8volt fla deep cycle batteries

[Tom Reed]

Well I guess I'll be the forum guinea pig for the desulfator. The one I have is the same as linked. It runs full time off of the battery power. The first deslufator I had came with an attached solar panel and with instructions for mount on tanks and missile launchers, I guess the military wants to start when needed. If the military has determined that they are effective that's good enough for me. I don't believe they cause lead to slough off, but cause the sulfate crystal to go back into solution. When run continuously the crystals that form are supposed to be smaller and go back into solution easier during charging improving charge efficiency. I'm running one on my $8K battery bank so we'll see how it goes 10 years from now when the bank starts to reach the end of it's life.

[mobile_bob]

Tom

i meant no disrespect to your posting or use of a desulfator

i only related that i haven't as of this date came across a white paper that supports their use
based on real world testing with supporting documentation.

not saying it doesn't exist, or that it can't work, only that i am not aware of such documentation
as of yet.

if you or anyone has or comes across a link to information or testing of desulfators please feel free to post it so we can take a hard look.

bob g

[BruceM]

Steve U.  OK, I'll start a new thread on 120VDC, but suspect we might have a better exchange by phone.  There is understandably more interest on this forum for more mainstream off grid power systems with off shelf hardware and support.

[LowGear]

If the military has determined that they are effective that's good enough for me.

Well that's one of us.  As a reformed user of military equipment and decision making I just can't let these blanket statements float by.  And gentlemen, stuff does float downstream!

Casey

[BruceM]

There may be technical merit to the pulsing desulfators, but the use of same by some DOD group is meaningless.  I used to select and order stuff (computers, boards, tools, test equipment) for an AF research lab. Several hundred thousand $ a year, often more for big projects.  My choices were based on what I thought looked cool or useful in glossy advertizements. Or just a whim.  No one else scrutinized my selections.  Many DOD groups have a similarly high degree of autonomy in what they buy to support their mission.  Claims of a product's use by some DOD group is the common marketing practice of many hucksters.  I chuckle every time I read such a claim.

[Tom Reed]

Well perhaps that is a naive opinion on my part. They have could have been purchased because they were made by someone's brother in-law. The Pulse tech web side does reference 2 university studies that were requested by the military though the way they report the results is a bit sketchy.

[Ronmar]

If the military has determined that they are effective that's good enough for me.

Well that's one of us.  As a reformed user of military equipment and decision making I just can't let these blanket statements float by.  And gentlemen, stuff does float downstream!

Casey

Gotta agree with Casey on this also:)  I don't doubt their use, but they were probably sourced as one of their main features is that they, being solar powered, will keep the battery floated on vehicles that spend more time parked than in operation...

[Jens]

 I ordered a ProNautic 50 amp charger today. Delivery would probably be in 3 - 4 weeks as it is currently out of stock.

[mobile_bob]

well it looks like the batteries are probably going to be fine

i still need to pickup my new temp compensated hydrometer to verify the specific gravity
at full charge, but for now as far as i can tell they seem to be doing fine.

after recharging them up to as near full charge as i can tell with a digital voltmeter (which is only
good at telling state of charge on batteries of known good condition) i placed a 325watt load on the bank
via the apc ups unit i used to charge them with.

so at a measured efficiency of ~86%  and a measured load of 280watts AC, then 280 / .86 = 325 watts
from the batteries.

the batteries carried the load for a bit over 5 hours and the batteries dropped to a bit over 80% SOC
as measured by the digital voltmeter,, (again with the same qualification above) so 325 x 5hrs = ~ 1.6kw/hrs.

that is a bit under what the bank is rated at, however i have not ran through enough cycles to break them in yet and i have not verified that they started out as fully recharged as tested with a hydrometer
rather than a voltmeter.

they appear to be in good enough condition that i won't be raising a bitch with the supplier especially given the deep discount i got on the set.

i think when it is all said and done, broken in fully, and tested with a hydrometer  my bet is they will be
very close to spec, so i am happy with them.

for future reference the model number of these batteries is  gc8-890  which as far as i can tell
they are , gc = golf cart deep cycle, 8= 8volt, 890 =190amp hours 20 hour rate.

