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Old 05-20-2018, 12:52 PM   #1
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Venice , Florida
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How to keep the house batteries charged

I just replaced the two house batteries on my 2016 Interstate GT EXT. The original ones went bad. It is a preowned unit that had only 5,500 miles on it.
Do I need to keep the shore power connected when not in use?
Do I need to keep the main battery switch on when connected to shore power?
The top of my unit looks like something was removed on the roof at the backend.
there is one small solar panel on the front top. I am wondering if the last owner broke one panel and just removed it and the is the reason I am having problems with keeping it charged. Could just be another problem.
This is my first RV so I have a lot to learn.
I am beginning to think I made the wrong choice with an Airstream for boon docking. I might have been better with an e-trek from Roadtrek!
Thanks for any help.
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Old 05-20-2018, 01:02 PM   #2
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Hi

Power management on an RV when off grid is complicated. There are *lots* of threads here that dig into various aspects of what you need to do. First step in your case sounds like it should be to work out what you actually have. A single panel is not putting out much power at all. If even that is non-functional for some reason ...you are even worse off. If you are going to depend on solar ( and are very careful how you do this or that) four panels is probably the minimum setup.

Storage wise, there are systems on the RV that stay powered up all the time. They pull down the battery. In some cases that happens in less than a week. If you don't provide some sort of charging power, the batteries die pretty fast. Again, you need to figure out what the previous owner did to you ....

Bob
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Old 05-20-2018, 01:07 PM   #3
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Your house batteries should survive storage fine if they are fully charged and you add a disconnect switch near the batteries that disconnects ALL loads when in storage.
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Old 05-20-2018, 01:38 PM   #4
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Yes newer car and trailers have items that run in the background all the time and they will kill batteries of a unit left for several weeks. You can disconnect the house batteries when in storage or install a trickle charger. I say a separate charger because the units that come with new equipment are junk battery charger that will do more harm than good if used for long periods. They will boil the water out of a battery if there is no measurable load on them.

I have a trickle charge on my TV as it can sit for weeks between trips and the batteries will go dead in less than 2 weeks because of all the things running in background. I have added a few beyond the factory stuff.


My trailer is old enough not to have this useless stuff and I have installed a Progressive 9000 charger that allows me to remain connected to shore power for months if necessary.
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Old 05-21-2018, 08:22 AM   #5
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Hi

Sorry, but I get really tired of this "boil the batteries" nonsense. We pass the story around here a lot and it's simply not true.

You boil a battery by putting to much voltage on it. That is the *one* thing that the stock chargers do not ever do. They *do* have a number of drawbacks, but that's not one of them.

Bob
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Old 05-21-2018, 10:15 AM   #6
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After owning my AI for four years now, I think I've figured out the whole house battery situation. And I don't like it. It's been too easy for me to forget something when periodically parking for several weeks in my heated garage, only to find out the batteries are at 2 volts again. I'll spare you the details how and why that can happen (unless you really want to know), but I made the decision to 1) completely disconnect the house batteries with a switch in the back, and 2) put a placard on dashboard that says "Disconnect house batteries and plug-in battery tender when parked". as a consequence, the batteries never get below 12.65v while the rig is in storage.
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Old 05-21-2018, 02:35 PM   #7
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Wow... I am going through the same thing right now... which to get.. what to improve on and what works and not. Off the grid you need BIG batteries.. as you will need to figure about 75 to 100 amps of current per 24 hours...

Solar works but its location location location.. so we also use back up gen set.. which then brings us to another problem.

Most of the A/S converters are set up for GLAMPING. If you go on the gen set its going to take 6-10 hours to get the bats back up into shape for the following night... The old Univolt system isn't what it should be these days.. So we started looking for better newer higher tech converters that are state of the art so to speak.

We found one that we are going to try out... matter of fact the manufacture has asked that we give them feedback on how it does work. We have a couple of parameters that we want to achieve... one being that we can use the ham/cb radio on the electrical system without having to obtain a seperate power supply for the trailer and the radios...

