DII Parasitic Draw Test - Nominal Value

The Fourth Amigo

Well-known member
Apr 20, 2009
641
2
I have been testing for a parasitic draw on my DII. I get a value of 0.06 A on my meter when I remove the negative battery lead and connect the meter in series between the terminal and post. All doors closed and no key in the ignition. Is this too high?
 

the deputy

Well-known member
Sep 20, 2017
86
0
michigan
That's not terribly high, normal range for total parasitic drain "on most vehicles" would be in the 25mA/40mA (.025/.040) range. But, if you have add on accessories...like GPS radio, etc...that may add to draw.

I'd imagine a drain like you are experencing would be fine if you drove the vehicle every two weeks or so.

Brian.
 

jymmiejamz

Well-known member
Dec 5, 2004
6,008
361
35
Los Angeles, Ca
That is a little high, but not crazy. Are you sure you don't have any interior lights on or anything like that? Also, how long after disconnecting the battery did you check it? The vehicle will need time to go to sleep. I don't know about a DII, but newer Land Rovers take 20-40 minutes.
 

Howski

Well-known member
Oct 19, 2009
1,483
209
Alabama
I had some parasitic drain issues about a year ago and finally tracked it down to the wireless OBDII adapter I run my diagnostic app with. Now I just make sure to take it out after I won't be driving it for a few days and it's eliminated the issues
 

discostew

Well-known member
Sep 14, 2010
7,706
1,015
Northern Illinois
I have been testing for a parasitic draw on my DII. I get a value of 0.06 A on my meter when I remove the negative battery lead and connect the meter in series between the terminal and post. All doors closed and no key in the ignition. Is this too high?

It's a little high. I think a general rule of thumb has always been under 50ma is desired. Your at 60ma. I figure a normal glove box light draws about 120ma.
 

the deputy

Well-known member
Sep 20, 2017
86
0
michigan
Never noticed...does the discovery even have a glove box light? Good mention about waiting (jymmiejamz) for the vehicle to go to "sleep". Not sure about this model, but always a good rule of thumb to wait a bit before checking readings.

Brian.
 

K-rover

Well-known member
Jan 15, 2010
2,163
62
Raleigh, NC
I had something similar. Since the Rover isnt my primary vehicle it sits most of the week. sometimes for 2 weeks. So when I would go to start it, the battery was dead or dying..
Did the same test, Pulling the negative terminal and using a volt meter to check draw, except I started pulling fuses until the draw went away.
I found that my ABS modulator was/is the cause. I can hear what sounds like electrical pulsing sounds faintly coming from the modulator. Didnt matter how long the truck sits it will constantly make the noise.
Not sure what that is, but my solution was just to make sure I drive the truck at least once a week and I havent had an issue since. That was 3-4yrs ago.
 

The Fourth Amigo

Well-known member
Apr 20, 2009
641
2
I didn't give it time "to sleep" but I'll check it out.

My battery went dead when the vehicle sat for a week. I charged it and had it load tested. It barely passed the load test and had a low standing voltage 12.44. It was a group 31, AGM battery, 5 years old. Since it passed the load test, I left it in the vehicle. That was a mistake. The DII then sat for another week and and it wouldn't start again. This time I just went and got a new group 31, LA battery. Now the standing voltage is 12.6 and I can hear the starter is faster/more powerful.

Anyhow, I'm away for yet another week. It will be interesting to see if the new battery solves the problem. I have worked on ships during most of the 10 years I have owned my DII and routinely left it sitting in a garage for periods of 30 to 42 days with no trouble and never used a battery maintainer. Its ironic that when I finally started a shore job requiring relatively short periods of travel the thing wouldn't start, for the first time in 10 years. I suppose I've been lucky so far. Hopefully she'll fire up for me this weekend!
 

the deputy

Well-known member
Sep 20, 2017
86
0
michigan
5 years seems to be about the length of time anymore...for a battery to last. Maybe, driving it more often or throwing it on a charger (on 2amp) for a day or two...may...bring it back to life...or maybe not...not too familiar with AMG batteries.

Good luck.

Brian.
 

Rob371

Well-known member
Nov 29, 2016
150
1
Charlevoix, Michigan
My D2 also makes a ticking noise after shut down. I traced it to the ABS relay. I inquired here once but didn't get any leads. The ticking stops after some time but I haven't sat around to see how long. I've cleaned all the obvious grounds. To me this doesn't seem like a normal situation but it hasn't caused any trouble.

60mA is a touch on the high side for a passenger car. I've seen many vehicles, including countless boats that range form 30 to 70mA. The radio memory is usually good for about 20 to 30mA. Starter motors, relays, alternators, bad grounds, timers that don't time out can all be culprits. I was tracing a draw on a boat once and found a wire chafed through and was contacting the base of the distributor intermittently.