my hope is these turn out to be as good as any other typical battery of this type and capacity, and my supplier can source and supply more of these for a lower cost than the USBattery he sells most of.  he told me he brought in two sets of these, one went to a golf cart the other to me for inverter use in testing.
he figures the golf cart set will probably get average attention given most golf carts and probably be lucky if they make two years, but is thinking with better attention given by me in my lab they ought to last at least 4 years, and maybe more if i do as i say and limit the cycles to something less than 50% DOD.  he is convinced if they are maintained properly, recharged properly and cycled no more than 50% they will last 4 years.  that is a nice target to shoot for.

we shall see

i would be nice however to come across an alternative battery that could give good service for our use, and do it for less up front cost.  it is hard for me to get my head around how this is possible to do given they are built in korea, shipped half way around the world, warehoused and redistributed and sell for less than batteries built here in the states?

i thought maybe they cut corners, by using less lead?  but they weigh within a lb of the trojan equivalent. so it would appear they didn't skimp on lead, and it is hard to see how they could cut lead weight and not add the difference in plastic case?  the case looks to be adequate in thickness but not overly so.

who knows, just glad i got a string to work with.

this weekend after fully recharging them, testing the specific gravity to verify full charge, i plan on another capacity test this time with approx 850 watts of resistance heater load.  that ought to stretch them a bit and get the pores in the plates opened up!

bob g

[Jens]

I am glad to hear that all is well ! I am puzzled about the 8V thing - you talk about normal electrolyte and you talk about lead plates so how is it that these things are 8V each. Further, are golf carts running at 48V because 48V seems to be the only point where these things would fit properly. Why would they even make an 8V battery seeing they cut themselves out of the 12V, 24V and 36V market.
Colour me puzzled !

What hydrometer are you buying ?

[mobile_bob]

just as the 6 volts have three two volt cells in a common case, 12 volts have six two volt cells in a common
case the 8 volts have 4 two volt cells in a common case.

yes it puts them out of the 12 and 36volt usage but 3 of them  work in a 24 and of course 6 will work in a 48volt system.

i can only speculate that they  take up a bit less foot print in a golf cart and 48 volts probably make a bit more hp when it comes to powering motors?

i will post the specs on the hydrometer when i get it, hopefully later today, if not it will be tuesday
labor day weekend is a big thing around here, 3 days of celebrations

bob g

[mobile_bob]

back with an update on the 8volt golf cart deep cycle batteries

did a few shallow cycles down to ~70% SOC and back up to full charge

then topped off the electrolyte with distilled water, and put them back on the charger
for several days at ~4amps @ 54.4vdc, while waiting to get a decent hydrometer

the one i had leaked so badly it was just a mess

after looking at a few at my local napa he finally ordered me in a very expensive unit (his words)
and i waited for it to come in,,, it did and i picked it up for the princely sum of $9.79 including tax... no wonder the crap they sell is so cheaply made, if a decent one cost less than 10 bucks one really doesn't even want to think about a cheaper priced unit... i really would like to have gotten one priced at 30 or more dollars but apparently they can't get one that good or the sales dude would have died rather than order it.

anyway it works, has a built in thermometer and the temp compensation chart all in a nice unit.
while it drips a bit it is usable.

i checked the batteries, each cell and they all come in  at 1.275 plus 2 for temp compensation, meaning they are all at 1.277 which is what they should be at full charge.

so the voltage is correct for each battery, all within  a couple hundredths of a volt and all the cells electrolyte specific gravity are spot on, so...

it looks like these are all ok, and will do what is expected of them.

it looks like i will have to take back half of the ugly things i was thinking about the dealer!

lol   

seriously i am happy with the purchase, at 60 bucks each, plus a 20 dollar core charge each
i got six 8volt 190amp/hr batteries that are true deep cycle, and in good condition.

for my intended use, which is more of a buffer bank than a deep cycling proposition, i think with good care and maintenance i can get at least 6 years out of them.

i am thinking of setting up a regime where they will be used to no more than perhaps the top 20% for the most part (6 out of 7 days) and down to 50% state of charge on the 7th day.

it would appear that the lifespan is dramatically higher in shallow cycling, however electrolyte stratification can be a problem, so my thinking is to go ahead and take them down to half tank once a week or maybe extend that to once every two weeks to stir up the electrolyte and open up more plate pores in the process.

