Battery Charger - via lighter plug
- Thread starter Ndx
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JHZR2
Staff member
First off, is your cigarette plug ALWAYS active? Do you get 12V when all the accessories are off, key out, door open, etc?
If not, then its a non-starter unless you jumper it on another circuit to keep it live.
If it is active, then youre OK. Just check the fuse rating and ensure you dont go higher. Your losses may be a bit higher, and the wire through the door seal always bothers me, but otherwise its OK.
If not, then its a non-starter unless you jumper it on another circuit to keep it live.
If it is active, then youre OK. Just check the fuse rating and ensure you dont go higher. Your losses may be a bit higher, and the wire through the door seal always bothers me, but otherwise its OK.
Cig lighter plugs are good for ~10 amps, so a 2 amp trickle charge is well within their capability... BUT.. Lighter plugs are notoriously poor connections at best, so its not a very reliable way to charge. Also many modern cars shut off power to the lighter and "power" ports when the key is shut off, so it wouldn't work at all on that sort of vehicle.
unless our cigarette plug is always "live" (or on, whatever it makes sense to you), otherwise: the traditional, ignition key completely off, pop the trunk and connect to battery post is the best.
There are just simply far too many stuff gets turned "on", drawing additional current from the battery if yours is the one requires "ignition key" to be on the "ACC" mode type.
Q/
There are just simply far too many stuff gets turned "on", drawing additional current from the battery if yours is the one requires "ignition key" to be on the "ACC" mode type.
Q/
Cigarette plugs are fused and maybe switched. Aside from that, I would think they would be OK.
Both my current vehicles have one on always and one switched.
Both my current vehicles have one on always and one switched.
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Originally Posted By: Ndx
Its not always live... only when IGN ON.
Strange part is that Porsche sells those chargers and recommends them ... ( they are just re branded C Tek I believe )
Battery is under driver seat
So no easy access.
Thank you guys.
Could be a dodge intrepid with it under the fender!
Its not always live... only when IGN ON.
Strange part is that Porsche sells those chargers and recommends them ... ( they are just re branded C Tek I believe )
Battery is under driver seat
Thank you guys.
Could be a dodge intrepid with it under the fender!
Last edited:
JHZR2
Staff member
Originally Posted By: Ndx
Its not always live... only when IGN ON.
Strange part is that Porsche sells those chargers and recommends them ... ( they are just re branded C Tek I believe )
Battery is under driver seat
So no easy access.
Thank you guys.
BMW does too (rebadged deltran batter tender), but their cars no longer have always on cig ports. These are for older cars and classic garage queens.
There WILL be power underhood, and you can easily make a harness with a proper DC connector and O terminals. I have them on most of my cars, even my 135i. That would be my route.
Im not a fan of sticking wires through door seals.
Its not always live... only when IGN ON.
Strange part is that Porsche sells those chargers and recommends them ... ( they are just re branded C Tek I believe )
Battery is under driver seat
Thank you guys.
BMW does too (rebadged deltran batter tender), but their cars no longer have always on cig ports. These are for older cars and classic garage queens.
There WILL be power underhood, and you can easily make a harness with a proper DC connector and O terminals. I have them on most of my cars, even my 135i. That would be my route.
Im not a fan of sticking wires through door seals.
Most European cars had always-on cigar lighters. U.S. cars have traditionally had them switched through the ignition switch, or perhaps an 'unloader' relay.
Recently U.S. mid-range and higher cars have come with two (or more) sockets, with some unswitched. The cheapest base models are 'defeatured' by have only one.
At the same time European cars have tended to change to electronically switched sockets, with software configuration for their behavior. The problem with these is that back-feeding power may not work, or may cause overheating.
If the electronic switch is a simple MOSFET, back-feeding power when its switched on will cause a negligible increase in heating. Back-feeding power when switched off will result in a 0.6V drop from the intrinsic body diode, with is far higher than the operational voltage drop. Overheating could result. Mitigating this problem will be that the voltage drop will cause the charger to falsely detect the battery as full charged and drop the charge current.
Recently U.S. mid-range and higher cars have come with two (or more) sockets, with some unswitched. The cheapest base models are 'defeatured' by have only one.
At the same time European cars have tended to change to electronically switched sockets, with software configuration for their behavior. The problem with these is that back-feeding power may not work, or may cause overheating.
If the electronic switch is a simple MOSFET, back-feeding power when its switched on will cause a negligible increase in heating. Back-feeding power when switched off will result in a 0.6V drop from the intrinsic body diode, with is far higher than the operational voltage drop. Overheating could result. Mitigating this problem will be that the voltage drop will cause the charger to falsely detect the battery as full charged and drop the charge current.
Originally Posted By: Miller88
Originally Posted By: Ndx
Its not always live... only when IGN ON.
Strange part is that Porsche sells those chargers and recommends them ... ( they are just re branded C Tek I believe )
Battery is under driver seat
So no easy access.
Thank you guys.
Could be a dodge intrepid with it under the fender!
You mean Stratus/Cirrus/Breeze....the Cloud cars??
Originally Posted By: Ndx
Its not always live... only when IGN ON.
Strange part is that Porsche sells those chargers and recommends them ... ( they are just re branded C Tek I believe )
Battery is under driver seat
Thank you guys.
Could be a dodge intrepid with it under the fender!
You mean Stratus/Cirrus/Breeze....the Cloud cars??
JHZR2
Staff member
Originally Posted By: djb
Most European cars had always-on cigar lighters. U.S. cars have traditionally had them switched through the ignition switch, or perhaps an 'unloader' relay.
Recently U.S. mid-range and higher cars have come with two (or more) sockets, with some unswitched. The cheapest base models are 'defeatured' by have only one.
At the same time European cars have tended to change to electronically switched sockets, with software configuration for their behavior. The problem with these is that back-feeding power may not work, or may cause overheating.
If the electronic switch is a simple MOSFET, back-feeding power when its switched on will cause a negligible increase in heating. Back-feeding power when switched off will result in a 0.6V drop from the intrinsic body diode, with is far higher than the operational voltage drop. Overheating could result. Mitigating this problem will be that the voltage drop will cause the charger to falsely detect the battery as full charged and drop the charge current.
good explanation!
Most European cars had always-on cigar lighters. U.S. cars have traditionally had them switched through the ignition switch, or perhaps an 'unloader' relay.
Recently U.S. mid-range and higher cars have come with two (or more) sockets, with some unswitched. The cheapest base models are 'defeatured' by have only one.
At the same time European cars have tended to change to electronically switched sockets, with software configuration for their behavior. The problem with these is that back-feeding power may not work, or may cause overheating.
If the electronic switch is a simple MOSFET, back-feeding power when its switched on will cause a negligible increase in heating. Back-feeding power when switched off will result in a 0.6V drop from the intrinsic body diode, with is far higher than the operational voltage drop. Overheating could result. Mitigating this problem will be that the voltage drop will cause the charger to falsely detect the battery as full charged and drop the charge current.
good explanation!
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