Leisure Batteries

[Rudski01]

Looking for a little advice from the wealth of experience on here, first weekend away in our m/home, when I called in to pick it up from storage the step wouldn't deploy, when I checked the batteries on the panel it was showing under 11 volts, everything was turned off when I left the van, so is it the case you will always get a little draw on the batteries even when everything is off?
They are fairly new batteries and even if the tracker runs off them (not sure if they do) I am informed it's not enough to use that much, it was only left approx 3 weeks in storage so I'm a bit concerned as it will be another 5 weeks at least before we get to go away again and I don't want the batteries to be completely flat.
Can you just disconnect them to preserve charge?

Thanks in advance
Mark

 

[pappajohn]

Depends how old they are and what kind of life they have had in the past.
There will always be some self discharge and that will depend on the above.
Disconnecting may help but they may be on their last legs.
I suppose if you're going to disconnect you may as well take them home and bench charge them.
Ideally, to prolong their life, they should never be discharged below 50% ...around 12.2v.
Prolonged discharged state will kill them in a short time....10v is nearly always terminal if not charged immediately.

 

[Rudski01]

Thanks for the speedy reply Pappajohn, I was informed that they were new, how new I don't know but he only had it twelve months and they were always kept topped up with EHU, don't fancy having to disconnect and bring home every time I leave it in storage, but if needs must!
Could anything else be taking power?

Cheers
Mark

 

[magicsurfbus]

Cold weather will do for them if you're not careful, especially the temperatures we've had recently. I've just my MH home after a while in storage to top up the batteries on the mains. Both batteries brand new this year, but were getting too close to 12v for my liking. Even with a solar panel the input can get very weak at this time of the year, plus the panel ices up.

Our MH's control panel has a remote monitoring system so I can keep tabs on levels online or with a phone app - there was a noticeable drop as the temperature dipped. Part of the problem with this MH is the leisure battery is slung below the boot floor so it's more exposed than in the last one where it was under the front passenger seat.

 

[tonyidle]

Batteries self-discharge regardless of any load on them. You don't say how long it has been since the batteries were charged. Even if the batteries were fully charged before you stored the van a month (with no load on them at all) is the safe limit before a top-up charge is needed. With a load, however small, even a month is too long.

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[PP Bear]

My batteries sit in a cocoon I made from a sleeping roll mat which, as you can imagine, has brilliant insulation properties.

During the really cold spells, I also fit a side panel of the same material, it may only keep them a few degrees warmer, but it does make all the difference.

 

[magicsurfbus]

My batteries sit in a cocoon I made from a sleeping roll mat which, as you can imagine, has brilliant insulation properties.

During the really cold spells, I also fit a side panel of the same material, it may only keep them a few degrees warmer, but it does make all the difference.

I've been wondering about going down that route myself, given that the battery is sealed. I hadn't thought of chopping up a foam sleeping mat - thanks for that idea.

 

[Pausim]

Trackers and alarms only eat small amounts of electricity but it mounts up over a few weeks. If you remove the batteries you won’t be protected. My alarm is attached to the engine battery and I use a 100w folding solar panel to keep it topped up if leaving for more than 2 weeks. My mh has an Elektroblock which I always turn off with the switch on the unit, if I only switch off at the panel the leisure battery seems to drop slowly, so I guess some circuits stay live.

 

[tonka]

I know my Autotrail has a constant very small draw even with everything off. If you do some simple maths a draw as low as 0.1amp will take around 50amps n 3 weeks.. Solar panels will help.

 

[robnchris]

You don`t say what cab unit you have but I can tell you our 2013 Fiat Ducato will drain it`s batteries in 6 weeks if it wasn`t for the solar panel, during the winter months when the solar doesn`t generate much I will have to plug it in to the mains to keep batteries going.

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[Lenny HB]

In standby mode with the panel switched off some vans can draw up to 100ma, not a lot but over 3 weeks that is 50A/H plus the natural discharge of the battery but most are less than that and are fine for 4 or 5 weeks. I would be more worried about the starter battery I certainly wouldn't want to leave that more than 3 weeks especially in cold weather.
If you can't or don't want to plug into an EHU while the van is not being used best option is to fit a solar panel.

