usable amp hours

[Mobilesport]

A pair of Samsclub GC2 golf batteries
220 amp hours
110 usable amp hours
Say if i only get them charged to 80% full each time i charge.(once per day)
I take them down to 50% each time(once per day)
Does'nt that give me 60 usable amp hours per day given that i'm
charging everyday 50% to 80% ???????

 

[29chico]

A pair of Samsclub GC2 golf batteries
220 amp hours
110 usable amp hours
Say if i only get them charged to 80% full each time i charge.(once per day)
I take them down to 50% each time(once per day)
Does'nt that give me 60 usable amp hours per day given that i'm
charging everyday 50% to 80% ???????

For the first very few cycles.  Then the capacity of the battery bank will get smaller.  At that point a full and proper recharge will restore most of the 110 usable amp hours.  Providing you did the "recovery" charge after only a very few partial stage of charge (PSOC) cycles.  A few more PSOC cycles beyond that will have you resorting to a full equalization (EQ) charge with a hydrometer in hand to make sure that you get it right.  Doing an EQ charge does do some damage to the battery bank, but nowhere near the damage that would happen if one left the sulfation on the battery plates to harden more over time.

A number of PSOC cycles will do to a lead acid battery bank's capacity what the term "significant shrinkage" will do to a man who goes out into a blizzard nekkid...

 

[ccbreder]

Lead acid chemistry wants to be kept at a full charge. It is better to get to a 100% charge, often. Even more confusing, they like to be cycled through discharge/recharge life. They don't like to be discharged and left not recharged 100%.

 

[Mobilesport]

I've heard alot of boat guys just bulk charge the best they can like to 80--90% and then just buy new batteries when they die because they dont have shore power , so thats what i'm trying to do since i dont have shore power

 

[MrNoodly]

Why are you unable to charge more than 80%? Not enough solar power? Using something other than solar? Buying new batteries seems more expensive (and wasteful) than dealing with whatever is preventing you from properly charging.

 

[Mobilesport]

Why are you unable to charge more than 80%? Not enough solar power? Using something other than solar? Buying new batteries seems more expensive (and wasteful) than dealing with whatever is preventing you from properly charging.

I dont use saor because i live in the midwest , i'm not sure if solor would work in my weather conditions .
I have a post on that topic

https://vanlivingforum.com/Thread-would-solor-panels-work-for-me

 

[MrNoodly]

I dont use saor because i live in the midwest , i'm not sure if solor would work in my weather conditions .
I have a post on that topic

https://vanlivingforum.com/Thread-would-solor-panels-work-for-me

Okay, but how ARE you charging your batteries? If you can only charge to 80%, then it's not a good solution. Or maybe batteries are the wrong thing for your situation.

 

[SternWake]

If one is unwilling to run their generator long enough to occasionally get to 100%, then there is no option but to accept a shorter battery life. Attempts to increase battery life when fully charging is not possible or unwilling to be pursued, is irrational.

Accept it or pursue 100% recharges more often. Those are the two options.

There is no way to avoid sulfation with lead acid batteries when not regularly recharging to 100%. They will walk down in capacity, sulfate, and lose capacity and this cannot just be recovered with hope and 15 volts applied for 48 hours.

Lifepo4 would have no issue with these partial recharges, but they would likely not deal with his current location's temperatures( well below freezing) very well.

 

[blars]

Lead-acid also have problems with extreme temperatures. See the battery box thread. LiFePO4 do not have a problem with discharge below freezing, only charing. Some people put them inside in a more temperature controlled climate, others heat them before charging. It depends on your situation.

 

[GotSmart]

I dont use saor because i live in the midwest , i'm not sure if solor would work in my weather conditions .
I have a post on that topic

https://vanlivingforum.com/Thread-would-solor-panels-work-for-me

I live in Missouri.  Even today, the panels are charging through the snow. granted there is only about 1/2 inch on them, but still.   They produce power until full dark. 

Solar works.

 

[Mobilesport]

Why are you unable to charge more than 80%? Not enough solar power? Using something other than solar? Buying new batteries seems more expensive (and wasteful) than dealing with whatever is preventing you from properly charging.

