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bobrok
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# Posted: 12 May 2011 17:42
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I have a 12v deep cycle marine battery (625A @ 32*F) that I've kept on a maintenance charger all winter in my unheated shed. The charger light has been green all winter, as I expected it to be. Tested it at 11 volts all winter. I didn't check the water levels thru the winter because the light was fine and I wasn't using the battery to power anything, just keeping the charge. So the water levels were way down last week and I added distilled (plates were not exposed, everything was still covered but it took cup and a half of water to top off.
I don't think I damaged the battery, did I? Now all of a sudden the charger is running on yellow showing that is in charge, not maintenance, mode, and the battery tests at 14A. I can also see bubbling and hear the reaction from inside the vents.
What's going on? Is it because of our sudden ambient temp increase to 75* from low 50s and 40s?
Do I have a problem?
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MtnDon
Member
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# Posted: 12 May 2011 18:40 - Edited by: MtnDon
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After adding water it would be expected to see the charger have to build the charge up as adding the water reduced the specific gravity of the electrolyte.
Do you own a good hydrometer? By good I mean one with a graduated float, not a series of colored balls. And by good I mean one with a thermometer built in, so it is easy to apply the temperature correction if the electrolyte is warmer/colder than 77 - 80 F. (diff batt mfg may use diff points)
Also is that a typo, where you stated the voltage was at 11 volts all winter. ii is a dead battery. 12.7 is fully charged. Also voltages are a poor indicator of charge. If/when using volts as a guide the battery should be left off charge and not have any discharge for 3 or more hours.
If leaving a charger on all winter the charger should be one that produces a true float charge. Float voltage should be around 13.02 to 13.20 volts
Problems? Get it charged fully, get a hydrometer and check the readings. Let it sit a week or so and check again. A good battery will have minimal drop in SpGr over a short period. may not even be able to measure the difference.
NAPA sells a hydrometer with a thermometer in it. Their rubber parts, like many today, are not so good. It helps a lot to rinse it out after use.
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MtnDon
Member
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# Posted: 12 May 2011 18:50 - Edited by: MtnDon
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FWIW (Note: flooded wet cell lead acid batteries only. AGM should not be equalized and gel cell have their own special charge requirements which is why I don't like gel cell. Like AGM tho')
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MtnDon
Member
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# Posted: 12 May 2011 19:13
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more FWIW
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bobrok
Member
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# Posted: 12 May 2011 21:53
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Don,
Thanks very much for the detailed response. I have to digest this and teach myself a thing or two.
Quoting: MtnDon is that a typo, where you stated the voltage was at 11 volts all winter. ii is a dead battery
Not a typo. I have a Schumacher brand maintenance charger (Model SEM-1562A from Wal-Mart) which, according to the manual, automatically adjusts voltage for 6v or 12v, adjusts the maximum charge voltage and maximum maintain voltage based on ambient air temperature, and has a thermal runaway current reducer to prevent overheating of the battery.
It's simply a plug-and-play device; nothing to set.
Does that qualify as a float charger?
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MtnDon
Member
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# Posted: 12 May 2011 22:20 - Edited by: MtnDon
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Yes, I googled the manual and it seems to be a charger with a proper float.
The user manual states
Maintain Voltage----------------------------------------------12V – 13.3V
So that 11 volts throws me for a loop.  It sounds like it was near dead all winter. 10.5 is the "officially dead" point. Even in the coldest part of winter we had readings of 25.2 on our 24 volt system when we'd arrive at our cabin (no input, no draw). That's equivalent to 12.6 on a 12 volt battery.
A hydrometer will tell the true state of charge. (That's one of the two things I don't like about AGM batteries; no ability to take a specific gravity reading. The second thing are their prices.)
Does the meter that was used to get that 11 volt reading give higher readings on other 12 volt batteries, known to be fully charged, or close to full charge? Connecting it to an auto battery while the engine is running should provide a reading around 13.8 volts if the battery is well charged. That would give a rough calibration check.
