Batteries?

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PeteCole

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So one of my next projects is my dual battery setup…and I’m looking for some feedback on brands, models, etc so I can make an educated purchase….

I have a 2021 Tacoma and plan on getting the Genesis dual battery mount/kit…
 

hummerinajeep

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The last battery I bought was a NorthStar based off one of Michael's video recommendations and it was great! I've got a new Jeep now with the OEM battery, but when it's time to replace it, I'll go NorthStar again or Odyssey. I believe the company that owns Odyssey bought NorthStar not too long ago so the 2 battery brands may be basically the same thing now just with different labels on them, I'm not sure.
 

TahoePPV

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The last battery I bought was a NorthStar based off one of Michael's video recommendations and it was great! I've got a new Jeep now with the OEM battery, but when it's time to replace it, I'll go NorthStar again or Odyssey. I believe the company that owns Odyssey bought NorthStar not too long ago so the 2 battery brands may be basically the same thing now just with different labels on them, I'm not sure.
That's what they were before. Odyssey did not make their own AGM.
 
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FishinCrzy

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AGM question...I saw on here or somewhere recently that most alternators don't fully charge an AGM battery. So, I hooked up my semi-smart charger with an AGM setting on my fairly new AGM battery and sure enough it was only holding about 80% charge. After charging and sitting for a day it was still holding 95% or so. Is it correct that the alternator on my '17 Tacoma is not fully charging the AGM?? How often should I "top it off"?
 

RJ Howell

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AGM question...I saw on here or somewhere recently that most alternators don't fully charge an AGM battery. So, I hooked up my semi-smart charger with an AGM setting on my fairly new AGM battery and sure enough it was only holding about 80% charge. After charging and sitting for a day it was still holding 95% or so. Is it correct that the alternator on my '17 Tacoma is not fully charging the AGM?? How often should I "top it off"?
Curious.. What are your running for a controller? I run a DC/DC charger that's settable for different batteries (mine being lithium). Again assuming this about running a house battery, not just a second truck battery..
 

FishinCrzy

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Curious.. What are your running for a controller? I run a DC/DC charger that's settable for different batteries (mine being lithium). Again assuming this about running a house battery, not just a second truck battery..
Controller is what ever is stock with the vehicle. I also use a lithium battery that charges off DC, solar, or AC. It will run my refrig for 5-6 days at least...depending on how cold one sets it and how much heat it has to overcome. I have the single AGM for my vehicle systems and some LED lights. There was a thread that mentioned that most vehicles didn't produce quite the voltage that an AGM would be to be fully charged. I did not know that. Just wondered what is easier than an occasional charge from an AGM specific charger if that is the case?
 

Road

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AGM question...I saw on here or somewhere recently that most alternators don't fully charge an AGM battery. So, I hooked up my semi-smart charger with an AGM setting on my fairly new AGM battery and sure enough it was only holding about 80% charge. After charging and sitting for a day it was still holding 95% or so. Is it correct that the alternator on my '17 Tacoma is not fully charging the AGM?? How often should I "top it off"?
.

Though I love my pair of Odyssey AGM in my trailer (charged only by solar through a solar charge controller), I won't put AGMs in as cranking battery(s), at least in my 2008 GMC diesel with an older 140amp alt.

AGM-battery-under-hood-800.jpg
..
Like anything else with vehicles, you'll find all kinds of guys that will swear by using AGMs with regular alternators that say "I've been doing it for years with no problem and never had to charge them!" I'll bet their AGMs were not appropriately charged and did not last as long as they should have, and I bet they didn't even know they were shortening their battery's life.

Same with mixing batteries of different types, or even different ages or sizes of the same type, in a dual-battery set up with just an isolator between. With a proper DC-DC charger, yes, because they do not "combine" the two batteries but keep them separate and send the charge from the cranking batt to the house batt when appropriate. I explain it more in post #7 here, in the Super Simple Dual Battery Project, which also includes a link to a great Optima article on the subject.

Back to AGMs in cranking positions: In my own research I've found wildly contradictory info; even on battery mfg pages. Some say AGMs do not get enough voltage from alternators to properly maintain a charge and that regularly being 15-20% under-charged will shorten their life. Others say they get too high a voltage from alternators so have a shortened life because of that. Some even show conflicting charts on what voltage AGMs should get and what alternators typically put out.

Some of the conflicting info is, no doubt, to the age of the article, the understanding--or lack of--the poster, and the fact that battery and alternator technology has advanced, rendering some older info obsolete. Though it still is all over the 'net, confusing folks and conflating facts.

Conflicting info, too, out there on how to accurately test an AGM. Here's one from Texford Battery Company that seems reasonable, and is pretty much what the Odyssey dealer around here does: How Do I Test an AGM Deep Cycle?

Battery Chargers: If you're using a 110 battery charger to periodically maintain and top off your batteries, having a Smart Charger in which you can change the setting for various battery type profiles is important. Sounds like you are, @FishinCrzy. Good smart chargers have microprocessors that know what type of battery they are connected to and adjust output accordingly. I've been using a Potek Smart Charger and Maintainer for a few years and like it. It's not the most advanced or expensive, though has three levels of charging rate (2/10/20) and selectable battery type including AGM and GEL. Newer ones include lithium type. It's small enough I keep it in the van for travel now, and when around shore power hook it up occasionally to see what it says.

