Help! National Luna Dual Battery Problems.

[NPA]

Any input or suggestions here are very much welcome.

I just installed my National Luna Dual Battery system on my 2010 4Runner Trail, and installed an Odyssey 25pc 1400 auxiliary battery. Currently still using the oem size battery for the main (interstate) roughly 2 years old.

I connected the National Luna system according to the instructions & made sure to firmly crimp & heatshrink all connections.

Upon starting the car, it turned over and had a very low idle. I turned it off, re-started started, and stayed on, however the idle continued to sound REALLY low/quiet and way lower than normal. I left the car running for 5 minutes (as that's the default timer until the solenoid engages) and all appeared normal via the dual battery system monitor according to the instructions (main battery reading 12.6v & aux fully charged). At this point I disconnected the monitor, b/c I hadn't routed the cable thru to the cabin yet & needed to leave where I was doing the install.

I left the car running another approx. 5min and pulled out of driveway. When I came to a complete stop to put the car back in drive it dropped its idle below 500rpm and then died. I was able to start it again and drove away.

I had a few more times where the battery would die at red lights on my way home, until I figured I'd come to a stop, put it in neutral and keep my foot on the gas and idle it around 1,000rpm until the light was green. This worked until I got home.

Can anyone point out some suggestions to help diagnose this issue? Is this happening b/c it's still a stock alternator & not high output? Prior to installing, I had NO issues starting the car with the main battery.

I will connect the battery monitor again and drive around with it to see what the actual volt read out is when I'm driving and coming to stops.

Anyone have this issue with their dual battery? Or the NL system if your using that?

Thanks!!

 

[NPA]

After a few hours, I went out and drove around again and the car continued to have low idle, however did NOT die again. I tested the batteries with the car off & on and these were the readouts.

12.47v at main & 12.87v at auxiliary (car off).

13.8v at main & 12.85v at auxiliary (car on).

 

[dwh]

With both batteries basically fully charged, there wouldn't be a heavy enough load on the alternator to drag down the engine speed.

And even if both batteries were dead, it still wouldn't drag down the engine speed even if the alternator was fully loaded.

Those voltage readings make it look like the aux battery isn't being tied in.

Troubleshooting 101: Unhook everything and make sure it's the new stuff causing the problem.

 

[Jeffe1]

Has nothing to do with the dual battery install except for the fact the throttle control lost its memory due to the battery being disconnected. Throttle body idle control needs to relearn. Throttle plate is also probably dirty. Turn the key to the on position (engine off) have someone push the throttle down and hold it while you clean the blade off. Brake cleaner and an old tooth brush or a shop rag will work. Turn key off reinstall intake boot and start the vehicle. May start a little hard from the brake clean but it will start. Should be all better.


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[NPA]

@dwh I'll be re-checking again this afternoon. the solenoid hadn't engaged yet when I re-tested after start (it has 5min delay engage after start).

@Jeffe1 - good call. Its got 95K miles and probably hasn't been done yet (I bought it with 85K mileage). I'll clean the throttle body & MAF and see if that helps.

 

[NPA]

Cleaned the throttle body & MAF and happy to report idle back to normal! :smiley_drive: