Solar System Problems

Have you had this device for some time? I would think that your "charge controller" would switch to trickle charge when the battery is full. Normal charge (at least what it used to be, newer batteries might be different) is 10% of the amp-hours of the battery. Trickle charge would be 5%. Normal charge takes about 14 hours while trickle charge can go on indefinitely (I have a feeling the meaning of "indefinite" may be contested).

Possibilities:

• your battery is too large and takes too long to charge.
• your charger is a one-rate charger (doesn't change when battery is full) in which case, you should disconnect it when the battery is full).
• your charger may have a switch-off setting that is too high maybe even above the battery voltage (assuming it has an adjustment).
• You mentioned 3 sunny days. Can I assume that there was at least one or two "cloudy days" in between? In which case, your battery discharged during the cloudy days.
• Related to the last one, your battery is discharging during the night.

May be more possibilities but these are what comes to mind at the moment.

Great idea for emergency power! I had the same system in a boat for years, and it worked extremely well.

Good charge controllers will (generally) prevent overcharging the battery, making loss of electrolyte unlikely (although still its worth checking. (They will also prevent the battery from discharging through the panel, via a simple diode or two.)

When you put a new battery in, you should fully charge it with a good battery charger, but thereafter, the solar charger should do the trick (with a good charge controller). Periodically, I think it is worthwhile to run the battery all the way down with a significant load (which may happen naturally, if you have enough power outages), and then recharge it with a battery charger. Otherwise, with several partial discharges, the battery will experience some memory effect, and the full rating of the a battery is diminished. (This effect varies, depending on the battery tech used -- so read up on your battery. )

Kurtzweil (the keyboard, voice recognition, etc. guy) thinks that in about 10 years -- i think -- solar cells will be pennies per watt. In fact, I think he was envisioning pennies-per-sq-meter for paint-on cells, which seems a little bizarre, because that would be cheaper that the cheapest current house paint (but maybe the article wasn't edited right). It would be great to cut loose from the grid, and the pollution associated w/ generating power.

If it is a lead-acid or similar type storage battery: DO NOT EVER run it all the way down. These batteries do not experience memory effects as Ni-Cads for instance, and will be permanently harmed by a deep discharge. Normally, you never want to run your lead acid batteries down much below 1/3, and these are the "deep discharge" variety which is what you want to use, not regular automobile type or marine "cranking" batteries, although these are cheaper and you may use them with the understanding that they are primarily made for frequent, shallow discharges at high amperes, rather than much deeper discharges at lower amperages and less frequent intervals, so their performance in your application would be less than expected over time.

Hi Ken,

I know a number of people who use solar panels (or would like to) to conserve energy and/or reduce their dependence on The Grid. One thing many folks don't realize that the resources saved by using this technology over its lifetime is comparable to the energy resources consumed in manufacturing the panel itself.

Aside from that, I used a panel to keep a spare lead-acid battery charged - one in my truck's toolbox. Seems that particular model year had a chronic problem with the alternator. Three of the six diodes would pop every few months, forcing me to swap out the alternator with a rebuilt one no less than seven times over the period I owned the truck. Unfortunately, at one point my commute was 80 miles each way (I was doing consulting then) and so I drove much of the time in darkness - both morning and evening.

Twice during that contract period my alternator failed, forcing me to drive on battery alone while using my headlights. The first time it happened I made it about 50 miles (the drive was on a lonely stretch of road along which there were no towns or gas stations) before the battery died.

The second time I had a solar panel strapped on the back of my toolbox, along with a charge-regulator and a hefty lead-acid battery anchored inside - not to mention a handy set of tools to swap out the battery on a moment's notice. The panel on the toolbox garnered me a look of quizzical looks from passing truckers. I just smiled, but the setup saved my behind on a number of occasions.

Btw, the truck was a Ford F-150. Spell "Ford" backwards and you get Driver Returned On Foot. I now drive a 2006 Honda Civic Hybrid and I love it. That crappy F-150 (all my experiences with Fords have been negative) was doing well if it got more than 15 mpg.

-e

One thing many folks don't realize that the resources saved by using this technology over its lifetime is comparable to the energy resources consumed in manufacturing the panel itself.

I think there is some truth to that, but it has taken on a mantra quality. If it were entirely true, then the companies that sell panels would be selling them at a huge loss, because they have to pay for the energy used all along the way, plus a profit at each point in the supply chain, plus materials cost, plus labor, plus overhead, etc. etc. Even now, with the incredibly inefficient panels available, I doubt that the cradle-to-grave costs are as high as they are sometimes reported to be.

I'd like to think that Kurzweil is right, at least in principle. Photons whacking electrons around seems just too logical to be so inefficient. I have high hopes that in the near future, solar power can supply many of our needs.

