Mixed batteries and surprised with converter/inverter

[outofcontrol]

My root problem is that the batteries won't run the heater for the night.

We bought this Excella in Feb 2013. It was sold by the owner's son, who made a lot of bad decisions, one of which was replacing just one battery. My first step was to see what size the batteries are, what date is stamped on them, check the charger and see what it is, etc. I did this when we bought it, but I was a little overwhelmed with the solar system and the control panel. I do remember reading somewhere on the converter that it was a 3 stage charger, and in my mind, that meant I could leave the trailer plugged in while in storage and not worry about the batteries. Not only are the batteries of different age, but different brands, and slightly different amp/hr ratings.

Note: My last AS was an 81 and when the batteries needed replacing, I upgraded to a Progressive Dynamics Charge Wizard 4 stage converter and two group 27 6 volt batteries in series. I did all the work myself, but that was 8 years ago, and my memory has faded. I only say this because I'm not a total noob. More like a sophomore noob.

So I went out to check everything out and I noticed when I was pulling out the newer battery that it was warm. The old one was dead cold. The old one had no date on it, but the new one said October 2012, which is only 18 months old. My assumption is that the converter is stuck sending out a charge mode and is never leveling off because of the old battery is not taking and holding a charge. This is over-charging and unnecessarily warming the newer battery. That's my assumption anyway.

I went inside and got down to the converter and it finally sunk in to me that this is also a 2000W Inverter! Yay. Didn't even know that. And it is indeed an Automatic 3 stage charger. At least that's what it says.


It is a model that's discontinued, but I did find the manual for it online. I'm also assuming it's not the original "battery burner" that Airstream put in in 1996.


I was planning on plopping down $$$ on a new converter and new batteries just to bring everything up to modern standards, but I think this unit will do. And it's a 100amp charger, so we're going to upgrade to group 27 Costco batteries for $87 each. That's the plan. The Costco (Kirkland) batteries are made by Johnson Control in Oregon. They also make the batteries for Interstate and Diehard, and supposedly the exact same thing. They do only have a 30 month warranty. And yes, there's about 6 inches of extra room in the boxes for the 3 inch longer group 27 batteries.

I have gotten up every day we camp and fired up the generator for the sole purpose of grinding coffee, then shutting it down. Last night I unplugged the trailer from the house power and pushed the "inverter" button and wouldn't you know it? I ground some coffee with 110v power from the battery via the inverter. Amazing. I didn't even know such a thing existed. A combo unit, moreover, didn't know we had one!


So here are my questions:
1. Is one battery warm because the other one is dead?
2. Is this Automatic 3-stage combination Converter a good one?
3. Once I get new matching batteries, can I just leave it plugged in for months at a time? or is it not that "Automatic".
4. There's a phone cord going to one of the battery boxes labeled "TSC" (pictured above). It's not plugged into the battery at all. When I saw it upon purchase from the outside, I just thought it was for a phone hookup. I couldn't find it in the manual, but what is this for? Is it a temperature sensor compensator? I've read Lewster lecture over and over how important it is for the charger to compensate the charge based on temperature. That would be cool if it is.

Thanks in advance,
-Kevin

[Jammer]

Originally Posted by outofcontrol

My root problem is that the batteries won't run the heater for the night.

Common problem

My assumption is that the converter is stuck sending out a charge mode and is never leveling off because of the old battery is not taking and holding a charge. This is over-charging and unnecessarily warming the newer battery. That's my assumption anyway.

Converters cannot read the mind of a battery. They only "see" the relationship between charge voltage and charge current.

It is a model that's discontinued, but I did find the manual for it online. I'm also assuming it's not the original "battery burner" that Airstream put in in 1996.

The Heart Interface Freedom is the predecessor of the Xantrex inverter-chargers, and is a good product. Some might say that the Heart Interface inverters were better made than the Xantrex ones are today, but who knows. Anyway, I doubt very much if it was installed by the factory.

And it's a 100amp charger, so we're going to upgrade to group 27 Costco batteries for $87 each. That's the plan. The Costco (Kirkland) batteries are made by Johnson Control in Oregon. They also make the batteries for Interstate and Diehard, and supposedly the exact same thing. They do only have a 30 month warranty. And yes, there's about 6 inches of extra room in the boxes for the 3 inch longer group 27 batteries.

Good choice.

Be aware though that just because the batteries are the same size and rating and come from the same factory as Interstate does not mean that they have the same internal construction or are of identical quality. Perhaps they do, and indeed I've seen battery wholesale operations where they warehouse a bunch of batteries and apply any of a dozen self-adhesive label sets to them as they go out the door depending on what brand they need to ship that day. But it's not a guarantee.

So here are my questions:
1. Is one battery warm because the other one is dead?

