[MsNomer]

Given that our van battery is dying and will soon be replaced, I've been thinking about the conditions under which it lives. Unless I'm missing something in my ignorance, if the house batteries lived under those conditions, we'd be accused of murdering them.

I have recently come to understand that my van battery is an AGM, rated for cold cranking because that's its primary job. Yet it is also forced to undergo the kinds of drains it is not designed for--the deep cycle drains our house batteries are designed for.

Then to add insult to injury, it is being charged by an alternator apparently designed for flooded batteries, which is why it took me so long to figure that my battery is AGM. In all of my research, I have not found a single charge profile for an AGM that is a steady one-stage 14.1-3V. I have monitored van battery voltage as we drive and that appears to be all this battery gets. No absorption phase, no float.

So what am I missing?

Now here's my other discovery: Our first battery setup included a SurePower 1315a battery separator. We later became disenchanted and disabled it, but did not remove it. Because it is bi-directional, it can allow the house batteries to help a weak van battery start the vehicle--we had to use that feature last week. Yesterday, I connected it in starting mode and left it. Near as I can tell, the solar charger charged the van battery along with the house batteries. So I'm wondering why not leave it like this when the van is parked.

So what am I missing here, too? Is a way to protect the van battery?

 

[keeponvaning]

MSN, I've never removed my starting battery and I've always assumed it's flooded because I see what looks like maintance caps on the top for checking the electrolyte level. I've never had any problems with my starting battery in 73k miles and 3 years. You said the dealer replaced yours shortly after you bought it and you believe they replaced it with an AGM not flooded - correct?

I don't really think your problem is related to the type of battery but something else, a slow leakage that draws it down perhaps. I monitor my voltage continually on both the starting and hous batteries and my alternator puts out 14.1 to 14.3 volts continually. I never see it vary much either way where my house batteries charge from between a high of 14.7 to a low of 13.1 from the solar charge controller.

Does anyone have any factual info on whether or not there are actually two different atlernators for the Promaster (one for AGM and one for flooded)? I seriously doubt it but I suppose the charging profile could be controlled by the ECM. Maybe the computer needs to be tweaked to reflect the starting battery type? I don't know but it's something to think about.

I think under real world conditions many people use either type no matter what came with the vehicle with no problems. Battery type isn't something the typical consumer thinks about but more what they get sold on by whomever is selling them a new battery.

 

[MsNomer]

I was mistaken about my battery being flooded. This is the original AGM battery going bad. It is 3.5 years old and spent its first year on the dealer lot, probably mostly discharged. I hoped to get the dealer to replace it but no such luck. We plan to replace it in New Hampshire.

 

[tgblake]

I was mistaken about my battery being flooded. This is the original AGM battery going bad. It is 3.5 years old and spent its first year on the dealer lot, probably mostly discharged. I hoped to get the dealer to replace it but no such luck. We plan to replace it in New Hampshire.

How can you tell what type you have?

Someone posted a photo once, may have been RD, which clearly said AGM on the battery label. I have had 2 batteries. The original went bad and was replaced under warranty.

Here are photos of both. They both seem to have screw caps, so I assume they are both FLA.




What made you think your original was FLA and what makes you now think it is AGM?

 

[Charger7022]

I Have been doing research on the 12v-12v chargers and I'm learning a lot! one thing I learned and this is another reason not to buy a Transit is whats called Regenerative Braking which ford uses in there transit vans and is not good for charging house batteries. The way I understand it is that the alternator charges at 14ish volts at idle than at cruising speed/highway the output drops to 12-12.2 volts to eliminate any load on the engine from the alternator (for lower emissions and better MPG) Than when you slow or brake to a stop the alternator kicks back in at a higher voltage sometimes as high as 17 volts (don't take this a correct info cause I'm just learning myself) So this led me to do a test recommended but Sterling Electric in this video

. Now I'm keeping in mind that this guy has a product to sell and while this and his other videos are very informative bottom line is that he is a salesman.


Now you 2 are saying your charging at a constant 14.1-14.3. Now last night I took a 20 min drive to do the test in the video to see if I had a Regenerative braking alternator and for all 20 mins I had a constant 14.70-14.75 volts, my van in a 2016 gaser. Now maybe it has to do with the TEMP as it was 23 last night and I'm not sure how the voltage changes with temp. Or maybe I have a different alternator.


