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Bad batteries or am I wrong in my calcs?

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TakeFive
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Response Posted - 03/06/2011 : 22:08:50

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Stinkpotter
 ...I'm not sure, but the internal resistance of two batteries might be too much for a light-duty solar panel--it might not even get a peak of .37 amps to either of them...
<hr height="1" noshade id="quote"></blockquote id="quote">
Two identical batteries in parallel will have half the resistance of one. I think it's Kirchoff's law, but not sure. So the more relevant problem might be one of too little resistance, such that the panel cannot deliver the voltage needed to drive current into the batteries. But that's just a guess - I'm not much of an expert at this.

Edited by - on

NautiC25
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Response Posted - 03/07/2011 : 06:49:12

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Stinkpotter
 I agree with Rick about the exposed plates. My single battery on my C-25 was over 7 years old when I sold her--don't know how much over because the PO bought it. The two batteries on my Eastern are now 4 years old. None of those three have ever needed a drop of water added to stay above the top of the plates. When one does, that'll be my signal to replace it, and also to check my engine's voltage regulator. And if I replace one, I'll replace both--two different batteries (age and/or spec) should not be charged and used together. The fact that one of yours lost more electrolyte than the other is not a good sign.

All that said, unless you're in Arizona, I really don't think 9 watts of solar power is going recharge two Group 24s from any level of discharge--it may or may not even be enough to maintain them for a significant period of time. I'm not sure, but the internal resistance of two batteries might be too much for a light-duty solar panel--it might not even get a peak of .37 amps to either of them. "Voyager" Bruce the EE can speak to that better than I. But my portable plug-in charger specifies it's for one battery at a time, only.
<hr height="1" noshade id="quote"></blockquote id="quote">
They both had equally exposed plates.

Why wouldn't the solar panel be enough when it brought BOTH batteries from 5v to 12.1-7v in less than 7 days? I've never had a problem with the panel and it keeping the batteries full.

Edited by - NautiC25 on 03/07/2011 06:56:55

NautiC25
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Response Posted - 03/07/2011 : 06:50:44

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Tradewind
 The plates should be covered. Fill the cavity up to the bottom of the filler hole "tube", use only distilled water or demineralized water. Put them on a good charger with an amp charging indicator, individually, to top them off. When the charger reads zero they're fully charged. Then have them load checked.

If they pass they load check then I would suspect the solar charging system as insufficient or faulty or an electrical leak somewhere in your 12 volt system.

I'm not an electrical engineer but I have dealt with batteries on my boats since 1979. And I also stayed at a Holiday Inn express last night.
<hr height="1" noshade id="quote"></blockquote id="quote">
Thanks. I'll get the water today, charge them up, and take em to VatoZone to get them checked.

It may be possible that they are being drawn by the radio (presets) that the PO installed. It's ancient and I couldn't get it to work anyways, so I'll cut the wires and see how that does.

Edited by - NautiC25 on 03/07/2011 06:52:18

NautiC25
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Response Posted - 03/07/2011 : 06:55:14

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by RhythmDoctor
 <blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by NautiC25
...I looked inside them and the top of the plates are 1/8th inch exposed. Do I fill them just to cover the plates, or do I fill up the entire cavity?
<hr height="1" noshade id="quote"></blockquote id="quote">
You need to be asking why the plates became exposed in the first place. Although 9 watts is small enough that a full charge takes a long time, I believe that it is much more than a typical float charger IIRC. If you are using the solar cell to "top off" the batteries as you said, you may be boiling off your water (or, more accurately, electrolyzing it into hydrogen and oxygen). In addition to harming the battery by exposing the plates, this is a potentially hazardous situation in a confined space. Disconnecting your cables could cause a spark, and if hydrogen is present - BOOM!

You really should pick up a solar controller.
<hr height="1" noshade id="quote"></blockquote id="quote">
I think you're right. I originally thought that a "trickle-charger" wouldn't do this to any battery, so I didn't need a controller.
I'll do some shopping. I saw this cheap one:
http://www.walmart.com/ip/Coleman-7A-Solar-Charge-Controller/15063161

Will it be fine for my application? Or do you have a better option?

Edited by - NautiC25 on 03/07/2011 06:59:22

Davy J
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Response Posted - 03/07/2011 : 07:00:10

That looks exactly like the one that I have, except I paid 29.99. It works with my new 80W panel, so I would think it would be good for yours as well.

This is the unit I have:
http://www.westmarine.com/webapp/wcs/stores/servlet/ProductDisplay?productId=490088& catalogId=10001& langId=-1& storeId=11151& storeNum=10109& subdeptNum=10544& classNum=10545

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NautiC25
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Response Posted - 03/07/2011 : 07:10:53

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Davy J
 That looks exactly like the one that I have, except I paid 29.99. It works with my new 80W panel, so I would think it would be good for yours as well.

This is the unit I have:
http://www.westmarine.com/webapp/wcs/stores/servlet/ProductDisplay?productId=490088& catalogId=10001& langId=-1& storeId=11151& storeNum=10109& subdeptNum=10544& classNum=10545
<hr height="1" noshade id="quote"></blockquote id="quote">
Cool! Coleman probably just rebranded the same controller. It says it'll handle 105w. If it works for you, then I'll pick it up before I head back out this weekend.

