[BentZero]

I'm looking at a few on Amazon. It's not exactly clear which one I should buy though. Would either of these do?

STANLEY BC15BS 15 Amp Bench Battery Charger with 40 Amp Engine Start and Alternator Check https://www.amazon.com/dp/B01BM51QD6..._V0KYAbNK8RTQ4

NOCO Genius G750 6V/12V .75A UltraSafe Smart Battery Charger https://www.amazon.com/dp/B004LX3AS6..._i4KYAbAVKAW0W

Schumacher SE-82-6 Dual-Rate 2/6 Amp Manual Battery Charger https://www.amazon.com/dp/B0009IBJBM..._G6KYAb0JG3QKD

[Taunto]

honestly if your using it strictly for flashing any normal battery charger will do. many people flash their cars without a charger installed. as long as your battery state of charge is good you should be fine. that being said I would recommend a charger just in case some sort of which craft happens with the electronics.

[M235SDCA]

I just bought this Dewalt 30 amp:

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Before this one I used an old 10 amp Sears charger and never had an issue. Taunto is probably right that for the short duration flashes these low amperage chargers are good as long as your battery is not depleted.

[M235SDCA]

Originally Posted by BentZero

I'm looking at a few on Amazon. It's not exactly clear which one I should buy though. Would either of these do?

STANLEY BC15BS 15 Amp Bench Battery Charger with 40 Amp Engine Start and Alternator Check https://www.amazon.com/dp/B01BM51QD6..._V0KYAbNK8RTQ4

NOCO Genius G750 6V/12V .75A UltraSafe Smart Battery Charger https://www.amazon.com/dp/B004LX3AS6..._i4KYAbAVKAW0W

Schumacher SE-82-6 Dual-Rate 2/6 Amp Manual Battery Charger https://www.amazon.com/dp/B0009IBJBM..._G6KYAb0JG3QKD

Of these the Stanley would certainly be the best. Don't bother with the NOCO. Less than 1 amp would only be good as a tender for something like winter storage. This Schumacher is also a little light for the price.

[BentZero]

Okay, I think I'm gonna go with the Stanley.

[BentZero]

Crap, I just noticed that it ships in 4-5 MONTHS. No thanks lol. Went with the 25a instead.

STANLEY BC25BS 25 Amp Bench Battery Charger with 75 Amp Engine Start and Alternator Check https://www.amazon.com/dp/B01BYFSUJW..._7fPYAbKA8TG2E

[itzzoscar]

I have a Matco portable jump pack. Could i just leave that on the engine bay terminals? Or should i get a dedicated battery charger?

[gtmax500]

For what its worth, I was doing some audio tuning last night on my DSP with my charger hooked up and set to 2amps. After about 30 mins I got a low battery warning and a CEL and then my car turned off saying it should be driven for longer periods. I cranked the charger up to 20amps and had no problems for the 2/3 hours I was tuning.

Moral of the story, 2 amps is not enough to keep our cars charged for longer than 30 mins.

[M235SDCA]

Originally Posted by gtmax500

Moral of the story, 2 amps is not enough to keep our cars charged for longer than 30 mins.

Also FWIW, my M235 takes 22 amps off my charger with lights / climate control / audio off. Trickle chargers that put out on the order of a couple of amps aren't going to do anything if you are going to be coding for a while.

[M235SDCA]

Originally Posted by itzzoscar

I have a Matco portable jump pack. Could i just leave that on the engine bay terminals? Or should i get a dedicated battery charger?

These jump packs look like a big LiION battery. Don't know what model you have, but one I looked at had a 24 Ah battery and could put out 10 amps at 12 volts out one of the ports. If the jump port could provide this it would certainly be better than nothing. My recommendation would be a bigger charger that could source closer to 20 amps.

[BentZero]

Originally Posted by M235SDCA

These jump packs look like a big LiION battery. Don't know what model you have, but one I looked at had a 24 Ah battery and could put out 10 amps at 12 volts out one of the ports. If the jump port could provide this it would certainly be better than nothing. My recommendation would be a bigger charger that could source closer to 20 amps.

My charger just came in. BM3 OBD device will be in Thursday. I plan on flashing Friday when I "work from home" lol. I'll keep you guys posted.

[Rony316]

Updates? How'd it go?

[BentZero]

Originally Posted by Rony316

Updates? How'd it go?

Oops, sorry. Went well. Pretty easy process overall. I had an issue once, but it's been resolved. awesome product for sure.

[RoundelM3]

Also - FYI, when using a charger, connect it directly to the battery in the trunk area instead of the lugs in the engine compartment. Works much better that way.

[gtmax500]

Originally Posted by roundel335

Also - FYI, when using a charger, connect it directly to the battery in the trunk area instead of the lugs in the engine compartment. Works much better that way.

Do you have a reason for that? Not saying you're wrong just curious since I've always used the lugs in the engine bay and they work just fine. There's at least 2 AWG wire running up there which should easily handle 20amps at that length.

[BentZero]

Originally Posted by gtmax500

Do you have a reason for that? Not saying you're wrong just curious since I've always used the lugs in the engine bay and they work just fine. There's at least 2 AWG wire running up there which should easily handle 20amps at that length.

Doesn't the manual say to use the terminals under the hood to jump start the car? If so, then the charger should use them as well IMO.

[frenchfry675]

Originally Posted by roundel335

Also - FYI, when using a charger, connect it directly to the battery in the trunk area instead of the lugs in the engine compartment. Works much better that way.

Not true.

[RoundelM3]

Originally Posted by gtmax500

Do you have a reason for that? Not saying you're wrong just curious since I've always used the lugs in the engine bay and they work just fine. There's at least 2 AWG wire running up there which should easily handle 20amps at that length.

Yes - after doing the install of a flash tune on a friend's car that took about 2 hours to complete, the car's battery was unable to start the car, despite having a charger connected to the lugs during the process. Even using the 50 amp "start car" setting, it wouldn't work. Connecting the charger direct to the battery allowed the car to start. Apparently, the 15-amp charger didn't keep the battery up while connected to the lugs during the software download. This was on a 2012 Z4 35i with its original battery. Could also be that since the charger was several years old, it wasn't adequate for the job.

[ceedawg]

Originally Posted by roundel335

Yes - after doing the install of a flash tune on a friend's car that took about 2 hours to complete, the car's battery was unable to start the car, despite having a charger connected to the lugs during the process. Even using the 50 amp "start car" setting, it wouldn't work. Connecting the charger direct to the battery allowed the car to start. Apparently, the 15-amp charger didn't keep the battery up while connected to the lugs during the software download. This was on a 2012 Z4 35i with its original battery. Could also be that since the charger was several years old, it wasn't adequate for the job.

Good info. But I think you are both right depending on state of battery and charging system