SEARS PM-1 battery voltage at rest? (1 Viewer)

[superjuice]

I have 2 pm-1's hooked up through a hellroaring unit. I also run a 150 amp alternator from a sequoia using photomans bracket. Outside temps here are 20-30 deg.F.

The main battery is 1.5 years old, the the backup is 1 year old. This is setup for one to be a true (backup) battery where there are no loads connected to it and all ways reads 13.2V at rest. The other pm-1 (main) has everything else connected to it, but no large loads (like a frig) after shutdown.

I have been watching the voltage of the main battery gradually decrease over the last year. It used to be about 12.8-13V at rest and now when i check it before starting it reads 12.2V I was fine with it being a little lower but 12.2 on a AGM is like 50% discharged (possibly less) from what I have read.

Today it finally gave up the ghost, turned the key and the dash lights just dimmed. Hit the switch to combine and it started right up. I checked the ground and other connections and I know it could also be my starter contacts or NSS connector. I'm starting with the battery because its easier and also under warranty.

The charge voltage is 14.4 at startup and drops to 14-13.8 while driving during the day. If driving at night with the lights it stays about 14.2V I attribute this to the alternator/regulator keeping up with the current draw. It also rises when using the power windows.

I'm going to sears tomorrow to swap out the main battery for a new one, Its close and then i only have to pull it out once (hopefully).

Questions:
Has anyone ever had a problem returning batteries at sears? Does it matter that I was using it in a car and not a boat or RV?

Does anyone else run a pm-1 and monitor the voltage regularly? What kind of voltage readings do you get with the car off or on? Thanks for any input

 

[alia176]

I'll occasionally put all of my Platinums on a trickle charger for topping off and de-sulphatization (spell?). So far so good, knock on wood.

edit: don't use a traditional battery charger on these batts, something about resistance is not seen by the charger so the batteries don't get charged properly. Or some such thing.

 

[Vasir]

Has anyone ever had a problem returning batteries at sears? Does it matter that I was using it in a car and not a boat or RV?

they dont care what vehicle its been in. i have the same battery. sears is like home depot, if they sold plants they would take a dead one back...

 

[wearsabrowncoat]

Same problem here with my main PM-1 (dual Slee style setup). Same sysmptoms - tops off easily but voltage rapidly drops below what is needed to start (within two days of sitting). At first I thought it was because the main was subjected to a deep freeze while in a ND snow bank for a couple days. Also thought it might be from some sort of a parasitic draw that the 2nd battery was isolated from. Wanted to trade it out at Sears during my 15 days of R&R but something else always came up.

 

[superjuice]

Interesting Thanks for the input but also THANK YOU FOR YOUR SERVICE Well see what happens to the next one I guess.

 

[superjuice]

Went to SEARS yesterday and got a new battery (for free) under warranty. Word of advise, don't tell them its been in a vehicle! They wanted to test it in the vehicle but i told them I woulden't let them touch my truck I dont know how many times they said its not supposed to be used for a starting battery, my response was that it was an off road vehicle that wasnt driven alot (half true)

So i brought it in and they put it on some handheld electronic gismo that said it was "good". I told them it wasn't and to check it again. They checked it again and said it was good so i coulden't have a replacement.

Mad as hell i walked out and bought a load tester from the tool section and cooked it a few times in the parking lot. Brought it back in and said to check it one more time for heck of it. Now its (BAD) Ended up walking out with a new battery.

Its not in yet but i did swap the "backup" battery to the "main" battery location and have much better at rest voltage 12.9v.

That's my battery story...for now

 

[superjuice]

I saw that someone else was having a problem with their pm-1 in this thread Dead Sears Platinum 31M so i thought i would update mine as well.

I'm out of town and got a call from the wife about the truck not starting Seems the "backup" which was moved to the "main" location has now failed as well. Since the new battery is still sitting in the back of the truck it's hard to say for sure that its not something else. She made it to her friends house fine but a few hours later when she went to leave, the truck would not start. Got a jump and let it run for a bit, turned it off to make sure it would start again and nothing. Jumped it again and drove it home with a follow vehicle.