The reason I'm looking at the 12v-12v chargers is cause I was only seeing 4-5 amps going to my house battery and I would like to see the 30-40 amps that Sterling Electric claims with there charging unit not to mention each one has a 4 stage charging with selectable charging for different battery types.

Im going out right now to turn all my lights on and plug in a very high draw (4-5 amp cooler) to drain the battery down, than I'm going to see how many Amps I can get to go to my house battery with the battery doctor setup I got using 4 ga. wire from my starting batter to the house battery. I will also see if I can find some sort of part number on my alternator and than maybe we can compare part#'s on alternators. another thing we can do is take our vin numbers to a dealer and ask them to look up a replacement alternator and see if they differ for our vans.


Ill see what I come up with late today I'm headed out now to put a load on my battery for a few hours before my charge test. Right now the temp is 27 but going up to 50 today so ill try the charge test at the warmest part of the day.

 

[Rookerlw]

MsNomer-Might it be that the battery was well into sulfation due to being in a partially (or fully) discharged state for the year that it sat on the dealer's lot? It is well known that this will contribute to a battery's early demise. This is what kills most RV house batteries - they sit much of the time with no charge. Batteries that should last 5-8 years die in 2-3 years.

My guess is that if you replace the battery, you'll get the expected life from it as you'll be using the vehicle often enough that the battery will remain in a more or less fully charged state. Lead Acid batteries last longest when they are 100% fully charged, and when discharged, promptly returned to a fully charged state and then kept there by a trickle charger.

I understand that the Promaster has a small continuous parasitic draw that will deplete the battery within a few weeks. If a vehicle of this type was not my daily driver (thus getting a daily or almost daily charge), I'd add one of those small solar panels that sit on the dash to keep the battery topped up. It's sulfation from discharge or partial discharge that kills lead acid batteries. BTW, 95% charged is not good enough for maximum life. That 5% of the lead plates that are not fully charged will start to suflate and the batteries will begin their downward death spiral.

This has been my experience after over 30 years maintaining telehpone switching center batteries for a major utility.
Lex

 

[MsNomer]

tg, that first one is our battery. It does not have the ports like our flooded batteries have and the manual says it is sealed, no water ever to be added.

 

[Charger7022]

I to have the first battery and I'm assuming its AGM but my alternator is clearly putting out 14.7-14.75 volts unlike others who state they are getting 14.1-14.3

 

[medicineman4040]

A lot of learning to be had here.
From my simplistic view I see the methods of charging the
house batteries as follows and l'm listing in order of preference-
#1 best way is from a smart inverter-charger that allows 3 or 4 stage charging
#2 best way solar panels with a good solar charge controller
#3 from a generator that puts out clean signal and even better if it goes
through a smart inverter-charger forcing the generator output into the
3 or 4 stage model
#4 least best way from a dumb alternator.

The alternator method from my algebraic summation of this and many others forums
is best avoided IF you want to maximise life-span of the HOUSE batteries. But the alternator
method is great for emergencies.
Just yesterday my sparky asked what the big battery disconnect switch is for. He thought it
was for disconnecting the house batteries. Well there is one for that but the one he was questioning
is to separate the house batteries from the Battery Doc isolator/charger we are using.

So I'm leaving on a one week trip in the PM. The house batteries are fully charged via shore power via
the smart charging of the inverter-charger when I leave. The solar panel is doing it's thing. On said trip
we plan to stay every 2-3 days someplace with shore power. In this scenario there is no reason to even
employ alternator charging.
Next scenario. We're out for 2 weeks boondocking. Eventually the charger-inverter shuts down, we'd been
using the laptop daily, the ARB frig continuously, the (future) Webasto daily in the morning, etc. It's been
cloudy-rainy and the solar panel can't keep up. I have two choices. Start the van and turn the Battery Doc
to on and now charge via the alternator; or in my case pull out the little Earthquake 700 watt generator and
plug it into the 30amp shore power inlet.

So why even continue with the Battery Doc? I'm thinking a scenario where the van battery is dead, just push a button
on the Battery Doc and start the vehicle using the coach batteries; or a situation where I'm just too lazy to fire up
the little gen-set to charge the batteries.