At this point they're probably both shot. Typically a battery gets warm because it has a shorted cell. Unless it's caught right away, the battery in parallel with the one with a shorted cell will be damaged too because it will discharge through the shorted cell and then sit for days/weeks/months in a discharged state.

2. Is this Automatic 3-stage combination Converter a good one?

Yes IMO.

3. Once I get new matching batteries, can I just leave it plugged in for months at a time? or is it not that "Automatic".

Yes, if it's working the way it should and it's not too hot out (unless there really is a temperature compensation probe connected). Check the battery electrolyte level regularly, especially at first and in hot weather, until you're confident it doesn't drop. I would start checking once a week and then every two weeks, every month, etc, until I saw a noticeable drop.

4. There's a phone cord going to one of the battery boxes labeled "TSC" (pictured above). It's not plugged into the battery at all. When I saw it upon purchase from the outside, I just thought it was for a phone hookup. I couldn't find it in the manual, but what is this for? Is it a temperature sensor compensator? I've read Lewster lecture over and over how important it is for the charger to compensate the charge based on temperature. That would be cool if it is.

Probably. A photo of the other end would help. Typically temperature probes have a metal ring at the end so that they can be put under one of the nuts on the battery terminals, which allows a more accurate measurement of battery temperature than just leaving it dangling in the battery compartment.

If it's really charging at 100a then that's too much for a pair of group 27s. Usually the maximum charge rate is configurable. You would want it somewhere between 1/4 and 1/5 of the amp-hour capacity of your battery string, probably around 40 amps for two group 27s.

[idroba]

Jammer's advice is sound.

[outofcontrol]

Thank you so much for the detailed reply. Makes me feel a lot better about all of this. Batteries can be such a mystical subject sometimes.

Originally Posted by Jammer

Converters cannot read the mind of a battery. They only "see" the relationship between charge voltage and charge current.

I need to educate myself better to understand this statement.

Be aware though that just because the batteries are the same size and rating and come from the same factory as Interstate does not mean that they have the same internal construction or are of identical quality.

Agreed. The manager at Costco I talked to was very convincing about the quality of the batteries. He had been involved in the choice, and toured the factory only 30 min from us. He told me it's a matter of a different plastic color and sticker. Same manufacturing line. Even if they weren't of the same exact quality, I'd still buy them. Costco is so amazing when something goes wrong. They just make sure you're happy.

Probably. A photo of the other end would help. Typically temperature probes have a metal ring at the end so that they can be put under one of the nuts on the battery terminals, which allows a more accurate measurement of battery temperature than just leaving it dangling in the battery compartment.

Will get this picture today. I think the other end is wrapped in electrical tape. I'm also going to comb through the manual again and see if I can find info about it. The manual I found was for a variety of models and somewhat generic about features.

If it's really charging at 100a then that's too much for a pair of group 27s. Usually the maximum charge rate is configurable. You would want it somewhere between 1/4 and 1/5 of the amp-hour capacity of your battery string, probably around 40 amps for two group 27s.

I'll also check into this. 100a is just what it says on the tag. I thought I read something about 1/4 the amp-hour in the manual and some dip-switches somewhere, but I was speed reading and didn't see dip switches on the case.

Thanks again for all the comments that I didn't address. I fully digested them and really appreciate the feedback. I'm going to buy the Costco batteries, and I will monitor the condition carefully at first. We have some time before our first big family outing for Memorial Day weekend. She's been out 4 times this winter and no heat in 34F weather is not fun for my 1yr old niece who likes to kick off all her blankets.

-Kevin

[87MH]

IF you camp a lot, you may want to consider a Lifeline AGM battery.


They are pricey, but for a reason. I installed a single Lifeline 27 T in 2008, it's coming up on 6 years and, like the energizer bunny, still beating it's drum.


See post #70 in my '78 31' Sovereign signature thread.


Lifeline's can be purchased (at least in the past) from 2 well known members of the Forums, 68 Overlander and Lewster.


If and when it ever craps out it will be replaced by at least one, if not two Lifeline AGM 27T's. Money well spent.

[ventport]

If you found the manual on line, why not look up what it says about the TSC plug?

[Bruce B]

I have one comment/question. Although Jammer is correct in his assessment of 100 amp charge current vs your battery bank size my understanding is that the actual internal battery chemistry will limit the charge current itself. In a healthy battery powered 12 volt system you can not "manage" this current beyond controlling the voltage. In other words, although technically speaking the charger is too large for the battery bank and thus not an efficient purchase in terms of dollars it will only provide the current the bank can absorb. If you are in fact seeing 100 amp output something is amiss!


The other thing I wanted to touch on was that AGM batteries (Lifeline) can easily accept up to 50% of their 20 hour rating in charge current during the bulk phase of the charge. You may want to consider taking better advantage of the output of that charger if in fact it has settings for AGM batteries.