I ussually get them to around 90%  with gen and 75 amp charger, i'm just 
curious if i figured 50 to 80% correctly , i came up with 59 usable amp hours

 

[Ticklebellly]

50% to 80% of a nominal 220 Ah battery tells me you are cycling 30% of the nominal battery capacity. I come up up 66 AH. As others have said, not getting the batteries all the way up to 100% as much as possible will damage the capacity of the batteries before design life finishes.

Some of the better DC to DC chargers do an equalization charge at the top of the recharge cycle to overcome surface charge and ensure 100% has been reached. A lot of the the mains power chargers do similar. Is your 75 Amp charger mulit stage?

 

[Mobilesport]

50% to 80% of a nominal 220 Ah battery tells me you are cycling 30% of the nominal battery capacity.   I come up up 66 AH.   As others have said, not getting the batteries all the way up to 100% as much as possible will damage the capacity of the batteries before design life finishes.

Some of the better DC to DC chargers do an equalization charge at the top of the recharge cycle to overcome surface charge and ensure 100% has been reached.   A lot of the the mains power chargers do similar.   Is your 75 Amp charger mulit stage?

My charger is single stage adjustable voltage

 

[jimindenver]

A example of the difference even a smaller amount of solar can change things would be my 6 year old marine Grp 27. When used the first night after being on a auto charger at home, it would read 12.5v the next morning. 2 hours even with my pitiful 55a/ 13.6v single stage and it would be at 12.4v the next morning and every morning that I charged with the generator. In the same conditions with solar it would show 12.57v day after day. The solar would have it in float early and the battery sat there sucking up float voltage all day long as the solar covered the trailers needs. Why the .07v difference between the freshly charged battery and the battery on solar? The solar battery did not have to handle the day time loads as a few hundred watts covers exhaust fans, LED lights and other parasitic loads during the day.

In your case the solar could be that float voltage at low amps all day long after the generator did the bulk charging. Float is what replaces that last bit of power needed for the battery to get closer to 100%. It may even mean shorter generator run times.

 

[Ticklebellly]

My charger is single stage adjustable voltage

Not sure how you are determining SOC.   My charging set up from solar applies 15.1 volts for a short time after battery reaches float for predetermined time.   The higher voltage breaks through surface charge and ensures all cells are topped up.   I suggest you Google equalisation charging for some ideas.   If you can adjust your charger voltage, that could be a way to get to 100% regularly.   There are dangers.   In old tech lead/acid flooded cell days, equalisation was described as 'boiling' the batteries as lots of gassing could result giving the appearance that the electrolyte was actually boiling. 

A 75 amp charger should be able to replace 66 A/Hs pretty quickly, IF, the batteries can handle high charge rates.

 

[SternWake]

TB, he just does not run his generator long enough to reach maximum specific gravity. His charger is one of the most capable for his intentions as it will not prematurely revert to float voltage as will most any 3 or 4 stage charger, wasting gas to run the generator holding only 13.6v.

50 to 80 will sacrifice battery life, but in the end it is about saving money, why spend 100$ in fuel for the generator to extend battery life by 50$ worth of cycles

He should be adjusting his voltage higher for the cold temps he is experiencing. Being able to plug in and run a complete recharge, then bump up voltage even higher for an EQ charge would incur a batterygasm, but running the generators for 8+ hours to accomplish this makes little sense financially.

 

[Ticklebellly]

50 to 80 will sacrifice battery life, but in the end it is about saving money, why spend 100$ in fuel for the generator to extend battery life by 50$ worth of cycles.

......... running the generators for 8+ hours to accomplish this makes little sense financially.

Certainly agree.   Just trying to put a few more ideas out there.   I manage my ins and outs on a daily basis depending on what is available in solar or alternator.   All calculations done in my head while standing on one foot and looking to the West.  My only concession to battery life is to try to achieve 100% if easily possible.   There is a lot of dollar value in not getting too stressed about it.

 

[SternWake]

  There is a lot of dollar value in not getting too stressed about it.

Wise words.

What I found stressful was not being in control of the voltage and relying on 'automatic' or marketing mumbo jumbo of most of the products that simply cannot do what they claim they can.  
So I remedied that with adjustable voltage power supply as a 40 amp plug in charger, and I can twist a dial to control my vehicles voltage regulator for upto 106 amps, if the rpms and requirements for it are there, and of course my solar's setpoints are adjustable.

I Just can't always control the time in which to apply them.