Sitting there with nothing hooked up to it a fully charged 12 volt battery should be reading 12.7 volts. With a charger hooked up to it, on float, the voltage reading should be higher than that. If the charger voltage is not higher than the battery voltage it can not charge the battery. Simplistically put, the charger voltage has to be higher than the battery voltage in order to "push" the electricity into the battery.
An auto parts store could also test the battery.
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Rob_O
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# Posted: 15 May 2011 14:45
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Updates? Has the battery taken a charge?
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bobrok
Member
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# Posted: 15 May 2011 15:27
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Sorry guys. I haven't forgotten. I was going to give a couple of days on the charger, have it tested at a shop and then get back to the forum tomorrow.
Nothing different as of Sunday afternoon. The charger is still charging, the battery is still sizzling and bubbling along on all vents, and with the charger connected I'm reading about 13.5 volts. I haven't disconnected the charger and taken a reading.
What do y'all think?
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Rob_O
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# Posted: 15 May 2011 15:47
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Take it off the charger for a few hours and measure the voltage. Top off the water and charge it for a few more days. I've had some batteries come back from completely dead and some that were just gone
Let us know what voltage readings you get
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bobrok
Member
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# Posted: 15 May 2011 19:38
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I took the battery off charger at 4:30 edt and it sat untouched and unconnected to anything until just now, 7:30 edt.
I have a real inexpensive analog meter but I am reading over 12v, probably 12.2 or so.
I think the battery is still good but just needs to continue topping off.
No?
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Rob_O
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# Posted: 16 May 2011 09:10
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Keep it on the charger for a few more days and see what happens, that's about all you can do right now
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bobrok
Member
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# Posted: 16 May 2011 13:15
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I went one better and took my battery to Advance Auto and had them test it. It's one of their batteries.
The battery tested good. 12.56v 505cca at 65*F.
They told me to go home and put it back on my charger and enjoy using it.
So far so good...now here is what they also told me that I didn't know.
My battery has 2 sets of terminal posts and they asked me which posts I had been using for charging/power. I really didn't remember which I used for power but that they were on the large cable posts for maintenance charge all winter.
Evidently there is a cell-fusing syndrome if you continually swap posts and it is not at all recommended. Fortunately I haven't destroyed the battery but they told me to use just one set of posts.
Quoting: MtnDon Also is that a typo, where you stated the voltage was at 11 volts all winter. ii is a dead battery. 12.7 is fully charged
Don, they told me that a fully charged 12v battery should read 12.06v. Was yours a typo and should it have read 12.07v instead of 12.7v?
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p0rtia
Member
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# Posted: 16 May 2011 17:49
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Thanks, Bobrok! I will continue to use one set of posts. BTW, it's 12.7v
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MtnDon
Member
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# Posted: 16 May 2011 18:38
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If that store employee told you a fully charged battery should read 12.06 they are dead wrong. I did not make up that chart I posted. If they told you that I would not ask that person for any further advice because in my book, once they give out something as incorrect as that 12.06 volts everything they say is suspect.
And I totally disagree with that hogwash about the battery posts. I'll explain why. For those who don't care for long winded stories I'll skip to the heart and place the story at the end of the post.
There is a difference in the battery terminal connections built into all batteries that come with dual, top and side, terminals. Both the top and bottom sets can be used for engine cranking; that's why the mfg combines the two sets in one battery (saves inventory). Engine cranking draws lots of power. That does not wear out any mechanical parts inside the battery. If using one set did damage something it would seem that it should be the terminal set that was doing all the work. That would leave the other unused set perfectly fine.
There is a some truth to the matter about potential damage and this is likely where that misinformation comes from. However it does not stem from any normal charge or discharge uses. IF a winch is connected to the side terminals on a dual terminal battery, there is a chance that under heavy winch use the current draw through the side terminals can over heat and melt like a fuse. The internal connectors to the side terminals are not as robust as the connections to the top terminals. I got that straight from the folks at Optima battery some 10 years ago. They said most batteries could have that problem.
