DRAINING ON BATTERY

i just installed an Odyssey dual battery set-up, after tossing my dead, red-top optima battery, living only 3 years and 6 months... the factory 130 amp alternator still tests good; but something appears to be draining the batteries... i pulled every single fuse, using a test light, and apparently the door lock fuse was the item that was pulling some juice while the ignition is off. Isnt that normal thought?? Seems the door locks have to be "on call" whenever you hit the key fob?? What else would it possibly be??? (2005 tacoma trd dbl. cab, lg. box, 4x4 off rd.)

 

Check the grounds for your battery set up

 

What was the draw when modules are "asleep" and when the door lock fuse is pulled? Do you have remote start/alarm? Spec is under 50mA

 

yeah, how much current is drawn ?

door lock listener/alarm shouldn't be that bad

hell, my 4runner got an easy 5 years on original battery

 

There are most likely other components on that fuse besides the door controls. We have to find out what it is. I'm not home at the moment.

 

What sort of battery isolator/solenoid or dual battery wiring kit did you use?


I know odyssey makes the mounts for duals, but I don't know about a wiring kit.

I'm assuming that you installed dual batteries because you have a decent amount of electronics installed, could any of them be drawing power?

 

i simply wired the 2 batteries inline.. pos. to pos, and neg. to neg. they are 740 cca/pc. but i believe there was a "draw" before i did the dual battery set-up... thus, the early death of the notorious red-top battery. (3.5 years old).

 

The batteries need to be isolated from each other or they will drain each other. This is your main problem. Disconnect them from one another until you get some kind of isolator or solenoid system, or they may very well die even faster than 3.5 years.

 

x2 I agree. The batteries are basically constantly trying to balance each other. Meaning say on has 13.4 volts and the other has 13.8 they will trying to balance each other.

 

They will balance each other, but they will not drain each other.

The risk of running batteries in parallel is if one has a shorted cell, it will pull the other battery down, but it will also force the charging system to kick up a notch and will result in the "good" battery alternating between being overcharged and dumped by the bad battery.

 

thanks.. i will have to check that. it only has the factory remote system in it.

 

i run a snow plow, and have a significant quality sound system, which is why the 2nd battery. i was told that wiring inline would be fine; but you disagree with that?? im getting too many opinions here, and have ALOT of money into this system that i cant risk going bad. ???

 

You need to isolate the batteries, with either an isolator, solenoid, or smart solenoid.

Rich said they will balance each other, not drain, and that is one interpretation of it.

Even batteries that are almost identical in brand/type will have slightly different internal resistances.

If one cell in one battery is bad, and that battery now has 85% of the charge capacity it could originally hold, the 2nd battery that's still at 100% will constantly be trying to equalize and charge the lower capacity battery...
Because they are not isolated, the batteries will continue to do this even when the vehicle is off.

This is avoided with an isolation kit. The simplest (not best) is a solenoid, that is high powered, between the positives of the two batteries, wired to a relay, wired to a spdt switch on/off/on. One position of the switch is wired to the ignition, so that when the truck is turned on, the solenoid activates and connects your positives, and both batteries charge together. Basically, when the truck is on, they are wired in parallel, when it's off, they are disconnected from one another. Say, your truck is not running but you want to run your stereo for the entire night, and your stereo is wired to the aux battery. Even if that battery is below the voltage you need to start the truck, it is isolated from your starter battery, so you start your truck, the solenoid engages and both batteries charge, even though only one is more discharged than the other.


The "smart solenoid" systems (like national Luna) are computer controlled, so that they won't connect the solenoid until the main (1st/starter battery) has reached a certain voltage, so you know that your main battery is always charged first.

I'm typing this from a phone so I'm sorry for any errors. You REALLY need to do some more research into this. Google dual battery systems and do some reading. Learn about solenoids, isolators, and smart solenoids. Go from there.

 

Agreed, and as I mentioned, if a battery has a shorted cell, it will draw the good battery down as well as cause the charging system to overcharge the good battery.

But if both batteries are in good condition, there will be no problems.

My 2006 Duramax 2500 ran dual batteries with no isolation from the factory. It's not a problem under normal conditions, provided the two batteries are identical and replaced at the same time.


Isolation can be critical depending on the application.
Most traditional dual battery setups use one battery for the vehicle, and a 2nd marine battery for a camper or trailer.
These MUST be isolated so your starting battery is not drained by your accessory use in the camper/trailer.
Likewise for stereo systems, if the intent is to use it for competition in parking lots where it will be run at high power levels with the engine off or at low RPM.

Normal stereo use with the vehicle moving, and snow plow use, a parallel setup is fine.

 

thanks. the only one that i found is the national luna... it looks pretty good for the price. i typically dont run the sound system without the truck running; but i can see the "insurance" behind the idea of the solenoid. both batteries are identical though. im going to check into it. thanks again..

 

yes, both batteries ARE identical, and im also putting on a 270XP alternator seems my factory 130 just died.. i guess its been 8 years now; its an '05. it sounds like the smartest way to go is with a solenoid; but i still dont see why running them inline would hurt, if i have proper grounding for the system itself.. thanks again!

 

Isolated dual battery systems are designed to (1) to operate high current appliances (plow, winch, audio, two-way radios, lighting, etc.) off a deep cycle battery, (2) isolate the deep cycle battery from your starting battery so that you can restart your engine, and (3) when the engine is running above idle, satisfy the vehicle's electrical load and enable recharging both batteries simultaneously. The isolation can be manual with a high current SPST switch or automatic with a solenoid or diode bank. Car [starting] batteries are designed for shallow discharges and will prematurely fail if discharged deeply. For more information on dual battery systems can be found in Section 7.1.9 in the Car and Deep Cycle Battery FAQ 2013 on www.batteryfaq.org.

 

Thank you.

 

hi all I hav a 07 Tacoma my batt was dead a few days ago.in the am. thought I left an int. light on?? so I charged it up 10- 6- 2 amps (it has ben getting a little slow when cranking lately) today I tried starting it an it was dead. I was on my way fishing so I jumped it and brought a extra batt and cables. it was dead 3 times and needed a jump from my xtra batt. when I got home I disconected the batt and cheched for a draw with a test light (removing all fuses) the test light was still on.neg-neg the light still lit closed doors every thing I could think of was off but still drawing . I have a tow hitch. but im shure that's gd. base model remote start . wich I havn,t ben using. any help would gr8. as I know I shoule toss out the 73/4yr batt. also iwas getting 13.5 from alt
thanks in advance.. an old time mech...........

 

Jim, I would fully charge the old battery and test it and test the charging system. Depending on the ambient temperature, 13.5 VDC is to low to recharge a battery, but will maintain a full charge. Most auto parts and battery dealer will test them for free. Excessive parasitic load problems are sometimes difficult to find because the there are a number of fuses and always hot circuits. I would suggest using a ammeter and measure the load if the battery tests good. I would expect under 150 milliamps key-off load.