I think its the battery not taking a charge in the "main" location. Seriously, this battery was put in as a "backup" 1 year ago and has never shown any signs of degradation. I've used it a few times to self jump my truck after not driving it for a few weeks and thats about all its ever done.

When i get back to town i'm putting the brand new one in the "main" location and see how it goes. If i'm seeing 14.4v while its running it should be charging right!

Maybe i'll bring this one to a different SEARS with a different story line this time.

Maybe I'll add a THIRD ground directly to the block just to make sure the charge is making it to the battery.

Maybe all if the above will remedy the problem.

It goes without saying that these AGM's are not living up to my expectations of a $250 battery, I all most hope its something else

 

[alia176]

I am not convinced that it is not your Hellroaring unit that's the culprit. You have a beefy alternator and the battery that sits in the secondary position doesn't drain. However, ANY battery in the primary position seems to be draining rather quickly.

One easy thing to do is simply disconnect the Hellroaring system and go back to stock. See if everything is back to normal again. I've heard of another Hellroaring system going bad in the past.

 

[superjuice]

So as an epilogue to my battery story, I brought the "backup" battery to a different sears this time, had a new one within 15 minutes. I should mention that i did not charge it this time and also told them it was in my boat and would no longer take a charge

While i was there I purchased a sears platinum battery charger since it was on sale, for $89. Only $10 off but now i can be sure its topped off to their specifications.

Everything is working great but when I put the charger on it every other day (just to make sure i don't lose two more batteries) it reads 77% charged every time. One hour later its all topped off reading 100%. I just connect it to the main battery and let the hellroaring unit combine them so they are equalized. I first connected it one at a time but the readings were the same. It starts charging at 14.5v but drops to 13.5v when its done.

End of story (for now) I'm happy to have two new batteries and don't mind toping them off regularly just for piece of mind. I think the problem is that I only drive 5 miles to work and back and the 150 amp alternator doesn't charge much under 1500 rpm's. So even when warming up the car in the morning not much charging is being done.

Feel free to post your thoughts, comments, or whatever might be of importance to the thread

 

[alia176]

The fact that you have to put a charger on your battery 3x a week is ridiculous. You have a drain somewhere that needs to be fixed!

 

[superjuice]

All most forgot, the "backup" battery still reads 13.2v at rest - due to the 13.2v isolation from the hellroaring unit, but the "main" battery now reads 12.9v in the morning after sitting for 12+ hours. Much better I think

I did check the current draw at rest and something is pulling .4 amps. thats only 5.2 watts @ 13v but was wondering what others have measured (NLXTACY?).

I do have a car-puter/stereo but it turns off after 15 minutes and only draws .04 amps when off. I checked this with a high quality FLUKE multimeter.

 

[superjuice]

Looks like 13.54v is optimal voltage at rest for dual pm-1's FYI

 

[Dave 2000]

I did check the current draw at rest and something is pulling .4 amps. thats only 5.2 watts @ 13v but was wondering what others have measured (NLXTACY?).

I do have a car-puter/stereo but it turns off after 15 minutes and only draws .04 amps when off. I checked this with a high quality FLUKE multimeter.

I think your method of measuring could be flawed or your meter is not correct? For starters (no pun intended) you should be measuring at the 'mean' battey voltage which would be 12 volts. This is because a brand new battery would be indicating a full charge @ 12.6 but as we know it is rare that a battery maintains that voltage for a long time, of course having just come off charge this would be higher. We also know the voltage should be a 'resting' voltage, the simple act of opening the door and the interior lights coming on, along with the clock, the activation of the central locking and of course the radio memory, temperature ect all come together to 'skew' the results. If your technique is measuring .4 of an amp (and let us assume for a minute that it is correct) that really is way too much draw. At that rate a typical battery (50 amp hr for example) would be flat in 125 hours which is a little over 5 days. Remember that is flat, in the real world it could be only two or three days before the car would not start. Also your alternator should not need 1500 ENGINE rpm to produce a charge, specifications for alternators are usually rated at ALTERNATOR rpm hence the smaller pulley to make it turn faster, your alternator should easily run your lights/heater or air con at idle in traffic period. If not then think about all the town dwellers that drive to work sitting in traffic all the way there and on the return with their lights/heater/radio on, there would be thousands of people recharging there batteries from an external source on a daily basis.

