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Lead acid... it's dead isn't it?

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SilverSolder:

--- Quote from: paulca on February 24, 2021, 04:36:35 pm ---
--- Quote from: SilverSolder on February 24, 2021, 04:22:53 pm ---Lead acid really hates standing around while discharged or even partially discharged.  If the solar system isn't generating enough to keep the batteries topped up during winter, you will get much better life out of the batteries if you hook up a float charger during that time, just to keep them in good condition.

I do that with cars.  I just noticed that the battery in my wife's car (daily driver) is getting a little weaker than it used to be, but still passes the load tests.  It will likely need to be changed this year.  That battery is 8 years old now...

--- End quote ---

That's impressive innings for a car starter battery.  My last one lasted 3.5 years and lockdown - stood for weeks and short trips to the shop - killed it.  That is one advantage of having a 100Ah marine lead acid sitting in the garage.  I can just disconnect it from the solar panel and jump start the car with it.

--- End quote ---

A float charger is  your friend.

I like the cheapy Harbor Freight ones, they are often on sale for around $6!   :scared:

They work like a champ and I havent broken one yet (oldest one >10 years).  I measured mine (I have 3) and they are bang on spec.

paulca:

--- Quote from: Renate on February 24, 2021, 02:40:12 pm ---Lead acid is still a bit voodoo to me.
Can you get a battery acid hydrometer reading off it?
Is it sealed? How are the levels?

--- End quote ---

Good point.  I think it's sealed.  It has a plastic top where you can see circles for the cells, which I think is just the cap.  I haven't found a way to open it yet though.  It doesn't have anything affording opening.  So I expect it is sealed.

I think I just bought a marine starter battery.  Too much YouTube has led me to know that boats have two batteries.  The starter battery and the house battery.  If you leave the lights on you drain the later.  You can still start the engine.  I got the starter battery when I wanted the house battery for solar.

Ian.M:
When it comes to flooded cell Lead Acid batteries, read 'maintenance free' in the advertising as 'unmaintainable'.  In cyclic use they NEED an equalizing charge at somewhat regular intervals, which involves overcharging till the cells are gassing sufficiently to stir the electrolyte, sampling the S.G. periodically until it stops rising significantly in all cells, then topping up with distilled water to the correct level.    Obviously you cant measure the individual cell S.G.s of a sealed battery, so the best you can do is a timed equalizing charge, but the reserve electrolyte capacity is minimal and you cant top up the cells, so the total cumulative time you can equalize for before the electrolyte level is down to the plates is very limited so the service life is likely to be significantly shorter than a comparable battery with removable caps.  Also with no caps to remove to allow the hydrogen to freely escape, the equalizing charge fills the battery's cell headspaces and vent passages with a highly explosive hydrogen/oxygen mixture, so you are one spark (e.g. from a cracked link) away from a nasty explosion.

A good quality flooded Lead Acid battery with removable cell caps, properly charged, regularly maintained and not deep discharged for significant periods should be good for a service life of five to seven years, assuming its of the correct type for the application, with sufficient capacity to have an adequate reserve so the reduced capacity towards the end of its life isn't problematic.

Renate:
I think that the solution is Leyden jars.
They are very efficient.
Ok, volumetrically they aren't so great.
Also converting several hundred kilovolts to 12 V is not currently efficient.

duckduck:

--- Quote from: paulca on February 24, 2021, 04:36:35 pm ---
--- Quote from: SilverSolder on February 24, 2021, 04:22:53 pm ---Lead acid really hates standing around while discharged or even partially discharged.  If the solar system isn't generating enough to keep the batteries topped up during winter, you will get much better life out of the batteries if you hook up a float charger during that time, just to keep them in good condition.

I do that with cars.  I just noticed that the battery in my wife's car (daily driver) is getting a little weaker than it used to be, but still passes the load tests.  It will likely need to be changed this year.  That battery is 8 years old now...

--- End quote ---

That's impressive innings for a car starter battery.  My last one lasted 3.5 years and lockdown - stood for weeks and short trips to the shop - killed it.  That is one advantage of having a 100Ah marine lead acid sitting in the garage.  I can just disconnect it from the solar panel and jump start the car with it.

--- End quote ---

I kept my deep-cycle battery for my electric trolling motor even after I sold the boat. I have the battery in a trolling motor battery case that has a couple of cigarette-lighter plug connections. When there is a power outage (frequent out here in the sticks where live) I just pull the USB charger out of the car and plug it into the battery and we've got USB charging outlets for a couple of phones. I'm sure this 20+ kg SLA battery could power our phones for a week. Yes, I'm looking into getting a natural-gas powered generator and the whole electrical switching stuff so we can open the refrigerator without worrying during a power outage. Usually the utility gets things back up in a few hours, so I usually just grill dinner and we bust out the flashlights. Anyway, my point is that I agree that it is nice to have a big SLA around the house. Comes in handy for sure.

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