It has long since been known that the newer environmental effecency regs have taken us over to the switching type power supply.. they actually are really more adaptable to the RV and its wavering shore power voltage... and do a better job of not only charging but maintaining the Bats... Not only do they help keep them in good shape but they also can recover them faster... saving gen run'n time... and then automatically switch to a maintenance charge that extends their life. The final ice'n on the cake is that they also de-sulfnate the battery... automatically as well...

So when hooked up to shore power.. or on the gen set.. it will be quicker, better and maintain the battery's with less maintenance on the owners part.

I plan to put my findings on conversion and updates on how its working out on the blog... so that way we all can find information from my project.

Indeed your asking the right questions.. that seems to be a deep dark hole when it comes to information about which is best and what works and doesn't. A lot of old timers just went with what A/S put in .. and never questioned it.. just went out and bought more battery's when they went turtle. Today that gets expensive and we all would like to get the most from our bux out of the electrical system.

I don't think in the past that A/S did any real engineering on the system... and from all accounts the new one sure don't seem to be much better... as from what we hear the new converters are being made in china... oh joy... and are just as bad as the old boat anchor converters of years ago... least they kept going on and on and on... but, at what cost to the battery ?

Stay in touch.. this is a on going topic... of interest..
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Old 05-21-2018, 05:40 PM   #8
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Quote:
Originally Posted by GM Airstream View Post
Wow... I am going through the same thing right now... which to get.. what to improve on and what works and not. Off the grid you need BIG batteries.. as you will need to figure about 75 to 100 amps of current per 24 hours...

Solar works but its location location location.. so we also use back up gen set.. which then brings us to another problem.

Most of the A/S converters are set up for GLAMPING. If you go on the gen set its going to take 6-10 hours to get the bats back up into shape for the following night... The old Univolt system isn't what it should be these days.. So we started looking for better newer higher tech converters that are state of the art so to speak.

We found one that we are going to try out... matter of fact the manufacture has asked that we give them feedback on how it does work. We have a couple of parameters that we want to achieve... one being that we can use the ham/cb radio on the electrical system without having to obtain a seperate power supply for the trailer and the radios...

It has long since been known that the newer environmental effecency regs have taken us over to the switching type power supply.. they actually are really more adaptable to the RV and its wavering shore power voltage... and do a better job of not only charging but maintaining the Bats... Not only do they help keep them in good shape but they also can recover them faster... saving gen run'n time... and then automatically switch to a maintenance charge that extends their life. The final ice'n on the cake is that they also de-sulfnate the battery... automatically as well...

So when hooked up to shore power.. or on the gen set.. it will be quicker, better and maintain the battery's with less maintenance on the owners part.

I plan to put my findings on conversion and updates on how its working out on the blog... so that way we all can find information from my project.

Indeed your asking the right questions.. that seems to be a deep dark hole when it comes to information about which is best and what works and doesn't. A lot of old timers just went with what A/S put in .. and never questioned it.. just went out and bought more battery's when they went turtle. Today that gets expensive and we all would like to get the most from our bux out of the electrical system.

I don't think in the past that A/S did any real engineering on the system... and from all accounts the new one sure don't seem to be much better... as from what we hear the new converters are being made in china... oh joy... and are just as bad as the old boat anchor converters of years ago... least they kept going on and on and on... but, at what cost to the battery ?

Stay in touch.. this is a on going topic... of interest..
I am forever puzzled reading all this stock battery/charger/converter drama.
We are on our third AS, 2012,2013 and now 2017. All three were always plugged in to shore power 24/7 with the switch on mode except when boon-docking for 2 or three days or being towed. Never had any battery or charger problems matter of fact I sold the previous 2 with the original batteries going strong. All I ever do is monitor the water levels and keep them clean.
Since doing nothing with my batteries and chargers has worked so well for me I will continue the same way.
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Old 05-21-2018, 08:24 PM   #9
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So uncle-Bob, my one battery in my new trailer was boiling and "very warm to almost hot" to the touch and smelled of rotten eggs. If the charger didn't cook the batteries with too much voltage, then how did it end up this way?
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Old 05-21-2018, 10:35 PM   #10
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cooking batteries

