Batteries replaced for free, 22 months replacement remaining

Camper_Jeff_&_Kelli wrote:

...
Odyssey and Lifeline promote differing recommendations on how best to maintain their batteries. The Boondocker power supply appears to adhere more to the Lifeline standard
....
Jeff

If this Boondocker is the one you are reading from, you need to look at the chart on page 2. The middle stage 2 - absorption, which they call normal, is 13.6V. That is not enough Volts per the manuals you read.

I doubt that 13.6V would do anything useful on a cold AGM. My solar controllers hit 15V in absorption around freezing. In summer, I have seen as low as 13.37V. I trust my solar chargers enough to leave them unattended.

I recently STFW for a charger that I would trust to leave unattended on my AGMs. Boondocker missed the cut. I did find two, a Xantrex Truecharge 2 and a Samlex.

Can you go into more detail for your solar controller(s) charging profile?

HTH;
John

Finished reading,
Lifeline
Best Converter
and
Odyssey
Manuals.
Lifeline says at 77 degrees F Absorption is at 14.3 volts and Float is at 13.3 volts.
Odyssey and Lifeline promote differing recommendations on how best to maintain their batteries. The Boondocker power supply appears to adhere more to the Lifeline standard.
A charger senses the state of charge the batteries have and will charge accordingly to the present state of charge. My charger has rarely gone into the bulk charge mode but has gone into the absorption mode, then dropped to the float mode. My solar panel provides daily bulk mode voltage of 14.6 but will only supply up to 3.6 amps current. As the state of charge of the battery comes up to the value of whatever state of charge mode the converter is operating in, the current will drop to the next lower mode as the voltages become equal. As the voltages become equal, the converter senses that and drops the charge mode to the next lower state. Bulk to absorption, absorption to float, then a steady state of float with an occasional 15.6 boost or equalization/desulfation mode charge, then a drop back to float.
Lifeline states an AGM is considered fully charged if the open circuit voltage is 12.8 volts or higher after a 4 hours rest from charging.
There are lots of voltage and current numbers being stated but the main objective is to keep from discharging your batteries too deeply, not exceeding a drop to 12.2 or 12.0 on occasion and then to restore batteries to full charge as quickly as possible after discharge. A discharged battery will not always require a bulk charge and the converter will sense that. The amount of charge is a function of the internal resistance of the battery and the state of charge voltage. The lower the battery voltage, the higher the charge current can be applied. The new smart electronics make all this automatic.
To recover a dead battery, you apply a 15.6 bulk charge for at least 8 hours or until the charge current drops to .5 amps then apply enough voltage to the battery to maintain a 5 amp charge current which will require a steady escalation of charge voltage to keep the current flow at 5 amps and you apply the 5 amps over charge voltage current over a 4 hour period keeping a safe temperature watch over the batteries undergoing the procedure.
The main thing is to achieve a static rest voltage of 12.8 or a little greater voltage and that means your AGMs are at 100% charge.
Jeff

Mark;

I use a P-4 as a starting battery and as a possible backup for AHs.

I agree with your analysis that the batteries were not properly charged. The same short life of the warranty set is inevitable unless the charging systems are improved.

AGMs need the 14.4V temp compensated during stage 2 - Absorption, not the 13.6V that many chargers use. I rely on my solar chargers to use 14.4V with temp compensation to get the batteries ready for stage 3 - float. AFAIK, the Boondocker has the 13.6V problem, as do most converter/chargers. 13.6V is an upper range float for AGM specs.

The Enersys(Odyssey, Sears P-?) line of AGMs tip the scale towards high draws over long low draws as far as service category. Their C20 AHs are way under 10% of their CCA ratings. They are popular with the boombox car radio folks(Ick!) for their instantaneous Amps.

IMHO, Deka, Lifeline and Trojan are better for RVing with adequate low draws along with useful potential for high draws.

On a price basis, it is hard to beat the 6V and 12V 100AH AGMs which are now found for $169 at the club stores.

HTH;
John

Hi Jeff
Check out "procedure 2" on page 13:
"Charge the battery for 24 hours using a constant current charge that is 5% of the 20-hour capacity of the battery (5A for a 100Ah battery). The charger should be able to provide a driving voltage as high as 18.00V. Monitor the battery temperature; discontinue charging if the battery temperature rises by more than 20°C."

A termperature probe is a very good idea, but the battery warmer is unnecessary unless you are camping in near (or below) freezing temperatures. Batteries should not be heated during storage.

The open cell voltage is one data point, but its not sufficient info to make a diagnosis... and of couse there's no way to measure SG. As I mentioned previously, it is my opinion that given your low-current (& low voltage) charging sources, you will never get those batteries to 100% SOC. Continued use and storage in a discharged state will lead to reduced battery life.

As a point of reference; When camping by batteries get a daily charge to 14.7V until the current drops to .001C (300mA). The batteries now are 3 years old, I have done many hi-current discharges (with data logging) and I'm not able to measure any loss of capacity.

Keep us posted.
Cheers,
Mark

msiminoff wrote:
Hi Jeff,
It's awesome that Sears was happy to replace the batteries for you under warranty. I often recommend the DieHard Platinums for exactly that reason (plus the nationwide availability).

However those EnerSys batteries are very hard to kill (I have been abusing mine for a long time!)... and based on the description you provided I suspect that root cause of the issue is related to the charging, and not the batteries themselves. In other words; I think that the batteries were simply discharged, not defective. For starters, your charger (and solar panel/controller) are small considering your 200Ah of AGM's. At the voltage you stated (13.2) the batteries would never have reached 100% SOC. They should have been absorption charged at 14.7V and should have been float charged at 13.6. In addition if they had been fully charged and then disconnected when you parked the TC for the winter those AGM's would have a storage life of more than 2 years.

