Help for mathematically and mechanically challenged re: house battery use and life

[pamerica]

If you will, please explain this to me in simplest terms possible, for the simplest of minds...

 AGM yellow top battery....no idea how many whatever it is that you describe it as having to explain its strength, staying power?

 1500 watt starting, 750 running inverter

If I use a 110 watt electric blanket, for example, how many hours can I use it and not run the battery down too far?  Saying that the battery is full to start.

Is there an easy way to figure this out for various items?  Fantastic fan, laptops, anything.  Thanks.

 

[SternWake]

If you will, please explain this to me in simplest terms possible, for the simplest of minds...

 AGM yellow top battery....no idea how many whatever it is that you describe it as having to explain its strength, staying power?

 1500 watt starting, 750 running inverter

If I use a 110 watt electric blanket, for example, how many hours can I use it and not run the battery down too far?  Saying that the battery is full to start.

Is there an easy way to figure this out for various items?  Fantastic fan, laptops, anything.  Thanks.

"Yellow top"

Indicates an Optima battery, which is a spiral cell AGM battery.

These 6 pack style batteries have 25% less capacity than a rectangular AGM battery

lets say the optima yellow top is a group 31

According to the optima site a group 31 optima is 75AH. A group 31 Odyssey or Northstar AGM is 100AH, A  lifeline group 31 is 105 or 125AH( gpl-31t or GPL-31XT)

110 watts at 12.2v is  9 amps.

  If this 110 watt heating blanket was running full blast the whole time at 9 amps,, well lets generously say it is 10 amps as the inverter powering it is at best 90% efficient. A 10 amp load would deplete the  healthy fully charged 75 amp yellowtop optima to 50% in 3.5 hours.  But this is not technically correct

There is the Peukert effect which says the bigger the load, the less capacity the battery has to give.

The 75Ah battery could power a 3.5 amp load for 20 hours before complete 100% depletion at 10.5V, but you have a 9 amp load.

According to this site:
http://www.csgnetwork.com/batterylifecalc.html

A 9 amp load on a healthy AGm battery with a peukert component of 1.15, would only have a total of  53.94 AH of total capacity
 54 AH divided by 9amps  is 6 hours until complete depletion of the healthy, fully charged battery( pipedream)
Ideally you want to not go below 50% charged.

So assuming the 110 watts did not cycle on and off( it likely will, depends on ambient temperature) in 3 hours it could take the new healthy fully charged optima yellow top group 31 to 50% charged.

Returning this 50% depleted Optima battery to 100% charged ( or any lead acid battery) is not going to happen in less than 5.5 hours under ideal conditions.

Ideal conditions means a charging source capable of high amperage initially and one which holds 14.7ish volts for 4 to 5 hours after it gets the battery to 14.7 ish volts.

Also unlikely to happen in real usage.

A 12v mattress heating pad will likely use less electricity.

https://www.amazon.com/Mattress-Ele...2880&sr=8-1&keywords=12v+mattress+heating+pad

These can consume 6.2 ish amps and cycle on and off depending on the ambient temperature.   how much they consume varies widely on the setting chosen and the ambient temperature of the temperature controller.

These heat slowly. When I had one, it took a while (45 minutes to 2 hours) to heat the bed to 112f , and I usually turned it off as soon as  I got in bed. and in 48f minimum overnight, if I left it at the lowest setting, it used about 35 AH in an 8 hour period.

Sorry, Electrical heating on battery power just does not work very well for very long.  It can be done, and Optima batteries might be well marketed, and have a loyal following, but they are not a high capacity battery, having only 75% the capacity of a rectangular battery, and simply are not a good choice for a house battery application.

 

[WheelEstate USA]

If you'll recall, I mentioned that battery would only handle basic daily needs, at best.

 

[pamerica]

Thanks SternWake and Jay (WheelEstate).  I actually do understand that, for the most part, SternWake.  I appreciate your explanation.

Jay...then why was this battery promoted so highly to me?  Should I have just kept my regular old marine battery?  Should I replace this now?  Batteries don't cost that much, when you consider how valuable they are to you.  You have seen my smallish battery compartment.  What should I get?  Thanks and HI to you and Margie!  Oh, and oops, I am not out there now.  Who the heck will know how to replace it anyway....with the wires and such.

 

[DannyB1954]

This 12 volt electric blanket uses 4 amps, or 48 watts.  and has a timer that will shut off after 30 or 45 minutes. https://www.amazon.com/dp/B0000DYVN9/ref=psdc_14058581_t1_B0009Y2CFS By that time the bed will be warm and you will be asleep.

I sometimes use a regular heating pad on low. The one I have can be set to shut off after 2 hours. I am asleep by then and never wake up cold. Once the bed is warm, my body tends to keep it that way. On high they typically use about 70 watts.  I put it in the small of my back. The directions always say do not lay on it. I think that is for liability. On low it is plenty warm and I have never had a problem.

 

[pamerica]

Thanks, Danny.  That's a good price, too.  And thanks for the info on heating pads.

 

[SternWake]

then why was this battery promoted so highly to me? 

Optimas batteries are well marketed.  back in the 90's and early 2000's they were made in USA and for their limited capacity, were very durable and reliable batteries.

Then Johnson Controls bought them, and moved production to mexico and increased their marketing budget, and with the earlier batteries performing well, were able to ride that magic carpet into executive bonus land all while putting out an inferior project.

The news has just not spread wide enough that the quality has dipped tremendously.

The best rectangular AGM batteries are Northstar( rebranded as X2Power at batteries+) Odyssey, and Lifeline. But these also need to be recharged occassionally at high amperages to live up to their potential. Without it they will not, and might not be any batter value than a regular marine battery.

There is a huge difference between a 75 and 100Ah battery when one is using 50Ah per night.  The well marketed Optimas are only well marketed, in my opinion.

The spiral cell six pack design is Very tolerant of high vibration environments, more so than their rectangular AGM counterparts. The six pack casing is also stronger in  the case of physical stress to the battery casing.  These attributes are not really relevant to house battery duty in a Rv  deep cycle scenario.

Always beware of marketing.  The new business model is not furthering quality, it is cutting quality to lawyerly acceptable minimums while increasing the marketing budget.

Any well marketed item, seems to have sacrificed quality as that has proven to be more profitable.

 

[WheelEstate USA]

Others liked that yellow top but I never recommend AGMs without proper equipment for charging.
I don't think the marine batt would hold up to much more either.

As I see it, your solution (for the rig) is to make space for 2 X 6V...if you need power for extras.
Most likely mean mounting 1 on each side back there.

 

[DannyB1954]

I should have mentioned the best way that I found to stay warm in bed was with a hat. The kind that cover the ears and tie under the chin. Your brain will keep itself warm at the expense of the rest of your body. If the brain is toasty, it will allow warm blood to go elsewhere. My favorite one was a Russian Ushanka Hat. They sell them on Ebay. You can get them made out of faux fur, wool, cotton, fox, mink and rabbit. This hat will also keep your neck and face warm. It says one size, but It might work. http://www.ebay.com/itm/Men-Winter-...6d4291a59010d62f199c4c&pid=100643&rk=1&rkt=1&

This add has a chart to convert the different hat sizes. http://www.ebay.com/itm/D-Y-Russian...713861?hash=item35f336aec5:g:46IAAOSw7R5WFXrg

 

[Gypsy Jane]

If you sleep on real sheepskins, you don't need to warm the bed you'll be comfy in no time. Get a down duvet for the top of you, and a blanket to keep the heat in. If it's really freaking cold, add a hot water bottle. No electricity needed.

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