I just cooked my 2 batteries the winter.
Had it on charge all winter. Suppose to trickle charge automatically
when almost full charge is attained. Not sure that ever happened.
Wife kept complaining of a sewer smell, rotten eggs. I have a terrible sense of smell. But, sure enough, come April water in batteries almost gone and what remained I could see it boiling/bubbling ? Filled with distilled water but would no longer hold a charge. Next winter will put on charge but will remove charger
when batteries are fully charged. Will monitor with voltmeter and reconnect as necessary. Too expensive to replace 2 batteries yearly.
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Old 05-22-2018, 07:45 AM   #11
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Originally Posted by Sammy99 View Post
So uncle-Bob, my one battery in my new trailer was boiling and "very warm to almost hot" to the touch and smelled of rotten eggs. If the charger didn't cook the batteries with too much voltage, then how did it end up this way?
Hi

Very simple: You have a shorted cell in the battery. Once the cell shorts, the rest of the process happens regardless of the charger you happen to have. The shorted cell is a battery defect or a worn out battery. We run batteries hard using them in a TT. They do indeed die in this sort of usage. They don't die all the time, but there is a percentage of them that do.

Can you do stuff that "encourages" the batteries to die? You most certainly can. Running them down to 2V is one really good way (yes, I know how to do that, I don't have to ask ...). Even getting them down to 12V when it's cold out is a pretty good way to damage them.

What we get used to are batteries in cars. A car battery lives a life of luxury compared to a TT battery. It's charge profile is trash compared to a TT, but otherwise it has it easy. It gets very little discharge ( vs capacity ) and zero time spent in a low charge state.

Bob
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Old 05-22-2018, 01:16 PM   #12
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Quote:
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Hi

Very simple: You have a shorted cell in the battery. Once the cell shorts, the rest of the process happens regardless of the charger you happen to have. The shorted cell is a battery defect or a worn out battery. We run batteries hard using them in a TT. They do indeed die in this sort of usage. They don't die all the time, but there is a percentage of them that do.

Can you do stuff that "encourages" the batteries to die? You most certainly can. Running them down to 2V is one really good way (yes, I know how to do that, I don't have to ask ...). Even getting them down to 12V when it's cold out is a pretty good way to damage them.

Bob
Ah ya... sounds to me like your picking on the battery instead of the device that is SUPPOSED to support it... Uncle Bob...

What we are concentrate'n on here is the Converter... and the ones that A/S puts in their new trailers are JUNK... to say the least... some do work.. Most don't. That is why we started looking for something else that is better (after all A/S are supposed to be the best... arn't they... )

So aftermarket is where one looks today for ANY parts for A/S or others... as it seems most aftermarket sellers went thought the same issues and came up with the solution to the problem.

One thing I would like to ask you to do... go in and turn everything on all at once or do a max electrical load sheet like we published before in a different blog... and find out exactly how much 12 volt juice your really asking the converter to put out in current. You will be surprised at how feeble the converter is for the load.. and how you can actually be drawing from the bats even while plugged into shore power (120v)

A lot of owners never take the time to actually check their trailers out.. thinking that the manufacture already did... well they haven't... and most are sized for about half of what you CAN use at full load...

Why.. its all about the money...

So once we have the facts.. then we can start to retrofit so that we can get max life out of the bats .. that are not enviromentally frendly.. according to the environazi's today... and drive the price up... costing US more... etc...

Oh and don't even get started on lithum bats... They claim that they are the battery of the future... well maybe for cars/trucks.. but they have their share of problems in the RV also... beside's being expensive... Not quite their yet...

So don't shoot the battery for being bad... its the device that is supposed to maintain it... that is the weak link in the chain...
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Old 05-22-2018, 10:38 PM   #13
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How to keep the house batteries charged

Don’t almost all Airstreams come with a 55amp converter? What DC accessories are you running to add up to 55amps? The inverter? It would make less than no sense to run an inverter when a converter is powered. Maybe I’m missing something here.

