Why 6 volt vs 2 12 volt

[johnbryanpeters]

Originally Posted by Jay2504

Speaking of deep cycle vs marine type batteries, does anyone know for sure if the 31 DC 12 volt battery sold at sams club is a true deep cycle battery like the GC2 6 volt batteries that they sell? Thanks in advance Jay

Easy. If it's rated in cold cranking amperes (CCA), it's not deep cycle.

[TitanMike]

Originally Posted by Jay2504

Speaking of deep cycle vs marine type batteries, does anyone know for sure if the 31 DC 12 volt battery sold at sams club is a true deep cycle battery like the GC2 6 volt batteries that they sell? Thanks in advance Jay

It's a deep cycle that's pretty much designed for the electric trolling motors.

It's not as sturdy as the GC-2's but a lot better than the Marine Starting/Deep Cycle type that have the thicker plates, yada, yada, yada. They are about 1/3 more capacity than a Deep Cycle Grp 27 and only a little more capacity than a group 29 Deep Cycle.


A lot of them are used in series for the trolling motors that run off 24V.

[TitanMike]

Originally Posted by johnbryanpeters

Easy. If it's rated in cold cranking amperes (CCA), it's not deep cycle.

Not necessarily so. If the manufacturer wants to show a CCA on a Deep Cycle battery it's up to them. Most true deep cycle batteries are more than capable of starting marine engines, just not the ones that require super high current like Diesels.

You'll also see RC (Reserve Capacity) ratings on some Deep Cycle Batteries. It's all going to depend on the Manufacturer and what market he's serving.

You'll usually find that the CCA's on a Deep Cycle battery are much lower than on a pure starting battery and starting batteries will usually have lower RC ratings.

There is no "One Size Fits All" when it comes to what you see on labels.

[Hclarkx]

Originally Posted by babock

Not surprised at the fallacies people believe. The large battery banks with multiple series parallel connections in cellular base stations and other type backups don't have the issues. Neither did the GM EV1 that I worked on while at GM. Of course who believes an EE that works with these battery banks. Internet lore at it's best!

X2 .... though I wouldn't argue if someone said that it's best to match the two parallel 12V batteries in as many respects as possible (age, rating, manufacturer, etc.).

[Hclarkx]

Originally Posted by Larry-NC

. . . . . . this little niche is stuck in the dark ages. With application of some simple, well-known engineering and inexpensive hardware changes, a company could eat both WFCO and Progressive Dynamics' lunches.

Larry

X2 ....... but, though we all like to bad mouth WFCO and are disappointed in PD, WFCO has recently come out with a proper 45 amp LPF (lithium) battery charger that is fairly competent and for well less than $200. It sure beats PD.

[babock]

Originally Posted by Hclarkx

X2 .... though I wouldn't argue if someone said that it's best to match the two parallel 12V batteries in as many respects as possible (age, rating, manufacturer, etc.).

Agree with that

[babock]

Originally Posted by Hclarkx

X2 ....... but, though we all like to bad mouth WFCO and are disappointed in PD, WFCO has recently come out with a proper 45 amp LPF (lithium) battery charger that is fairly competent and for well less than $200. It sure beats PD.

I bought the 60A PD lithium charger for $200. Would never buy the WFCO version if PD has one.

[Jay2504]

Thanks everyone for answering my 31DC question. When I shop for batteries for the camper or our just recently purchased golf cart I look for a combination of low CCA and high reserve capacity. Two common batteries that we sell where I used to work were either 925 or 750 CCA in a group 31. The 750 CCA batteries always had a higher reserve capacity rating. That’s the one I went with. The
DC 31 from Sams Club has a 650 CCA, 185 RC @25 amps and a 105 ah @ 20amps. I’m talking about wet cell not AGM which is better but more$$$. Jay

[wabakami]

Originally Posted by babock

Not surprised at the fallacies people believe. The large battery banks with multiple series parallel connections in cellular base stations and other type backups don't have the issues. Neither did the GM EV1 that I worked on while at GM. Of course who believes an EE that works with these battery banks. Internet lore at it's best!

You're right about mobile (cellular) transmitters, they don't have issues of parallel discharge; they are constantly being topped up when used for stand-by power by the chargers. The same with the EV1, they are being maintained by chargers.

The batteries (in stand-by use) we are mandated to use are also certified as being balanced for parallel use so there is minimal losses through mismatch when on hydro outage which when I worked on them for 10 winters was almost weekly January through March. Keep in mind though the gensets would kick-in until power resumed.

A totally different environment to RVs being parked for weeks at a time with no chargers running, over time the batteries will self discharge quicker in a parallel setup than a single or series set-up battery bank.

