Charger for use during programming?

[LVP]

I'm looking for a charger that will hold voltage over 13V for programming and diagnostics. Most smaller trickle chargers aren't big enough to keep the battery alive during extended programming. I have a large booster, but it doesn't get the voltage up over 13V. I've seen some in shops, but have not been able to find what they are using. Anyone have one they use/recommend? Thanks.

[Doru]

The newer generation chargers are too small for that. The good news is the old style (cheap) chargers will be up to the task. you need charge rates around 10Amps. If it's set to 2 Amps, the battery will be discharged very quickly while doing programming.

[garrett.fell]

I recall reading something recently from BMW (some sort of manual excerpt ) suggesting you should have a power supply capable of providing 40 amps? That sure seems like a lot but, I actually had this exact same question so I am glad it was asked.

I've knocked my battery down a few times doing diagnostics with DIS that required me to hook up my little jumpstart pack to start the car again.

How about hooking up a jumpstart pack to supplement the battery with a little extra juice? Not the best long-term solution but might help you keep the battery happy while the ignition is on for an extended amount of time.


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[Doru]

I wouldn't use a jumpstart pack - too hard. I should have probably said "at least 10 Amps".
The conventional chargers are like the modern chargers build for different battery size(s). For our battery, the smallest charger will have the 10Amp setting, that's why I mentioned that. Also, there are conventional chargers that can go to 75Amps, which I think is too much and might do harm. Even the 40 Amps seems a tad on the hi-side...

[Jungerishere]

I have also heard that the mechanics select 40-50 amps during diagnostics. However, I have always selected 10 amps during prolonged programming and never had issues. BTW... Alternator output is around 50 amps while driving.

[LVP]

Any brand recommendations so I can hunt one down? I've seen ones (in videos) that let you set the voltage and it'll keep it at that.

[white46]

I have 10amp charger which hasn't fail me yet throughout multiple codings and NAV update for my MB which takes about 2 hours.

[David.X5]

I haven't got into coding, but I started looking for these a while ago when I was having ABS module problems. The schumacher INC-700A shows up several places (around $400) and some have said it similar to the snap-on power supply sold for coding. Decided not to DIY, so didn't look for cheaper alternatives.

FWIW, if these things are labelled a "power supply" it will provide a (fairly) constant voltage and vary the current within its limits to do that.

A "charger" will push a certain amount of current even if the voltage increases (as in charging a battery) or decreases, which can be bad in that the voltage may move out of range and the coding abort.

[LVP]

Power supply, not charger - that did it. I imagine something like this would work.
http://www.amazon.com/SUPERNIGHT-TM-.../dp/B004OLJHCI

You could use the pot to dial in the voltage at say 13.5 to make sure it never dips below. 20A I would guess would be enough to not allow the battery to drain while programming.

I'll check my local electronics store and see what I can cook up.

[4.8isX5]

I use this when its cold and im messing around in gt1 or inpa for a longer while.. Works great for other uses as well.. I think i paid about $30 from Harbor freight