UPS Batteries

poppa wrote:
i will be camping with and without but will have generator if shore power isnt available so 1 or 2 12v should work fine? thanks Gdetrailer

Need to stop referring to "12V" batteries, you need to be pretty specific to the TYPE of battery. The 12V vs 6V around here on this forum tends to start a lot of fights.

If you are referring to say RV/Marine Group 24 or Group 27 size batteries which happen to be 12V, yeah, one is not going to cut it for more than one day IF you conserve power like a miser.

Group 24 batteries have roughly 70 Ahr of capacity, of that you do not want to use more than half or 35 Ahr of the capacity.

Group 27 batteries have roughly 80 Ahr of capacity, of that you do not want to use more than half or 40 Ahr of the capacity.

Golf cart (GC2 size) batteries have 210-230 Ahr of capacity depending on the manufacturer. Granted to use the GC batteries you will need to buy 2 or a pair and wire them in series (pos of one battery goes to the neg of the other battery).

Group 24/27 batteries generally will get you no more than one day of real operation.

So for a 2 day weekend warrior type of camping you will need 2 or more Group 24/27.

Now, to help put this into perspective a pair of group 27 will get you 160 Ahr of capacity and will cost you around $80 per battery for $160..

One pair of GC2 batteries gets you 210 Ahr capacity for Sam's club or Costco batteries, cost runs about $90 each for $180 for the pair..

So, in reality, you can get much more Ahr capacity in the GC2 batteries for only $20 more than two of the Group 27 batteries in pretty much the SAME space.

Do be aware, the GC2 battery specification is a bit taller than the group 24/27 so if height is a problem you might be forced to use the Group24/27 size unless you can modify the battery location.

What you decide to do with this information is entirely up to you, myself, yeah, no brainer for the GC2 batteries..

i will be camping with and without but will have generator if shore power isnt available so 1 or 2 12v should work fine? thanks Gdetrailer

poppa wrote:
why 2 6v vrs 1 12v? new to this

Age old question..

In reality, EVERY "Lead Acid" type battery (flooded as in liquid, AGM as in Absorbed Glass Mat or Gelled lead acid IE gel battery) consists of 2V "Cells" which are internally wired in series.

THREE 2V cells for a "6V" battery.

SIX 2V cells for a "12V" battery.

Then there is the type of use, you have "starting batteries" which are typically used in your vehicle to well, start the engine, they are built to give high current, shallow discharge for starting and the life depends on being quickly recharged by the alternator as soon as the engine is running. Typically will not handle long deep discharges more then 10% of the battery capacity without damage

Then you have dual use RV/Marine which are a hybrid Start/Deep cycle, typically 12V only and Group sizes 24 and 27 are common for these. They typically tend to do either job not as good as a starting battery or as a deep cycle. Typically this is the battery design used with most RVs as the house battery. Can often be discharged to 50% without affecting battery life.

Then you have deep cycle battery, these puppies are designed for long deep discharges as much as 80% discharge without severely affecting battery life (although 50% discharges will increase battery life over 50%) .. The common easy to find and low cost in the this category is the Golf Cart batteries which are 6V or 8V so you do need to make sure you pick the right voltage.

What you need depends on how you plan to camp..

Camp in campgrounds with commercial power only, a single 12V RV/Marine Group 24 or Group 27 should work for you.

Camp in campgrounds with and without power, 2 12V RV/marine group 27 might work for you for say a weekend in you conserve power.

Camp in campgrounds with and without power AND you have a residential fridge then you will need to skip the 12V RV/Marine batteries and go with GC batts..

Plenty of other possible scenarios but it boils down to how you are going to camp and how long..

Generator and or solar can also make a difference..

why 2 6v vrs 1 12v? new to this

Generator

Mrwizard,

So generator or power pole princess at this time?

That bank was in the DP
600+ Watts of solar and a Pwm controller with custom settings, plus generator use with 75 amp adjustable voltage converter

Here in the Bounder, two old 6v interstates up front
And one big deka 4d 198 amphr AGM, in the side storage compartment,
With the same converter i moved to this RV

Would love to hear about how you charge your bank MrWizard.

Most people here seem to be thinking of small home or office ups batteries

I got over three years of full-time everyday use cycles from my first set of Telco/server AGM batteries

How many years of use will the avg weekender get out of 1200+ cycles ?
50 weekends equal 100 cycles If they charge on Saturday and again when they come home
That's about 12 years of use

Don't confuse the 11# home ups battery
With the 105# 136 amphrs telco batteries
Different quality of mfg, and much denser lead to rated capacity ratio

I don't know what happen to anyone elses batteries
But i don't do 50% > 90%
Because i full time, I attempt to keep my batteries SOC
As high as possible, i charge everyday

I have experience with an 18Ah AGM that weighs the same as the UPG UB12180, 11.4 lbs.

