What's the big deal with 6v batteries?

[rvpopeye]

The lead batteries are much more forgiving about how they are charged than the more picky exotic formula batteries are.

 

[jimindenver]

And you'd think y'all never saw a 6v starting battery.

 

[highdesertranger]

our Ford tractor had a 6v positive ground system. talk about a headache. no jump starting that. highdesertranger

 

[DannyB1954]

And you'd think y'all never saw a 6v starting battery.

They still make them https://www.amazon.com/Optima-Batteries-8010-044-Starting-Battery/dp/B00099HVN6


They are built different than the deep cycle or "golf cart" variety.

 

[Vagabound]

Bigger cells = bigger plates, more electrolyte = more capacity.

Add to the list:
6.  6V, deep cycle batteries each have 1/2 the weight of a comparable 12V deep cycle battery:  6V, 200AH battery = ~60 lbs; 12V, 200AH battery = ~120 lbs.  I'd rather lift 60 lbs twice than 120 lbs once.  Becomes very important if your battery box is in a hard to reach place.
7.  6V golf cart batteries are easy to find (I got mine at Sam's Club).  True deep cycle 12V batteries, not so much.

 -- Spiff

And the clouds continue to part!  Thanks for the explanation and those very practical additions to the list.

Vagabound

 

[jimindenver]

6 volt golf cart batteries are popular because it is a affordable solution. Other batteries like my Lifeline are designed better too but they cost three times as much. The difference is the Lifeline was designed to act on it's own or in a bank. A golf cart battery is designed to be in a bank where high draw loads are spread over many batteries. Just two in a bank wont be able to handle the draw of a microwave like one of my 8-D's can. it's a trade off. Two will run my trailer and it takes four for the inverter. Four 6v start getting expensive and take up some space.

I will say this after being on various forums for five years. People worry and fret over their batteries when they buy and I'll bet the vast majority are either cooked, under charged, partially charged or drained. People have no idea how long it can really take to charge a battery or how easy it is to damage it. High end, low end, marine, golf cart, AGM, they are all the same if not treated right...cores. Buy high end and you'll likely need a high end charger. Have solar, you need a back up to not only provide the power needed but to protect the batteries as well. A well cared for 12v marine battery will easily out last a poorly cared for set of 6v. Mine is 5 years old and still does it's job.

 

[Vagabound]

... That's what.

[and]

Wait, aren't Nerds the cool kids?

???

OK then!  ;-) 

Yeah, what can I say, it's really perverse.  On that "cool kid" front, the universe is now upside down, but simultaneously right where it should be now that brains have mostly replaced spears.

Thanks for the clarification.

Vagabound

 

[Vagabound]

...

Now, to start on a budget, a 12 V "deep cycle" from Wally's and a 100 watt solar kit will get you started with a basic system...you can always upgrade over time.

Good practical info.  Very sensible.  Helping me get a better grasp.  Thanks.

One confusion is that the responding crowd here seems to be somewhat split.  Half seem to think that 6v saves money, while the other half cautions about its cost.  Another one of those "how can both be true?" conundrums.

Vagabound

 

[Vagabound]

Keep in mind that all the 12 volt batteries you see in the common battery stores that are labeled marine "deep cycle" are not true deep cycle. All Golf Cart batteries you see in the common battery store are true deep cycle.

A crucial, but not particularly obvious difference that I would never have known otherwise.  Thanks to you (and others in the thread) for pointing that out.

Vagabound

 

[SternWake]

If one decides all they need is 100 ah of capacity, then buying 220 ah of golf cart battery makes little sense.

I make due with one 90 ah agm 12 battery for engine and house. After once having 345 ah total.

The trick to good battery longevity is regular 100% recharges.

12V marine batteries take longer to reach 100% and might require higher voltages to reach this goal.

If these parameters can be met. Then a 12v marine battery can give good cycle life. If one can not ever be bothered to attain 100%. The the best battery will only slightly outlast the worst. If one does bother them the good battery will easily double the deep cycles accumulated before capacity is compromised to the barely adequate level.

100% recharges around attained by bringing the battery to absorption voltage. And holding it there for a long enough duration.

That duration varies depending on depth of discharge and battery health.

Best case scenario. From 80% to 100% take s no less than 3.5 hours when brought upto and then held at proper temperature compensated absorption voltage.

Older abused batteries take longer and longer to reach this threshold. And rarely get it.

 

[jimindenver]

Golf cart batteries are designed to be discharged and recharged more times than other batteries. So in the long run you will have to replace them fewer times saving you money.

On the other hand if you don't need the capacity, you still have to buy two 6 volt's regardless so you are spending twice as much vs a single marine battery that will last years if taken care of properly.

 

[Vagabound]

[excerpt for example]
Best case scenario. From 80% to 100% take s no less than 3.5 hours when brought upto and then held at proper  temperature compensated absorption voltage.  

To all:  You know, some threads sit and sit and die of thirst for waiting for good responses.  Not this one!  Thanks for all of the great answers so far.

To SternWake:  Excellent response.  Bit heavy on the wonky, technical side, but still good stuff.  That prompts a question that could apply to others also:

It almost sounds practically impossible to live a normal vandwelling life and do this "battery care" thing correctly.  The first obstacle is understanding what needs to be done.  The second obstacle is giving it the correct amount of attention at the right time.

