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General Tech Trickle Chargers

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KVH

KVH

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Maybe an old subject by now, but do many of you feel comfortable leaving your cars on a trickle charger while you’re away for an extended trip of two weeks or more? I’ve heard stories of fires caused by faulty chargers. I’ve also read instructions advising that trickle chargers not be used unless there is someone present periodically to check on the functioning and status. Any opinions? Thank you.
 
Yeah, it's just one of those things. Frankly, I'm uncomfortable leaving any battery on charge when I'm not around. This is especially true of lithium-ion batteries, which are prone to self-immolation. I worry much less about a smart, trickle-charger for a lead-acid battery, as the charger current is small and the batteries don't burn. If you are concerned about attaching one and leaving it unsupervised, you might consider installing an in-line fuse in series with its output, so a short in the charger won't suck up high battery current. In fact, the charger may have one already.
 
The Bently Continental has one and is recomended to leave the car on charge when it not being used for a couple of days,
There are so many things alive even when ignition off and the car locked that the battery goes flat pretty quick.
but i am sure the charger that bently supply is no ordinary charger.
For information : if ever your Bently does go flat you will not be able to open the boot to put a charger on the batteries.
You will need a big sucker on the left hand rear light and pull the light cluster off the locating balls, then you can reach in
and connect a charger to one of the batteries.
 
hmmm - doesn't the Bentley key fob hold an internal (metal) key? so you can open the door and release the boot lid from inside?
 
NutmegCT said:
hmmm - doesn't the Bentley key fob hold an internal (metal) key? so you can open the door and release the boot lid from inside?
Click to expand...
no mechanical boot release on the car inside or out, no sparks, no work. the one i repaired the fire brigade cut a hole in the boot lid to get access to the mechanism, it was only after i repaired the boot lid and the battery went flat i called the dealership and they told me how to get in through the light
bently_Original.jpeg

bently1_Original.jpeg

Before and after
 
I leave a trickle charger on our 2002 Audi. In the summer it may sit for three or four weeks (it’s my wife’s baby), and I’ll just connect a charger and leave it be. In the winter it is not driven for ~4-5 months, and I plug the charger on a timer, so it only charges an hour or so each day.

In both cases I leave it unattended.
 
Modern sealed lead-acid (AGM / RG) batteries are not (as) prone to boiling dry on a charger. Also, modern trickle chargers -- specifically the Battery Tender brand -- can be left on indefinitely. The old-fashioned 10 Amp / 20 Amp chargers that buzzed like a tube amplifier are the ones that are not to be left alone.

I keep a Battery Tender on one of my newer cars 24/7 (the radio memory takes way too much electricity). I just took it out on Saturday and realized it had been in the garage since last November.

When I raced a car with a total-loss system, I would put a Battery Tender on the onboard battery and another on the starter battery between races, which would often stretch to a month or more. No worries at all.

On the other hand, I recently purchased a more powerful OptiMate brand smart charger that I planned to use on a non-sealed battery, and its instructions warned to check the electrolyte level weekly. A less-powerful smart charger from the same brand did not have that warning.

So, if your instructions warn to check the electrolyte level weekly, do it at least until you get a feel for how much water you lose. If you can't do that for whatever reason, look for a Battery Tender.
 
We too have cars (and a small tractor) that will sometimes spend months at a time on a trickle charger. The Battery Tender smart trickle chargers are in a whole 'nother league from the trickle chargers of old as JHaydon alludes to. Plus, they have a fuse in line between the battery and the charger like Sarastro mentions. It's almost like we are the Battery Tender "poster children" around here between how many we have and ones I have given away like one to an elderly neighbor after her husband died that didn't drive her diesel car enough to keep it charged or to my mother when she had to store a niece's car while she was away at school.
 
Whatever you do, do not use harbor freight trickle chargers. I killed 2 batterys with them. Switched to "vector" maintainers from home depot and have not had a issue. One is on the Triumph all the time.
 
I am 6 months in Fl and six in NC. I do not use chargers. Cars always start (including the TR3) unless an unexpected parts failure creates a parasitic load. I assume that would kill the battery even on a trickle.
Bob
 
I might have added--keeping your battery well charged is the best way to maximize its lifetime. 1960s-era electrical systems don't do a great job at that. Even though I have an alternator on my Porsche and a generator with an electronic regulator on my TR4A, I often put a SMART trickle-charger on them when they're parked a long time. The "smart" word is critical; it means that the charger adjusts itself to the battery's state of charge. That way, it can't overcharge the battery (which is difficult anyway with 1 amp maximum output current) and will shut off when the battery is fully charged.
 
I just replaced my battery in the TR3 that was 9 years old. Only warning was early in the spring, it was dead. Trickle charged it for 48 hours and it started the car, etc. Drove it several times without problems thru the summer until last week, no start and would not charge sufficiently. Replaced with a $75 Walmart (group 24 I think). I'm interested to know how long the new battery will last.
 
Interesting subject,

I have a NAPA 5024 battery installed since April 2010. Still performing great but, admittedly it leads an easy life. I use it to start the car relatively infrequently and I do regularly connect a trickle charger to always keep it topped up. From Jan 1 to April 1 the battery sits on my work bench in the garage with the trickle charger connected pretty regularly (usually a couple weeks at a time as I rotate the charger across three batteries which have been pulled for the winter). I am comfortable with the smart technology of the trickle charger (0.75amp) but, would never leave a 2amp or 10amp charger on unattended.

Two things really kill lead acid batteries:
  1. a full discharge - once fully discharged to the point of needing a jump-start, they will never bounce back to the same level. That is why, as Steve said, it is so important to keep batteries at or near full charge (and thus the support from a trickle charger).
  2. heat. A lot of people think it is the cold but, heat kills a battery's health. It is the cold which then subsequently exposes that weakness. That (and F/R weight balance) is why so many modern car manufacturers place the battery in the trunk now.
I was considering proactively replacing my battery after 10 years but, now I am going to see how long I can get out of it - as a challenge!

Bob
 
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