6v vs 12v Batteries

[john61ct]

Yes those are probably fine,

L16's can go up to 380Ah and I know the Trojan RE versions last just as well as the 6V ones

but man I wouldn't want to wrestle with them!

At only 63lbs the GCs are much more managable, personally I'd redo my box, give a bit of extra room so the slightly different sizes don't getcha next time.

Once you are looking at a trusted maker's line, no longer browsing big box aisles,

then you're already within the top 0.01% of choices, realities like location / stock, special deals coming up can safely influence you.

[john61ct]

I just realized I'm in the skoolie forums!

Y'all have **all the room in the world** spoiled for space compared to the boats, little vans, even many off-grid cabins I've worked on. . .

Go undercarriage if you need to

one good justification for spending extra in AGM, is you can install them on their side!

[gs1949]

Well, if I were planning on doing solar now, I would want to get the tallest batteries I could and I would not mind building or installing a new battery box.

But solar will come later, and so will the new battery box on the other side of the bus. Right now I want batteries for lights, fans, and a water pump, and I want them in the OEM battery box with the starting batteries. I can make it handle 4 batteries.

Later, I guess I will have to build a battery box. I have tried to find an NOS BlueBird battery box, but have not been able to do that.

[BarnYardCamp]

No matter what batteries you choose, if you plan to use the same battery box as your starting battery you should probably reinforce that box.

[kazetsukai]

Originally Posted by gs1949

But solar will come later, and so will the new battery box on the other side of the bus. Right now I want batteries for lights, fans, and a water pump, and I want them in the OEM battery box with the starting batteries. I can make it handle 4 batteries.

If you just need DC power and have access to shore / AC power you could get a power supply, hook it up to your DC load center and wait on the batteries until you're closer to completion.

[john61ct]

Not sure what that's supposed to mean specifically, greater precision in terminology would be more useful there.

[gs1949]

I intend to take my battery box apart for a good look, but I think it is probably strong enough to handle 2 golf cart batteries, at 64 lbs each and 2 Group 4 starting batteries, at 47 lbs each. I say this because there is absolutely no sign whatsoever of rust or corrosion anywhere in or near the box. And I can see from the paint on the roller tray the batteries sit on that there were once two much larger batteries there. Batteries that filled roughly 2/3rds of the whole tray, which I would estimate from their footprint weighed well over 100 lbs each.

I do intend to disassemble the tray and clean, prep, paint and lubricate everything before making any firm decisions about what to put back in there.But I am in no hurry to get new batteries. I didn't start this thread, so the timing is not mine. I just jumped onto the thread as it went by.

I was hoping that this might be the year I have enough money to complete the bus project, but now coronavirus has shut down the real estate market and put the plan to sell my late father's house on hold, again. I can continue to finance the bus project from my pension income, but that won't be quick.

But it could be fun though. I have a 12 volt power supply in my Amazon shopping cart so I can put my composting toilets system into action. I believe I have designed a composting toilet system that will actually compost with a minimum of fussing. There will be more on this later. I don't know that much about compost toilets. I've only met one compost toilet, and it was not working properly, but that was a long time ago, and I have had several decades worth of composting experience since then.

I apologise if there is any lack of precison in my use of terminology, but I am not an electrician or an engineer. I consider myself a legal historian of Aboriginal Relations in North America, with a very strong literary interest in Ethnic Cleansing and Genocide worldwide. In those areas I can be precise, but most people are bored by that kind of talk.

[john61ct]

BTW an out-there option to consider.

Dedicate that whole big box to GCs if 4+ will fit

Get a small LFP capable of reliably cranking your engine Starter and mount elsewhere, 30-50Ah would be overkill, I bet 10Ah would work fine.

If far away, could wire with an ACR capable of jumpstarting, would be trivial for the House bank to act as backup.

Use a 2-way and any charge source on either side would feed both, otherwise isolated.

Blue Sea ML version is top-notch, handles 300-500A, will outlive your next three skoolies.

[john61ct]

"Power supply" - please link.

