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Anonymous
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# Posted: 1 Dec 2011 20:11
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I have 340 watts of solar panels, ran through 2 charge controllers, connected to 1 trojan 1275 golf cart battery and 2 deep cycle batteries. I have been using this system for about 7 months every day without any problems at all. I bought a hydrometer to check the gravity of the batteries after reading about it here, so I get the most life from the batteries. The reading on the hydrometer shows that the cells need attention and are not fully charged. The voltage is good every day (even after a few days without sunshine ) The controllers are a sunsaver 10 amp and a phocos 14 amp. I have another 45 watt solar panel I am planning on adding to the array also.How do I bring the gravity up to a good level? The voltage has never dropped below 11.9 even if we fall asleep with the TV and fans on and by the next afternoon, it always is back up to 12.5 or more. I don't want to ruin anything. Everything is new. Any advice would be appreciated.
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MtnDon
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# Posted: 1 Dec 2011 20:49
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You need a charger that has an equalization charge mode. Common battery chargers and charge controllers do NOT have this function. The better brands of inverter/chargers like Outback, Magnum and the upper end Xantrex have this feature is most/many models. Xantrex also has a couple of quality chargers that have the equalization option. Sorry I don't have part numbers for them off hand. Many of the better chargers will have the basic three, bulk, absorb and float, but still lack equalization capability.
What that does is apply a higher voltage at low amps for a period of time. This does several things. The battery electrolyte "boils" and mixes it up good. Battery acid can stratify and the sp gr can vary from top of cell to bottom of cell. The process will force cells with lower readings to get fully charged (unless the cell is already kaput). Equalizing can cause fluid level to drop so that must be monitored. Equalizing can also overheat and damage a battery; don't let the temp get much over 120-130 degrees F.
Start with a battery that is fully charged, then apply an equalization cycle. Measure the sp gr of each cell and record before the EQ cycle. Then after an hour or so, check the low cells to see if they have come up. Continue until the low cells have better sp gr.
Different battery manufactures may have different recommendations; Trojan specs 2.58 volts per cell as the equalization voltage for their golf cart size deep cycle batteries. That's 15.4 to 15.5 volts for a twelve volt battery.
AGM and gel cell batteries should NOT be equalized.
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Anonymous
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# Posted: 1 Dec 2011 21:02
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thanks for the quick response Don. Would it be possible to get a regular battery charger (110volt plug in type) and maybe once a month equalize the batteries? Also, will it eventually harm the batteries leaving them hooked up to these charge controllers? ( I guess I am actually asking how soon do I need to buy a better controller?) Also do the better charge controllers equalize the batteries automatically?
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MtnDon
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# Posted: 1 Dec 2011 22:08
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There are 2 schools of thought on equalizing frequency. One states that equalizing should be carried out on a regular basis; every 30-45 days or so, The other is that it is better for the batteries to only equalize as necessary or twice a year tops. The "as necessary" is decided by taking and recording the sp gr of each cell every month and equalizing whenever one or more cells are lower than the others by +/- 0.015. I subscribe to the only when necessary theory and so far, after 2.5 years on the present batteries, that works out to twice a year.
Good Info Here
The Outback FM controllers have auto and manual EQ settings. I'm sure the Xantrex top end ones do too; not sure about others. The best way to tell may be to download the manual for any you are interested in and reading them.
NOTE: The higher voltage used for EQ may damage some equipment if left connected to the system while battery EQ is being carried out. Check first, the spacs on good eqipment should list min & max voltages. If in doubt "pull the plug"
I am not familiar with the controllers you mentioned. However, any battery left for long periods of time without having each cell "peaked" once in a while could suffer early failure. You can help the situation a little by using the hydrometer to "stir up" the electrolyte by using the squeeze bulb to withdraw and then rapidly re-inject the fluid. Be careful of splashing yourself or equipment.
On a side note, it may be a personal idiosyncrasy, but I do not like using a base like baking soda to clean battery exteriors. Too much chance of accidentally contaminating the battery fluid, IMO. I use clean water and rinse with a brush off beforehand to get rid of dust/dirt. I also use the spray laquers to coat terminal connections; that seals them and helps prevent the green corrosion crap.
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razmichael
Member
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# Posted: 1 Dec 2011 22:31
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Quoting: Anonymous Would it be possible to get a regular battery charger (110volt plug in type) and maybe once a month equalize the batteries?
