Battery Charger - Car Outside

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Alex225

MB Enthusiast
Joined
Aug 23, 2015
Messages
2,368
Car
CLS63 AMG
So, my CLS has been sat still for some time covered up and as you'd imagine the battery is knackered. Tried charging it but not having any of it so I have an OEM one I'll be picking up today.

Over the winter I know the car will be laid up and covered as I won't be using it during the winter months. In that time I'd actually like to keep the battery in decent condition and I'm aware that you can buy various trickle chargers.

My problem is that it won't have access to a permanent power source, don't have an outside plug but I will be able to put it on charge for a day or so here and there.

Any ideas on a solution? If I got for one of these intelligent battery chargers, I'd hope to run the cable out of the boot and underneath the cover so I can just plug in as and when but will a few hours a week be enough to keep the battery healthy?

I'm wary of disconnecting the battery entirely as knowing my luck it'll have a funny turn and I'll end up down at the local Merc specialist! :dk:
 
I did try one of those but it's not really helped. Even had one in my E320 and just doesn't seem to put enough charge back into the battery. :(

I blame the British summer personally haha
 
When you get it started, and after a few hours, trigger the car alarm to see if it is still working, a long period without a power supply can damage the internal rechargeable alarm siren batteries.
This can result in false alarms or battery drain if the alarm siren is faulty.
How long was the car idle for?

Dec
 
Alarm was ok as it went off on me yesterday as the car was locked but the boot was open so I'm not too worried about that. Probably three months or so.
 
Solar should work.
Last year after leaving my car at the airport for 16 days the battery was as flat as can be. I do have a few extra things that affect the loading, DRL that detect floating and running voltage, GPS Tracker & after market kenwood HU. So this year, I experimented with a solar panel.

I bought a 20w flexible panel, and fed that to a charge controller, then the charge controller looks after keeping the battery charged.

This year I came back to Heathrow after leaving the car for 16 days again and there were no issues at all.
 
Alarm was ok as it went off on me yesterday as the car was locked but the boot was open so I'm not too worried about that. Probably three months or so.

If I leave my boot open and then lock the car with the remote, the hazards flash two times and the alarm siren doesn’t go off, that is what should happen if a door or boot or bonnet is open when locking.

Try that again, with the boot open, after a period of time, to allow the rechargeable batteries inside the alarm siren a chance to fully recharge.

Dec
 
A few years back, when I used to travel a lot across the pond, leaving the car for a few weeks / months at a time, I fitted an extra, permanently live, power socket, to plug a simple, foldable type solar charger in - worked fine, and it's only 4W.

Still got the changer in my current car, haven't used it for a while though.
 
If I leave my boot open and then lock the car with the remote, the hazards flash two times and the alarm siren doesn’t go off, that is what should happen if a door or boot or bonnet is open when locking.

Try that again, with the boot open, after a period of time, to allow the rechargeable batteries inside the alarm siren a chance to fully recharge.

Dec

To be honest, there was a delay then the alarm went off so that probably means the alarm battery charged up. I've got no cause to worry about that just yet though....I hope haha.

Solar should work.
Last year after leaving my car at the airport for 16 days the battery was as flat as can be. I do have a few extra things that affect the loading, DRL that detect floating and running voltage, GPS Tracker & after market kenwood HU. So this year, I experimented with a solar panel.

I bought a 20w flexible panel, and fed that to a charge controller, then the charge controller looks after keeping the battery charged.

This year I came back to Heathrow after leaving the car for 16 days again and there were no issues at all.

Maybe I'm just not using the right kind of charger but I've got one in the CLS and one in the E and it's not really stopped either going completely flat over a long period of time. :dk:

That said I'm sure there's something that drains the E Class battery as that misbehaves more often. Either that or it just doest' like sitting still!

Either way though a solar charger would work better if the car wasn't covered. Ideally what I need is something that connects to the terminals on the battery with a lead that can be run from the boot. Which I can easily connect to and sit charging half a day or so. :confused:
 
use a smart charger and just leave it on when your home .
 
....If I got for one of these intelligent battery chargers, I'd hope to run the cable out of the boot and underneath the cover so I can just plug in as and when but will a few hours a week be enough to keep the battery healthy?

That should be more than enough

A solar panel helps and if you get one big enough it will do the job but beware of using an unregulated panel without a charge controller as once the battery reaches full charge the output voltage can get too high and damage the battery. They are effectively an unregulated battery charger and you wouldn't leave one of those permanently connected.
 
Just need to suss out which intelligent charger is sufficient for such a large battery.

I swapped the battery over last night so it now has a brand new OEM battery. Car started up perfectly, no errors and suspension raised accordingly so all is well on that front.

Once I have sorted out the battery conditioner, I'm going to see if I can charge the battery I just took out of the CLS. Could be handy to have charged as a spare. Also wondering if it's the same as the battery in my E320. Certainly same size!
 
I have a couple of cars which get very little use, one of which is kept outside.

I bought a CTEK MXS 5.0 charger (good for batteries up to 110 Ah) and connect it to each of them for 24 hrs once every couple of months. This has kept their batteries in a 'ready to start' state for the past two years.

I would think a monthly charge to a good condition battery would be satisfactory.
 
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I use the same charger as Codger, my 110 leisure battery is 3 years old, still going strong, i charge it about every 3 - 4 months. There not cheap but they are very good
 
I have a couple of cars which get very little use, one of which is kept outside.

I bought a CTEK MXS 5.0 charger (good for batteries up to 110 Ah) and connect it to each of them for 24 hrs once every couple of months. This has kept their batteries in a 'ready to start' state for the past two years.

I would think a monthly charge to a good condition battery would be satisfactory.

+1 as above
 
Solar should work.
Last year after leaving my car at the airport for 16 days the battery was as flat as can be. I do have a few extra things that affect the loading, DRL that detect floating and running voltage, GPS Tracker & after market kenwood HU. So this year, I experimented with a solar panel.

I bought a 20w flexible panel, and fed that to a charge controller, then the charge controller looks after keeping the battery charged.

This year I came back to Heathrow after leaving the car for 16 days again and there were no issues at all.
Just remember not to park in the underground/covered car park :)
 
I bought a charger from Halfords specifically for stop/start engines. You can select a proper charge or a maintenance (trickle) charge. Only cost about £30 with a Trade card.
 

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