Can anyone recommend an amperage I'd need to keep my batteries charged up when not driven? Such as a tender/charger

I picked up a 1A and it's way too small, so I figure maybe a 10A would be enough?

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I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

Why isn't 1A enough?

Been on there for three weeks and hasn't gotten one battery up yet.

Maybe the battery has to be disconnected?

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

I've liked the Guest brand units available from the usual marine stores (West, etc.). I use a 3A for winter storage--4-5 months--and have had no problems; I leave the battery connected and simply clip on the charger leads . That said, I've had no problems *without* a charger for a month or two, ever, and that goes back to the 1960's. The only times I've had trouble getting and keeping batteries charged are when the battery's bad or there's a drain that shouldn't be there (checkable with an ammeter). BTW, I've never had a battery go truly flat, for whatever reason, without finding that it didn't do well afterwards and needed to be replaced.

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Craig Bethune

'97 SL500, 40th anniversary edition

'04 Olds Bravada (SWMBO's)
'06 Lexus ES330
'89 560SL (sold)


SL--Anything else is just a Mercedes.
(Kudos to whoever said it first)

Mercedes sold a kit at one time, a cigarette type jack that mounted in the trunk liner and a jack with a transformer that plugged into the wall. A couple of amps should be plenty unless you have a bad battery. West Marine has a 2 amp battery maintainer, it comes with three cables, clips, lugs (wire to your battery), and lighter jack (wont work unless ignition is on) $49.99. You can unplug the charger portion and leave the cable attached to the battery.

5 Amps would be about right for a big honkin' diesel battery. 1 Amp would probably maintain, but would not be enough to recharge a battery that was down a bit.

Here's one with built in overcharge protection.

http://www.a-aengineering.com/

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Palangi

2004 C240 Wagon 203.261 Baby Benz
2008 ML320 CDI Highway Cruiser
2006 Toyota Prius, Saving the Planet @ 48 mpg
2000 F-150, Destroying the Planet @ 20 mpg



TRUMP .......... WHITEHOUSE
HILLARY .........JAILHOUSE
BERNIE .......... NUTHOUSE
0BAMA .......... OUTHOUSE

Hit Man, I've got a couple of these smart charges made by Yuasa. Have been pleased with them and they get slightly higher ratings than the Battery Tender products. They won't charge a completely dead battery, FWIW.

http://www.yuasabatteries.com/chargers.asp

1 amp is perfectly fine for maintenance charging. The best is to get a standard
10amp charger PLUS a 1amp to balance things out. I use an Ampere Damper
which simply drops the 10 amp charging system down to .5 amp and 1 amp
(switchable). This allows me to handle the big jobs, eg when I leave the lights
on, fast charge (the 10amp charger has 50amp boost) as well as the safer
trickle / maintenance charge.

Neither the car's charging system, nor the 1amp chargers were designed to
restore depleted charge of the battery. To do that, you should use charger
which is 10% of the total amperage of the battery. Usually 10amp charger
will do the trick most of the time w/o fear of overheating or overcharging.

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-- raymond~
47º 34'N 122º 18'W

Mercedes Benz makes a solar charger, P.N. W900 589 02 63 00. They were made available to dealers about two years ago to trickle charge stock vehicles. I don't know if they're available for sale to the public though.

Be very careful about what kind of charger you put on a battery when the battery is attached to the car. Some cheap ones have a lot of ripple (some don't even have "full wave" rectifiers). This can harm the electronics in a modern car, especially if you are trying to charge a dead and/or bad battery. This is because the dead/bad battery won't smooth out the waveform from the charger very well.

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86 560SL
With homebrew first gear start!
85 380SL
Daily Driver Project

http://juliepalooza.8m.com/sl/mercedes.htm

Thanks. This is the best explanation I have run across about how to choose a battery charger. When I went to buy one, I was totally baffled by all of the choices.

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" We have nothing to fear but the main stream media itself . . . ."- Adapted from Franklin D Roosevelt for the 21st century

OBK #55

1998 Lincoln Continental - Sold
Max 1984 300TD 285,000 miles - Sold
The Dee8gonator 1987 560SEC 196,000 miles - Sold
Orgasmatron - 2006 CLS500 90,000 miles
2002 C320 Wagon 122,000 miles
2016 AMG GTS 12,000 miles

I have found a Chicago charger at HF for $25-30.00. I think I'll pick one up this weekend. it's rated as 2/10/50, which means it has a boost charge of 50 amps, a regular charge of 10 amps, and a trickle charge of 2 amps. Is this correct?

__________________
" We have nothing to fear but the main stream media itself . . . ."- Adapted from Franklin D Roosevelt for the 21st century

OBK #55

1998 Lincoln Continental - Sold
Max 1984 300TD 285,000 miles - Sold
The Dee8gonator 1987 560SEC 196,000 miles - Sold
Orgasmatron - 2006 CLS500 90,000 miles
2002 C320 Wagon 122,000 miles
2016 AMG GTS 12,000 miles

and it works quite well for keeping my 300E charged in the winter when stored in the garage.

1.5 or 5 Watt

Youch! the Mercedes branded solar charger is well over 100 dollars.
(AND the little sunlight rays don't know they're being converted into Electrons
by a cheap Chinese photovoltaic array.)

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'84 300SD sold
124.128

I picked up one from Sears years ago and it has performed well.

It has 3 switches for different auto & marine requirements :

6 / 12 V

2 / 10 / 60 A

Manual / Automatic Deep Cycle / Automatic Regular

I set it at 12V, 2A, and Automatic Regular to top up the car battery during winter months. Plug it in at night and it's done next morning.