To specifically answer this - yes. If you don't want to replace the controllers then shop around for a decent smart charger with an equalization function. These are not nearly as expensive as they were a few years ago. Here is a link to the trojan site Trojan . As MtnDon and the trojan site suggests, probably best to disconnect the batteries when doing this. For the basic charging cycles you need to make sure the charger can handle the amps needed for the larger of the two battery banks and can be turned down for the smaller since you have a mixture. It is generally suggested that the charger setting is about 10% of the battery amp-hr rating.
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Anonymous
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# Posted: 1 Dec 2011 22:48
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Thanks to both of you..... I will do some homework and see if I can resolve the situation. I have just under $2000.00 invested, and so far so good, but I want to get the most bang for my buck so to speak. Once again, thanks for your help.
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razmichael
Member
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# Posted: 2 Dec 2011 07:15
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Anonymous (you need a better forum name) - how are you using/wiring the three batteries? I assume the golf cart batteries are 6 volts (and paired). So are you running the two 12V groups in separate circuits? It is not a great idea to mix battery types (or even mix old and new of the same type) if you can avoid it. You have a good amount of solar panels for a relatively small set of battery banks (although I have no idea on your daily load). I really just curious on your setup!
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Anonymous
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# Posted: 2 Dec 2011 22:22
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Quoting: razmichael Anonymous (you need a better forum name) -
My actual forum name is darz5150, sorry just didn't sign in.LOL
I have one trojan 12 volt battery and 2 everstart deep cycle batteries(12 volt) wired in parrallel. Originally I had the 2 matched everstart batteries connected together, with its own inverter, and used it mainly seperate for outdoor use ie. TV (nascar sunday, gazebo rope lights, fan etc.) The trojan was hooked up to a seperate inverter, and was used for inside TV,shed lights , 2- 12volt water pumps and a 12 volt fan, also power tools occasionally. I combined the 2 set ups when the daylight savings time kicked in. I wasn't sure if combining the 2 seperate sytems was correct or not but since everything was 12 volts I figured it would be OK. I just don't want to wreck anything since everything is new. When I first started this project, I only wanted a backup power source We have very frequent power loss where we are(over 16 times this year so far, mainly due to Kamikaze squirrels and tree limbs) The main power line runs about a half mile through the woods. I figured since I had solar power produced every day, that I should go ahead and use it ....... so I do. I have knocked my power bill down to less than a dollar a day.
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razmichael
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# Posted: 2 Dec 2011 22:50
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Hi darz5151 - there are potential problems mixing different battery types and/or ages as each will discharge and charge at a slightly different rates. With different ages of batteries mixed what tends to happen is the newer batteries get 'cycled more than the old ones and wear out prematurely - so the whole set only lasts as long as its weakest. this may be an acceptable situation rather than buying a bunch of new batteries but you need to be aware. Mixing different types will certainly compound the problem. This is what makes it difficult when designing a system that you intend to expand later - it is not optimal to just add more batteries when the others are more than 6 months old. On the other hand you have really cut down your electrical bill!
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darz5150
Member
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# Posted: 2 Dec 2011 23:23
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Quoting: razmichael there are potential problems mixing different battery types and/or ages
Everything is new ( within 30 to 45 days of each other ) but I have heard that mixing battery types isn't the best choice as you said. I have no problem splitting the system up again. Actually it might be better since I don't have a huge draw on the system, I can use one while the other is recharging, and then switch back and forth between the 2. I have dedicated outlets in the cabin, and switching between them is as simple as pulling the plug from 1 and sticking it in the other.( I wired the cabin outlets to a male plug connected to a 12-3 romex wire) Also I would like to add another trojan battery to the system shortly (within the next month or so ) Just under $200 bucks. I would connect it with the other one. Would you consider that adding a new battery with an old one or would that be OK in UR opinion?
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razmichael
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# Posted: 3 Dec 2011 20:42
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If you are saying that the current batteries are only a month or so old then you are really good to go to get another matching battery. Even if the original is older, as I mention it may still be cost effective to add a new battery as long as you realize that you are reducing the life of the new battery somewhat. At what point the trade-off is no longer worth it is up to you. Mixing different types of batteries (types, manufacturer etc) is not a good idea anytime and can cause a lot of problems.
An option to plugging and unplugging is to pick up a 4 way switch such as Battery Switch which can provide a lot of flexibility in switching from one battery bank to another.
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