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How do you charge/trickle charge?

13K views 18 replies 9 participants last post by  steveberde  
#1 ·
In another thread, I found:

"Warning never charge the car with the key in the ignition,never put a jumper on it with the key in the ignition,never charge the battery via the battery post and a good ground with the key in the ignition."

My 2001 E320 has 4,800 miles on it and while I drive it once in a while, I like to run the engine a bit at idle but I don't think it does much for charging the battery and I've ruined two over the years due to not charging it enough.

What is the proper way to use a battery charger or trickle charger to top off the battery?

Thank you,
 
#2 ·
Harborfreight

tools has a battery tender for about 8bucks,you just hook it up to the charging post under the hood and a good ground and set it and forget it:)
it will keep the battery up to a good complete charge and then it only comes on when needed at very low amp level to keep it maintained.I know from your history of low miles that you get kidded all the time,but you do need to make sure you also run the a/c on full blast at least monthly.And even though the car has less than 5k miles it is a good idea to flush the brake fluid and change the spark plugs.They get old just from sitting unused.:thumbsup:
:bowdown:
 
#3 ·
tools has a battery tender for about 8bucks,you just hook it up to the charging post under the hood and a good ground and set it and forget it:)
it will keep the battery up to a good complete charge and then it only comes on when needed at very low amp level to keep it maintained.I know from your history of low miles that you get kidded all the time,but you do need to make sure you also run the a/c on full blast at least monthly.And even though the car has less than 5k miles it is a good idea to flush the brake fluid and change the spark plugs.They get old just from sitting unused.:thumbsup:
:bowdown:
Thanks ohlord; don't want to lose another battery due to non-use. I do run the engine, sometimes with the heater, sometimes with the a/c, and sometimes I even drive it around the block so the transmission will change a few gears. I drive it during the summer but never take it out during a winter rain, so I want to go with the trickle charger...

Thanks again,
 
#4 ·
Rather than the Harbor freight charger, I'd recomend the real "Battery tender" brand. Costs more, but does a better job of preventing overcharge. neighbor had a harbor freight unit, boiled a battery almost dry. Don't know if that is typical of the harbor freight unit, but I'm leary. We measured the voltage and it never did drop down to a float charge level like the real "Battery tender" or equivalent. But it's going to cost you more the $8.!
 
#5 · (Edited)
Rather than the Harbor freight charger, I'd recomend the real "Battery tender" brand. Costs more, but does a better job of preventing overcharge. neighbor had a harbor freight unit, boiled a battery almost dry. Don't know if that is typical of the harbor freight unit, but I'm leary. We measured the voltage and it never did drop down to a float charge level like the real "Battery tender" or equivalent. But it's going to cost you more the $8.!
I had one before for a Harley, but gave it away when I sold it... my local H-D dealer sells a Battery Tender for approximately $39.

Harbor Freight:
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=95533
 
#6 ·
Trickle charger can go as high as 18V what can damage electronics. Battery maintainers, or float chargers like the mentioned HF keep the voltage at 13.6 volts.
I've been using HB maintainers for years. They fail occasionally so there is a need for monitoring. Usually I keep my motorhome batteries in the garage and put a voltmeter on them once a month. One failure when the maintainer vent up on the voltage did boil my PWC motorcycle-style battery, but that is rare.
On the side of maintainers I do have sophisticated charger that helps in desulfating the batteries by charging and discharging according to the program. Than the battery in our ML have never seen charger even when the SUV was parked for months at the time. It is running 11-th year. I also have other experience that batteries religiously charged die faster, than those neglected in the cars.
Ironic.
 
#7 ·
What you should look for is some variant of the term "float-mode charger." That's the final maintenance stage of charging, which is why you buy a battery tender in the first place. This stage charges the battery at just a few milliamps, and only very slightly raises the voltage above nominal.
 
#8 · (Edited)
Do you think the one at Harbor Frreight would do the job properly? It says:

Fully Automatic
Charges small motorcycle, ATV, snowmobile and lawn tractor batteries.
Maintains 12V automotive batteries
Recharges portable jump-start units faster than wall adapter
Reverse polarity protection
Versatile quick disconnect harness with battery clamp, cigarette lighter, or ring clamp connectors

2 amp trickle charge rate for 12V batteries; 4 amp trickle charge rate for 6V batteries

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=95533
 
#11 ·
What would you understand under "tender" ?
As we can see the selling tactics are very deceiving. Usually "fully automatic" means that after reaching certain voltage the charger turns off, but each manufacture might have different understanding.
The critical word should be "float" meaning the charger adjust the amperage to the voltage and keeps the "maintaining" voltage, not the other way around.
 
#13 ·
Many "automatic" chargers simply shut off when a certain voltage is reached. These are fine for normal service, but not fine for a maintenance charger.

"Float-mode" chargers don't shut off, but instead reduce voltage to the value where a very small charge is being applied when the battery can no longer be fast charged. This is an additional feature that is missing from most consumer-grade chargers.
 
#14 ·
This

one.
Harbor Freight Tools - Quality Tools at the Lowest Prices
make sure the battery is properly filled with distilled water to the correct level if it is an old battery.Hook up the charger and when you start the car monthly to run the a/c just check its operation.Never had a problem with one.Always shut off and remove before starting the car.Always begin with a properly charged battery.10amps overnight with a regular charger.Then use the floater to keep it maintained.
:bowdown:
 
#16 ·
Aside from the ribbing & technical details... the life-cycle you mention in terms of how long your batteries are lasting, is about in line with what more active drivers can expect. it's just that your batteries-per-mile number is very low.

Various items, fluids, and systems won't take kindly to under-use anyway: you have a car there that can stand up to all manner of abuse - except being ignored. Wouldn't it be both cheaper, and more satisfying, to get a long trip once a month out of the car, than have to keep on playing catchup with malfunctioning bits?

I just drove my CL500 through some floods; along some salt and crud-encrusted british motorways; and gave it a damn good clean. That's most of the fun, in my book. It looks great, too...

(all the instructions about not jump-starting and the like are ass-covering exercises, because people can do way stupid things while jump-starting. Volts and amps are high and stay that way for a while if you are not careful. I've jumped a couple of W210's here and the best strategy seems to be to put the cables on with the donor car idling, rev it up for a minute or two, leave it for a few more minutes, THEN start the dead car. Whip the cables off ASAP and get the dead car to go round the block to do it's own charging. Yet to lose any car done this way, including a Ferrari 550 Maranello! ... I should explain that my house backs on to a parking structure where people occasionally store their pride and joy: there's a 612 Scaglietti covered in dust, down the back of the lower level...)
 
#17 ·
I've used a 9$ "maintain" charger from Harbor Freight for years - My friends have always said buy a Battery Tender (which I have 2). So far I can't
discern any difference in their function - I keep a maintain charger on all three of my motorcycles during the down months of which where I live there are usually three. In all the years I've used both a Harbor Freight brand and a Battery Tender I've never replaced a battery.

On another note - I am going to be storing my 2014 E350 4matic for 3 months and plan to hook up the BT. Do I merely clip the positive to the terminal under the red + and the neg to a ground on the frame?

Thanks and yes i am bit slow on things

Best

Steve
 
#18 ·
Sure.. + to +, and - to - :). I seldom use my LS430, and I have installed some special wiring across the battery terminals with in-line fusing, and a connector, that I bought it up right under passenger side tip of the wiper blade. So when the car is not used I just plug the wiring to the trickle charger's plug which keeps it fully charged. The HF one comes with alligator clips that requires me to keep the hood open, and I do not want to do that. When I use the car, I plug the connector (with a built in plastic plug), so the elements will not get in the terminals.