If I connect a newer style, electronic battery charger [Noco or Schumacher 15 amp], to my trolling motor battery and leave it a couple of weeks with no electricity to the building, will the charger draw current from the battery?
Electronic battery charger connected but not plugged in, drain battery?
- Thread starter WobblyElvis
- Start date
I dont think it will. I have a small 2 amp electronic charger connected to my motorcycle battery and plugged into a 7 day timer to come on for 2 hr/week. I have never noticed any drain and the battery is borderline sized to barely start the bike when its new so any drain would be immediately apparent. But I have never done any meter testing so now you have me thinking I need to go hook up the Fluke and see.
I would test for this with a meter but I don't have the charger. I saw a Schumacker on clearance and thought of buying it.
OK so I went out to the garage and hooked up the meter on the 200 microamp scale and there is 0 current flowing with the charger unplugged.
Its a Schumacher 2A charger/maintainer.
Its a Schumacher 2A charger/maintainer.
That sounds good, I'm currently waiting on the phone for customer service. This could take a while......
Well the woman I spoke to at Schumacker [not the most cheerful person in the world] was sure that it would draw zero current from the battery. You learn something everyday.
I just checked my Noco G7200. It pulls 0.47 mA, so I'd say that's negligible.
Also checked my Solar Pro-Logix 2320 - this one draws 1.16 mA when not connected to power.
If you're only going to be away for weeks, why not just disconnect it anyway? Trolling aka deep cycle batteries aren't effected much by sitting months in between charges.
JHZR2
Staff member
They do dissipate a tiny amount. Enough to matter? Probably not unless poor quality or broken, but you don’t want any real amount of parasitics regardless.
My adjustable voltage power supplies, I have added quiet Noctua 12v fans to prevent the loud internal fan from coming on above 30 amps output, so when they are hooked to the battery, the fans spin, even if not hooked to AC power. I also have a shunted ammeter/ amp hour watt hour counter on its output, which would also stay on.
They now have an 'Ideal Diode' on the output. It only drops 0.04v at 40 amps output and is rated for 50 amps. I can now unplug AC and the fans do not spin and no parasitic draw, plug it back in and it automatically seeks to bring battery to the voltage I had previously chosen. No worrying about disconnecting the DC side and no parasitic draw.
I use 45 amp Anderson Powerpoles as connectors, and have one Ideal Diode on 8AWG that I can plumb inline on any sub 50 amp load.
It is very convenient, and the 0.04 voltage drop across it, is inconsequential.
They now have an 'Ideal Diode' on the output. It only drops 0.04v at 40 amps output and is rated for 50 amps. I can now unplug AC and the fans do not spin and no parasitic draw, plug it back in and it automatically seeks to bring battery to the voltage I had previously chosen. No worrying about disconnecting the DC side and no parasitic draw.
I use 45 amp Anderson Powerpoles as connectors, and have one Ideal Diode on 8AWG that I can plumb inline on any sub 50 amp load.
It is very convenient, and the 0.04 voltage drop across it, is inconsequential.
You should be OK with the better brands such as Noco or Schumacher. However, some of the cheap brands such as Pittsburgh(HF) battery maintainers will indeed drain your battery if left connected to the battery while not being plugged in. Many poor reviews about this on the HF site. And, the often will overcharge the battery or have a higher output of voltage during the charging process for too long before turning off. Again, this was stated in their review section.
