Battery "maintainer" for automobiles

[cgrutt]

Is a battery maintainer (used predominantly when programming or flashing pcm) same as a battery charger?

Have to work on my son's BMW and I know, from experience unfortunately, that vehicle is extremely sensitive to voltage fluctuations. Particularly the FRM module, which controls lights, windows and some others. Want to put a "maintainer" on front positive post (used when jump starting, etc) before disconnecting battery in rear. Can I use a battery charger for this? I also have a jump pack that has two lead acid batteries, maybe that would be better than charger? What is actually used when programming? Thanks in advance.

 

[L.Cheapo]

There are special maintainers used when programming. They tend to be expensive. I'm told some vehicles can need 100 amps or more during programming. The standard ~20 amp maintainers may not cut it. Fluctuations in power can cause problems while programming.

 

[theoldwizard1]

Many (most?) modern chargers will "cut back" once they sense the battery is charged. Probably NOT what you want. Some "maintainers" do the same ! Better ($$$) chargers may have a "constant voltage" output, which is what you want.

If your jump pack batteries are good, just use that.

 

[cgrutt]

There are special maintainers used when programming. They tend to be expensive. I'm told some vehicles can need 100 amps or more during programming. The standard ~20 amp maintainers may not cut it. Fluctuations in power can cause problems while programming.

So my jump pack, which is rated for starting, would be better than a charger? Im not programming just want to keep voltage steady when disconnecting battery.

 

[cgrutt]

Many (most?) modern chargers will "cut back" once they sense the battery is charged. Probably NOT what you want. Some "maintainers" do the same ! Better ($$$) chargers may have a "constant voltage" output, which is what you want.

If your jump pack batteries are good, just use that.

Ah, got it. Thanks I'll use the jump pack. Replaced batteries within past year I'll make sure its charged.

 

[zendriver]

Never heard of any jump pack being a "maintainer". Not sure I'd want to feed high amps into a system without a battery anyway.

I'd use a low amp charger or even a cheap battery maintainer from HF. you just need some stable voltage not a bunch of amps.

 

[theoldwizard1]

If I was shopping for a new charger, I would take a hard look at a TOPDON Tornado4000-4A. Yes, it is only 4A, but does have a "voltage maintain" mode !

 

[theoldwizard1]

Never heard of any jump pack being a "maintainer". Not sure I'd want to feed high amps into a system without a battery anyway.

You need a better understanding of electricity !

You can not "feed" high current into a system unless the source (jump pack) is at a higher voltage than the rest of the system or the system is at a very low resistance (cranking).

 

[cgrutt]

I just don't want to fry the FRM module (again) when I disconnect the battery. I'm not going to be putting any high amps through vehicle with battery disconnected. My jump pack is about same size (weight wise anyway) as the battery that's in vehicle now. Just want the FRM module to see steady voltage, again, I'm not programming anything.

 

[L.Cheapo]

So my jump pack, which is rated for starting, would be better than a charger? Im not programming just want to keep voltage steady when disconnecting battery.

Sorry, not my area of expertise. When I disconnect a battery, I just reset the radio stations when I reconnect it. I've read too many horror stories about "memory saver" devices so I don't use them.

I have a charger/maintainer made by Solar (rebranded by MAC and others) that has a "power supply" function. It's the one you see Eric @ SMA or Sherwood @ Royalty using in their videos for diagnostics if you happen to watch them. It provides up to 20 amps in this mode. It's what I use when doing key-on diagnostics, but the battery is still in the vehicle. I believe the manual specifically states "not to be used for programming".

 

[zendriver]

You need a better understanding of electricity !

You can not "feed" high current into a system unless the source (jump pack) is at a higher voltage than the rest of the system or the system is at a very low resistance (cranking).

Wouldn't the jump pack be the highest voltage, when the battery is removed?

Not my car, have at it.

 

[cgrutt]

Wouldn't the jump pack be the highest voltage, when the battery is removed?

It should be same voltage (+/-) as battery, which is what I'm looking to accomplish. I basically don't want FRM module to see any difference.

 

[theoldwizard1]

Wouldn't the jump pack be the highest voltage, when the battery is removed?

If there is no other "power source" (battery) in the system, the amount of power delivered (current/amps) is strictly up to the load/resistance of the systems.

Batteries, especially lead-acid, are kind of weird. If there is another power source in the system (charger) that is HIGHER VOLTAGE than the nominal voltage (plus a bit) of the battery, they will accept the charge. Depending how much higher the voltage of the second source is over the nominal voltage of the battery (13.2V for lead-acid), the electrolyte (water/acid) will boil. The gas bubbles from a lead-acid battery contain hydrogen which is EXPLOSIVE !

 

[zendriver]

It should be same voltage (+/-) as battery, which is what I'm looking to accomplish. I basically don't want FRM module to see any difference.

I'm probably wrong and the jump pack is fine.

 

[Wrench97]

Battery maintainers used for programing have to provide clean(no ripple) steady power that's why they are more expensive.
Look at them more as a power supply then a battery charger.
Some units have the ability to do both but they are normally separate functions.
Using your jump pack is good solution but if the battery voltage starts to drop a charger on low can be used for what you are doing.

 

[cgrutt]

Thanks.