Better to use a proper charger.

Amps capacity is relative to the target bank, voltage must match mfg specs also

[gs1949]

I turned 70 last year. This will be my only schooly. I won't have time for another. My next project will be a cabin in the hills. That's the main reason I am in a hurry to get the bus usuable

The power supply that I am looking at, which I see as only a possibility if it becomes obvious that I will get the composting toilets ready to roll well before I am ready for batteries, is: https://www.amazon.com/dp/B07TZMJBZX/

I am aware that power supplies like this are not suitable for battery charging; that's why I have no intention of using it for that. It's sole purpose will be to get the composting toilet trial up an running ASAP. The first set of batteries will be charged from the alternator when the engine is running. Solar will come later.

[john61ct]

OK, cheap enough to be a throwaway.

But you could just use any old 12V battery you can scrounge up and use any old charger

for that purpose.

Then as you get a better battery, or your various charge sources in order, upgrade as you go.

And a PSU can indeed be used as a charge source, but only if

1. current limited if the batt pulls more than it supplies

2. Voltage output setpoint within mfg spec for the battery

3. you watch the charge process with a voltmeter and ammeter to tell you when to stop. FLA being much more forgiving of holding Absorb too long, no damage so long as the electrolyte doesn't go down too low

[kazetsukai]

Originally Posted by john61ct

Better to use a proper charger.

When charging batteries, yes. When just running appliances, no, I'd think a charger would not do what is intended.

To clarify, my suggestion was to forego buying batteries for now if uncertain as to what batteries or configuration would be best. One could use a power supply instead to run stuff until their build is more complete and they have a better idea for their needs/wants. You can hook up and test all of your DC without having to buy batteries this way.

And if after hooking up all the DC you decide on a different battery bank voltage you can connect the load center to the bank with a transformer, assuming the transformer is big enough to handle the loads required. This is why 12v DC appliances are usually a safe bet even if your bank differs... I'm in need of a 48v -> 24v step down because I'm changing up my battery bank... Amazon delivery times for these are measured in weeks, not days. Ugh.

[RolesvilleMarina]

For shore power I put in an AC/DC converter panel I salvaged from a pop up..

mine is 30 amps...

but this is something similar

https://www.amazon.com/Arterra-0318-...921653&sr=8-12

has AC breakers
DC panel and fuses
charges leisure batteries when connected to shore power

there are other brands and price ranges... but it is an all in one unit.. so no need to buy an AC panel, and also a DC panel

[john61ct]

There is no difference anymore between a modern (US RV industry usage) "converter" of decent quality and a good charger. (And not the correct use of that term, very confusing)

Except some chargers do not have a power supply mode that feeds load devices fine without a battery as buffer.

And some converters may not be as adjustable as a good charger without paying for extra modules per chemistry?profile adjustments.

Originally Posted by kazetsukai

When charging batteries, yes. When just running appliances, no, I'd think a charger would not do what is intended.

> I'm in need of a 48v -> 24v step down because I'm changing up my battery bank... Amazon delivery times for these are measured in weeks, not days.

That is properly referred to as a DC-DC converter, outside the US RV industry.

Best to just stick to a 12V system unless you know you have a very good reason, besides just saving copper on wire gauges.

[john61ct]

A good quality shore power charger, as with all charge source categories, should be fully user-adjustable in output charge profiles, so you are future-proof, can select any chemistry bank in future including GEL and LFP

without having to replace any infrastructure.

Both the Sterling Power ProCharge Ultra and ProMariner Pronautic P series are good examples, as are most Victron, Mastervolt and Magnum units.

Be sure to get a high enough amps current rating, especially for AGM or LFP.

[kazetsukai]

"Power supplies" is what they're called in scientific/industrial applications.

Originally Posted by john61ct

Except some chargers do not have a power supply mode that feeds load devices fine without a battery as buffer.

Even if some chargers have this function, if you have no intention on charging batteries, there's no need for a charger. If all you want is a supply of DC current at a desired voltage a "power supply" is sufficient. These are commonly used for a wide variety of applications, LED lighting is a prime example.