Edited by - NautiC25 on 03/07/2011 07:11:22

Stinkpotter
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Djibouti
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Response Posted - 03/07/2011 : 07:59:54

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by RhythmDoctor
 Two identical batteries in parallel will have half the resistance of one. I think it's Kirchoff's law,...<hr height="1" noshade id="quote"></blockquote id="quote">You're probably right--I probably got it backwards. But I do know that my little 3-stage charger specifies that it's for one battery only, which suggests that there's something different about two. Over the winter, I switch it between my two batteries every few weeks. And I have a long-term lease at a Holiday Inn Express.

Edited by - on

NautiC25
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Response Posted - 03/07/2011 : 12:56:48

On the topic of power...... I just found that $50 red/green LED bulb for $18! Some boat store on Ebay was clearing it out apparently. I just saved 9 watts! lol

Edited by - NautiC25 on 03/07/2011 12:59:06

NautiC25
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Response Posted - 03/08/2011 : 20:58:17

I took both batteries to AutoZone to have them checked. Both failed.

Charger should get here by friday from Wallymart. LED navigation bulb also by friday. And I'll pick up a new battery from Bass Pro Shops since they have 5yr warranties on theirs. I don't think anyone else has warranties that long.
All this should come together by this weekend for an overnight fishing/sailing trip.

Edited by - NautiC25 on 03/08/2011 21:01:46

NautiC25
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Response Posted - 03/11/2011 : 11:22:28

I changed my mind. I did some searching and saw that Interstate had the best bang for the buck battery out there. Their Group 29 Marine has a 210 min. reserve capacity which blew other batteries away, has a 30 month warranty, and only cost $118 each. So, I'll see how they hold up.

The only problem is that they'll be a super tight fit in the factory box. If they don't fit, then I'll have to figure something else out.

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Voyager
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Response Posted - 03/13/2011 : 11:34:28

I checked the Interstate Group 29 batteries - the specs look good. Each one provides approx 105AH. This size battery (especially 2 of them) will provide you with plenty of reserve power on your C25. You will need a very capable charger, however, to keep them fully charged. A quality three-stage plug-in charger will do the job when you're on the slip.

If you don't always have shore power, then I'd suggest you purchase a high efficiency solar panel (80W) with a 7A regulator, and supplement that with your engine's alternator. With about 4A for 8 hours and generally sunny TX weather, you can expect the panel to provide approx 50AH a day, so in two days, you'd likely be able to fully recharge both batteries from 1/2 empty.

Just a note about Interstate batteries: the people I know who buy them swear by them. Several folks in our local club are customers and will never replace them with anything else. This is mainly because they're well built, but moreso because they're well supported by their sales organization.

If you have a problem fitting the battery into your existing battery boxes, ask your dealer what they recommend. They've seen and heard it all before....

Edited by - on

NautiC25
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Response Posted - 03/14/2011 : 05:53:03

I went on my first loong overnighter and it went VERY well. The batteries came from the dealer with 12.7Xv each, and it was the day before leaving, so I didn't top them off. I dropped both into the box and they fit perfect! Had about 3/16" to spare, so they shouldn't roll around or anything.
That night I sailed around with navigation lights on for a couple hours. Then anchored and went inside with some friends to sit around for a few hours before calling it a night with the cabin lights on. My friends and I also plugged in our cell phones into the 12v sockets to charge. I was pleasantly surprised to see that the batteries only read 12.63v by morning.
So we used the batteries for everything we wanted and only lost .1v.

Voyager,
The panel I have produces 9 watts. I only go sailing on the weekends, and I almost never go 2 weekends in a row. It's usually a month between visits. Do you not think that the panel will keep them charged? Charge time is not an issue for me since I rarely see my boat.
I do plan to get a quality 40w panel when the money comes for it.

I also got to use "My Tracks" on my phone as I did a wing on wing on a long downwind run. I could only use the main and jib since I put a nice tear in my 150 genoa. The winds were pretty gusty saturday but I don't know the speed. I don't know where to see the recorded wind speeds for the area. I recorded a max speed of 8.68mph, and averaged about 7.3mph on the run. It was awesome to do, and my friends were going nuts over the whole sailing experience.

Edited by - NautiC25 on 03/14/2011 06:04:25

jbkayaker
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Response Posted - 03/16/2011 : 19:06:10

NautiC25

You can find weather history here:
http://www.wunderground.com/history/

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NautiC25
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Response Posted - 03/17/2011 : 07:40:01

Thanks!

That day:

Wind Speed 10 mph (South)
Max Wind Speed 21 mph
Max Gust Speed 25 mph

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Stinkpotter
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Djibouti
9081 Posts

Response Posted - 03/17/2011 : 10:33:45

That's all you need! I've gotten Passage to plane on a broad reach in 18-25 under the 130 genny alone--spray from amidships, rooster tail and all--almost like dinghy sailing!

