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 > Floating vs Storage Voltage Question

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BFL13

Victoria, BC

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Posted: 11/29/20 03:00pm Link  |  Quote  |  Print  |  Notify Moderator

Moved this from another thread to open the topic generally. Question was if PD converters with the 13.2 storage voltage were compatible with floating voltage specs at 13.5 and above.
----------------

Many (all?) battery specs have the same floating voltages (2.25 a cell or so) My AGMs did and also the flooded batts I have had.

PD's are used successfully with all those other batteries according to various reports

Trojan eg, has 2.25 too, and says not to float either flooded or AGM at all if they will be charged frequently. ("cyclic use"?) So the PD's "storage" mode at only 13.2v is confusing. Is "storage" really "float" or something else?

https://www.trojanbattery.com/pdf/TrojanBattery_UsersGuide.pdf

Float is supposed to just make up for self-discharge so 13.5-13-8 typical seems high for that, unless it is GC2 6s?

Resting voltage of a full flooded is more like 12.8 so 13.2 is more above that. My ordinary AGMs spec resting at full was 13.0 though, and nobody said a PD is no good with AGMs.

Now I am not sure what "floating" vs "storage" is all about. Anybody explain? Thanks.


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pianotuna

Regina, SK, Canada

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Posted: 11/29/20 03:06pm Link  |  Quote  |  Print  |  Notify Moderator

BFL13,

The best is to have the voltage vary with the temperature of the battery. That feature is available on most good solar charge controllers, and also on high quality inverter/chargers such as Victron.


Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp hours of AGM in two battery banks 12 volt batteries, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

time2roll

Southern California

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Posted: 11/29/20 03:15pm Link  |  Quote  |  Print  |  Notify Moderator

13.2 works well when combined with the 15 minute boost charge at 14.6v every 20 hours.
Otherwise storage and float are the same thing as far as I am concerned.

Although if the battery has been floating in storage for an extended period I do find that first cycle is a bit weak and seems to restore on the first charge cycle. Might be virtually the same to let them just rest disconnected for storage.


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BFL13

Victoria, BC

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Posted: 11/29/20 03:18pm Link  |  Quote  |  Print  |  Notify Moderator

Sure, but 13.2v at 85F is like 13.7 at 50F so 13.2 is way low for 50F. The question is why store (float?) at 13.2 when the spec is for 13.6 at 77F

Randy still has this float voltage table-scroll down, eg. I think there are better tables but gives the idea sort of.

http://www.bestconverter.com/Parallax-Paramode-with-TempAssure_c_104.html

time2roll

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Posted: 11/29/20 04:08pm Link  |  Quote  |  Print  |  Notify Moderator

US battery says float 13.02 at 80F

Nothing wrong with following the manufacturer's specification.

https://www.usbattery.com/technical-info/charging-instructions/

Lwiddis

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Posted: 11/29/20 04:22pm Link  |  Quote  |  Print  |  Notify Moderator

Lots of battery myths would be corrected if RVers would read the Trojan Users Guide.


Winnebago 2101DS TT & 2020 Chevy Silverado 1500 LTZ Z71, 300 watt solar-parallel & MPPT, Trojan T-125s. TALL flag pole. Prefer USFS, COE, BLM, NPS, TVA, state & county camps. Bicyclist! 14 year Army vet-11B40 then 11A - (MOS 1542 & 1560) IOBC & IOAC grad


BFL13

Victoria, BC

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Posted: 11/29/20 04:45pm Link  |  Quote  |  Print  |  Notify Moderator

Interesting about that US Battery float voltage for flooded at 2.17 per cell. Their AGM is 2.23

Meanwhile Trojan is at 2.25 for both types, and East Penn (Deka) is at 2.24-2.26 for AGM and 2.30-2.35 (13.8-14.10v) for flooded.

Seems they all agree on AGMs but are all over the map for flooded batts.