in any event they will be very closely monitored for any signs of changes, and the regime altered to keep the batteries in peak condition.  the idea being those lessons learned and procedures developed can then be applied to a more expensive battery set, and have some idea how best to utilize the investment.

bob g

[uber39]

Hi Guy's     
    don't forget some of us still use some 32v stuff and 4x8v still works for us. In my EV the 12v acc batt died while shopping so needed a new batt there and then ( controller works off the 12v batt ) so went beck into dept store and could only get standard auto batt, so bought the cheapest one I could $79.00 later , get home and order another deep cycle batt but also put 12v desulfator on the little one I just put in there. That was 4yrs ago and the little batts still in there and going fine it gets charged when the main pack is charged and runs all 12v items in the car, lights wipers radio etc. I do sometimes get home in the dark with dim lights and a buzzing instead of a radio- so a very run down batt but it charges back up again and still seems happy.
    Just saying that I to do like the desulfators and run them on all lead acid batts here   
Out of curiosity what are you guys paying for Trojan T104's $360.00 each here.
         Ian

[Jens]

after looking at a few at my local napa he finally ordered me in a very expensive unit (his words)
and i waited for it to come in,,, it did and i picked it up for the princely sum of $9.79 including tax...
no wonder the crap they sell is so cheaply made, if a decent one cost less than 10 bucks one really doesn't even want to think about a cheaper priced unit... i really would like to have gotten one priced at 30 or more dollars but apparently they can't get one that good or the sales dude would have died rather than order it.

anyway it works, has a built in thermometer and the temp compensation chart all in a nice unit.
while it drips a bit it is usable.

That same unit (presumably) costs $19.99 plus tax up here in the not so frozen north. If you are feeling badly about how cheap yours was, I can sell you one for a mere 29.99   BTW, be vely vely carefull about the thermometer. It is like ultra fragile and if you push on it by accident it will break (the 29.99 high precision unit that I offered above does not have a broken thermometer by the way - it has a custom shorter thermometer to be able to reach into smaller confined spaces)

Although it did the job, I find these specific gravity measurements to be very frustrating and highly misleading as to the accuracy and precision attainable.

I am glad the batteries worked out for you and 60 bucks is a steal !

[mobile_bob]

thanks Jens

i too find the hydrometer to be very tedious to get accurate results with, however it is able to do
so if you are very careful with it.

is it as easy as a cheap digital voltmeter is at measuring voltage?  hell no!

but it beats anything i have so far at measuring specific gravity.

i am going to keep looking to see if i can find a better one, i know that they used to make
very good, high quality hydrometers, but that was maybe 40 years ago since i last saw one.

at least this one will work well enough to get a baseline and determine if the cells could be charged up to full and give me some assurance that they are not heavily sulfated.

i would still like to do about a 3 hour equalization on the string, just to make sure they are as good as can be from the start, however i am not seeing anything that tells me that is needed right now, so maybe that will wait until i can get my charging system up and running so that i have a tightly controlled equalization capability.

the thought also comes to me that maybe i would like another string of these batteries to alternate between, an A and a B set.   that would allow me to be much more careful with the batteries in use, and in charging, and allow for a 24 hour rest before a string would be put back into service,, this would allow for better accuracy using voltage as an indicator of true state of charge between service intervals.

failing that, i think i will at least call and get one more battery to match this set, to use as a spare, and rotate it into the string on a weekly basis, sort of like a spare tire in the trunk. this would allow me to take out a weak sister if one pops up and give me time to do some remedial work on it before putting it back in the lineup.  i think that would be very beneficial, in that i could probably correct a problem before it got to the point of being very hard or impossible to correct.

in the end this is all to do research on, and it seems to me that if i am going to all the trouble to try and do accurate/repeatable testing, i might as well do as many facets of testing at the same time as is economically possible.

the goal now is to get this system fully functional before next cooling season, i want to have the trigen fully online and burning nat/gas before the need of heavy air conditioning hits again. these 300 dollar electric bills for this little place while manageable seem to me that i might be able to trim a bit off of.

with my luck however, by the time that comes around, natural gas prices will double or worse and make using it as an alternate (cheaper) fuel source not viable.

bob g