Depending on battery condition, wiring condition, the 60mA is enough to give you a no start after several days. Pulling fuses and relays is a good place to start. You might wait overnight to see if the draw drops as suggested by "sleep mode" theory. It's definitely plausible.

Another consideration, in some cases once you break the ground the draw may not come back through the meter connections. Make the meter connection before breaking the ground. I usually start with 7.5 amp inline fuse on one of the leads because most meters will blow internal fuses at ten amps.

Just reading a comment on voltage. Static voltage on a 12 volt battery is 12.6. 1.2 volts per cell. AGM and LA are virtually the same as far as charge and discharge rates. Gel cells are a little fussy and can be easily damaged by overcharging with conventional chargers. I think they're a waste unless you need to lay them sideways or something for tight installations. I got eleven years out of a pair of group 24 lead acid AC Delcos in my boat. Just gotta maintain them properly. Deep discharges shorten life, and overcharging kills them.
 

MNinWI

Well-known member
Dec 19, 2007
83
2
My 03 D2 will start if I park it for two weeks, but three weeks will drop the battery too low to start it. I have not measured my current draw.

I bought a small solar panel, but that has proved semi-useless. I put it in the back in a side window. The glass tint cuts over half the sunlight. It might help a little, but not as much as I hoped.
 

discostew

Well-known member
Sep 14, 2010
7,706
1,015
Northern Illinois
Rob371 hit the nail on the head with the AGM batteries not surviving long when not charged correctly. I see a lot of people put AGM batteries in the wrong car and the AGM just gets cooked by the alternator. So if your car doesn't call for a AGM battery don't put one in it.

I think the optimal parasitic load would be about 26 ma. When your up over 50ma your kind of asking a lot of your battery if it's not a daily driver. When your up around 300ma it will go dead overnight and its usually a module not turning off. Some modules draw more. Like a navagation module under the passenger front seat of an LR2 can draw pretty near an amp. That could killl the battery while your shopping.
 

discostew

Well-known member
Sep 14, 2010
7,706
1,015
Northern Illinois
My 03 D2 will start if I park it for two weeks, but three weeks will drop the battery too low to start it. I have not measured my current draw.

I bought a small solar panel, but that has proved semi-useless. I put it in the back in a side window. The glass tint cuts over half the sunlight. It might help a little, but not as much as I hoped.

I've seen the solar chargers cause more trouble because it back feeds whatever circuit feeds the rear power outlet. usually not hot unless key on. So it can turn on all kind of goofy shit.
 

Rob371

Well-known member
Nov 29, 2016
150
1
Charlevoix, Michigan
That's a good point. Anything powered by the circuit that supplies the auxiliary port will also be energized if you are attempting to back feed the charge through the port. In this case the solar chargers put out such a small amount of amperage that it would likely be used up before it ever even gets to the battery. On the other hand, if the port is only hot with key on then it's just never going to get to the battery because the circuit is open with key off.

Sounds like the problem was resolved with a new battery so maybe we're beating a dead horse here but I want to clarify a couple things,...

Rob371 hit the nail on the head with the AGM batteries not surviving long when not charged correctly. I see a lot of people put AGM batteries in the wrong car and the AGM just gets cooked by the alternator. So if your car doesn't call for a AGM battery don't put one in it.

Just FYI, the AGM and Lead Acid are pretty much the same as far as charge and discharge rates. An AGM is basically a lead acid battery but the acid is in an "absorbed glass mat" hence "AGM". In the marine world we go to the the AGM primarily in cabin space installations where ventilation may be limited. In most applications this is for a bow-thruster mounted in a V-berth and the point is two fold, avoid long cable runs where three to four hundred amp loads are common, and avoid excessive hydrogen gases generated by charging and battery gassing.

It's the Gel cells that are the fussy ones. Newer smart chargers all come with a selector switch. One position is for AGM/Lead Acid, the other position is for Gel. The gels require lower peak charge rate and lower peak voltage. I just did a quick search and copied and pasted the following article. On another note, I see a lot of discussion about adding batteries, isolating batteries, charging multiple batteries. Follow this link to blue sea systems. They have all the necessary products and some good tech related articles using the "SUPPORT" tab. https://www.bluesea.com/support/articles

The following article came from batterystuff.com

AGM (absorbed glass mat) is a special design glass mat designed to wick the battery electrolyte between the battery plates. AGM batteries contain only enough liquid to keep the mat wet with the electrolyte and if the battery is broken no free liquid is available to leak out.

Gel Cell batteries contain a silica type gel that the battery electrolyte is suspended in, this thick paste like material allows electrons to flow between plates but will not leak from the battery if the case is broken.

More often than not AGM Batteries are mistakenly identified as Gel Cell Batteries. Both batteries have similar traits; such as being non spillable, deep cycle, may be mounted in any position, low self discharge, safe for use in limited ventilation areas, and may be transported via Air or Ground safely without special handling.