This is a good page on Battery Charge Settings AGM vs Flooded vs GEL; content which is worth paying attention.

IF I was to put and keep an AGM under the hood, I'd be checking it more often and hooking it up more regularly to a smart charger.

I'm sure there will be a wild array of opinions and response to the OPs query and subsequent questions/posts, especially in a place like this with such a wide array of experience, though this is what I've learned so far.

I certainly don't pretend to be an expert, though did sleep in a Holiday Inn last night. :tonguewink:

.
 

FishinCrzy

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Though I love my pair of Odyssey AGM in my trailer (charged only by solar through a solar charge controller), I won't put AGMs in as cranking battery(s), at least in my 2008 GMC diesel with an older 140amp alt.

View attachment 202679
..
Like anything else with vehicles, you'll find all kinds of guys that will swear by using AGMs with regular alternators that say "I've been doing it for years with no problem and never had to charge them!" I'll bet their AGMs were not appropriately charged and did not last as long as they should have, and I bet they didn't even know they were shortening their battery's life.

Same with mixing batteries of different types, or even different ages or sizes of the same type, in a dual-battery set up with just an isolator between. With a proper DC-DC charger, yes, because they do not "combine" the two batteries but keep them separate and send the charge from the cranking batt to the house batt when appropriate. I explain it more in post #7 here, in the Super Simple Dual Battery Project, which also includes a link to a great Optima article on the subject.

Back to AGMs in cranking positions: In my own research I've found wildly contradictory info; even on battery mfg pages. Some say AGMs do not get enough voltage from alternators to properly maintain a charge and that regularly being 15-20% under-charged will shorten their life. Others say they get too high a voltage from alternators so have a shortened life because of that. Some even show conflicting charts on what voltage AGMs should get and what alternators typically put out.

Some of the conflicting info is, no doubt, to the age of the article, the understanding--or lack of--the poster, and the fact that battery and alternator technology has advanced, rendering some older info obsolete. Though it still is all over the 'net, confusing folks and conflating facts.

Conflicting info, too, out there on how to accurately test an AGM. Here's one from Texford Battery Company that seems reasonable, and is pretty much what the Odyssey dealer around here does: How Do I Test an AGM Deep Cycle?

Battery Chargers: If you're using a 110 battery charger to periodically maintain and top off your batteries, having a Smart Charger in which you can change the setting for various battery type profiles is important. Sounds like you are, @FishinCrzy. Good smart chargers have microprocessors that know what type of battery they are connected to and adjust output accordingly. I've been using a Potek Smart Charger and Maintainer for a few years and like it. It's not the most advanced or expensive, though has three levels of charging rate (2/10/20) and selectable battery type including AGM and GEL. Newer ones include lithium type. It's small enough I keep it in the van for travel now, and when around shore power hook it up occasionally to see what it says.

This is a good page on Battery Charge Settings AGM vs Flooded vs GEL; content which is worth paying attention.

IF I was to put and keep an AGM under the hood, I'd be checking it more often and hooking it up more regularly to a smart charger.

I'm sure there will be a wild array of opinions and response to the OPs query and subsequent questions/posts, especially in a place like this with such a wide array of experience, though this is what I've learned so far.

I certainly don't pretend to be an expert, though did sleep in a Holiday Inn last night. :tonguewink:

.
Thanks @Road . I read all of that, twice even, and I understand some of those numbers too! Thankfully, I do have a smart charger:


I will pay a bit more attention during future use of the AGMs but it seems like it might not get the full charge from the vehicle alone. The heat question with AGM seems odd since I have always had to keep an eye on the wet cells during the summer and during charging especially. I have stockpiled some deionized water for that use. If the AGMs don't have liquid? Oh, well. It will either work or it won't.

I just counted in my head all the 12V batteries I have in and around various vehicles/equipment and it's about 15. Hard to keep up sometimes.
 
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Road

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Thanks @Road . I read all of that, twice even, and I understand some of those numbers too! Thankfully, I do have a smart charger:


I will pay a bit more attention during future use of the AGMs but it seems like it might not get the full charge from the vehicle alone. The heat question with AGM seems odd since I have always had to keep an eye on the wet cells during the summer and during charging especially. I have stockpiled some deionized water for that use. If the AGMs don't have liquid? Oh, well. It will either work or it won't.

I just counted in my head all the 12V batteries I have in and around various vehicles/equipment and it's about 15. Hard to keep up sometimes.
.
I know @MOAK uses a Schumacher charger and likes it.

I think the thing with AGM batts, is that being VRLA (Valve-Regulated Lead Acid) and non-vented they re-combine the gases back into the glass matts as liquid. One piece I read said something about that making them more tightly packed than a typical flooded cell, so potentially more susceptible to damage from excess heat for long periods.

Though like everything else, you don't have to look far for someone to say just the opposite. Hard to keep up with it all and to tell which opinions are based on fact and which on assumption and, sometimes, just on ego because that's what they happen to be running.