Your rant and reference to “environazis” will surely encourage active participation in your threads. Terrified of technology IMPROVEMENTS. Just because you don’t understand Lithium battery technology doesn’t mean it isn’t viable for those that do. I suppose LED lighting is witchcraft and will make you impotent too.

Of course if you are trying to compare a 30 year old Airstream to anything _modern_ within the RV world, then there is your failure. Technology has changed, and I’m sorry Airstream didn’t have for ability to transport all of today’s capabilities back in time to when your vintage trailer was built.
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Old 05-23-2018, 07:08 AM   #14
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Originally Posted by GM Airstream View Post
Ah ya... sounds to me like your picking on the battery instead of the device that is SUPPOSED to support it... Uncle Bob...

What we are concentrate'n on here is the Converter... and the ones that A/S puts in their new trailers are JUNK... to say the least... some do work.. Most don't. That is why we started looking for something else that is better (after all A/S are supposed to be the best... arn't they... )

So aftermarket is where one looks today for ANY parts for A/S or others... as it seems most aftermarket sellers went thought the same issues and came up with the solution to the problem.

One thing I would like to ask you to do... go in and turn everything on all at once or do a max electrical load sheet like we published before in a different blog... and find out exactly how much 12 volt juice your really asking the converter to put out in current. You will be surprised at how feeble the converter is for the load.. and how you can actually be drawing from the bats even while plugged into shore power (120v)

A lot of owners never take the time to actually check their trailers out.. thinking that the manufacture already did... well they haven't... and most are sized for about half of what you CAN use at full load...

Why.. its all about the money...

So once we have the facts.. then we can start to retrofit so that we can get max life out of the bats .. that are not enviromentally frendly.. according to the environazi's today... and drive the price up... costing US more... etc...

Oh and don't even get started on lithum bats... They claim that they are the battery of the future... well maybe for cars/trucks.. but they have their share of problems in the RV also... beside's being expensive... Not quite their yet...

So don't shoot the battery for being bad... its the device that is supposed to maintain it... that is the weak link in the chain...
Do you have a list of the better Converter /Chargers that are an easy swap out for the stock Parallax the AS comes with ? Considering the heavy use these converters are subjected to the cost of upgrading is well worth it.
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Old 05-23-2018, 07:17 AM   #15
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Quote:
Originally Posted by GM Airstream View Post
Ah ya... sounds to me like your picking on the battery instead of the device that is SUPPOSED to support it... Uncle Bob...

What we are concentrate'n on here is the Converter... and the ones that A/S puts in their new trailers are JUNK... to say the least... some do work.. Most don't. That is why we started looking for something else that is better (after all A/S are supposed to be the best... arn't they... )

So aftermarket is where one looks today for ANY parts for A/S or others... as it seems most aftermarket sellers went thought the same issues and came up with the solution to the problem.

One thing I would like to ask you to do... go in and turn everything on all at once or do a max electrical load sheet like we published before in a different blog... and find out exactly how much 12 volt juice your really asking the converter to put out in current. You will be surprised at how feeble the converter is for the load.. and how you can actually be drawing from the bats even while plugged into shore power (120v)

A lot of owners never take the time to actually check their trailers out.. thinking that the manufacture already did... well they haven't... and most are sized for about half of what you CAN use at full load...

Why.. its all about the money...

So once we have the facts.. then we can start to retrofit so that we can get max life out of the bats .. that are not enviromentally frendly.. according to the environazi's today... and drive the price up... costing US more... etc...

Oh and don't even get started on lithum bats... They claim that they are the battery of the future... well maybe for cars/trucks.. but they have their share of problems in the RV also... beside's being expensive... Not quite their yet...

So don't shoot the battery for being bad... its the device that is supposed to maintain it... that is the weak link in the chain...
Hi

I am in no way at all claiming that the stock converters are great stuff. All I am pointing out is that they do *not* boil batteries. They throttle their max voltage to *keep away* from boiling batteries. The stuff you are talking about is *because* they don't boost voltage / boil batteries.

