How Am I Hurting My New Batteries?

[GorillaToast]

Info-

40w solar panel
Genasun 4 controller
2-6v 235ah batteries in series
No generator or alternator
No shore power
Location; central Ohio

Incandescent cabin lights
Nav lights
Depth sounder, knot meter
Steaming light
Stereo
Fan
12v wet/dry vac
12v TV

17v at the panel, 13.2v at the battery. Rarely, do I draw it down to under 12.6v. Granted, I havent had a long spell of cloudy days since I installed the panel, so conditions have been pretty ideal for solar. Just wondering if not taking the batteries down to 50% occasionally, and charging with a charger is doing any damage to them.

 

[Benny17441]

It is a good practice to exercise new batteries but not knowing the age of yours I would not know. Take a voltage reading on the battery at rest for at least two hours and determine the state of charge. A fully charged battery to 100% can be a healthy one but a partially charged one will invite sulfation. Your voltage readings are good but we understand they will oscillate accordying to the available sunlight and the angle at which they hits the panel. My main concern would be to insure the batteries are reaching full charge. If you have a charger with an equalizing function it would not hurt to equalize them every few months. A solar panel does not preclude the use of a charger and you can use them both without having to rely completely on the electrical one.

 

[Stu Jackson]

http://www.amplepower.com/tech_docs/index.html

 

[GorillaToast]

It is a good practice to exercise new batteries but not knowing the age of yours I would not know. Take a voltage reading on the battery at rest for at least two hours and determine the state of charge. A fully charged battery to 100% can be a healthy one but a partially charged one will invite sulfation. Your voltage readings are good but we understand they will oscillate accordying to the available sunlight and the angle at which they hits the panel. My main concern would be to insure the batteries are reaching full charge. If you have a charger with an equalizing function it would not hurt to equalize them every few months. A solar panel does not preclude the use of a charger and you can use them both without having to rely completely on the electrical one.

Benny,
Over the winter, I ran them down to 12.2v and charged to full several times. They were new this January. As I am at a marina with no shore power, I will either have to buy a generator, or pull them out of the boat to equalize them .
Thanks .

 

[heritage]

You might try bypassing your solar controller and allow the panel to raise the batteries voltage to the equalization range. Your looking for 15-16 volts for a couple of hours. It would need to be done when the sun is high and the batteries are already fully charged. Keep the battery compartment well ventilated and watch the water levels.

 

[Bill Roosa]

There are LOTS of examples of batteries staying on float charge for YEARS and they work fine when called upon. Emergency power batteries being the prime example.
Battery life is measured in charge - discharge cycles. Shallow cycles allow the battery to cycle a greater number of times before they fail. Deep cycles allow fewer cycles before failure. Completely discharging or deeply discharging is NOT recommended from a batter live view.

 

[Benny17441]

I guess I wandered from your question. No, taking the batteries down to 50% and then charging with a charger will not help them. I believe this is what Bill may be trying to convey. Good luck.

 

[Deckhand]

Hopefully this will help.

Gorrillatoast,

The batteries you bought in January are just dead and need recharged. You can verify this by buying a hydrometer and checking the charge of each cell. I check deep cylcle batteries everyday for a living and when you are dealing with a true deep cycle you cannot get by without a hydrometer. Battery voltage alone can be very decieving. MAKE SURE YOU GET A GLASS ONE (around $10) the plastic ones are shit. When checking the batteries with the hydrometer a fully charged battery will read about 1265 to 1275. Over 1275 is overcharged and will harm the battery (note- All cells should be identical. Make sure the float is not touching the sides of the tube have a lot of bubbles stuck to it or hitting the top of the tube these will all cause faulse readings). This will confirm that the batteries are in fact dead and just need recharged. The 40W panel will maintain a fully charged battery when not in use but will not even come close to recharging it. AS far as recharging them I would not recomend using a generator if you can take them home and recharge them at the house using a good desulfating charger this seems like more work but will give you less problems in the future. I also have a C-22 and spend the weekends on the lake. We use a 12V T24 Trojan deep cycle battery that will run the lights (led bulbs), radio and low draw fan through a three day weekend . I also thought about installing a larger battery bank but for our use its just more money out of pocket and more expensive to maintain. I would be replacing two batteries every four years verses one and still have to remove the batteries to recharge just not as often. The way I look at it is you may get away with charging your batteries 1/2 as often with the larger bank but I would rather just take my 45lb battery with a handle back to the house each trip and start the next trip with a 100% charge and no problems than try to keep track of how much reserve I have left and lug two 61lb 6V's back and forth. Hopefully this will help you and for my two cents well its just that.

 

[FourPoints]

I beleive the answer to your question is you are not hurting them, you are taking rather good care of them.

The only suggestion I have is to replace your incandecent bulbs with LED bulbs so you don't draw the bank down as quick, thus leaving less for the panel to recharge in the morning and ensureing that it is able to recharge fully in a quick enough time frame. A 50w panel (4a max charge rate) will take a couple days to fully recharge a 470ah bank.