Charging batteries is not the only or even a guaranteed use case.

Originally Posted by john61ct

That is properly referred to as a DC-DC converter, outside the US RV industry.

Step-down (step-up for going up in voltage) transformer/converter is a commonly used term for these as well.

Originally Posted by john61ct

Best to just stick to a 12V system unless you know you have a very good reason, besides just saving copper on wire gauges.

Well, if you have > 1200W in solar panels or anticipate loads of over 2000W with any regularity, I'd say that a 12V battery bank starts to become increasingly impractical. I'm happy to stick to 12V where it is (our van's solar is 12V), and it just isn't in my bus build. I've been at 24V for a while and I'm switching to 48V for good reasons.

[gs1949]

I do not have any batteries that I am not using. And I already have a battery charger: https://www.amazon.com/gp/product/B01L28E5L8

I don't think this charger will serve particularly well as a power supply, but it seems to be doing an excellent job of slowly desulfating my starting batteries so I can get some more use out of them and use that money for something else.

Right now my focus is on getting ready to ask the Oregon DMV to retitle my bus as a motorhome, so my desire for electricity soon is just to that end. I need to run a few lights and 3 fans in the toilet system. I have an inverter generator that will manage everything on my current electrical wish list, but I want to be able to plug into 120 when I can.

By shutting down the real estate market Coronavirus has forced me to continue financing my bus conversion gradually as I can afford it. In order to do this I will need to think a little differently than I have been, but I can do that.

[kazetsukai]

Originally Posted by gs1949

I do not have any batteries that I am not using. And I already have a battery charger: https://www.amazon.com/gp/product/B01L28E5L8

I don't think this charger will serve particularly well as a power supply, but it seems to be doing an excellent job of slowly desulfating my starting batteries so I can get some more use out of them and use that money for something else.

No, I have a "battery tender" brand equivalent. They only put out an amp or so and aren't designed to act like supplies.

I've used lots of supplies like these:
https://www.amazon.com/ALITOVE-Unive.../dp/B06XJVYDDW

It really depends on how much juice you're going to need for all of the appliances together. You could even just get a 12V power "brick" if one puts out the amperage you need:
https://www.amazon.com/SHNITPWR-100V.../dp/B07PWZQ33N

I was looking around for 5.5mmx2.5mm pigtails but couldn't find any female.

EDIT: That brick comes with one!

[gs1949]

My battery Tender is 1.5 Amps. It is really doing good things to my starting batteries, but it certainly isn't fast. From hydrometer readings I can see the batteries are much stronger. All the cells in a particular battery are now at the same level. One battery is still at a lower charge that the other, but the difference is gradually decreasing. This next Monday it will be 3 weeks they've been desulfating, and it now looks to me like that may be just about enough.

Yes, I've noticed all the different power supplies that look like they were all made in the same factory. The only difference I can see from the listings on Amazon is that some are 20 Amps and some are 30 Amps. Maybe I should switch to the one you posted because that is 30 Amps. The one on my list is 20 Amps, and the 30 Amps is only a dollar more.

[john61ct]

I know what a power supply is, fron yours to the $3000 lab style ones.

My point is a good **charger** that also has a power supply **mode** can be useful for the double duty you're talking about.

Normally 40A and up is the starting point, so we're not talking $18, more like $400+

DCDC converters are different, the above are rectifiers technically, AC input.

Originally Posted by kazetsukai

Well, if you have > 1200W in solar panels or anticipate loads of over 2000W with any regularity, I'd say that a 12V battery bank starts to become increasingly impractical.

No idea why that would be the case, 800-1200Ah banks are very common in 12V.

Some people have very high amp loads like winches, air compressors for SCUBA, big RO water purifiers, or specialised freezer / aircon systems that need higher voltages for greater efficiencies. . .

But regular household load devices, not too huge a living space, just sticking to regular KISS 12V is usually the way to go, avoiding wasteful conversion as much as possible.