isn't the best way of taking care of the charger or maintaining the batteries : http://www.aandncaravanservices.co.uk/ehu-full-time-yes-or-no.php


Victron Energy, the manufacturers of some of the best batteries in the World as well as the best Motorhome chargers, IMO, suggest an alternative strategy which we publish on the webpage.



Link to comment
Share on other sites

If it's practical, the easiest thing to do might be just to plug it in overnight once or possibly twice during the 3-week period. That way there is no risk of an overcharged battery, but also you can be assured the van will be ready for use next time you want it.
Link to comment
Share on other sites

Hi Pete


Perceived knowledge on this forum seems to err towards charging, when required, rather than leaving it plugged in continuously.


The alarm will presumably be powered by the starter battery. The starter battery will also keep the vehicle electronics ticking over, probably drawing a current of about 60 milliamps or 20Ah over 2 weeks.


The leisure batteries shouldn't need charging over a 3 week period as there should be no current draw, providing the power is turned off at the control panel.


I regularly check the voltage of the starter battery. If it drops below about 12.2v, I connect it to a Ctek charger for 24hours (every 2 to 3 weeks).


Having said all this, it probably won't do any harm to continuously charge for just 3 weeks but probably best to charge for a couple of times for 24hours during this period.


Checkout aandncaravans website for more informed information on this subject.


Link to comment
Share on other sites

Colin, sorry but the exact issues that afflict Long Term EHU connection, also affect Solar battery charging. They are both about charging a battery when it doesn't need charging.


Roadpro used to say the Banner wet batteries were maintenance free, but November 2016 the Roadpro website had changed tack :

"'When used with a solar panel, a battery to battery charger or a mains charger that's on for days at a time, the electrolyte levels of Energy Bull batteries must be checked on a regular basis".


Excess loss of fluid usually goes hand in hand with internal battery corrosion and degradation.


Permanent Solar connection can be worse than permanent EHU as each day many Solar Regulators wake up in 'full power' 14.4v mode. Even though the battery might be fully charged and can remain in this profile until the chargers 'Timer' expires. Sometimes up to 4 hours.


If you don't have one of the new Solar chargers, which have an additional 'Storage' charging profile of 13.2v, then we suggest you isolate the Solar panel with a fuse holder, populating it only when you need to charge the battery or through the Winter when the Solar day is only about 4 hours.


All covered on the website webpage mentioned above.






Link to comment
Share on other sites

aandncaravan - 2017-05-12 9:08 PM


Colin, sorry but the exact issues that afflict Long Term EHU connection, also affect Solar battery charging. They are both about charging a battery when it doesn't need charging.



My decades of use of solar would indicate otherwise.

Link to comment
Share on other sites

Hi if you fit a battery master https://www.vanbitz.com/product/battery-master/

This will help to keep your engine battery topped up whilst you are away.


Re the permenant charging of leisure batteries by solar panels shortening battery life! I have 300 watts of solar panels, mttp controller, charging two 110 amp batteries, a battery master, van is stored away from hook up, have had this system on my last three vans. Current van four years old just changed the batteries as having them tested they are 70% efficient. We wild camp a lot but the trick is not to let them go very low.

Link to comment
Share on other sites

Weldted, The industry say a battery should be discarded when it drops to 80% efficiency, so I am guessing that at 70%, yours were past it last year, probably meaning they have only lasted 3 years in real terms, maybe less?

For someone who knows how to look after their batteries, I am making that assumption based on your comment "the trick is to not let them drop too low", that sounds like a pretty poor battery life to me.


How long would your batteries have lasted if you had followed the advice of the battery manufacturers, maybe as long as 6 years?


But look at the other angle, you might as well have covered up 33% of your Solar Install the last 12 months as you have been discarding more than 30% of the Suns energy because of the batteries poor state. That is equivalent to disconnecting a 100watt panel!!!