 

[Rudski01]

Cheers Everyone
I don’t have EHU at the storage I’m afraid, I think I need to investigate what the tracker is connected to before disconnecting the batteries, @robnchris I have the i890 elegance, would switching the RCDs in the garage have the same effect as disconnecting? Looks like I need to invest in solar, but until then remove and take home and put on my CTEK charger.
Thanks for all your responses folks
Cheers
Mark

 

[Lenny HB]

The RCD's are for mains 240v only, tracker could be connected to either hab or engine battery, they usually draw between 50 - 100ma.

 

[PhilandMena]

Others have given you good information. Yes you can disconnect your batteries and this is one way to stop them discharging over a relatively long time. However, ant services, radio, clocks alarm, door locks that may be dependant on battery current will not work. If this is going to be the long term method of storing your motorhome, install a solar panel, the bigger the better and connect to both sets of batteries with a monitor that will divert charging current as required, or put on hook up it possible. I suspect you current batteries can be fully recovered if only a few weeks/months old with a good long charge.

 

[Rudski01]

Ok cheers
Short term remove batteries or fit isolator switch, long term, get solar fitted.

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[autorouter]

I don’t have EHU at the storage I’m afraid

If you have a battery and a CTEK charger, all you need is a small inverter to give you an excellent charging facility at your storage site. You could use this for example to top up the starter battery without having to remove it or run the engine on idle. Or even to just transport one battery and keep the other leisure batteries topped up.

I'd recommend a pure sine wave inverter rather than a modified sine wave inverter. I use a 150 watt PSW inverter with my CTEK MXS5.0 charger. I tried a 100 watt inverter, but it wasn't up to it, even though the theory says it ought to be. For a 10 amp charger you'll need a bigger inverter, maybe 250 to 300 watts.

My other solution is a small solar panel that's placed on the dashboard. It doesn't need to be very big to keep batteries topped up. I use a couple of 2.4 watt panels, but if I was buying one I'd get something in the 20 to 30 watt range. That's quite enough to power the alarm, tracker etc and still keep the batteries topped up, assuming you can get the sun to fall on it some part of the day.

As a bonus, I find the inverter has other uses, to charge electric toothbrush, run a mains Ipad charger etc. The 150 watt inverter can plug into a cigarette lighter socket, but anything more powerful needs to go directly on the battery.

 

[Rudski01]

[QUOTE=
My other solution is a small solar panel that's placed on the dashboard. It doesn't need to be very big to keep batteries topped up. I use a couple of 2.4 watt panels, but if I was buying one I'd get something in the 20 to 30 watt range. That's quite enough to power the alarm, tracker etc and still keep the batteries topped up, assuming you can get the sun to fall on it some part of the day.

Forgive my ignorance, electrics are not my strong point, do yo just connect direct to the batteries?

 

[PhilandMena]

If you have a battery and a CTEK charger, all you need is a small inverter to give you an excellent charging facility at your storage site.

Did I miss something here ? @Rudski01 stated he had no EHU in his storage facility. How is fitting an Inverter going to solve his charging problem.

 

[funflair]

Did I miss something here ? @Rudski01 stated he had no EHU in his storage facility. How is fitting an Inverter going to solve his charging problem.

Spare battery in back of car, inverter and charger to dump one battery into the other and then take it home to charge again, at a guess.

Martin

 

[Rudski01]

Think I've answered my own question, looks like its through a controller.

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[PhilandMena]

Spare battery in back of car, inverter and charger to dump one battery into the other and then take it home to charge again, at a guess.

Martin

I get connecting a good battery directly to flat battery in order to get enough juice in to start it. But connecting a good battery to an inverter to connect to a battery charger to charge a flat battery does not make sense to me. How would this achieve more than connecting the two batteries directly together ?