Edited by - Stinkpotter on 03/17/2011 10:34:20

NautiC25
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Response Posted - 03/17/2011 : 11:48:57

I wish I could have used my 150, but it's got a nice tear in it. :(

http://img.photobucket.com/albums/v214/SharkRacer/Catalina/IMG_20110312_173942.jpg

http://img.photobucket.com/albums/v214/SharkRacer/Catalina/IMG_20110312_173936.jpg

Edited by - NautiC25 on 03/17/2011 11:56:19

NautiC25
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Response Posted - 03/22/2011 : 06:50:41

I've got another solar panel question.

I'm gonna take the advice here about my panel not being enough and try to get a bigger panel. My question is, how big is too big? If batteries can only be charged at a slow rate (2amp?), then isn't there only so much panel you can get before its power production is a waste?
I know the charge controller turns the panel flow on and off, but what limits the amp charge to the batteries? If you got a 10amp panel, wouldn't it charge too fast and cause damage?

Edited by - NautiC25 on 03/22/2011 06:52:32

OLarryR
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Response Posted - 03/22/2011 : 09:32:22

Solar panel controllers are rated for certain max amps. Up to the max amps, the controller should be smart enough to "control" the charge appropriately. Those that just want to trickle charge the batteries and not really consider any loads that may be put on the batteries, then the rule of thumb is that they can get by without a controller using a 5 watt panel for one battery and a 10 watt panel for two batteries. Any panel larger than that then require a controller so they don't cook the water out of the batteries.

A 10 watt panel for one battery or a 20 watt panel for 2 batteries with a solar controller should be ample for minor loads on the battery(ies) each week (ie. keeping nav lights on for 3 hours or so one, maybe two nights each week or perhaps one night having the anchor light on for 8 hours. When you increase weekly battery loads above that usage, that's when going to a largewr panel would be adviseable. Also, if you are using a boombox or have radio/speakers hooked up and use that during the week in addition to light usage of lights during evening hours, then going with a larger panel makes sense.

I generally have light loads on my bateries each week. I use the fishfinder regularly but mostly daytime usage. Occasionally will use the nav lights and it is rare that I use my anchor light but it is an LED. Cabin lights...they are also LEDs but the only time I put havier loads on my batteries, it usually is when I am docked at a marina and I am generally hooked up to shore power and my battery charger via AC is charging at that time. So, for me a 20 watt panel works okay and my two batteries have been in use sine Fall 2005 and PO had them for at least a year before I bought the boat. If I had to do it again, maybe I would have gone with a slightly larger panel. Then that would be excellent for any forseeable future loads/use.

Last thing, if you are considering going with a larger solar panel, panels are not all made the same way. recommend check out a bunch and you will find that some require a much larger footprint than others based on the way the solar cells/crystals are arranged (mono/poly). For example, my 20 watt is 20"x 14" but I know there are many other 20 watt panels that are much larger and the large rthey are, the more cumbersome they become to support and tuck out of the way.

A good source to compare solar panels is from Northern Arizona Wind and Sun. You can do a search on them. I bought a Kyocera 20 watt panel and a Morningstar Pro 15M Digital controller (w/digital readout) from them over 5 years ago.

Edited by - OLarryR on 03/22/2011 09:36:27

Davy J
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Response Posted - 03/22/2011 : 10:15:07

<blockquote id="quote">quote:<hr height="1" noshade id="quote">A good source to compare solar panels is from Northern Arizona Wind and Sun<hr height="1" noshade id="quote"></blockquote id="quote">
Northern Arizona Wind and Sun is a great resource on solar panels, charge controllers, batteries.
http://www.solar-electric.com/

To get 10 amps of solar, you are going to need multiple or very large panels. My 80w panel is just under 5 amps. One thing I can say, when there is no load on the batteries, the controller is only charging for about, (in my case), 30-45 seconds. As soon as the voltage reaches 14.2, it shuts off

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NautiC25
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Response Posted - 03/22/2011 : 11:46:52

^^But does the controller allow the full 5 amp charge? Or does it step it down to ~2 amps?

Edited by - NautiC25 on 03/22/2011 11:47:56

Douglas
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Response Posted - 03/23/2011 : 10:50:30

Lots of good replies: Do you have a Hydrometer ? Great tool for checking your batteries and cheap to purchase at any automotive store. Read the directions. I also don't thing charging up your batts with a solar pannel will do the job. Sounds like they need to be equalized. I.E run down to about 50% of their capacity and then charged at 14.5 volts until topped. You should use a good battery monitor.

http://www.google.com/search?q=Heart++Interface+Link+20+Battery+Monitor&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox#q=Heart++Interface+Link+20+Battery+Monitor&hl=en&client=firefox&hs=Phn&rls=org.mozilla:en-US:official&prmd=ivns&source=univ&tbs=shop:1&tbo=u&sa=X&ei=hzKKTY6yH8ew0QHDlJmGDg&ved=0CDUQrQQ&biw=1272&bih=826&bav=on.2,or.r_gc.r_pw.&fp=bb933d458efd766

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