Replace House Batteries (Magnum Inverter)

[MILATV]

Lewster (or anyone experienced in upgrade/repair of batteries).

So after charging 48 hours I'm going to unplug and see how the batteries hold up (I figure 1-2 hours with inverter & fridge as only load based on prior experience). So should confirm batteries are toast. Dealer (Dayton where I bought the unit, 4 hours away) has said that they would take a look at them, but wouldn't guarantee they'd replace them if bad (I've had the unit - and this problem for a year now) and since it is cheaper for me to buy new batteries ($299 cost each) than to drive to Dayton and deal with service department. I'll probably be doing that.

QUESTION: While I'm in there what all should I do to this thing to make it operate the way it should? I got a temperature sensor for the Magnum, but haven't installed, it yet; but figure while the batteries are out I might as well get the electronics working the way AS should have configured things from the factory.

Should I go back with GPL24T; or is there a better long term solution that won't require major overhaul to charger / inverter, etc.

We use LiFePO 4 batteries in some of our military applications and they are amazing, but expensive (and require a special conditioner/charger) but open to adding more capacity if it doesn't kill my pocket book or my weekend

Your advise?

- replace batteries
- install temperature sensor
- ??? replace / upgrade panel in cabinet? to what?
- ??? install 2nd Propane switch in cabinet (really want to do this, what size wire? can I just put it inline on one of the two wires running to existing switch?)
- any other stuff easier to do while the batteries are out?

[c21]

I guess I am fortunate in that my coach was a factory order and I picked it up from the dealer a couple days after he received it so he didn't have time to run the batteries down. I did install the temp sensor for the Magnum and my coach has always been in the sun or plugged in to shore power and as a result my batteries appear to be in perfect condition and stay at full charge. They have never been below about 65%. From my experiance, with my 13 month old coach, I would install the temp sensor, replace the batteries then keep the coach plugged in. I also had my dealer install an interior propane switch in line with the outside switch and what a convenience that is.

[73shark]

Since the propane valve uses less than one amp, 16 ga wire will be more than adequate. Someone on the forum found the wire leading to the outside switch somewhere in the curbside wheel well bundle so did have to pull wire outside.

[fonman]

Inline is fine. For grins I installed a pilot light next to the new switch. Annoys my wife so it gets turned off.

Murphy tends to get involved, but if you can keep the new batteries from accidentally running dead you should get plenty of service life without anything fancy.

The folks that had our 2013 did not realize that it is a hard click to turn off the fridge. Between the fridge on and the propane switch......it was just a matter of time.

[paullovern]

Milatv:
We replaced our house batteries with lifeline 24t (2). I bought them from a battery seller in Texas via internet. Prior to replacement the old ones wouldn't hold a charge. We had ground power connected for two days and when we disconnected and traveled they wouldn't last through lunch.
In a edition to the batteries, I upgraded the Airstream supplied remote with a magnum ARC50 remote we also added a BMK battery monitor kit and an AGS auto generator start. All of these three things were purchased via amazon. Also, one key step is to set the "low battery cutoff" setting so the house batteries are disconnected when they are discharged more than 50% this prevents the degradation that you current batteries suffered.

[MILATV]

Originally Posted by paullovern

Milatv:
I upgraded the Airstream supplied remote with a magnum ARC50 remote we also added a BMK battery monitor kit and an AGS auto generator start. All of these three things were purchased via amazon. Also, one key step is to set the "low battery cutoff" setting so the house batteries are disconnected when they are discharged more than 50% this prevents the degradation that you current batteries suffered.

I like the auto generator start idea. I found some if the items on amazon, do you mind sharing exact items?

Also; what is the main advantage to ARC50 over stock remote.

Thanks.


Mike

[paullovern]

Mila:
The three units together allow you to control and monitor your battery charge using the SOC ( state of charge) rather than voltage. The ARC50 allows you to see the SOC and set the AGS parameters. The AGS really facilitates boondocking by keeping the batteries charged without much intervention. If your installer installs the BMK correctly, it will keep track of the energy provided to the batteries by the engine charger while driving. All of my control parameters are based on the SOC now. If you're interested, i will send the link for the battery seller in texas. Here is the link for amazon package.

http://www.amazon.com/Magnum-Energy-...Cdub18YKRBB_tt

[toskeysam]

@Paullovern...I am curious where you located the shunt for your battery monitor. I am in the process of relocating mine. The installer put it in the negative line from the inverter to battery.....obviously not going to work there since it cannot see the other loads going through the chassis bus(es). It appears mine is headed to the inside of the battery box, when I get back to the unit.

