I recently (today) purchased a used battery charger of the large economy size at a pretty good price.
It charges both 6V and 12V batteries at low, medium and somewhat high amperages.
Put it this way: It has an amperage setting for quick-start at 400 amps!

Even tho our batteries typically are 800+ cold cranking amps, I wonder if it's worth it to use the max setting.
Or will I fry everything and knock out the transformer on the end of the block?

Another guy wants to trade it for a new one with a more tame quick start of 100 amps. Certainly this one would charge 'em quick.

Certainly something like this would be good if you owned a Caterpillar D-9 earth mover but other than that, I dunno.

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Strelnik
Invest in America: Buy a Congressman!

1950 170SD
1951 Citroen 11BN
1953 Citroen 11BNF limo
1953 220a project
1959 180D
1960 190D
1960 Borgward Isabella TS 2dr
1983 240D daily driver
1983 380SL
1990 350SDL daily driver alt
3 x Citroen DS21M, down from 5
3 x Citroen 2CV, down from 6

Does it do continous (for a time limit) of 400A, or is it a booster...that is a monster charger.

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My Primary Driver - '85 300CD - 4-speed conversion, 2.47 rear, lowered, euro headlights, rebuilding (not restoring so much)

Wife's - '08 Saab Sportcombi Aero

Riding a '03 Yamaha Warrior

the 400A setting is for "jump starting". for regular charging use the lowest setting possible.
a D9 would need much more than it puts out if it was cold out and it's battery was dead.

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1985 300SD
1998 Jetta TDI
Previous: lots of diesel VW's, MB's, KW's, Pete, Freightliner


Walking isn't a lost art: one must, by some means, get to the garage.

400 might be overkill unless you're starting up a bus, construction equipment, or semi....

My 100A start unit fires off my 617 like nothing, it will start in 2 seconds at -13F without glowing!

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

The "400a" setting is not for charging, but for starting as mentioned.

This type of charger simply has a multi-tap transformer usually. The higher charge rates are simply higher voltage. On the higher rates, especially the 400A boost type of settings, you are likely looking at around 16volts with a really nasty chop to it, which is not at all healthy for your car's electronics.

Proper battery charging is a whole different topic that can populate pages. The simple part is: charge a dead battery at a low rate, until it begins to register some charging current on the gauge. At this point, a medium rate is fine, ~20amp. If faster charging is necessary, the charger probably has a ~40a setting, I wouldn't suggest leaving it there for more than an hour though as the voltage will probably drift too high. Most of the time, a low to medium charge rate is best with typical low-tech battery chargers.

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Gone to the dark side

- Jeff

I have a solar 480 that I got at an auction for $20. love that thing, would not trade it for a 100 amp unit. ( i already have 2 of them, too)

IMHO, anything that was built back in the day is gonna be better than the new plastic crap. steel case. copper windings. built to last.

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1984 123.193 372,xxx miles, room for Seven.

1999 Dodge Durango Cummins 4BTAA 47RE 5k lb 4x4 getting 25+mpgs, room for Seven.

Ditto, the previous comments. Charge at a slow rate with low amperage for decent battery life. If you use the 400A Start rating, ensure that you use proper procedure for jump starting, ie.. POS to Batt. and Neg. to Engine block. A slight spark, from a less than ideal connection, and 400A could easily turn your battery into a bomb with the hydrogen off-gassing.

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Sam

84 300SD 350K+ miles ( Blue Belle )