OK, all the above is theory since my Promaster hasn't been on a trip yet

 

[Winston]

Yet it (vehicle AGM battery) is also forced to undergo the kinds of drains it is not designed for--the deep cycle drains our house batteries are designed for.

Then to add insult to injury, it is being charged by an alternator apparently designed for flooded batteries . . . No absorption phase, no float.

MsN, we tend to agree with the opinion, above, that you've probably done nothing wrong and your misfortune was that fatal first year of battery abuse (prior to your ownership).

We do not understand your comment or reasoning why you believe your vehicle battery was forced into the same "deep cycle" regime as your house battery. If, in fact, this were so, then there's your explanation. Vehicle batteries, whether AGM or not, are not designed for deep cycling.

We assume that that your system 'breaks' the connection between your vehicle and house batteries when the engine is not running and, if so, it would seem that only your house battery should suffer from deep discharge. Whenever the two batteries are interconnected, the engine and alternator are running.

I'll try and avoid my rant on Bulk, Absorption, Float . . . it is true that simple alternators don't cycle through such a multi-stage profile. They shoot for one voltage - - the question being, "Is that voltage harmful to the battery(ies) being charged, in particular, if that voltage/charge is maintained during, say, an all-day drive?" We have pondered this question elsewhere in this forum and have concluded, for two reasons, that such a long charge profile is not harmful. The first being, the thousands of alternator, battery, and car engineers can't all be wrong. And, secondly, in looking at the specifications provided with our 245 AH CaRV AGM house battery, we could find nothing that suggested that these voltages weren't expected and ok.

Here, and of possible interest, is a table from our Magnum charger manual:

It suggests that flooded lead-acid should "float" 13.4 volts (we use 'float" as a measure of what a battery can sustain for extended periods of time without damage) and that AGMs, depending on the manufacturer, should float at 13.1 or 13.5 volts. So, it would seem, if you have an alternator designed to float a flooded battery at 13.4v and you happen to have one of those 13.1v AGMs, maybe you have a problem.

Unfortunately the weakness of the above is that most vehicle alternators regulate closer to 14.3 volts (the absorption voltage published in the above Magnum table). Where does that leave Winston in his reasoning? Guess I'm 'falling back' to the above two justifications: "all those engineers can't be wrong" and my "battery manual says it's ok".

PS: We are reluctant to challenge anyone with decades of experience charging substation battery packs, but we've never heard that charging a lead-acid battery, flooded or AGM, to 'only' 95% charge is harmful.

 

[Charger7022]

A lot of learning to be had here.
From my simplistic view I see the methods of charging the
house batteries as follows and l'm listing in order of preference-
#1 best way is from a smart inverter-charger that allows 3 or 4 stage charging
#2 best way solar panels with a good solar charge controller
#3 from a generator that puts out clean signal and even better if it goes
through a smart inverter-charger forcing the generator output into the
3 or 4 stage model
#4 least best way from a dumb alternator.

The alternator method from my algebraic summation of this and many others forums
is best avoided IF you want to maximise life-span of the HOUSE batteries. But the alternator
method is great for emergencies.
Just yesterday my sparky asked what the big battery disconnect switch is for. He thought it
was for disconnecting the house batteries. Well there is one for that but the one he was questioning
is to separate the house batteries from the Battery Doc isolator/charger we are using.

So I'm leaving on a one week trip in the PM. The house batteries are fully charged via shore power via
the smart charging of the inverter-charger when I leave. The solar panel is doing it's thing. On said trip
we plan to stay every 2-3 days someplace with shore power. In this scenario there is no reason to even
employ alternator charging.
Next scenario. We're out for 2 weeks boondocking. Eventually the charger-inverter shuts down, we'd been
using the laptop daily, the ARB frig continuously, the (future) Webasto daily in the morning, etc. It's been
cloudy-rainy and the solar panel can't keep up. I have two choices. Start the van and turn the Battery Doc
to on and now charge via the alternator; or in my case pull out the little Earthquake 700 watt generator and
plug it into the 30amp shore power inlet.

So why even continue with the Battery Doc? I'm thinking a scenario where the van battery is dead, just push a button
on the Battery Doc and start the vehicle using the coach batteries; or a situation where I'm just too lazy to fire up
the little gen-set to charge the batteries.