Here's an article on The Differences Between AGM, GEL, and Flooded Batteries

One thing I have not seen much about is whether newer 'smart' alternators--which change the amount of voltage output depending on load and what the ECU says is needed--are good at keeping AGMs in good condition. I know smart alternators are NOT considered good in dual-battery set ups because of that (it's another reason DC-DC chargers are growing in popularity), though no idea how smart alternators are in a single AGM battery set up.

Here's a good REDARC article on fixed voltage alternators vs 'smart' alternators: Comparing a Traditional Alternator to a Smart Alternator.

In your situation I would bet keeping on eye on it and topping it off with a smart charger periodically, especially if it switches to a float stage when at the appropriate voltage, is going to be just fine.

My AGMs, in the trailer and powered only by a solar panel, are under a big-assed shade tree right now when parked. So, even though my panel's cells are super-efficient and pull in power even in shade, the batts are pretty consistently at 3/4 power if left alone for days on end. So I either pull the trailer into full sun, take the panels off the roof and put them into full sun, or hook up my smart charger and remove the panels from the equation for bit.

Lastly, I referred in my previous about info on testing AGM batts. I found this paragraph, which has been copied into more than one other article. No idea who wrote it originally):
"These types of batteries (AGM) have lower internal resistance than flooded batteries. Older capacitance battery testers/analyzers may not be able to accurately read these batteries. Most new battery analyzers have a special mode for AGM/gel cell batteries. Old-school load testers might not provide conclusive results."

This instance was from Three Misconceptions about AGM Batteries.

.
 
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FishinCrzy

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I know @MOAK uses a Schumacher charger and likes it.

I think the thing with AGM batts, is that being VRLA (Valve-Regulated Lead Acid) and non-vented they re-combine the gases back into the glass matts as liquid. One piece I read said something about that making them more tightly packed than a typical flooded cell, so potentially more susceptible to damage from excess heat for long periods.

Though like everything else, you don't have to look far for someone to say just the opposite. Hard to keep up with it all and to tell which opinions are based on fact and which on assumption and, sometimes, just on ego because that's what they happen to be running.

Here's an article on The Differences Between AGM, GEL, and Flooded Batteries

One thing I have not seen much about is whether newer 'smart' alternators--which change the amount of voltage output depending on load and what the ECU says is needed--are good at keeping AGMs in good condition. I know smart alternators are NOT considered good in dual-battery set ups because of that (it's another reason DC-DC chargers are growing in popularity), though no idea how smart alternators are in a single AGM battery set up.

Here's a good REDARC article on fixed voltage alternators vs 'smart' alternators: Comparing a Traditional Alternator to a Smart Alternator.

In your situation I would bet keeping on eye on it and topping it off with a smart charger periodically, especially if it switches to a float stage when at the appropriate voltage, is going to be just fine.

My AGMs, in the trailer and powered only by a solar panel, are under a big-assed shade tree right now when parked. So, even though my panel's cells are super-efficient and pull in power even in shade, the batts are pretty consistently at 3/4 power if left alone for days on end. So I either pull the trailer into full sun, take the panels off the roof and put them into full sun, or hook up my smart charger and remove the panels from the equation for bit.

Lastly, I referred in my previous about info on testing AGM batts. I found this paragraph, which has been copied into more than one other article. No idea who wrote it originally):
"These types of batteries (AGM) have lower internal resistance than flooded batteries. Older capacitance battery testers/analyzers may not be able to accurately read these batteries. Most new battery analyzers have a special mode for AGM/gel cell batteries. Old-school load testers might not provide conclusive results."

This instance was from Three Misconceptions about AGM Batteries.

.
I just read some of those same articles also. One from BatteriesPlus said they weren't as affected by the heat and cold. Typical internet that one can find varying views, facts, and opinions. I have had AGM in vehicle for just over a year and it has a three year warranty so I will keep and eye on it and report back. I will try and see what my Toyota folks know also.
 
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LONO100

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Whatever batteries you go with, it is best practice to use two of the same battery type with similar specs. So if you go AGM on one, make sure the other is also AGM. Look into tying them together using an ACR (autocharge relay).
These handy little devices will join your starting and house battery in parallel when it detects that the engine is running (by sensing that the voltage has gone to 14V+). This will make it so that the alternator is charging both batteries.
When the engine is not running, the ACR will separate the two batteries allowing you to run strictly from the house battery without fear of draining the starting battery.
I am a fan of AGM batteries for vehicles that will see dirt because they don't have cells like a conventional lead acid battery which can be damaged if the vehicle takes a hard bump. an AGM can also be oriented pretty much in any configuration so you have more versatility when mounting the house battery if your goal is trying to hide it, or tuck it out of the way somehwere.
 

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I prefer AGM\SLA if for nothing else than to cut down on corrosive gasses in the engine compartment. On certain vehicles like my wife's van that we won't own for a long time I don't really care, but for my 76 CJ and my 95 XJ I prefer to not have corrosive gasses and liquids flying around the engine compartment if I can help it. Even if I shorten the service life of my AGMs by using them as starting batteries, I'm ok with that in those cases.