It, by itself, when I first got it ( 5 months old at that point and 12.82v) and cycled deep once and charging it until amps stopped tapering at 14.7v, was able to start my cold 5.2 liter gas engine, by itself, just barely, in warm ambient temperatures. My meters registered a nearly an 1800 watt surge and voltage dropped as low as 7.9v

I have not repeated this experiment, yet, 15 months later. The battery full charge resting voltage is 13.16 after 24 hours, 13.13 48 hours later and seems to lose about 0.01v each day there after

I wanted 24v of portable battery, and recently got a UPG UB12220, a 22 amp hour AGM battery of the same exact dimensions as the 18AH battery, but weighs 14.1Lbs, 2.6lbs more.

I've only got a few shallow cycles on it so far, but these two AGMs of dissimilar age, and weight, and capacity, did not discharge evenly in series, nor do they charge properly in series @29v, I stopped that quickly, and now charge them separately. But uncycled batteries always behave weirdly that initial charge discharge cycle and less so each additional one.

The 22Ah agm loses surface charge voltage much faster but both settle to within 0.02v of each other a day later.

Are these Asian UPS sized AGMs worth it, even in the larger common sizes, 35, 55 75 100AH? Impossible for me to say, I only have experience with an older 12Ah one, an 18AH(Ub12180) and now a 22Ah(Ub121220). The 12 is the only one that failed, many many years ago after many years of use, and highly suspicious initial recharging regimens.


They meet my needs and expectations, and I Will recharge them at more than 2x the recommended maximum rate without fear, in mild ambient temperatures, but not leave them unattended with a high absorption voltage for hours on end either.
The well depleted 18Ah battery accepts 38 amps peak from a 40 amp adjustable voltage charging source set at 14.7v and then levelled off at 32 amps, dropping to 25 amps some 5 minutes later. I didn't notice any case surface heating in that time, but lowered voltage/pressure/amperage to 10 amps and walked away. (5.4 amps maximum recommended)

It is not hard to pry off the lid of These. When one does they see 6 rubber caps, kept in place by the lid and the glue lines are designed to obviously keep the same general pressure across all 6 cell tops.

Remove a rubber cap under this lid, and one can try to see into the cell via a 5 to 7mm aperture.

The venting pressure is therefore Imprecise at best, and could be changed with the pressure on the top of the battery, holding the lid over the cell tops tightly. I had a few rubber caps pop off and go a fair distance when I pried on the lid.

I might add drops of distilled to each cell on the older one, its voltage retention after charging and surface charge retention 2 to 6 hours off the charger seem abnormally high, just like a flooded marine battery low on water.

The 'new' 22 Ah AGM was made the 19th week of 2019, when I got it, two weeks ago, arrived @ 12.81v@67f. I think that is a huge issue with these Asian UPG/UB batteries and their clones and relabels, they sit on a shelf for who knows how long before placing 'click order' and they certainly came over on the slow boat, and were they fully charged when they left?.

They do not have the great low self discharge of high$$ AGMs, and their 'recombinant' technology is a rubber cap held in place by the lid which can easily be pried off.

I think they have issues overheating once they've aged and require more and more amperage to be held at float, and perhaps have been floated too high for too long, at the occasionally too high an ambient temperature, while within their ergonomic enclosure.

I accept the potential age issues with these, and insure I hold absorption voltage as long as is required for amps to either stop tapering, or taper to 0.5% At 14.7v, indicating full charge. After this i discharge to 50% or more notine rate and voltage retained, then see how much it wants to feed upon at 14.7, when allowed 40 amps.

That MAX charge rate recommendation is a CYA statement, in my opinion. use common sense, and keep em from getting too hot.

My new 22 Ah AGM says 'NO amperage limit', with a 13.6 to 13.8v charging source in 'standby duty' but does say a 6.6 amp maximum at 14.6 to 14.8v in 'cyclic' duty.

Whereas they use to say only half the rateat 13.6vcompared to 14.7v. Obviously higher pressure , more amps flow, but hook a huge charging source set at 13.6v to 13.8v to a well depleted agm, and the first few minutes will accept huge amperages well over that 'recommended' maximum amperage rate, before the delta narrows and less amps flow.

Floating at proper temp compensated voltage(13.6ish@77f) for an additional 12 hours might have amps taper to near zero and quickly decline to near there when voltage is boosted back upto 14.7v, but sometimes amps at 14.7v never tapered to 0.5% of capacity with these but seems to get better with some cycles accumulated.

Really, these cheap Asian AGMs might be great, or lackluster, depending on your requirements and expectations and ability to attempt to recharge completely, on occassion.

In the bigger sizes, the Deka Intimidator AGM, perhaps relabelled by sams or costco or autoparts stores, can be had for similar prices, and at least is USA made.

Take your digital voltmeter and buy fresh,
but 'click order' of these UPG/ UB asian AGMS and you have no choice with the age of battery which arrives.

Good luck