AGM Batteries outsell Gel Cell by at least a 100 to 1. AGM is preferred when a high burst of amps may be required. In most cases recharge can be accomplished by using a good quality standard battery charger or engine alternator. The life expectancy; measured as cycle life or years remains excellent in most AGM batteries if the batteries are not discharged more than 60% between recharge. There are some AGM batteries we sell that offer excellent 80%+ deep cycle abilities.

Battery Tender Plus Gel ProfileGel Cell Batteries are typically a bit more costly and do not offer the same power capacity as do the same physical size AGM battery. The Gel Cell Battery excels in slow discharge rates and slightly higher ambient operating temperatures. One big issue with Gel Batteries that must be addressing is the GEL CHARGE PROFILE. Gel Cell Batteries must be recharged correctly or the battery will suffer premature failure. The battery charger being used to recharge the battery(s) must be designed or adjustable for Gel Cell Batteries. If you are using an alternator to recharge a true Gel Cell a special regulator must be installed.


So forgive me for being so long winded but I've gotten a lot of useful help on this forum and resolved many issues from the tips I get from members. Just trying to pay it back whenever I can.
 

The Fourth Amigo

Well-known member
Apr 20, 2009
641
2
I had a group 31 Interstate AGM battery that only failed after almost 6 years of service where the vehicle routinely sat for periods of one month or more and always started. So I don't really have anything too bad to say about them.

This never should have happened, I really had fair warning. When I replaced the alternator a while back I noticed the standing voltage on the battery was 12.4. I had the battery tested and it would just barely pass the load test. I should have replaced it then and there. But I pushed my luck and it let me down. At least it happened in driveway.

As for the parasitic draw I disconnected my Scangauge II from the OBD port and it dropped from 0.06 to 0.03 A. Case closed.

I couldn't verify the "going to sleep" theory.
 

discostew

Well-known member
Sep 14, 2010
7,706
1,015
Northern Illinois
Right now they are making us use a specific charger for AGM batteries. When an AGM battery drops below a certain voltage it's pretty much junk. I do see AGM batteries failing quickly when installed in the wrong aplication. Usually the way you know a Land Rover gets an AGM battery is if the vehicle has eco stop. So right at that vin break you see the wrong batteries installed.
 

Rob371

Well-known member
Nov 29, 2016
150
1
Charlevoix, Michigan
I'm curious about the "special charger". AGM and LA have similar charge profiles, gel is different. Smart chargers are designed to make these decisions for us essentially. I've had numerous occasions where a smart charger won't sense a battery that is too low and the charger never kicks on. In this case I will jump a charged battery to the dead battery, connect the smart charger, and the charger will take over from there. Depending on circumstances I might leave the jumped battery connected for a little while kind of as a buffer for the dead battery. I've recovered a lot of "junk" batteries this way. From a service department labor cost perspective it may make more sense to throw in a battery but when it's my own stuff I'll make the extra effort.

I suggested before, deep discharges shorten battery life, over charging kills them. Deep cycle batteries are labelled as such because they have heavier plates, slower discharge rates, lower cranking amps, and can withstand deep discharges, say below 9.6 volts, and can be brought back a number of times. With cranking batteries the plates are thinner, can deliver higher cranking rates in shorter bursts and the number of times they can be "deep cycled" is significantly less before failure.

Recalling from my training, a battery with 12.4vdc is considered a 75% charge. somewhere around 12.0 or 12.2 is 50%. I'd have to go dig out my notes from way back when but I vaguely recall 11.6 or 11.8 is considered completely dead. Those values might be enough to get some dimly lit interior lights or dash lights but not enough to deliver the 150 to 300 hundred amps required to crank.

At any rate, if OEM says use this battery and that charger then best bet is stick with recommendations.
 

Rob371

Well-known member
Nov 29, 2016
150
1
Charlevoix, Michigan
I'm not much of an expert on solar at all. Here in Northern Michigan they're kind of a wasted investment since we don't see much sun for a good portion of the year. Ambient daylight isn't enough to make them worthwhile so I've never looked at them too seriously. I had to chuckle recently when I was traveling downstate and saw an entire field of solar panels covered with about four inches of snow. If only we could harness the power of snow.

They are expensive but If you want lots of reserve capacity then the golf cart batteries are a good way to go. We do have several boats that we service that use golf cart batteries for inverter systems or just to run the house systems for lengthy periods between charges. They can be deep cycled more frequently also.

Sounds like maybe you're trying to run off grid? Or a cabin perhaps? What little I do know is you're going to need enough panel area to keep ahead of the disharge requirements. I think blue seas website has a formula calculate reserve requirements. I'll see if I can locate it when I get a minute. Back to reality (work) today.