[paullovern]

Mila,
Basically the negative side of the batteries need to be isolated from the chassis and connected only for through the shunt. To accomplish that, I had to enlarge the hole in my battery box to accommodate a "firewall connector" that connects wires inside the box to wires outside the box but isolates the circuit from the box itself.

[paullovern]

Mila,
Oops, hit the send button too early. The firewall connector can be found on amazon (Moroso 74145 black, thru panel connector). Also, you should contact Darren Massey at Magnum. He was exceptionally patient with me and helpful. (Dmassey@magnum energy.com).

[paullovern]

Sorry toskeysam, I missed you as the sender.

[MILATV]

Finally pulled my batteries for replacement and this is what I've got

Does anyone know if bulging sides is normal for lifeline? . Had to wiggle them side to side just to get them out of the battery box.


Mike

[73shark]

I'm guessing that a swollen battery is not good. Bet Lewster can tell you more definitive.

[paullovern]

Mine were swollen as well when we replaced them. I was told that it comes from freezing and they are more apt to freeze when they are discharged. Do you have the AI in a climate that freezes?

[Protagonist]

Actually, AGM batteries can become swollen from charging them too quickly, which causes overheating. The plates in the cells get warped, which causes the sides to bulge.

I don't think it's the fault of your Magnum inverter. In fact, I'm inclined to lay blame on the engine alternator, which is using a single voltage regulator to charge not only the Group 49 chassis battery, but also the Group 24 house batteries through the BIM. You know how they always say not to mix battery sizes in a battery bank? Well, the engine alternator sees all three batteries as a single bank when the BIM has the two systems interconnected for charging, and it doesn't charge the batteries proportionally with their capacity or state of charge.

[mefly2]

+1 with Paul...

[Protagonist]

According to the Lifeline Technical Manual (http://www.lifelinebatteries.com/manual.pdf) an AGM battery is very resistant to freezing temperatures:
100% charge, freezes as -94°F
75% charge, freezes at -53°F
50% charge, freezes at -13°F
25% charge, freezes at +9°F
0% charge, freezes at +21°F
So unless you winterized your Airstream Interstates with less than a 50% charge— which is I don't think you guys are so careless to have done— the electrolyte in the batteries shouldn't have frozen. Even though freezing temperatures may cause the electrolyte to expand, you guys shouldn't have experienced temperatures cold enough, for long enough, to let the whole thermal mass of the batteries get that cold.

I still think the culprit is overcharging, probably from the engine alternator, which would have bypassed the Magnum inverter/charger entirely.

[MILATV]

The van is outside in Decatur, IL; and we had some snow this year, so YES, but the van was plugged into 30A power so they 'should' have been at full charge all winter.

[MILATV]

Originally Posted by Protagonist

I still think the culprit is overcharging, probably from the engine alternator, which would have bypassed the Magnum inverter/charger entirely.

Which is why Airstream should by me new batteries for saving $20 and not installing the Magnum Battery Temperature Sensor - costing me nearly $600 for batteries.

Amazon.com: Magnum MEBTS15 Battery Temperature Sensor with 15' Cable: Automotive

(I have mine to connect when I put new batteries in).

OF Course if overcharged by the ALTERNATOR then that is a whole other issue - how do I resolve that from happening again? I can't control what it does - can I?

[Boxster1971]

I don't think the lack of temp sensor or the MB alternator are likely source of overcharging.

I looked up the charging voltages vs temp in Lifeline manual. The necessary charging voltage goes up as temp drops. So without the temp sensor the Magnum charger would not overcharge in cold winter weather. If anything they would be undercharged in cold weather.

According to the PCI BIM manual the BIM is designed to prevent overcharging of the coach batteries during long drives. The BIM relay does not close to charge the coach batteries when engine is running until the coach batteries are below 12.6V. Then it shuts off after an hour of charging and won't turn back on until coach batteries are again below 12.6V. If anything the BIM undercharges the coach batteries.

I recommend you check with your Airstream dealer and with Lifeline regarding these bulged batteries.


- - Mike
2013 AS Interstate on 2012 MB Sprinter