What's going on:

A fancy converter goes to higher voltage to push power into the batteries. Some that I have measured go as high as 18V to get that done. Do that for very long and indeed you *will* boil a battery. They try do do it until they see the current taper off. That's fine if you have zero load on the battery. It's bunk if you happen to have the vent fan running.

So no, the stock chargers are not in the "boil battery" category, but there are a number of designs out there that are. If you start swapping around converters, be careful with what you grab and what you use.

Why is this worth harping about?

The problem is, people hear the "boil batteries" stuff, swap to a random converter and assume the problem is solved. It's not solved. The converter is not the root cause of the problem. It's pretty likely that their running the battery down to 2V every other week is the main culprit .... If they don't fix *that* problem, ( whatever the issue is ) they will be right back in trouble with a cheap new converter and some expensive batteries.

Bob
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Old 05-23-2018, 11:43 PM   #16
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Quote:
Originally Posted by SilverHouseDreams View Post
Don’t almost all Airstreams come with a 55amp converter? What DC accessories are you running to add up to 55amps? The inverter? It would make less than no sense to run an inverter when a converter is powered. Maybe I’m missing something here.

Your rant and reference to “environazis” will surely encourage active participation in your threads. Terrified of technology IMPROVEMENTS. Just because you don’t understand Lithium battery technology doesn’t mean it isn’t viable for those that do. I suppose LED lighting is witchcraft and will make you impotent too.

Of course if you are trying to compare a 30 year old Airstream to anything _modern_ within the RV world, then there is your failure. Technology has changed, and I’m sorry Airstream didn’t have for ability to transport all of today’s capabilities back in time to when your vintage trailer was built.
Well if it happened to you.. sorry... impotency is a old mans problem you need to take up with your meds and medical director.... and your rant'n really is a little offensive because you ASSUME... that were all lost in space.. and your the only one who knows where they are at... really? And really enjoy the inability to comprehend that older... as you ' vintage' trailer... are not with to days technology. I wouldn't want what the factory is pushing out today in my .. as you infered...OLD A/s.

I have better more dependable, higher technology, etc.. at a much less cost than the new ones.

I won't go into why lithium batts are not only bad ju ju but also very unstable and unsafe. (look at all the fires they have started and KILLED people and MH/RV's.) not to mention the $$$$. Strange why the rest of us are still using good old bats... and looking for ways to improve on their lives... could it be that they ARE the better idea ?

Modern does not mean better in my books... as its whats inside that counts.. and what technology hath brought to the industry... most of the time due to disapointment in the RV manufacture for failing to provide... at the cost they charge.... indeed the new A/S are having problems... and the QC has basically hit the perverable head...

The factory is leaving the dealers to take the brunt of the dis-appointments due to lack of QC and engineering.

Indeed you are missing a lot here... but then again... some never do get on board the train... and get with the program... and instead just opt for throwing more money at a new unit.... oh well.. have a nice day as we cont'enue on to improve units we already are stuck with... without paying $100,000 for a new one. But hey if your rich.. go for it... after all that is why we can smile and chuckle around the campfire... while the new ones are back at the dealer awaiting repairs.... and sitting at home on the computer... missing the campout... whin'n at the factory QC ability....

They then actually help support the blog... looking for answers to fixing their probelms ...some right out of the factory.

Ever noticed that some new owners really do squeek when they walk... and wonder if its due to pain in the wallet.. medical issues or they are disguntal about spending more to get what they bought fixed as advertised... and don't want to admit it...
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Old 05-24-2018, 12:05 AM   #17
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Quote:
Originally Posted by uncle_bob View Post
Hi

I am in no way at all claiming that the stock converters are great stuff. All I am pointing out is that they do *not* boil batteries. They throttle their max voltage to *keep away* from boiling batteries. The stuff you are talking about is *because* they don't boost voltage / boil batteries.

So no, the stock chargers are not in the "boil battery" category, but there are a number of designs out there that are. If you start swapping around converters, be careful with what you grab and what you use.

Why is this worth harping about?

