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Interstate vs Lifetline AGM

Yahoo Message Number: 95601
Bought 2 Interstate batteries 8D AGM here in N. CA. While on a trip through Louisiana, my Interstate batteries were one year and one month old. Both batteries failed. There was no replacement or warranty on them. At $550.00 each, I will never use Interstate batteries again.
Bud

'94 Affinity

Re: Interstate vs Lifetline AGM

Reply #1 –
Yahoo Message Number: 95612
Bud, I do not know Interstates as I am in the UK, but I do know Lifeline, I have 1800 amps on the boat. I have not bothered on the coach as we only visit campsites. However, AGMs are very particular in the charging algorithm, it is important that you get the details from the manufacturer, it is important that you have battery temperature sensing, and volt sensing at the battery bank. The charging regime, assuming you have a good 3 or 4 stage charger, will then be properly compensated for temperature, this makes a big difference. AGMs are great in 2 respects, they can take a massive power out so using an inverter for short burst high power stuff is OK, also they take a massive power in, I think something like 2 or 3 times the battery amp. So you can get them charged up quickly. But like lead acid batteries once you get to 80% or so the last 20% takes a long time.
The problem is that many people do not recognise the need to get the batteries to 100% as regularly as possible, and that means without load the float amps in are around 1 amp, if you are only getting to 80-90% or so then going into a discharge cycle again, and or regularly discharging to low levels, i.e. below 50%, you are killing them, fast. For batteries to fail in one year suggests some abuse to me, and unfortunately this can happen out of ignorance, no critisism of you specifically intended, rather than just disregard for good practice.
Lifeline has some good documentation on their site which helps to give an insight into battery management.

Michael

2008 Allure 31683, in the UK!

Re: Interstate vs Lifetline AGM

Reply #2 –
Yahoo Message Number: 95614
Michael, I had Lifelines as my house batteries for 6 years of heavy boondocking for half the year and I loved them. I agree with what you say, but I need to point out that boats aside, the ability of AGM's to accept a massive charge is irrelevant to RV applications since none of the charger/inverters we have are capable of delivering such a charge. To my knowledge, the most that a Xantrex or a Magnum can deliver is about 130 DC amps, and that is assuming it is not dealing with other DC loads which it always is. I have very recently switched to Trojan 6V flooded for the first time. My Freedom 3k seems to kick in about the same bulk current (over 100 amps) as it did my Lifelines, I am not certain, but my impression is that the Lifelines charged up more quickly. If so, that is relevant since it translates to generator time and $$ of diesel. My initial impression, all this aside, to put it simply, is that the Trojans are at a higher voltage in the morning than the Lifelines. They seem to kind of settle in around 12.2 volts and just stay there for a very long time where my Lifelines would keep on dropping down. I only have about 10 cycles on my Trojans. As far as heavy burst draws, I was not aware that flooded deep cycle batteries have a problem doing that. I thought that is what they were designed to do.

Rich 2002 Magna

Re: Interstate vs Lifetline AGM

Reply #3 –
Yahoo Message Number: 95621
Rich,

Firstly to deal with charger output. It says on the box, 100, 130 amps whatever, but this will be at a particular voltage, normally circa 12 volts. Not normally quoted you have to press the manufacturers for spec, I know from experience based on the following. Bulk and absorption amp charge are, depending on temperature, up in the 14 volts region,. there is a corresponding reduction in maximum amp output as the volts have increased. So on a 130 amp charger you will never see 130 amps and 100 amps is about right. So your AGM could not get more than 100 amps although it may have been capable to take a lot more. The reason you would see AGMs charging still quicker in this circumstance is that the AGM will hold bulk and absorption a lot longer so therefore filling the tank at the fastest rate for longer, so to speak.
So the AGMs will enable you to run the generator less for more increase in SOC.
As to charging in boats the chargers are very similar, but I have a couple in parallel which doubles the available amps in and gives me 6kw of inversion, needed for some high start up load bits of kit.
Heavy loads on a wet battery will cause the liquid to boil and plates to buckle over time.