Considering that many people are still at the technical level of the modern version of the "blinking 00:00 on the VCR", how is an average person supposed to make use of that information on a daily basis?  Have some "battery care" guidelines been simplified to the point of being practical and widely understood?  Or can they be?

Of course, anyone can answer.

Thanks,

Vagabound

 

[SternWake]

I try and outline ' ideal' for maximum battery longevity. So reader knows what ideal is.

Readers can seek less than ideal. And achieve perfectly acceptable.

Acceptable is.subjective and falls deep in the realm of opinion.

newbs and everybody really should just aim to get battery as close to fully charged as possible as often as possible to prevent premature battery failure .

Those seeking maximum battery longevity need to attain ideal nearly every recharge.

Diff strategies for different needs and expectations.

simplifying battery charging for battery newbie, is not my forte
I can't say yes or no when the correct answer is ' it depends' and variables are.not given.

phone typing. Pls Forgive typos.and grammar

 

[Vagabound]

I try and outline ' ideal' for maximum battery  longevity. So reader knows what ideal is.

...

newbs and everybody really should just aim to get battery as close to fully charged as possible  as often as possible to prevent  premature battery  failure .

Ideal:  Understood.  Thanks for the good info so far.  Sorry to give your thumbs a real workout on the phone! ;-)

Goal:  Acknowledge that you said that newbie explanations ain't your cup of tea, but I'll give it one last shot (I have faith in you!).  Would you say that the simplest method is as follows:

1)  Somehow learn what "full charge" voltage is for your battery (12.7v, 13.2v, etc.). (How - same for all 12v or user's manual?)

2)  Monitor the voltage a few times a day to see that it reaches that level each day.

3)  If it doesn't, come up with a method of pushing it there, such as driving around a bit (if wired for that) or turning on a Honda generator for a while.

Am I on the right track here?

Vagabound

 

[Trebor English]

The original question was why the 6 Volt vs 12 Volt?  The golf cart business uses large quantities of T105s so their price is lower.  Golf carts have different shaped spaces for batteries so pairs of T105s glued together won't work in all of them so they stick to the standard size and shape.  They happen to need deep cycle.  Off grid electric people need deep cycle.  Off gridders and golfers both want more Watt hours for fewer dollars.

 

[anewbiewannabe]

^^^that's a simply beautiful answer Trebor

 

[Canine]

The good news is that batteries,panels,controllers,etc are getting cheaper every day.The sun is going down.

 

[Trebor English]

My mini van needed a new battery.  It had a group size 59 battery in it.  I wanted more Amp hours so I made this list to compare them.  They are all the same brand at the same store.  The group size 24 is bigger than the 59 but still fit in the original place (important to me).  I got the one with the least cold cranking amps, the most amp hours, the most RC minutes, the most pounds, and one of the lower priced models.

model       price     cca      Ah    RC  weight   description
grp 59     99.28    590   100             37.2      Passenger Car Lt. Truck Van
24agm   149.36    775    55    120                AGM Sealed Valve Regulated
  24F      102.47    725   120            42.5      Passenger Car Lt. Truck Van
24MS       59.88    550     90                         Marine Starting
24DC       74.87    550     65   120    44        Dual-Purpose Starting/Cycling Service
24DCC     79.62    500     75   130    45.5     Deep-Cycle-EV-Trolling Motor-Wheelchair

So if 12 volt makes it not "true" deep cycle then I'll deal with cheating deep cycle and unfaithful deep cycle. If there is going to be any unfaithfulness going on it will probably be me undercharging and underwatering.  It will be my cheating that breaks up this relationship.  After all, I can get another battery for only $80.  If I had paid a kilobuck for a gaggle of L16s (6 Volt) I would probably pay more attention to them yielding a greater number of cycles.

 

[SternWake]

Ideal:  Understood.  Thanks for the good info so far.  Sorry to give your thumbs a real workout on the phone! ;-)

Goal:  Acknowledge that you said that newbie explanations ain't your cup of tea, but I'll give it one last shot (I have faith in you!).  Would you say that the simplest method is as follows:

1)  Somehow learn what "full charge" voltage is for your battery (12.7v, 13.2v, etc.). (How - same for all 12v or user's manual?)

2)  Monitor the voltage a few times a day to see that it reaches that level each day.

3)  If it doesn't, come up with a method of pushing it there, such as driving around a bit (if wired for that) or turning on a Honda generator for a while.

Am I on the right track here?

Vagabound

Battery  voltage does not really give an accurate  state of charge i van dwelling.  A rested battery one not discharge  or for . several hours i more accurate . 


When charging battery  vvoltage must climb to the mid 14s and remain there. Many factors define how long it must remain there.  Solar is very good i th final 3 hours or so.  Alterrnator good for first hour.

If one can not hold absorption voltage  long enough that day and Try and use less.energy overnight to give a better chance of holding absV long enough next day.

Many days in row.of incomplete recharging and battery is punch drunk. A full charge  a ths point requires even more.time at absV. And possibly an equalization overcharge to return b attery to maximum remaing capacity.

Capacity is always declining. The rate of decline depends upon its treatment..

 

[Vagabound]

...

model       price     cca      Ah    RC  weight   description.

...

If I had paid a kilobuck for a gaggle of L16s (6 Volt) I would probably pay more attention to them yielding a greater number of cycles.

Thanks for all of that work and good info.

Just to be crystal clear for the battery-newbies among us (which includes me):  

Your infidelities aside ;-), did that list include only 12v batteries?

And maybe I overlooked it, but which did you choose?

Vagabound