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Trickle Charge

1726 Views 9 Replies 4 Participants Last post by  Qzyn

Here in Canada we got a 'free' inspection of our aging MLs by the stealership and I was told that my battery was getting weak after 7 years of ownership, everything else checked out fine even though they refused to tell me why my truck was vibrating at idle. I have been relatively happy all through these 7 years and am more than willing to spring for a new battery, but while i was shopping at the local hardware store (Canadian Tire), I chanced upon a solar powered battery charger. It looks kinda small but it might work and plus it was on sale at $9.99 from $39.99.

My question is - which socket should I plug it into? the one near the ashtray or the one at the passenger side? I know one stays on all the time whereas the other is on only when the car is on.

Any suggestions, ideas from the technical gurus here?

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From my professional experience with batteries (NiCd and Pb) and I use o lot of various electronic devices I can tell you one thing about trickle charge:


There is only one purpose of trickle charge - keeping the device ready for immediate use, usually in emergency ( like radiocommunication for example)

Save your dollars!!!

If you really need trickle charge plug it into always on socket.
In my 320'98 both ashtray socket is always on.

keyhole said:
While respecting your background and experience, I can think of no technical reasons for the statement you make above. I think that there are two types of low-current chargers - a trickle charger, and a 'maintenance' charger.

The trickle charger has no cut-off facility and will continue to deliver current even when the battery is fully charged, which can result in 'boiling'. Not literally, but that's the apppearance from the bubbling. So it needs to be monitored.

The maintenance charger is designed for non-attended operation, eg, on boats & motorbikes, which get laid up. When the battery voltage is sufficiently high (fully charged) the charger switches itself off. This is perfectly safe to be left connected for long periods with no damage to the battery.

Yes, you are right, my statement was not properly explained.
Maintenance charger is different from trickle charger, of course!
Anyway, I dont expect 9.99$ solar trickle charger to be fitted with cut off switch or to deliver boiling current to battery.;)

I have "motorbike" charger myself for so called "wintering" of my Yamaha battery.
But frankly speaking usually after few months of storage my bike starts right away without any additional charging.( disconnected for storage)

Same with my ML,last year I was abroad for over 4 months with ML sitting in the garrage.
Battery reconnected to terminals ( MB battery, 8 yrs old) and car started in first attempt without hesitation.
When yr batery is flat after let me say abt 2 months (disconnected), unable to crank yr vehicle usually it means, that the time has come for the new one.

Statement about shortening of batteries lifespan with prolonged, years long continous trickle charge (without boiling batteries of course) comes from my proffesional experience.
In same cases battery must be always fully charged with standing by device, but this is a different story.

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As Kajtek said, with solar charger delivering astonishing 125 mA (in full sunlight) dont expect much over natural discharge.
So called trickle charge means current equal to 1/30 - 1/50 of battery capacity in Ah.
So no worries about overcharging/boiling 100 Ah MB battery in this case!!!!
Check yr new gadget in some dark place to avoid the risk of yr battery being actually discharged !!

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