So the only danger is from heavy heavy current draw, usually only a concern with big winches being worked very hard. By hard I mean winching that causes a stall or near stall.
I have used Optima batteries in my Jeeps for probably 15 years. Most of those batteries have been the type 34/78 which have both top and side terminals. I have used two of those 34/78's in my Cherokee since it was first "built up" in 2001. I just put in the third pair; change them every 5 years even if they still are going strong. Anyhow I run one for engine starting off the side terminals, with the winch attached to the top terminals. Then they are interconnected via the top terminals using a solenoid based isolator system. The side terminals on the second battery are used for a reasonably powerful ham radio transceiver. None of the 4 older batteries ever gave any problems at any time. They were replaced simply because the time limit I imposed was up. There was lots of winch use, lots of radio use and of course lots of engine starting use.
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p0rtia
Member
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# Posted: 18 May 2011 18:13
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Thanks for your input also, MtnDon. Re: the posts, I assume it is the same for Marine Deep Cycle 12V such as mine, where the dual posts are not top and side, they are all four on the top--two threaded and two (bigger) normal car-battery type, unthreaded.
bob_rok: I'm sure your battery guy just mis-spoke about a fully charged battery. It is certainly 12.7, though a couple of my batts that are a couple years old top out at 12.6 the instant I take them off the charger. I've been working with 2 to 8 12v and 6v (wired in series parallel) batts for about four years, so I'm no expert--indeed I have no affinity for electrical work AT ALL. I have to keep it pretty simple due to financial constraints. I'm just at the point of getting a hydrometer this year, as the issue of dead batts is perennial. I've learned how not to kill them the hard way. :-) BTW, curiously, my wonky inverter died today--at least it beeped at me and isn't working. I popped in the replacement I bought last fall and life went on. I will play with it a little to see if it is something simple, but won't stress to much over it. Are you at your camp in the ADK? The rain is a bit depressing, but boy is it green around here!
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Rob_O
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# Posted: 18 May 2011 18:45
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p0rtia: Have no worries, unless you plan to be putting a sustained load of several hundred amps on your battery sometime soon.
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p0rtia
Member
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# Posted: 18 May 2011 18:59
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I think I'm safe then, Rob_O Thanks. :-)
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bobrok
Member
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# Posted: 18 May 2011 19:11
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p0rtia:
My battery is actually the same as yours, with all of the posts on top, two threaded and two clamp type. I maybe should have mentioned this but I'm still kind of playing the waiting game with the battery on charger to see if it will ever top off and didn't want to post unnecessarily. Still charging as of 15 minutes ago.
Have not been up north yet; the mud locks just came off the camp roads last week so I'll be doing a quick overnighter this weekend, mainy to see if my dock and canoe didn't float away in the flood!
MtnDon and Rob_O:
Your advice has been extremely helpful and reassuring. Like p0rtia I don't know diddly about batteries. Car doesn't start...you buy a new one...that's about it.
I can't wait to start my solar panel/battery upgrade! You will tire of me & my questions, no doubt!
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Rob_O
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# Posted: 18 May 2011 19:33
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Quoting: bobrok MtnDon and Rob_O: Your advice has been extremely helpful and reassuring. Like p0rtia I don't know diddly about batteries. Car doesn't start...you buy a new one...that's about it. I can't wait to start my solar panel/battery upgrade! You will tire of me & my questions, no doubt!
Always happy to help.
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p0rtia
Member
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# Posted: 19 May 2011 08:05
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So here's what looks like an inexpensive hydrometer. Can those who know about such things weigh in? Thanks!