Michael

2008 Allure 31683

Re: Interstate vs Lifetline AGM

Reply #4 –
Yahoo Message Number: 95623
My RS 3000 in bulk charges at 13.8 volts and 145 amps with 1000 amp hour AGMs. Bob 06 intrigue 12047

Re: Interstate vs Lifetline AGM

Reply #5 –
Yahoo Message Number: 95627
Michael,

If I understand what you are saying about charger output correctly I disagree. Our smart chargers will output full current for the full bulk charge cycle. Here is how I suggest that people should think about three stage charging. The following numbes represent most wet cell batteries but are different(but not very different) for AGM or gell. Also my assumption is that the battery bank is of sufficient capacity to utilize the full capacity of the charger.

Bulk charging is constant current, increasing voltage. In this phase, a deeply discharged battery is at about 12.0 volts. Taking my Prosine 3.0 as an example, it will start it's charge cycle at 125 amps and about 12.8 volts. Over time the amps will stay the same until the charger reaches about 14.5 volts(depending on temperature) at which time it enters the Absorption stage. The battery is now about 80% full.

Absorption stage should be thought of as constant voltage, decreasing current. In this phase the voltage will hold at about 14.4 volts while current will taper from maximum down a minimal level of current at which time the battery is full(or at least 95% full) and the charge will switch to float stage.

Float stage is constant voltage, constant current. Voltage will drop to about 13.4 and current will taper to a trickle.

My point in all this is to emphasize that a good three stage smart charger, which all CCs have, should put out maximum current throughout the bulk charging stage if your battery bank is big enough to accept that level of charging.

If I misunderstood what you were saying, my apologies.

George in Birmingham
'03 Magna 6298
George in Birmingham
2003 Magna 6298

Re: Interstate vs Lifetline AGM

Reply #6 –
Yahoo Message Number: 95637
George has it exactly right and that is exactly what my Freedom does. And my Link 2000 and Blue Sky Pro show about 100 amps at bulk. Steady until it reaches 14.8 volts and switches to accept. It is interesting, my Silverleaf shows 130. I assume that the other 30 amps are going to other DC loads (such as the Hurricane, lights, etc.).
Michael, I see the SW has 20 more amp capability. I stand corrected. But you could kick 250 amps into your AGM's, I believe. With Trojan flooded, you need to charge at 14.8 v at 77F. My old Freedom 458's flooded cycle is too low at 14.4. When boondocking I turn off the temp comp and tell the Freedom it is either 30 or 40F and it raises the voltage to 14.8-15. It takes about 2 hours when my 675 bank is down 50 % to take it up to 90 or 95 percent. Solar finishes it, also at 14.8 volts. That takes another 2 hours or less depending on sun.

Rich 2002 Magna

Re: Interstate vs Lifetline AGM

Reply #7 –
Yahoo Message Number: 95643
Michael,

Your technical knowledge is impressive. The intent of my statement is that both Interstate batteries failed. The mechanic said they were internally shorted. The gist of it all, is that after spending over $1.000.00, and Interstate's warranty for them only being 6 months, I would never buy Interstate batteries again. It was never a question of why they failed, they just were not warranteed for over 6 months. For over $1,000.00. I would have liked better customer service.
Thank you all for your intelligent input.
Bud

'94 Affinity

Re: Interstate vs Lifetline AGM

Reply #8 –
Yahoo Message Number: 95644
George, In simple terms I agree that there is a rise in voltage at the start but a very short time and I did not mention it as it was not generic to the point I was making. But a couple of things from your post. I am surprised that you get 125 amps from your PROsine as they are only rated at 120 amps max, according to the web site data sheet? Perhaps Xantrex have their Prosine 3.0 amp rated at 14.4 volts, I would be interested to know as it is highly unusual. And whilst you see full on AMPs at the start of Bulk this does tail down before entering Absorption. That aside the principle of the charge is as you describe, the difference we have is on the AMP output v voltage output. I will try and find the document I have on this and get back on here with it.

Michael

2008 Allure 31683