I need some battery education....

[spock123]

Originally Posted by boondocking

Thank you Cam!



There is a lot of false info in that write up.

I was just about to reply to spock123, but you beat me to it.

Opinions are like something else , every body has one


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[spock123]

Originally Posted by camaraderie

Just for fun I took the part 1 of the 12V Side of Life and found the things I disagreed with. There are many. Here are the statements and opinions I disagree with: (Bolded what I disagree with and wrote my own opinions in red.)

Slower charging and discharging rates are more efficient. This is meaningless in a charging situation. Your goal is to get the battery charged as fast as possible because running your generator to charge any battery is VERY inefficient and you want it over as quickly as possilble. This statement means it takes less WATTAGE to charge a battery at 5 amps rather than 50 amps...but it makes NO sense to run your generator 10x longer.
Practically all batteries used in RV applications are Lead-Acid type batteries. Even after over a century of use, they still offer the best price to power ratio. NO... actually lithium batteries provide a far better bang for your buck but they are prohibitively expensive for most.
In my opinion, the standard flooded cell battery offers better overall performance for the price and will probably last a lot longer in most common RV applications. Trojan specs out wet cells as lasting 10% more cycles with perfect care in lab conditions. AGM's will out perform them in actual use since batteries are so often neglected.
Deep cycle batteries are designed to be discharged down as much as 80% repeatedly, and have much thicker plates. While they MAY be discharged as much as 80%...there is a HEAVY price to be paid in life cycles compared to 50% discharge....you lose 1/3 AT LEAST of your battery life.

The major difference between a true deep cycle battery and others is that the plates are solid Lead plates - not sponge. Completely false. Deep cycle batteries typically use a PASTE of lead and antimony and other proprietary ingredients and a spongy surface provides MORE reactive surface area and is desireable! The only pure lead plate deep cycles I am aware of are the TPPL AGM's by Odyssey which are both expensive and excellent.
Most flooded batteries should be charged at no more than the "C/10" rate for any sustained period. "C/10" is the battery capacity in amp/hours divided by 10. Sorry....the goal is to charge quickly and wet cells will accept bulk charging at C/20-25 while AGM's will typically accept at at least twice that. Once the battery reaches 70-75% SOC ...then it will resist higher charge rates.
The truth is, most of the RVs on the road have very poorly designed battery charging systems courtesy of the factory. Why? Well, cost plays a key role in deciding what equipment a RV will have installed when it's sold. Most RVs depend on the 12volt converter to charge the house batteries. In most cases, that's a very poor compromise! Totally dated info...I'm not aware of ANY mfr. using anything less than a 3 stage charger for the last 4-5 years.

The best chargers on the market are 3-stage chargers. NO... the best chargers on the market are 4 stage chargers which periodically EQ the batteries so they avoid sulfation.
Float Charge:The 3rd stage of 3-stage battery charging. After batteries reach full charge, charging voltage is reduced.. NO...Float begins BEFORE full charge is reached and continues afterwards to maintain a full charge.
Since the converter is designed to not exceed a voltage of about 13.5 volts, it will never fully charge your batteries. Again...dated information...converters will supply roughly 14.5 volts to begin...and 13.5 volts WILL fully charge a battery...eventually...as will ANY voltage higher than FULL (12.7).
Also, after it has succeeded in partially charging your batteries, it will then commence to boil off electrolyte, as the "float" voltage is too high (should be about 13.2 volts max.). Dated and untrue today.
http://www.marxrv.com/12volt/voltchart2.gif differs from similar chart earlier on the page. Which chart should we rely on for battery state of charge? (The latter is closer.) SOC= Measured at rest voltage....minus 11.4...divided by 1.5 and multiplied by 100.
Example...measured voltage 12.2 -11.4=.8 /1.5 x100=53% charged.
Allow the battery to sit for six hours with no load or charger connected
24 hours is the proper wait time. 6 is better than nothing. Don't believe it?
Take a new battery and charge it fully. Remove the negative terminal. Measure it in 6 hours and you are guaranteed to have over 12.7V...since 12.7 is 100% full you are getting the surface charge voltage. This happens on ALL batteries so even if you read 12.7 on an older battery...it could be 12.2 and trouble!
some charging current will have to be applied to the batteries periodically during the storage period. NOT true for storage periods of 3 months or less for wet cells. Not true for storage periods of 6 months or less of AGMS (actually probably a year!) . Self discharge of a fully charged battery is 10% or less a month in moderate temperatures and much less in freezing confitions. 1% or less for AGM's.) Exception...if storing in FL or Arizona...you may need to apply a charge sooner. Batteries will NOT freeze if at least 70% SOC is observed. This means...charge fully and you'll have at least 70% 3 months later with no danger of freezing and NO need to keep a charge on them. (Assumes disconnected negative wire so no parasitic drain.)
Storage: It is a real good idea to check at the battery with an ammeter to ensure that there is no current drain. Simply disconnect the negative.