You should be looking for a TOTAL draw in the milliamps not amps.

Just my 2 euros worth

regards

Dave

 

[rhyary]

5 miles to work does not charge the battery enough. I have done a lot off reading about batteries and one common reason of the failure is not enough trickle charge time. In 5 minute, not alternator dependent, you only bring up the surface voltage up. As more and more days passed, more battery damage result up to failure.

I have a 2 miles commute and it is a real problem, especially on the deep cycle batteries.

The deep cycle are thick plates and do not do well with the short low amp charge the automotive alternator provides.

The issue is a bit more complex than this but it is hard to explain typing on the iPhone.

The only solution I have for now, with out getting into lengthy explanation is to put it on a trickle charge for a long time once a week. Overnight maybe enough. A short duration battery tender is not the solution

HTH

 

[superjuice]

It may be a short duration (1-3 hours) but the sears charger actually has a "platinum" setting which is also 40amps. I was under the impression that would suffice. Agreed that the short commute is the main problem, which is why I top it off every other day. Kinda funny having such a high capacity setup that it's more trouble to keep up

 

[rhyary]

The 40 amp is great, but it can only do up to the 80% charge.
Beyond that you need to trickle charge for a longer time due to battery chemistry.
Your charger will do that automatically but you need to give it time to go thru its 4 stages of charging.
If you only do the 1 to 3 hours with the charger, you are replicating what the alternator can do, but you are not solving the problem.

My recommendation is to counteract the short commute by putting the car on the charger for a long time. Doing it and making sure the battery is at true 100% once a week should make the batteries last a long time and it will be less hassle. Batteries should easily start the car after week and your symptom are classic problem using the deep cycles batteries. It is why I kept my main battery to be a starting battery (27F) and did not get to deep cycle. The thin plates of the starting batteries allow it to accept a quicker charge and get to 100% more quickly. It is also the reason why you can't deep discharge a starting battery.

Not letting a battery getting to 100% charge will shorten the life of the battery. I believe that is the problem for most of us with deep cycles batteries whether it is in the aux position or the start position.

Lastly the 150amp is only important for running more electronic stuff in the car, and doing it with lower RPM. My LX450 has all amp it needs sitting idle. It was not so with the 80amp OEM one. But you already know that

Commiserating with you on the dreadful short commute problem.
Oh, wait at 12MPG it might be a good thing. bhahahahahahahah

Rami

 

[rhyary]

Looks like 13.54v is optimal voltage at rest for dual pm-1's FYI

No.
13.54V is not at rest. 13.54 will be the surface charge.

You can remove surface charge by leaving your lights on few minutes until it drops to 12.6V

Than you can wait 2 to three hours (making it up, I don't know how long you have to wait) to measure true at rest voltage.

Better is to measure the voltage the next morning. Which will be more meaningful since that is when you have to start your car

 

[yoda-g3]

I just thought I'd throw this in here for reference since some people thing the standard flooded cell numbers relate to AGM's.

And yes, leaving a batt even at 80% for long periods of time will ultimately shorten its life.

 

[rhyary]

Can't see the chart

 

[Bryan E.]

I'm now regretting getting this battery when I needed one this summer. I thought this huge expenditure was a long term battery for when I got a winch together in a year or two. Now I'm wondering if it will last that long. The price was killer but I won't splurge again. The $90 Auto Zone batteries have worked well, as well as other premium batteries I've had, regular 6 yr batteries or so. Just thought this would do that plus be better for a big electric winch. Well...I didn't research it well enough I guess.

Oh well....

As for replacements with Sears...I've read more trouble with this than good experiences...another thing I didn't realize before purchasing it. I have a half hour commute each way to work. Hope it gives me better life than others here are seeing.