We have had many posts about how 13.8 is too high and how you have to keep adding water at that voltage, saying 13.2 is required to stop that. But the battery specs are as above for 77F.

EDIT--Note that Trojan says not to float floodeds if they are used more than once a week, but say for AGMs it is if they are used more than once a month.

* This post was edited 11/29/20 07:07pm by BFL13 *

wa8yxm

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Posted: 11/30/20 05:33am Link  |  Quote  |  Print  |  Notify Moderator

time2roll wrote:

13.2 works well when combined with the 15 minute boost charge at 14.6v every 20 hours.
Otherwise storage and float are the same thing as far as I am concerned.


My original house batteries lasted 9 years with a PD-9180+wizard doing the above pattern
Their replacement went to Insurance Auto Auction with the rest of the Rig after the Semi clipped it. 6 years later.


Home is where I park it.
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Gdetrailer

PA

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Posted: 11/30/20 09:07am Link  |  Quote  |  Print  |  Notify Moderator

wa8yxm wrote:

time2roll wrote:

13.2 works well when combined with the 15 minute boost charge at 14.6v every 20 hours.
Otherwise storage and float are the same thing as far as I am concerned.


My original house batteries lasted 9 years with a PD-9180+wizard doing the above pattern


X2!

9 yrs and could have gone a couple of more but wanted to make sure my home fridge wasn't going to run me out of battery.. And I am using a PD9160 with external Charge Wizard.

13.2V is what I have found maximizes battery life when not being used (AKA "Storage") combined with the PDs Charge wizard giving a short 14.6V bump every 20 hrs during storage.

13.8V in storage is way too much no matter what the temperature is, it WILL boil the battery to death if allowed for too long of time.

13.8V is the target charging voltage of a older automobile alternator/charging system from the 1980s and older.

Old linear converters had a fixed 13.6V and they boiled batteries to death. My first TT had a linear converter and it ate batteries for breakfast, lunch and diner, boiled quite a few batteries before I realized that I HAD to disconnect batteries while being stored, otherwise suffer the cost of another replacement.

And, I will say this, a few of the portable devices I have built for myself which use Gel and AGMs, well I set my charger voltage to 13.2V and they reward me with very long life.. One device with a gel battery is going on 15 yrs, still works although doesn't have the capacity it had new.

If you REALLY want to charge harder, then go with a fixed 13.8V supply and put it on a 24hr timer, give it 4-6 hrs of charge per day for storage.. That is what my local Ham club did for yrs for their backup emergency batteries.. Worked pretty well but with the advent of multistage charging it isn't worth the hassle to me.

Seems that a lot of folks here fuss and obsess way to much on batteries, folks like PD have figured out on how to build a converter which can maximize the life of your batteries without much intervention or fuss of the user.

Sure there are more "advanced" converters with temp comp and even different charge curves for different types of batteries but in reality that extra fuss might net you one more month of life, not years like folks think it will.

Ask Mex, I know he has built all kinds of charging schemes with all kinds of required human intervention.. Might give you a bit longer battery life, but at the cost of your own personal time which you can never get back.

Batteries you can replace, your own personal time you never can replace..

Best advice I can give is, batteries are a "consumable", each time you cycle it, you consume part of its life.

That harder you consume it, the faster you shorten it's life.

Shallow discharge followed by a quick recharge will net you with the longest life.

Over or under charge, will destroy a battery just as fast a deep discharge or allowing to sit partially discharged.

MEXICOWANDERER

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Posted: 11/30/20 10:05am Link  |  Quote  |  Print  |  Notify Moderator

When I go to bed I never feel like I have lost a damned thing. I avoid hundred dollar trips for fuel and settling for 70% storage capacity because of I'll maintenance. To me there is nothing worse than destruction of plans because of early battery death. A Wal-Mart battery death cost me a hundred dollars out-of-pocket for surprise hotel room and restaurant meals. Figure it out folks. Spend an extra twenty bucks on a better battery or a hundred in penalty. I haven't got enough money to be cheap.

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