Invest in a good digital voltmeter and use it.If you're gonna invest in something...invest in an AC/DC Clamp meter so you can see what is going on! Voltmeters are good but limited. A $50buck clamp/meter will be a better investment. If you boondock...get a true battery monitor before anything else. Victron or Trimetric.

The 12 volt side of life has served me well, I think I'll stick with it. Opinions doesn't mean much to me. It's like something else everybody has one


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[SidecarFlip]

My neighbors are cattle and a couple nags (horses). Don'r bother them at all. In reality, a diesel gen set runs much quieter than a gas powered one because it turns slower (1800 rpm verses 3600 for a gas unit).

If I lived in a condo (which I don't believe I could deal with), I'd have a small portable genny for double duty (RV and home use) too.

The wife has been talking about a condo in Florida for the winter months, I keep ignoring her.....

[Too Tall]

Here is what I did. These battery racks are not really designed for 2 12 volt boxes. 2 6v will handle CPAP much better.
https://youtu.be/foLGtyt9Rsg

[SidecarFlip]

You see, I'm in a unique situation. With a truck camper (Backpack SS), the batteries go INSIDE the unit, not outside so there are space constraints, you cannot just add a tray and call it good. Wish I could but I cannot and adding an additional battery in another location near floor level (I have floor storage cabinets) reduces the amount of room to pack items needed for camping, there isn't a whole lot of storage room to begin with....

One thing I did do was I changed out the battery cables to welding cable and the Inverter feed leads as well. I use copper stranded welding cable, neoprene sheathed with Western Union style compression solid copper lugs crimped and soldered on the cable ends. Fatter the cable, the less resistance loss there is and stranded versus solid in any application will carry current better in similar gauges.

I went overkill on the Inverter, 3000 watt Xantrex. My CPAP might pull 75 watts, I've never heard the inverter fan come on, it don't even get warm. I went with a Xantrex over other brands because it has the lowest idle current consumption and it ships with a remote hard shutoff switch, which I require as the inverter is in the mechanical compartment with the FW tank, pump, house battery and electrical components, under the dinette seat and isn't accessible easily.

[VTX Al]

Re - the "You must use two brand-new, absolutely equal in all regards batteries" statements, when connecting in parallel.

So, just for the sake of argument, what exactly happens if one simply adds a second new battery (same size, voltage and amp hours) to an already existing battery system ? For example: are they likely to go BOOM in the middle of the night and blow your whole camper into the next county, or are they just going to balance each other at something less than the efficiency of the new battery ?

...VTX-Al

[Too Tall]

They will balance at the voltage of the weakest battery

[OntarioFireFighter]

Originally Posted by VTX Al

Re - the "You must use two brand-new, absolutely equal in all regards batteries" statements, when connecting in parallel.

So, just for the sake of argument, what exactly happens if one simply adds a second new battery (same size, voltage and amp hours) to an already existing battery system ? For example: are they likely to go BOOM in the middle of the night and blow your whole camper into the next county, or are they just going to balance each other at something less than the efficiency of the new battery ?

...VTX-Al

Biggest concern - the battery state of health (plate condition, internal conductance, etc) may be different between a new and "seasoned" battery.

Will it go boom? No.

Will you get the maximum life and capacity out of the batteries? Also no.

Whichever battery has the greater conductance, will charge and discharge more quickly.

Some battery manufacturers will change their internal construction or chemical makeup between runs; which can lead to two "identical" batteries actually having very different electrical properties (internal conductance, and charge/discharge rates) depending on when they were produced...

[boondocking]

Originally Posted by spock123

Opinions are like something else , every body has one

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Well it is not really opinions, it is lack of accuracy. If you believe everything that is written there then carry on.

[Herk7769]

Based on my experience and education, Camaraderie's comments reflect an fairly accurate view of the subject.

As always, this is the internet. Caveat Lector

[KAS]

Originally Posted by SidecarFlip

My machine didn't come with an adapter so 110 is the only option (I use an older Res-Med unit). Some things never wear out.

I have an older Res-Med model also that I use for camping. I found a 12V adapter on this website. Works great!
Direct Home Medical: 12V DC Power Cord for Various Respironics, Sandman and IntelliPAP CPAP & BiPAP Machines