Possible Alternator / Battery problem

Philip.

Member
Hi I’m hoping to get some input on the issue I’m having in a 2017 TRD Off Road ( cdn ) so I’ll set the stage as to what’s going on.

Had the truck since new. It currently has 37 k on odo

Have a Viper SmartStart ( new low draw module ) installed

Have a BlackVue front and rear dash cam and I’ve shut off the features that take place when parked and it has a 12.0 low voltage auto shut off as as well.

Everything else is stock. No auto on interior lights no additional AV or accessories.

The stock battery has been acting up for the past 4 years and last winter it was jump started at least 6 times with my Noco

I replaced the battery and the problem is still there. The voltage drops from 12.4 to 11.8 over the course of 2 days parked.

It doesn’t turn over at 11.8 and lower.

I had the new battery checked and they seem to think it’s the alt as when on with wipers,lights,ac etc on the voltage is all over the place and dropping to the line were it drains

So I think because of the low kms and multi jumping starts I may have pooched the oem alt. There also might be a draw that’s causing it or just a perfect storm of all of the above plus driving habits. I have no ability to run a battery tender where it’s parked.

Do you think it’s good to do a parasitic draw test b4 I buy a high output alt like a DCpower ?

Any input would be great I’m just wrapping my head around all this electrical stuff it’s definitely not my strong suit but learning along the way.

Thanks and hoping to get some input.
 
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Take it to a parts store and ask them if their battery tester also checks the alternator. Or, if you have a multimeter check the voltage before starting
It should be around 12.5 volts or so. Start her up and the voltage should go just above 14 volts.
 
Since you’ve already replaced the battery and the current new battery is doing the same thing, it’s obviously some other component. It doesn’t sound as if you had the problem when new, so back track a little and remove offending accessories that draw your battery down. If your battery is charging while you’re driving it, I don’t believe it’s your alternator.

Call the camera maker and explain what is happening. Ask to speak to an engineer with the company. I bet they may have seen this before and may admit to it.
 
Ya I checked the voltage it’s always around 11.9 to 12.1 when starting then the test they did seems to show the voltage jumping around with the acc all on and running. That’s who thought it was the alt
 
I think that’s what I’m thinking as well. And I do think it’s a known problem so I ensured all the offending features that run when the engine is off and not on and it also has a manual shut off at 12.0

I tested the viper before and it was fine but that may have changed so I was thinking the parasitic test would identify any issues pulling

I’m thinking the draw if found may be draining the battery to the point were I’ve affected the stock altanator if that makes any sense.
 
Toyota electrical troubleshooting step 1. Remove all aftermarket crap. 99.5% chance that is the problem. Once confirmed, add each one back one at a time to figure out which one.

What is your voltage with engine running? If over 13v the alternator is probably fine. You should see what your amp draw is when ignition is off after 15 minutes - this is what is killing your battery, and is almost certainly coming from your aftermarket electronics.
 
Toyota electrical troubleshooting step 1. Remove all aftermarket crap. 99.5% chance that is the problem. Once confirmed, add each one back one at a time to figure out which one.

What is your voltage with engine running? If over 13v the alternator is probably fine. You should see what your amp draw is when ignition is off after 15 minutes - this is what is killing your battery, and is almost certainly coming from your aftermarket electronics.

I’m at 13.4 driving and 15 min later I’m at 12.2

I’m going to throw in a separate power supply for the dash cam and see if that fixes it. I might be able to run the alarm off that too so I will soon find out I’m at the shop now.

The alarm and dash cam are critical where I live. Car theft capital of Canada it’s insane.
 
If you have 12.2 volts with the engine running, something is wrong with your alternator. The voltage should be about 14 volts with the engine running.

Hi no it’s 12.2 after 15 min of shutdown. It’s mid 13 driving.

I put a stand alone accessory mini battery in for the dash cam so I’ll keep monitoring it.
 
Hi no it’s 12.2 after 15 min of shutdown. It’s mid 13 driving.

I put a stand alone accessory mini battery in for the dash cam so I’ll keep monitoring it.

"Mid 13" for the alternator when the engine is running is still considered low. Many auto parts stores will test the alternator for free.
 
Test the battery with a voltmeter, with the engine running.
That’s where you should get around 14 volts.

My 2017 is 13.9 volts at the battery & running.
 
Ok just to ask the obvious how much does short trips and super low kms affect battery / alternator health ?

I put the dash cam on a stand alone battery and the battery was at 12.3 yesterday it’s at 12.1 this am.

I can’t run a battery tender due to where it’s parked. What about a solar trickle charger any thoughts on that.
 
Ok just to ask the obvious how much does short trips and super low kms affect battery / alternator health ?

I put the dash cam on a stand alone battery and the battery was at 12.3 yesterday it’s at 12.1 this am.

I can’t run a battery tender due to where it’s parked. What about a solar trickle charger any thoughts on that.

Short trips will not effect the alternator at all.

Short trips will effect he battery because of the frequent engine starts. Also, if there is insufficient time during a short trip to recharge the battery from starting the car, the battery will eventually be depleted.

Solar charger would be a great idea. Years ago, when all VW were built in Germany, the cars were shipped to the US with solar panels attached to the inside of the windshield by suction cups and plugged into the cigarette lighter for the long sea voyage and storage in parking lots until they were distributed to dealers. The solar panels were returned back to the factory to put in a new ship load of cars. I have one of those solar panels.

But on Toyota cars, the 12 volt outlets are turned off when the car is off, so you would have to find another way to attach a solar panel to the 12 volt system.

Sorry! Something went wrong!
 
Last edited:
Ok just to ask the obvious how much does short trips and super low kms affect battery / alternator health ?

I put the dash cam on a stand alone battery and the battery was at 12.3 yesterday it’s at 12.1 this am.

I can’t run a battery tender due to where it’s parked. What about a solar trickle charger any thoughts on that.

Short trips don't let the alternator truly replenish the charge depleted by the starting draw. If you have the alternator tested and it comes back good, you might try the GM Diode trick with the OEM alternator. It will bump the voltage up a bit so you'll get a bit more charge on short trips. Warning: Remove this mod before you swap to an aftermarket alternator.
 
Update

Short trips don't let the alternator truly replenish the charge depleted by the starting draw.

Ok thanks for all the tips. I got those diode chips on Amazon so I will try that next.

I got the accessory battery for the dash cam and since I’ve had it on 4 days the Volts are sitting at around 12.1 prior to this they would drop a .# every day not driving. So that’s a plus.

Started the truck up and the volt at the battery was 14.0

Now that the good weather is here the kms will start to add up so hopefully this will be the last of it.

Keeping my noco in the back just I case lol.

Oh the alt test came back borderline. I could replace it it I could leave it so leaving it for now and if I replace I’ll remove the diode fuse and add a dc power alt.

Battery is still good.

In hindsight and what I’ve learned on here it’s a combo of that caused this. 2 high draw accessories plus extremely low kms and cold weather starts.

The guy at the battery shop is also prolly sick of seeing me. Lol.
 

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