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=370511317049&viewitem=& sspagename=STRK%3AMEWAX%3AIT
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MtnDon
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# Posted: 19 May 2011 10:25
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One with a thermometer would be better as fluid temperature influences the reading
http://www.acehardware.com/product/index.jsp?productId=1292142&CAWELAID=109343097
and Napa Auto sells them
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p0rtia
Member
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# Posted: 19 May 2011 13:34
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Thanks, MtnDon, I will go with the one you suggest. I had looked on the napa website but couldn't find it (I have to say I've been to the napa site various times looking for battery related stuff and it always defeats me. I'm sure it's there--just not for mere mortals.
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MtnDon
Member
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# Posted: 19 May 2011 18:01
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NAPA items are sometimes hard to locate online when it is not a vehicle specific part, but the store nearest me carries them in the store
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bobrok
Member
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# Posted: 24 May 2011 15:55
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I'm just bumping this up for closure and to thank everyone again.
So, today, 5.24.11, my battery is FINALLY CHARGED! YAY!
At least so says my charging device, to which it has been connected since, what, May 12th?
Forget all winter.
I still have no idea how it showed charged all winter and then all of a sudden became discharged. I was beginning to suspect my charger of being faulty.
Now I know what "trickle charge" and "maintenance charge" means.
I'm so excited I think I'll take the rest of the day off work!!!!
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p0rtia
Member
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# Posted: 12 Jun 2011 18:49
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Okay. So after the usual difficulties ordering anything on-line from Ace Hardware (or is it only me?), I've received my hydrometer and conducted my tests. I'm gonna start a thread on what I found, in the hopes that it will document my issues for my fellow solar newbies. Just wanted to direct anyone reading my contributions above to "False Voltage and Hydrometer Question." Come on down!
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TomChum
Member
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# Posted: 13 Jun 2011 00:55 - Edited by: TomChum
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I think I'll get mine from Napa......
Ace Hardware - Battery Hydrometer with thermometer
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p0rtia
Member
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# Posted: 9 Aug 2011 14:37
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Got the hydrometer, which changed my life. No seriously, it did. Enabled me to track the resuscitation of two sulfated batteries. Easy to use and invaluable. Thanks again MtnDon and TomChum!
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bobrok
Member
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# Posted: 7 Sep 2011 23:44
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Quoting: MtnDon Yes, you need a battery charger that you power with the 120 VAC output from the generator. The manual for that generator probably lists the 12 DC as an output. My Yamaha specifically ststea not for charging batteries. As mentioned above the output voltage is too low for charging. It is also too low an output to do anything by trying to feed through the CC. A battery charger that has two modes, like a bulk chage rate and an absorb is best. They will charge faster and ttreat your batteries kindly once the charge reaches full or near to full.Look for Iota brand.
MtnDon,
I don't want to step on mattthehairy's thread so thought I'd do this seperately.
Is my Schumacher brand maintenance charger (Model SEM-1562A as in the above thread) adequate to plug into my generator to "top off" my deep cycle battery as necessary? Rather than buy a 2nd charger to keep at my camp can I use this one for, say, an hour or two at a time while I am running the generator at night for other needs to supplement my battery at the same time? I know I probably won't give it a full charge on 1-2 hours each night, but would it help or hurt to do this?
I don't want to run the generator for the sole purpose of charging the battery. Is it OK to do this incrementally over several nights to keep it topped off?
Thanks,
bob
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MtnDon
Member
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# Posted: 8 Sep 2011 00:47
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Looks like that is only putting out 1.5 amps tops. That will take a long time to have much effect. Pretty much not much more than what is needed to replenish the natural self discharge.
FYI, the maximum charge rate for a lead acid flooded battery is C/8. C is the battery capacity at the 20 hour rate. A typical golf cart battery has a capacity of 220 amp hours. 220/8 = 26 amps. That's the maximum rate, anything less is okay but will greatly increase the charge time. It is also good to use a higher rate as the bubbling of the electrolyte will help destratify the fluid. I'm a little conservative so prefer to use C/10 as my maximum. Not much difference but possibly a little easier on the battery.
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Anonymous
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# Posted: 8 Sep 2011 01:00
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So what can you recommend I use for a quick charger? I value your opinion.
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