So by your own comments, for optimum efficiency, your batteries were probably past their best 18 months or more ago. Isn't that very short life?.



The advice from the battery manufacturers is based around creating the optimum solution, with optimum battery life. Just because someone thinks their system 'Works' doesn't mean it couldn't be a whole lot better.


Exactly as with the Battery Master, which does 'work', but there are solutions which are much more efficient.



Two weeks ago we saw one of the worst professional Solar installs ever, but the owner was pleased with the 1.2 amps it was generating on that sunny day. After some simple changes the Solar harvest more than doubled.


He had been pleased because he didn't know how much better it could be.

How do you know that adopting Victron Energy's advice wouldn't result in 30% better Solar harvest over 5 years with double the battery life?

You don't, and nor do I, but to dismiss what Roadpro, Yuasa and Victron say seems to be counter productive to others reading the thread who might be able to make major improvements on battery life (and Solar efficiency) with their own setup.


Our website contains links to the Yuasa website, documents from Victron Energy and the quotes from Roadpro, so I will now leave everyone to make up their own mind.






Link to comment
Share on other sites

Question to aandncaravan.


Is the following correct or wrong?


12v solar charge controllers are positioned between the solar panel and the 12v battery. They control or regulate the power that is given to the battery. Amongst all of the functions they perform its main value is to stop over charging and ensure the battery is charge efficiently.


If correct what's all the fuss about.


Link to comment
Share on other sites

Roadpro have obviously seen some thing bad happening to revise their advice, so maybe one to put to them?


I think that is a question you might also want to put to Victron Energy and Yuasa, they know a bit more than me?


However, there is a big difference between a products specification/description and it's ability to deliver what it is expected to.


A battery charger and a battery maintainer have in the past been of very different aims and technical specs.

It is now understood that Motorhome chargers and Motorhome Solar regulators need to be designed to perform both roles.

Hence new technology arriving that does both, charging a battery when it needs it and dropping to the gentlest of maintenance modes when it doesn't need charging.


To give you an example, we recently highlighted a Stecca regulator (often found in Motorhomes) whose design is clearly aimed at House Solar installations. The mounting instructions to use very long "40mm screws (might cause a bit of an issue with damp on some Motorhomes?) and fit onto a non flammable, Concrete wall" gives a clue to it's intended application.


This Solar regulator is designed to work flat out dragging as much power from the sun and throwing it into the Grid every millivolt it can. The design assumes it will rarely go into battery maintenance mode.


The one we found most recently was installed behind a curtain on a very flammable Plastic/wood surface. When the instructions specifically state it must be mounted on a non flammable surface, for obvious reasons. This was a professionally installed set-up yet had mounted it behind/touching a curtain, one of the most inflammable fabrics in the vehicle.


Totally unsuited to a Motorhome because of the fire risk, but with a Motorhomes long idle times that is not how you want a Solar regulator to target a fully charged battery.

As Victron state,

"the high end of the 12.9v to 13.98v range is fine for a few days or weeks, but not for a 6 months winter period".

So how happy will a battery be with 12 months?


Or an alternative view, how happy would the Insurance Fire assessor be?


The point being that what you might expect a device or install to deliver from it's description can be wide of the mark.





Link to comment
Share on other sites

Wilf, one other point. You write, "Is the following correct or wrong? 12v solar charge controllers are positioned between the solar panel and the 12v BATTERY......".


Which is not correct as the instructions for a quality Motorhome specific regulator would normally tell you to mount it between the Solar Panel and the Power Distribution Unit, not the battery.



Many of the better Motorhome Power distribution units either have a Solar regulator built in or a purpose made socket in place : Sargent, Schaudt, Reich, Arsilicii, Nordelettronica, etc..


Generally, only the generic, non Motorhome specific units talk about direct connection to the battery, like the Stecca, Sun solar, etc




Link to comment
Share on other sites


This topic is now archived and is closed to further replies.

  • Create New...