 

[PhilandMena]

20-30 Watt is no where near enough, plus you will loose a little charging from behind a window and you will not capture the sun for as long as possible as it moved across the hemisphere. I suggest you look at the solution in a little more detail so that you spend the minimum amount of dosh and also consider future needs. I would strongly recommend a shed load of solar power on your roof and feed this through a suitable controller to maintain all your batteries and perhaps other services you may be using if wilding, including fridge etc, etc,.

 

[PhilandMena]

You can do that with one of these.
https://www.photonicuniverse.com/en...ny-other-12V-system---German-solar-cells.html

They also produce them in other sizes. It's just a case of connect and forget. However, As I said in my last post these will not track the sun and will only be at their best for a few hours a day and only supply current to the battery they are connected to. If your going to be spending a lot of time wilding or off hook up, it's solar panels on the roof I'm afraid.

 

[funflair]

I get connecting a good battery directly to flat battery in order to get enough juice in to start it. But connecting a good battery to an inverter to connect to a battery charger to charge a flat battery does not make sense to me. How would this achieve more than connecting the two batteries directly together ?

Connecting two batteries together will level them out to the same voltage, doing it through an inverter and charger will raise the charge of the flat battery above the level of the donor battery, its like tipping the bucket in as opposed to connecting the two buckets together.

Martin

 

[Lenny HB]

My mh has an Elektroblock which I always turn off with the switch on the unit

You don't want to do that too often those switches have a reputation for failing.

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[PhilandMena]

Connecting two batteries together will level them out to the same voltage, doing it through an inverter and charger will raise the charge of the flat battery above the level of the donor battery, its like tipping the bucket in as opposed to connecting the two buckets together.

Martin

Are you sure about this Martin, the inverter will also consume current whilst charging as will the charger itself and at some point the inverter and charger will not be receiving enough supply from the battery to continue to charge. I do find this very odd. I've never come across this before however, serves me right for not understanding this level of detail in the first place.

 

[funflair]

Are you sure about this Martin, the inverter will also consume current whilst charging as will the charger itself and at some point the inverter and charger will not be receiving enough supply from the battery to continue to charge. I do find this very odd. I've never come across this before however, serves me right for not understanding this level of detail in the first place.

Sure, if you take one flat and one full battery of the same size and connect them you are going to get two batteries at 3/4 charge, the way suggested above will be a straight swap one full one empty less of course a few amps for the transfer efficiency, how many amps you loose will depend to some extent how long the transfer takes.

Martin

 

[magicsurfbus]

By the modern miracle of Swift Command (TM) I can introduce a new level of geekery into the battery performance discussion.

Below is the last 7 days of data from my MH's control panel. My leisure battery is a brand new Varta 140 fitted around March. The MH is in outdoor storage, has a 100W solar panel mounted flat on the roof, and the charger shuffles power between leisure and cab batteries as it chooses. The MH hasn't been in proper use for a few weeks but was put on EHU at home for a few hours a week or so before 7 Dec.

On 7 Dec when the temperature's beginning to decline from a balmy 10C the leisure battery is at a not too bad 12.6v. By early 11 Dec just before I drive it home to put it on 24 hours' EHU life support it's down to 12v, which is not good news. The difference? 2-3 days of 0C or below, a battery box exposed to the outside, and an iced up solar panel, plus low winter sunshine. Similar story for the cab battery. The drain from the deadlock alarm is minimal, 0.1 Amp at the most - nothing else is on. Even at this time of the year the solar panel will put an Amp back in at midday. The voltage drop is caused by the cold weather.

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[PhilandMena]

Sure, if you take one flat and one full battery of the same size and connect them you are going to get two batteries at 3/4 charge, the way suggested above will be a straight swap one full one empty less of course a few amps for the transfer efficiency, how many amps you loose will depend to some extent how long the transfer takes.

Martin

LOL That does not make sense to me either Martin. How can you get 3/4 of one battery charged from 1/4 of the capacity of another Identical battery. ???

 

[funflair]

LOL That does not make sense to me either Martin. How can you get 3/4 of one battery charged from 1/4 of the capacity of another Identical battery. ???

What we call flat is actually 50% charge still so take one at 50% and one at 100% and balance them out you get two at 75%.

Martin

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