Acceptable battery draw

[supton]

What is acceptable?

Our ‘03 CRV will drain the battery after a week or so. I don’t know how long it takes, but 2 weeks will do It, after that it’s low enough it won’t crank. Today I hooked up a Fluke and I measured 60mA just sitting there. I started pulling fuses and fuse #9, a 10A for “back” drops the draw down to 19mA. Poking around, that fuse powers some sort of communication widget.

60mA seems high to me, but maybe that’s normal? Seems like the battery should withstand that for quite some time. Battery is only a couple years old (I think) but it’s been discharged enough times that it’s probably old now. It’s a small group 51 battery, which I don’t think helps.

I’ll leave the meter hooked up in min/max for a few hours and see if something is waking up every few hours.

 

[JHZR2]

IIRC 30-50 is normal, and more like 30.

So id say you’re too high.

Some vehicles draw for odd reasons. I could never see a major draw on my Chevy truck, but the battery will drop to 11 in the course of a week if not on a charger.

 

[Rand]

did you have all the doors shut etc.. sometimes it takes 15-20min for everything to shut off.

 

[supton]

did you have all the doors shut etc.. sometimes it takes 15-20min for everything to shut off.

Everything shut, waited and watched for an hour.

 

[Rand]

Everything shut, waited and watched for an hour.

then it sounds abit high, but instead of chasing that issue maybe just mitigate witha solar powered trickle charger (if no wall outlet available)

 

[roger dodger]

I am really surprised to read that an '03 CRV draws 60mAs. Seems like a lot for such an old car. My '18 CRV draws 65mAs, which I consider to be a lot of draw as well. So I am not surprised when my 2 1/2-year old battery needs recharging every couple of weeks or so. My '16 Pilot however only draws 11mAs, and that battery is almost 5 years old. It is still strong as an ox, electrically speaking. My CRV has a bunch of fancy electronic features, and those computer modules do not shut down when the car is off. They draw battery power ALL THE TIME. That may be why the OP's fuse #9 pulls so much juice. The Pilot is a "plain Jane" model with virtually no electronics. Compounding the problem with Honda, is their "dual mode" charging system which defaults alternator output to 12.4 volts to reduce the alternator load on the engine to presumably improve fuel economy. The alternator only kicks into the higher charging mode of 14.4 volts (which will recharge the battery) when the car's electrical sensors detect an electrical load in play. That is why I always drive my Honda cars with the headlights on ... to trick the alternator into detecting a "load" so it will operate at the higher voltage output. Lights on = 14.4 volts. Lights off = 12.4 volts. I even splurged on Amazon to buy a cheap voltage meter that plugs into my 12V adapter so I can monitor the car's voltage level while driving.

Honda's combination of high battery draw with the engine shut off and low alternator charge with the engine running is a poorly designed engineering combination that is hard on batteries ... not that I have strong opinions on the matter mind you.

 

[kschachn]

The Honda FSM should have a graph or a chart that shows how the voltage drops off after engine shut off and what the final quiescent current should be. Do you have that? I know it’s in the manuals for all my cars even my old BMW has it.

 

[Number_35]

https://bobistheoilguy.com/forums/threads/2009-mazda-5-dead-battery-checking-dark-current.339866/

Hmmm, deja vu ... in my case, it was the Bluetooth unit, although the current draw was much higher than yours.

 

[wtd]

I think for most vehicles the accepted number is 50 mAs or under.

 

[supton]

The Honda FSM should have a graph or a chart that shows how the voltage drops off after engine shut off and what the final quiescent current should be. Do you have that? I know it’s in the manuals for all my cars even my old BMW has it.

Nope. I’ve not had to do any repairs on this one yet, and TBH I plan on letting a shop do most jobs, so I’ve not even looked for an FSM.

https://bobistheoilguy.com/forums/threads/2009-mazda-5-dead-battery-checking-dark-current.339866/

Hmmm, deja vu ... in my case, it was the Bluetooth unit, although the current draw was much higher than yours.

Well, I swapped out the dead stereo for a late model stereo, I suppose I could pull the fuse for that and see if it does something.

I found out there is a “common” mode to put in a larger 24 group sized battery for this vehicle. I bought the plastic bits and once I kill the battery a few more times (!) I’ll probably go down that route. In the meantime a battery tender is easy enough to rig up, as we’re still not using this vehicle very often.

 

[circuitsmith]

Compounding the problem with Honda, is their "dual mode" charging system which defaults alternator output to 12.4 volts to reduce the alternator load on the engine to presumably improve fuel economy. The alternator only kicks into the higher charging mode of 14.4 volts (which will recharge the battery) when the car's electrical sensors detect an electrical load in play. That is why I always drive my Honda cars with the headlights on ... to trick the alternator into detecting a "load" so it will operate at the higher voltage output. Lights on = 14.4 volts. Lights off = 12.4 volts. I even splurged on Amazon to buy a cheap voltage meter that plugs into my 12V adapter so I can monitor the car's voltage level while driving.

I started a thread about this issue, and I've got the same voltmeter:

Overriding a "smart" battery management system

Like many modern cars the 2017 Hyundai Tucson reduces battery voltage when it decides the battery is charged “well enough”. It does this to mainly save a little fuel and also avoid over charging the battery. I have a voltmeter plugged into a 12V port so I can monitor system voltage while...

bobistheoilguy.com

 

[bonjo]

If you find out the spec for the parasitic current draw for your car, then you'd know for sure.

A 60mA draw (alarm/ immobaliser??) would draw 1.4A/day; 20A in 2 weeks.
What is the Ah rating of your battery?

A battery that has lost some of its capacity (not voltage) will go flat sooner

 

[roger dodger]

I don't know about an '03 CRV, but since 2012 Honda has put 51R batteries in that car. My 2 cars did not spec Ah on them, but were 410 CCA each. A rough guess would be about 50 Ah's.