The problem is, people hear the "boil batteries" stuff, swap to a random converter and assume the problem is solved. It's not solved. The converter is not the root cause of the problem. It's pretty likely that their running the battery down to 2V every other week is the main culprit .... If they don't fix *that* problem, ( whatever the issue is ) they will be right back in trouble with a cheap new converter and some expensive batteries.

Bob
Indeed bob you have a good point here. if the bats are abused... no matter what converter your using.. you won't get good service ... I agree..

But....

The new tech converters are much better than the old transformer univolt system of yesteryear. They should be looked at and evaluated to see if they are something that will improve and extend the current battery life that has not been abused..

Most of the new converters .. such as the 4 stage ones (can't mention names but PD seems to come to mind) Are in fact going to give you better live out of your well maintained battery. They not only will charge faster and better but also will auto shift to maintenance charge so you won't boil the battery and cause damage. Then they have another feature that you found with the higher voltage... they equalizes the cell... we used to call it de-sulification.. but the new term is equalizing... where you actually DO want to boil the batter so that it will circulate the stratified chemical in the cell... thus instead of just the lower section of the plate providing the working current.. the whole plate now is doing it EQUALLY... (as they refer to).

However this part of the converter is timed.. so as not to boil the battery away.. it only goes into this stage for a set period of time ... thus not damaging the battery.

By doing this you actually can extend the bats life.. without abuse... and its done automatic'ly (in the case of PD once every 24 hours...for about 15 min) with the new high tech converters...

The current ones that A/S puts in their coaches.. is the typical one that you related to.. it provides steady lower voltage current so it doesn't boil the bat.. but then because the cell is not exercised... or brought up to 100% charge... it starts to sulfate... and dies a short life death.

So which is better.. my money is on the new tech that automatically takes care of the battery... and provides almost a maintenance free one for a longer more usable time.

Which is better ? if you don't maintain the bat... ? its a no brainer' answer their.. in my books.. neither one.
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Old 05-24-2018, 12:06 AM   #18
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NOTE: I think uncle bob is refer'n to 2 volts per cell... and not the whole battery being just 2 volts... (bob can you check me on that ?)
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Old 05-25-2018, 08:08 AM   #19
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Originally Posted by GM Airstream View Post
NOTE: I think uncle bob is refer'n to 2 volts per cell... and not the whole battery being just 2 volts... (bob can you check me on that ?)
Hi

Indeed, when the battery "shorts" it's only one cell. On a lead acid system, they each are roughly 2V. Three of them make up a 6V battery and six make up a 12V battery. Short one and your battery is suddenly a 10V battery.

One issue with talking about the "stock chargers" is that they seem to get lumped together. The Univolts were a *long* time ago. There have been several significant changes since they were a stock item. Using a Univolt as an example of what goes into a modern trailer ....not so much.

With any of the "boost" converters, they watch the current to decide what to do. That's great if you have no loads involved. The poor dumb converter (any converter) has zero knowledge of the 2A it is putting out going to the battery or into a load. The idea is that you keep from doing damage by cutting off the high voltage phase once the current drops. If the current never drops ( it's going into a load and not the battery ) you stay in high voltage mode *way* longer than you should. You also trigger high voltage mode more often. That stuff is what ( from the charger side ) boils batteries.

So what's to do? Well, you need to be pretty careful about what you put in. Work with a dealer you trust ( I most emphatically do *not* sell this stuff ). Talk to them about what is reasonable to put in. Do it when you *need* to ( like your converter died because of how they mounted the LM317 heatsink). Don't just do it for the entertainment factor.

Lots of fun !!!

Bob
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Old 05-26-2018, 04:06 AM   #20
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Originally Posted by uncle_bob View Post
Hi

One issue with talking about the "stock chargers" is that they seem to get lumped together. The Univolts were a *long* time ago. There have been several significant changes since they were a stock item. Using a Univolt as an example of what goes into a modern trailer ....not so much.

With any of the "boost" converters, they watch the current to decide what to do. That's great if you have no loads involved. The poor dumb converter (any converter) has zero knowledge of the 2A it is putting out going to the battery or into a load. The idea is that you keep from doing damage by cutting off the high voltage phase once the current drops. If the current never drops ( it's going into a load and not the battery ) you stay in high voltage mode *way* longer than you should. You also trigger high voltage mode more often. That stuff is what ( from the charger side ) boils batteries.