OK, all the above is theory since my Promaster hasn't been on a trip yet

I see the problem with my current connection which is start battery to battery doctor to house battery with no switch I am always charging when I drive. Now as I have mentioned I am now looking to the 12v-12v dc-dc chargers which seem to me to be the best of all when it comes to using solar and alternator charging. It also seems that I can still use the battery doctor in line to do just what you state for emergency jump start situations. Check out the Projecta IDC25 it does both charging in one, allows you to connect to the alternator and also allows the addition of solar and acts as a solar charge controller. it also provided the proper 4 stage charging needed.


here is a video discussing using what is essentially a battery doctor and the dc/dc charger

 

[tgblake]

I am still not convinced that these van batteries are AGM. As I mentioned, somebody posted a photo of an OEM battery with AGM clearly marked on the label. That was on a diesel. Neither of my batteries, and others have indicated they have the same as the first one pictured in my earlier post, have any label indicating AGM. They also seem to have screw caps, presumably to add water. So not totally maintenance free. Perhaps the diesels have AGM and the gas models have FLA?

Not that it matters to MsNomer because hers has failed anyway. But if the logic is that the alternator is set up to charge an AGM may not be correct if the OEM battery is FLA. Or that may not even matter if the profiles are close enough. But I still wonder what I have, AGM or FLA.

 

[medicineman4040]

Guys/gals we know that some people consider batteries as food, just something that you have to buy. Some want to maximize the meal and make it last as long as possible and are willing to go to great steps to do that eh.
There is one poster here who is going from alternator to the inverter-charger to make sure his coach batteries get the 3 stage treatment and others consider that way way overboard.
In lot's of ways it's like the continual insulation debate where in the end we throw up our hands, pick a method and go with it.
I learned quickly when we began this project that I could spend the next lifetime studying electrical theory....not going to happen Just give me a method that works and for coach batteries I'll plan to replace in 5-7 years. For the other vehicles lying about I change their batteries out every 3 years regardless.

 

[keeponvaning]

Good point MM. Most people way over think and spend on these things because it gives them "piece of mind"

That's ok if that what makes you feel good!

 

[MsNomer]

I am still not convinced that these van batteries are AGM. As I mentioned, somebody posted a photo of an OEM battery with AGM clearly marked on the label. That was on a diesel. Neither of my batteries, and others have indicated they have the same as the first one pictured in my earlier post, have any label indicating AGM. They also seem to have screw caps, presumably to add water. So not totally maintenance free. Perhaps the diesels have AGM and the gas models have FLA?

That was exactly my thinking for two years and the charging profile of the alternator appeared to support my position. Then I checked the owners manual. It clearly says that the batteries are sealed and water is never added. When I looked at the batteries in our other vehicles, I became even more convinced. These other – flooded – batteries have obvious ports and warnings about acid, etc., which our PM batteries are lacking.

In searching for a replacement battery, we learned that the battery for the diesel is indeed a different animal and much more expensive, probably because the diesel requires more cranking mojo.

 

[RDinNHandAZ]

MM and others.
When a solutions is most simple, as good or better than any other as far as we know and is also less money isn’t that a factor? I know you don’t want me to go through this again but is a 12volt to 12 volt charger (which with solar and alternator should almost never be needed) that solution? My $90 WFCO charges the FLA or AGM’s properly when plugged in, manages the 110 volt breakers and wiring, has the needed 12volt fuses and is a long-time proven solution in RV’s. It does all the electric management all the time and charges if I plug in to shore. The starting battery and house battery get used very differently, and treating them like they are a pair (even when not the same as mine) is just not thoughtful engineering. My last similar setup in my truck camper lasted 8 years and the battery seemed good at that time but I replaced it to assure the buyer years of trouble free power. These batteries are like a lunch as MM suggests, you can eat them slowly or fast and you will be replacing them if you use them long enough. My two 6 volt FLAs cost $165 together and I expect 10 years out of them, $16 per year. Not bad eh? The AGM starter battery will probably not last 7 years. Why would I ever want to charge them the same or connect them together if I could help it? The idea of making 12 volts and putting it through a black box to get 12 volts and using it regularly to charge my house batteries makes me chuckle. But hey, that just me. Sorry about your starter battery MsNomer.

