Tacoma3G is a beginner-friendly 3rd Generation Toyota Tacoma (2016-2023 model-years) forum. We are a community of people who are focused on good information and good vibes. T3G is the passion-project of a USMC/Toyota technician.
Group 31
That's the question I can't find an answer to. I've searched the web and the service rep at my local Toyota dealership didn't think the alternator output is controlled by the ECU, but from what I read on the internet it is. Also, odly the dealership didn't want me to buy a Tpyota Truestart battery. I have trust issue when it comes to Toyota dealerships. I'm not at all sure how I'll replace my stock battery on my 2021 Off Road when the time comes.Is an alternator voltage mod required for these larger deep cycle batteries to charge properly?
That's the question I can't find an answer to. I've searched the web and the service rep at my local Toyota dealership didn't think the alternator output is controlled by the ECU, but from what I read on the internet it is. Also, odly the dealership didn't want me to buy a Tpyota Truestart battery. I have trust issue when it comes to Toyota dealerships. I'm not at all sure how I'll replace my stock battery on my 2021 Off Road when the time comes.
That's the question I can't find an answer to. I've searched the web and the service rep at my local Toyota dealership didn't think the alternator output is controlled by the ECU, but from what I read on the internet it is. Also, odly the dealership didn't want me to buy a Tpyota Truestart battery. I have trust issue when it comes to Toyota dealerships. I'm not at all sure how I'll replace my stock battery on my 2021 Off Road when the time comes.
There’s a lot of real evidence that shows not fully charging an AGM severely cuts it’s lifespan.Just a word of dissent: You don't need to change the voltage for the AGM. It's a starter battery, not a house battery. It should never need to get above float charge, which is in spec for the stock alternator output. 14.6 is the fast charge voltage and batteries don't like to be at that voltage all the time. A proper charger will vary the charge voltage depending on the state of charge of the battery. The charging system in a car is constant because it's just meant to maintain a charge, not fast charge.
If you have a second battery that is an AGM you would want to have a charger that can vary the input voltage so that it can keep it fresh because presumably, you'll have a load on it when the engine is off.
I'm getting my info from an electrician who works on off-grid solar systems and a friend who runs AGMs in 6 different vehicles with no modifications.
I just installed an Optima Red Top (because it was the only thing available) without mods. If it dies early, I'll come back and admit my mistake.
-M
Well if that's the case, what's the best battery we should put in our rigs?There’s a lot of real evidence that shows not fully charging an AGM severely cuts it’s lifespan.
Tesla...Well if that's the case, what's the best battery we should put in our rigs?
A good quality lead acid battery? I already had OV tune, so I was able to change the charging voltage. Another not so convenient way would be to top an AGM off with a charger. You also aren’t able to utilize the amp hours you pay for with an AGM if you can’t fully charge it. So the question becomes, is the extra money worth it for advantages you can’t fully utilize?Well if that's the case, what's the best battery we should put in our rigs?
I'm interested in seeing it. All I've found is anecdata on forums.There’s a lot of real evidence that shows not fully charging an AGM severely cuts it’s lifespan.
Well one of your questions is easy, I think that I am right. You don't need to change your voltage output for an AGM. And float charging at the absorption voltage is bad.This is frustrating and a bit strange to me. My '21 Tacoma Off Road came with a barely adequate battery, a Clarios 582 CCA Group 24F. I use it mostly for towing a small camper and light "Off Road" (really on slightly rough road and a couple of beach surf fishing trips). Anyway I noticed the "Check Charging System" message popping up when I first got it and was told by the dealer that it just meant the motor wasn't running and I was draining the battery so I should just turn the car off so as to not drain the battery too much. OK, so I buy a multimeter and start digging around. After two years and only 16K miles of towing/camping/light off roading, and turning electronics off as soon as I can after the motor stops running, I find by my meter a reading of 12 volts after sitting overnight. So, I think my lead acid OEM battery is getting weak and I start looking for a replacement because I like to stay ahead of problems and I know what it's like to be stuck out in the boonies with a dead battery. It wasn't any fun. Toyota for some reason (I suspect money) decided to put a low capacity non-AGM battery in their "Off Road" built for towing and the AC outlet in the bed, truck. Searching around on the internet I read that the deep cycle AGM ideal batteries require more voltage than my vehicles alternator puts out. Figuring my dealer would know what to do I talk to the service rep. at my last free maintenance that came with the truck. He doesn't want to sell me a Toyota TrueStart battery. Instead he offers an AGM battery branded by someone I never heard of for $239 plus tax. When I mention that my alternator only pushes out 13.6 volts and I've read that's not enough to fully charge an AGM battery he doesn't seem to know what I'm talking about. So thinking that maybe I don't know what I'm taking about I go home and do more digging on the internet. Several places I read that on 3Gen Tacomas the alternator voltage delivery is controlled by the ECU. I had mentioned that to the dealer service rep and he told me the alternator voltage is not controlled by the ECU. Who do you think is right? Isn't it strange that for the most popular small truck in the USA there doesn't seem to be a straightforward answer as to how to best replace the battery? Maybe if I keep my battery on a trickle charger I can squeeze more use out of it without getting stuck and the answer will seem clearer later. If I need a tune to boost the voltage output of my alternator would that void my Toyota warranty? Any insight into this issue will be greatly appreciated.
So far it's looking to me like if I replace with an AGM I would just fully charge with my house AC charger set on AGM charging every once in a while. Someone suggested once a month. Is it right float charging at 13.6-13.8 volts while driving is OK for an AGM? Perhaps the better thing to do is just forget about going with an AGM and go with a good lead acid. I just don't know yet. Thanks for your reply. I won't overcharge an AGM as I hear that's a quick way to ruin them. I wonder if the voltage regulator inside the alternator is smart enough to adjust to whichever type of battery suggested by retailers we put into our trucks. That would be great.Well one of your questions is easy, I think that I am right. You don't need to change your voltage output for an AGM. And float charging at the absorption voltage is bad.
-M