Fix Or Repair Daily:

Honda is a remarkable company. Back in my college days, I worked as a mechanic (whenever lucid) and managed a Honda motorcycle service department for a while just after college. Our dealership also handled BMW, which then had a reputation (among some) for making the world's most reliable motorcycles. But in fact, we had far more warranty claims on the BMW's, and every claim was a fight. On the Hondas, we had 1/4 the claims (on a per-unit-sold basis), they tended to be minor (while some of the BMW claims required major work), and the company was remarkably easy to deal with. Even bikes clearly out of warranty were warranted if something that just shouldn't happen... happened. We had Honda 550 fours with rusty pipes after 2 or three years, and Honda would replace the entire set of four pipes (which, at retail, cost something like 25% of the entire bike's purchase price) at no cost whatsoever. It was as if Honda were saying "If there is any way we can make a customer love us, we will." BMW was saying "If there is any way we can make a customer hate us, we will."

We have a 2004 Honda and a 2004 Saturn. The Saturn has been generally OK, and it has some nicely engineered features. But the Honda feels like a solid well-engineered car, and the Saturn feels like an econobox. Weird little things happen with the Saturn's electronics routinely -- it hasn't completely let us down, but it keeps threatening to do so. Last time I checked, Honda was spending three times as much training American workers as GM was. So then, by buying "American" you were doing a disservice to American workers. Saturn had a reputation for a great buying experience, and for good customer service, and that was enough that I thought I'd give them a try. Am I horribly disappointed? No. Am I as satisfied as I am with the Honda? Hardly.

The fastest way to find out what you are doing wrong here (at least 2 things) is to go read about battery care on one of the RV Web sites.

No lead liquid acid battery is maintenance free except for the saturated glass matt batteries. So most require that you add distilled water from time-to-time.

The lack of use doesn't hurt a lead acid battery if you take care of it.

Most battery chargers and your charge controller are not very smart and they tend to overcharge the batteries. Look into a good controller with a 3-stage charge capability if you want to take good care of the batteries. It isn't that they are all that expensive but you have a system to take care of power requirements when there are emergencies and that cannot happen if the battery is dead from mis-management.

Please ClintB, define to me what are que caracteristics of this battery.

Cilmo.

This is all based on an educated guess that you are living in the northern hemispheres, it's winter and you are using a lead acid battery with about a 55 AHr capacity.

If that is the case the battery will take at least 19 hours to charge with a 35 W panel. Now that's assuming the panel is working at maximum output the entire time so in reality you are probably going to need more like twice that amount of time so depending on how many hours of daylight then from my calculations three days is not enough to charge the battery fully and it may take up to a week.

try these links:

http://hss.energy.gov/NuclearSafety/techstds/standard/hdbk1084/hdbk1084.pdf

http://www.humboldt.edu/~aej1/pubs.html

http://www.sandia.gov/pv/docs/PDF/caploss.pdf

http://www.sandia.gov/pv/docs/BattIntro.htm

http://www.sandia.gov/pv/docs/Charge_Controllers.htm

http://www.sandia.gov/pv/docs/Charge_Controllers.htm

http://power.ece.uiuc.edu/Balog/images/intelec02.pdf

How you switch between charging from PV and discharging (what type of load)?

The fact you mention that the battery was deep cycle and went dry from continuous charging with no discharge tells me that the problem is not with your solar panel or battery (although the battery is trash now), the problem is in your charge controller. Most likely, it was designed for a different type of battery, or simply was a low cost single-stage charger, and overcharged the battery. Overcharging a lead acid battery will cause the electrolyte inside the battery to "boil off", leaving a damaged and unusable dry battery in the case of a sealed battery, or requiring you to refill the electrolyte in a serviceable flooded cell battery.

I would strongly recommend that after replacing the battery, you purchase a different charge controller. The company I work for, Rogue Engineering Inc. makes some fairly nice ones that aren't too expensive. You can contact one of our distributors, or I am guessing our sales manager Bob would be willing to sell a single quantity charger to you directly if you called him (303-734-0706 x4100). Make sure you specify whether the battery type is flooded, gel, or AGM. (I'm guessing it is probably a flooded cell if it is a deep cycle "marine" battery). Our website if you want specs is http://www.rogue-engr.com

One other thing of note: Lead Acid batteries normally have a lifespan of 3-6 years depending on use, so your battery might just have died naturally if it is older than that.

TK

tkirk@rogue-engr.com

Thanks much for your information. You are probably right; it was a "low cost single-stage controller" However after 2 days of charging [we're having very bright, cold days in Md. right now} the controller began to cycle from "charging" to "charged" in brief increments. I also failed to properly maintain my old battery. Everythhing lookas it i'ts working now! CB

Just a note, if you leave the battery on the floor, and the floor is concrete, the battery will discharge over a period time through the floor. I don't know why it does it, but it does, so make sure you put something under it so the battery doesn't come in direct contact with the concrete.

MidniteFighter

Semiconducting to bad-insulation discharging effect.

Old station batteries had glass