Bruce

[outofcontrol]

Originally Posted by ventport

If you found the manual on line, why not look up what it says about the TSC plug?

The manual I found is not an exact match. The unit is slightly different from the illustration, and there's no mention of the TSC plug. I'm guessing the manual I found is an earlier version of the same model. On that note, I can't find a plate on the unit that even has the model number or serial number or anything. Unless it's on the bottom? I'm not really interested in unbolting it just to find out. I haven't called

There is indeed a ring on the end of the line, and it does look thick enough to have some sort of temp probe in the shrink wrap.

I hear a lot of suggestions to go with AGM batteries. Last time I did this dance, I concluded that there wasn't enough benefit to justify the cost. Double the cost doesn't mean double the performance or life. I personally think that the consumer that springs for the AGM battery is naturally more interested in and inclined to seek better battery performance, and takes care of the battery system better in general. I believe its like a self-fulfilling prophecy. I honestly would rather buy another set of new batteries in 5 years than hope my 2x$ batteries will last 10 years. But that's just me. We might not even have this RV in 10 years.

We 100% camp, boondock style. Maybe I am taking the cheap road on the batteries. By nature, Airstream owners should buy the best batteries because they have the best RVs right? Oh well. I'm bucking the trend.

-Kevin

[outofcontrol]

I did some more searching, and although my unit says Freedom Combi, it's more like the Freedom 458 unit. That one looks the same except for breakers on the unit, has all the same lights, buttons, and features. There's even mention of the TSC, and what it's for. And yes, there's instructions on how to set the unit to the specific battery type as well.

Now that I have the right manual, I figured out this is really a 4 stage charger. Bulk, Acceptance, Float, and Equalizing. And yes, it will only apply as much current as the battery(s) will take.

All this discovery is making me pretty excited about what we have. I guess if the batteries only last 2 years, I'll upgrade to some better ones next time.

-Kevin

[J. Morgan]

If it makes any difference on the AGM batteries, I have in the past few years been disappointed by one brand of AGM batteries, then moved to a different "better " brand to be disappointed again.

I am now a lead acid battery man, half the cost and in my experience they last at least as long.

There is nothing I despise more than paying premium price for a product that ends up providing substandard longevity. (I have a "list"among the entries are AGM batteries and Holley fuel pumps. . )

I can't say if my experience is typical, but I bought six or seven brand A batteries, and three of brand B batteries. That was enough to get me over my "gadgetitis" regarding AGM batteries, I think I will stick with the proven old design for a time.

When there is disappointment, I prefer the cheaper version.

[outofcontrol]

I appreciate your point of view.

There's no doubt in my mind that the AGMs are a better battery. I'm sure they'd perform better. I just don't think they're 3.5 times better. ($89 vs $309)

I'm still just excited that I have a 2,000W inverter that I didn't realize I had. Although now I have to explain to my brother-in-law's wife exactly the opposite of what I said about 110v and 12v and when we can use them.

-Kevin

[J. Morgan]

I asked myself what is it that makes a battery better?

The fact that AGMs don't really out gas is a point that makes them better for sure.

I suppose I was expecting longevity for the price I paid for these batteries, I didn't get it.

Sure there are posters on here who have gotten 8 and 10 years out of their AGMs, and I have seen posters here who have gotten 8 and 10 years out of their lead acid batteries. I believe both accounts.

On average , I have gotten better life from lead acid batteries. The first two brand A batteries lasted about what I would expect from lead acid batteries, the others were miserable failures.

This is simply my honest experience, I might be a little bitter about the whole thing..........

[Jammer]

Originally Posted by Bruce B

I have one comment/question. Although Jammer is correct in his assessment of 100 amp charge current vs your battery bank size my understanding is that the actual internal battery chemistry will limit the charge current itself. In a healthy battery powered 12 volt system you can not "manage" this current beyond controlling the voltage.

There is no guarantee that the current will remain at a safe level particularly with newer batteries and higher ambient temperatures. Excessive charge currents can lead to thermal runaway and battery explosions.

[Jammer]

I agree with J. Morgan that, for Airstreams, AGM batteries don't offer useful advantages commensurate with their cost.

They are useful in situations where it is not practical to check the electrolyte level. By way of example, some motorhomes in the 1980s had a battery under the center of the chassis between the frame rails, that was only accessible from below by crawling under the vehicle, removing two bolts, and lowering the battery and the base of the compartment with a floor jack or by brute strength. I'd use an AGM.

They are also useful in situations where the battery may be inverted causing the electrolyte to be spilled.

Finally, some people use them in situations where there is no practical way to provide venting, though this is controversial since AGMs may vent in the event of component failures.

There is no data to support the claim that they last longer than flooded batteries of otherwise comparable quality and identical operating conditions, except in high-vibration environments.

[J. Morgan]

By the way, it looks like you scored an A with that converter. I might envy it.