Good video here again I'm not programming anything but at least I learned something. BTW the charger in video is same as mine.

 

[theoldwizard1]

Battery maintainers used for programing have to provide clean(no ripple) steady power that's why they are more expensive.
Look at them more as a power supply then a battery charger.

True ! That is why I recommended this model !

If I was shopping for a new charger, I would take a hard look at a TOPDON Tornado4000-4A. Yes, it is only 4A, but does have a "voltage maintain" mode !

 

[Rusted Nut]

I wouldn't use jump pack, jump packs are good for high starting amperage, and I'd guess voltage would drop quickly. A maintainer only devise, is designed to keep a battery maintained, not provide a power source. With that said, my Noco 10 charger/amontainer has a 12v power source setting; that's what I would use.

 

[ronkz650]

A jump pack in lead acid like the JNC660 will work fine as a backup power supply. Of course a lithium pack won't work. Best bet though is buy a charger with the power supply feature. Noco 10 has it. I use it all the time. Many chargers have it.

 

[cgrutt]

I wouldn't use jump pack, jump packs are good for high starting amperage, and I'd guess voltage would drop quickly. A maintainer only devise, is designed to keep a battery maintained, not provide a power source. With that said, my Noco 10 charger/amontainer has a 12v power source setting; that's what I would use.

My jump pack is very similar to the factory battery except it uses 2 lead acid AGM batteries connected in parallel. I'm not sure of rating but believe its north of 500CCA. I just want the FRM module to see 12V +/- when I disconnect the main battery I'm not going to put any significant draw on it. I may even be able to plug jump pack into 120v if needed but have to test that not sure if it charges while on or not.

 

[cgrutt]

A jump pack in lead acid like the JNC660 will work fine as a backup power supply. Of course a lithium pack won't work. Best bet though is buy a charger with the power supply feature. Noco 10 has it. I use it all the time. Many chargers have it.

Its not a JNC660 but similar. Believe its a Schumacher DSR. Its a pro-level jump pack. Cost over $500 IIRC.

 

[ronkz650]

That pack will work perfectly.

 

[cgrutt]

I think this is the jump pack.

 

[cgrutt]

My jump pack is a PSJ-3612. Pulled it out it was at 12V but only 38% charge. Its been on the shelf unused since I replaced batteries about a year ago. Have it charging now and can confirm it charges while plugged in and turned on, so assuming I can keep it plugged in to keep voltage up while working on my son's battery. I just want to remove it from vehicle to test while keeping voltage at the FRM module. Pretty sure keeping it plugged in is way overboard and not necessary but I suppose its easy enough to do and will err on the side of caution. Fried the FRM module once before while working on battery and it was a PITA to repair. BTW DMM shows 0.05 VAC while pack is plugged in. It hunts between 0.03 and 0.04VAC unplugged so assuming ac ripple is minimal.

My actual jump pack:



Confirmed it does charge while turned on VDC was 12.0 unplugged



VAC minimal while charging



I just looked up specs 3600 peak amps and 470CCA.

Stock unit came with two 18 Ahr lead acid AGM batteries but I think I may have replaced them with 22 Ahr, which is used in the upgraded model.

Its pretty heavy, about 40 lbs, so pretty much a standard car battery with an internal 3A charger built in and a pair of 2 Gauge cables and clamps.

Decent jump pack. I bought it to use primarily with my boat which has a 496 HO. Never any issues starting it.

 

[Wrench97]

My jump pack is a PSJ-3612. Pulled it out it was at 12V but only 38% charge. Its been on the shelf unused since I replaced batteries about a year ago. Have it charging now and can confirm it charges while plugged in and turned on, so assuming I can keep it plugged in to keep voltage up while working on my son's battery. I just want to remove it from vehicle to test while keeping voltage at the FRM module. Pretty sure keeping it plugged in is way overboard and not necessary but I suppose its easy enough to do and will err on the side of caution. Fried the FRM module once before while working on battery and it was a PITA to repair. BTW DMM shows 0.05 VAC while pack is plugged in. It hunts between 0.03 and 0.04VAC unplugged so assuming ac ripple is minimal.

My actual jump pack:



Confirmed it does charge while turned on VDC was 12.0 unplugged



VAC minimal while charging



I just looked up specs 3600 peak amps and 470CCA.

Stock unit came with two 18 Ahr lead acid AGM batteries but I think I may have replaced them with 22 Ahr, which is used in the upgraded model.

Its pretty heavy, about 40 lbs, so pretty much a standard car battery with an internal 3A charger built in and a pair of 2 Gauge cables and clamps.

Decent jump pack. I bought it to use primarily with my boat which has a 496 HO. Never any issues starting it.

When you pull the battery with the jump pack hooked up place a old piece of rubber radiator hose over the positive battery cable end to ensure it does not hit a ground anywhere.

 

[cgrutt]

When you pull the battery with the jump pack hooked up place a old piece of rubber radiator hose over the positive battery cable end to ensure it does not hit a ground anywhere.

Thanks, I'm planning to hook jump pack up to post under hood but battery is in trunk. This vehicle has a crazy terminal on battery positive its almost like a distribution panel. Its covered pretty good though I get what your saying and will be careful not to short it out. Much appreciated.

 

[cgrutt]

Moved to different thread