(You're an Electrical Engineer, I'm a 30 year master Electrician with Mobile, Wind/Solar and Storage endorsements; so we should both know what we speak of. For 7 years and an additional 8 winters I did cell tower maintenance, the past 7 winters I've done remote fly-in maintenance from Northern Quebec to the Manitoba border. The last 15 summers I've been part owner of a seasonal resort. Both dream jobs)


I don't usually get into these solar/storage or electrical pissing matches but there is so much dis-information and dangerous (electrical) ideas out there that sometimes I cannot help myself, and usually regret opening my big mouth. Shall we hazard a guess that 25 to 50 % of these knowledgable experts got their facts from their mistresses who got it from one of their customers who learnt it at the corner bar from a pimply-faced 18 year old drunk?

With that I'll sign off, it's late and work comes early (oh how I long for retirement).

Geoff
.

[babock]

Not sure how a 30 year electrician would know much about battery banks doing cell tower maintenance. But as an electrical engineer who actually designed cellular base stations and worked on electrical vehicles, there is no EXTRA self discharge caused by putting batteries in parallel. If you don't believe me, put a meter between two identical batteries in parallel once they are at the same potential and read the current. You won't read any.

Batteries in parallel will discharge as fast as the worst battery. It however, won't make it worse than that. It's not some seesaw effect here. A battery that discharges less than it's neighbor won't be pulling current from it.

Since you don't like the cellular base station and EV examples, there are motorhomes that come with 8 batteries. If they are 6v, half of them are in parallel. If they are having such a huge parallel caused discharge issue, you would hear about it. In some motorhomes, the AGM upgrade is often 12V AGMs all in parallel. You will see 4 and up to 12 in parallel. Since you believe this is such a big problem, you might want to call them to offer up your services.

Concerning your 8v golf cart batteries with half a voltage difference between fully charged batteries, there are obviously old bad batteries there.

Back on July 27th, you stated you were backing out...what happened?

[NMWildcat]

Originally Posted by babock

Not sure how a 30 year electrician would know much about battery banks doing cell tower maintenance. But as an electrical engineer who actually designed cellular base stations...

Ah, then you know what is said about engineers and their plans. When it comes time to build something, you take those plans, throw them out, and build something that actually works in real life

I bet it is shocking to you to realize how much a 30 year electrician can know about how things really work

[babock]

Originally Posted by NMWildcat

Ah, then you know what is said about engineers and their plans. When it comes time to build something, you take those plans, throw them out, and build something that actually works in real life

I bet it is shocking to you to realize how much a 30 year electrician can know about how things really work

Lol ..of course you would think that!

As you type on your phone or computer designed by an engineer

[Comanchecreek]

And the fight begins.

[babock]

Originally Posted by Comanchecreek

And the fight begins.

Nnwildcat does this with everyone

[NMWildcat]

Originally Posted by babock

Nnwildcat does this with everyone

No, babcock..... just with you

[babock]

Originally Posted by NMWildcat

No, babcock..... just with you

And he also stalks me LOL

[SeaDog]

This thread is silly there will never be agreement 6V or 12V, engineer or real life, its like asking which female/male makes the best girlfriend/wife/boyfriend/husband, good luck!

[Comanchecreek]

You will find that this goes on every time a discussion is started about batteries, and electrical systems. Good information until somebody doesn't agree.

[BigLou80]

Originally Posted by wabakami

A totally different environment to RVs being parked for weeks at a time with no chargers running, over time the batteries will self discharge quicker in a parallel setup than a single or series set-up battery bank.



Geoff
.

I've never seen it go down quite like that. I guess someone could leave it in the woods for weeks and show up just expecting things to work but most of us have to tow or drive it there so it gets charged off the tow vehicle and most of us have the RV at home plugged in for a day or two before taking off to pack it. Either way you're staring off with charged batteries

[Chuck_S]

I've killed too many deep discharge parallel wired 12v batteries in offshore sailboats by not isolating them in storage where shorepower can't reach. Just 'cuz my camper doesn't float doesn't change the chemistry or physics.

I never remove my camper battery, not even in winter storage (the sailboats are long gone!). It goes in fully charged and come out 5 months later about 70% charged (12.3 volts). Of course my 12v battery is a really pair of 6v batteries in series.

Anyone with a pair of 12v connected in parallel is welcome to try this but don't expect to succeed. Put 'em in storage about Thanksgiving (Canadian or US) and let us know the voltage in April. If you insist on removing them wire them back in parallel in your garage. Just leave them, don't cheat and put them on a charger. Doesn't take heavy wire as the amperage is tiny. And, no, putting them on a concrete or dirt floor will not hurt them (assuming they were made after World War Two).

-- Chuck

(changed percent to 70%. was 50%)