Lots of fun !!!

Bob
Bob...
Indeed... I guess I should not call airstream converters UNIVOLTS... but that is what the books said they were.. Ok I will call them old single voltage converters...as that is really what they become...

From what I have tested and seen the OLD conveters were set on one voltage... based on the transformer inside. So in effect they were single voltage non regulated converters.
Several issues came up... first being that if you shore power was 132 volts.. or even 125 volts you got different voltages at the battery that caused it to boil boil..all the time reguardless of the current load.... stability was not the best. Now if the shore power dropped to 100 volts.. you got less out of the OLD converters and never did bring the battery back to 100% charge. Not good.. lead to sulfation and early battery death.. because it didn't put out enough to recover the battery fully. Not to mention that the heater motor or other 12 volt items were now drag'n down the battery because it had to make up for the OLD converters lower voltage.

The new switching converters don't have that problem.. as by design they can go from about 100 - 132 volts AC in.. and will hold a set output that WILL charge the battery to 100%. So they can operate on a wider range of power inputs and still do the job.. unlike the OLD converters can't

Now about the over voltage current sensing current draw (boosting)
The one that I have now.. I did some testing on it... it goes from 14.4 to 13.6 and finally to 13.2 volts...
I put it in service... and indeed it did go to 14.4 volts right away... but without a load other than the battery... it dropped to the 13.6 volts within 20 min... after a period of time it went to 13.2 volts... (several hours).

Now I wanted to see if it reacted as you said... so we turned on the 3 vent fans... sure enough it jumped from 13.2 to 14.4 as we started pulling about 30 amps. but indeed the battery still was in charge mode.. and didn't have to supplement the current as the converter picked up the whole load...

another thing that we noticed was that even with the fans on... after several min.. the converter sensed a steady state load.. and dropped the voltage from 14.4 to 13.6 while still meeting the load demand.

Then we turned everything off... to see if the converter would boil the battery as you described... here is what we found...

The min that we turned off the load... the converter detected a load difference... jumped back up to 14.4 volts.. from 13.6 volts....but didn't remain their long... within 3 min the converter went to the 13.6 volts and then after another 10-15 min dropped back to the 13.2 volts.. which is the maintenance charge... and stayed their.. till we turned something on that had a higher current demand. It liked staying around the 13.6 volt in steady state load.

We did the test several times to see if the converter would stay at the 14.4 volts longer without a load... nada... each time it floated back down to 13.6 followed by a short time later (about 5 min) it dropped to 13.2...

So I would say it is current sensing... as you said... but, it doesn't stay their long enough to boil the battery... as the min the current demand stablizes or
drops.. so does it voltage...

We also have the manual override pendent... but haven't found a need to use it yet... it is supposed to help save time when recharging the bats on gen sets and the like...as it allows you to control the auto function manually...

I didn't have 21 hours to wait and see how the equalizing function worked. but from the provided chart it looks like it goes from 13.2 volts every 21 hour intervals for about 15 min at 14.4 volts then returns back to the 13.2 maintenance charge

We found that at any time you increase the load for the converter.. it starts the whole process over again from 14.4 then drops to 13.6 and after a few more min.. of light load... to 13.2 volts... don't know if it resets the 21 hour equalization cycle as we haven't stuck around to see if it does... grin...

So do you have to check the water in the battery.. YES... but it seems with the new technology 4 stage converters.. NOT AS OFTEN.. as it really doesn't boil the battey per se...

Others that we have talked too... who have also made the jump to the 4 stage converters like our PD 92xx say that they have gotten a lot longer life out of their bats... so long as they don't go below the 50% current rating (about 12.6 volts... or about 2.1 volts per cell...)

So the new technology converters ARE much better...
about the only thing we have seen in others... are that some are noisy electrically when used around sensitive things like radios...reception.... and computers that plug into the 12 volt system.

good to go..
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