 

[Charger7022]

MM and others.
When a solutions is most simple, as good or better than any other as far as we know and is also less money isn’t that a factor? I know you don’t want me to go through this again but is a 12volt to 12 volt charger (which with solar and alternator should almost never be needed) that solution? My $90 WFCO charges the FLA or AGM’s properly when plugged in, manages the 110 volt breakers and wiring, has the needed 12volt fuses and is a long-time proven solution in RV’s. It does all the electric management all the time and charges if I plug in to shore. The starting battery and house battery get used very differently, and treating them like they are a pair (even when not the same as mine) is just not thoughtful engineering. My last similar setup in my truck camper lasted 8 years and the battery seemed good at that time but I replaced it to assure the buyer years of trouble free power. These batteries are like a lunch as MM suggests, you can eat them slowly or fast and you will be replacing them if you use them long enough. My two 6 volt FLAs cost $165 together and I expect 10 years out of them, $16 per year. Not bad eh? The AGM starter battery will probably not last 7 years. Why would I ever want to charge them the same or connect them together if I could help it? The idea of making 12 volts and putting it through a black box to get 12 volts and using it regularly to charge my house batteries makes me chuckle. But hey, that just me. Sorry about your starter battery MsNomer.

I to have a very similar panel to your WFCO and mine has a built in 30 amp charger and does great when I'm plugged in. just as you chuckle at a $50 dollar box to charge batteries I have to chuckle at drilling holes in your roof and spending a thousand dollars to do the same thing that your 180amp alternator was designed to do from the factory via the 70 amp lead in the bottom of the passenger side pillar. but for some people that 1. Park in the sun ( I never will unless I have to) 2. park in one spot with no power available and don't move for 3 or more days. (never gonna do that cause if I'm in the middle of nowhere camping ill be driving everyday and just 1 hour of driving will more than top off my batts from one nights use.) and like I said I'm chuckling at your solar but to each there own and we all use our vans differently.


Now on to what I was talking about and it seems no one wants to touch on the subject of 12v to 12v chargers which for me seems like the A+ #1 option for me. No need to worry about what voltage the alternator is putting out and its all automatic and the one in the video above will also act as a solar charge controller so I can put a port somewhere outside the van and have the ability to use solar and harness the 180 amps that are there everytime I turn the key and 100% free.


As long as we are both chuckling we are HAPPY!

 

[RDinNHandAZ]

Hey I respect your points and I already piped in on the solar. If you get the last laugh I will still be happy and support your teaching us that this is a good solution. I am thinking you are on the cutting edge on this one and there are not a lot of folks here to lead. Go man!
I have yet to fine a source that sells these and have ratings and observations by users not filtered by the folks that sell them. Send along some, I am interested of course.

 

[Charger7022]

now to follow up on my Amp test to my house battery from starting battery I put a 5 amp load on my house battery (currently 1 12v AGM 100ah) for 3 hours than with the load still on it I started the van with volt meter and clamp on amp meter installed. At start up I had 49 amps and 14.67 volts going to the house battery it quickly dropped to around 32 amps and stayed there for the few minutes I had the van running. So I removed all load from the house battery and drove to a freiends house about 15 mins away cut a few trees down for him than drove home. when i got home i left the van running and and check both amps and voltage, voltage stayed the same and amps was now down to 4 amps at idle.



What this proved to me is that i don't need the Starling or similar 12v to 12v charger to get the amps i need to charge the battery quickly but i also would like it to better regulate the volts and give my house batteries a true charge profile they are intended to have for maximum life.

 

[Charger7022]

Hey I respect your points and I already piped in on the solar. If you get the last laugh I will still be happy and support your teaching us that this is a good solution. I am thinking you are on the cutting edge on this one and there are not a lot of folks here to lead. Go man!
I have yet to fine a source that sells these and have ratings and observations by users not filtered by the folks that sell them. Send along some, I am interested of course.

RD that's why I'm digging for more info here. all I'm seeing is info from the salesman themselves. I'm trying to find info on my own from someone else who has the system and likes it but i think i may have to bite the bullet and be "THAT GUY". I'm gonna search around and send some more emails before i pull the trigger.