The test that Sears conducted is so far outside of EnerSys's charge & testing protocol that it's laughable... and a 4 minute charge (regardless of current) is followed by a high current discharge is meaningless.
EnerSys has specific guidelines for charging deeply discharged batteries and states that a group 31 battery should be charged at 5A for 24 hours and the voltage should be allowed to rise to as much as 18.0V (the Boondocker can't do that)... then the batteries should have been removed from the charger for 18 hours before capacity testing.

Anyway, now that you have fresh batteries I suggest that you download the TECHNICAL MANUAL from EnerSys and review the information in the charging section. If you are hoping to get many years of service and high capacity from the Platinums, you may also want to consider a larger and more configurable battery charger and solar controller.

Cheers,
-Mark

Hi Mark,
I'll read through the manual.
I read the manual and it states to use a charging power supply capable of up to 18 volts but not to actually charge at that voltage. They imply to use an absorption charge at 14.7-15 volts, then let it drop to 13.6 volts, then to a float of 13.2 volts.
When I took the batteries in to SEARS, they had been charging for a while since the PNW Rally and the solar took them up to 14.6 volts each day at low current. I removed them and placed them in my truck where they sat a couple days. They measured 13.7 volts each a couple hours after removal. I did not measure the voltage again before testing and replacement at SEARS.
I read a bit about Lifeline and they recommended desulphation or restoration from deep discharge charging at 15.5 volts for 8 hours per battery. I did that and it seemed to help but the batteries still only lasted a couple hours before suddenly dropping to 10.2 volts. It seems to me that that is about the voltage of one bad cell in each battery giving out.
All my reading on AGM batteries so far suggests 14.6-14.8 volts absorption, 13.6 acceptance, and 13.2 float charging. I don't know that they require an infrequent equalization charge. When the TC is on the truck, I have 4 AWG wire directly from the alternator to the TC batteries usually charging between 13.2 and 13.8 volts but have measured 15.2 volts for a few minutes. The 45 amp boondocker is supposed to sense what the batteries need and apply that voltage. Since they had 12.9 volts off the shelf when I installed them today, the 13.2 volts the Boondocker applied seems correct to me. The solar panel and controller will apply up to 14.6 volts at up to 3.6 amps tomorrow. That should bring the batteries up to full by most standards I've read thus far. Applying a battery warmer blanket for optimal battery temperature and remote temperature sensors on the batteries would be the next step for accuracy in charging.

We'll see what happens.
J

Hi Jeff,
It's awesome that Sears was happy to replace the batteries for you under warranty. I often recommend the DieHard Platinums for exactly that reason (plus the nationwide availability).

However those EnerSys batteries are very hard to kill (I have been abusing mine for a long time!)... and based on the description you provided I suspect that root cause of the issue is related to the charging, and not the batteries themselves. In other words; I think that the batteries were simply discharged, not defective. For starters, your charger (and solar panel/controller) are small considering your 200Ah of AGM's. At the voltage you stated (13.2) the batteries would never have reached 100% SOC. They should have been absorption charged at 14.7V and should have been float charged at 13.6. In addition if they had been fully charged and then disconnected when you parked the TC for the winter those AGM's would have a storage life of more than 2 years.

The test that Sears conducted is so far outside of EnerSys's charge & testing protocol that it's laughable... and a 4 minute charge (regardless of current) is followed by a high current discharge is meaningless.
EnerSys has specific guidelines for charging deeply discharged batteries and states that a group 31 battery should be charged at 5A for 24 hours and the voltage should be allowed to rise to as much as 18.0V (the Boondocker can't do that)... then the batteries should have been removed from the charger for 18 hours before capacity testing.

Anyway, now that you have fresh batteries I suggest that you download the TECHNICAL MANUAL from EnerSys and review the information in the charging section. If you are hoping to get many years of service and high capacity from the Platinums, you may also want to consider a larger and more configurable battery charger and solar controller.

Cheers,
-Mark

Artum Snowbird wrote:
You guys have been on here for years so no way you let them be connected for over the winter in parasitic discharge...??? Right?

I pull mine off and leave them on the charge they have when I leave them into the dark indoor storage they like.... they seem to work in the days later...

mike

The TC is always plugged in and the batteries maintained with 13.2V applied. There is also a 64watt solar panel with a PWM controller feeding the batteries up to 14.6 and up to 3.6 Amps and drops to no current when fully charged testing every 8seconds. The contoller has temp compensation in the controller not remote at the batteries.
So yes the batteries were maintained well. We keep the TC heated and stocked ready to go at all times.
It might have been a bad batch is my guess. The TC was plugged in all the time so there was no opportunity for a bad battery to ruin a good battery. I suppose there may have been a chance it could have happened during the times we did camp and the batteries dropped to 10.2 volts after only acouple hours of use and only about 5amps running.
Looking forward to camping and giving the system a good test.

kerry4951 wrote:
I'd be a little concerned with the reason why they BOTH failed. The two of them both going down seems a little strange. I guess there could of been a bad batch of batteries but just seems highly unlikey that both would fail unless there is another problem causing it.

One bad battery in true parallel duals will kill the second in short order

You guys have been on here for years so no way you let them be connected for over the winter in parasitic discharge...??? Right?

I pull mine off and leave them on the charge they have when I leave them into the dark indoor storage they like.... they seem to work in the days later...

mike

Did you do anything to keep them charged since last summer? If not, I'm not surprised that they were not doing well this spring.