Viability of deep-cycle 8Ds?

softdown
softdown Solar Expert Posts: 3,812 ✭✭✭✭
Recently learned about the availability of deep-cycle 8Ds from a local battery distributorship.
Their price quote:
8D: $205
Deep Cycle 8D: $250
These are good prices from what I have seen.

8Ds weigh about the same as the most common size used in serious solar applications.....about 125 lbs. Since this size of solar battery seems to average about $400, the deep cycle 8D becomes more interesting.

Thoughts?

I'm just trying to make solar more affordable. True off-gridders often have a tough time making a good income as those jobs tend to be in the larger cities. So we often face massive energy costs and lower incomes. Batteries have become ridiculously expensive.
First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries

Comments

  • CALLD
    CALLD Solar Expert Posts: 230 ✭✭
    What's always important to consider is the price-per-watt-hour storage over the lifetime of the battery. I say watt-hour instead of amp-hour because some batteries are far more energy efficient than others. A good 12v AGM battery will deliver a lot of its power at a voltage above 12.2v while discharging and will accept a lot of it's charge at a voltage below 14v. By contrast a poor flooded battery may deliver only a small amount of its power above 12v and accept a lot of its charge at a higher voltage than 14v. This ends up costing you a lot of energy over the battery's lifetime that translates into money ultimately.

    There are some very decent AGM deep cycle batteries on the market now that compare very favorably with FLA batteries. I have a very good pair of 12v 260ah AGM deep cycles, brand is SONX. They cost me about $300 each and are good for about 800 cycles to 50% DOD.

    When I considered them against 12 x 2v 300ah flooded deep cycle tubular cells, good for about 2000 cycles to 50% DOD but at a total price of over $2000 and requiring regular maintenance I just couldn't justify the upfront cost and the resulting financing costs (additional interest on the loan)...
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    You also need to know more about the specific battery construction... "8D" does not really tell you much other than physical size.

    Do you have a link to the batteries you are looking at?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • softdown
    softdown Solar Expert Posts: 3,812 ✭✭✭✭
    No link. The battery distributorship, based in Colorado Springs, simply quoted prices for both the 8D and the 8D Deep Cycle. Believe he said they weigh about 125 pounds. All of the 8Ds that I have seen are ~20x10x10. 20" from front to back. Used in large trucks and, I believe, some motor homes.

    My 8Ds are made by Johnson Controls and sold as "Energizer". Johnson also makes Deep Cycle 8Ds but they are sold under a different name. Hence, not available at Sams Club.

    If I ever meet with the distributor, I will get more data. It is pretty clear that Deep Cycle is worth an additional ~25% to the solar crowd.

    FWIW to those who don't know: Deep Cycle = less CCA as there are fewer lead plates albeit thicker lead plates. Multiple rows of thin lead plates yields more CCA....and sensitivity to deep discharge.

    I'll check if a quick net search turns up anything noteworthy.
    BB. wrote: »
    You also need to know more about the specific battery construction... "8D" does not really tell you much other than physical size.

    Do you have a link to the batteries you are looking at?

    -Bill

    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • softdown
    softdown Solar Expert Posts: 3,812 ✭✭✭✭
    So far....all of the Deep Cycle 8Ds are AGM and run around $6-700/each.

    Here is a 163 pounder for $329. An apparently solid deal if Apex is a good manufacturer.

    Edit: the manufacturer is Universal Power Group

    Edit: shipping fees ruin the apparent economy.

    http://www.apexbattery.com/12v-250ah...attery-ub.html
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • softdown
    softdown Solar Expert Posts: 3,812 ✭✭✭✭
    This info leads one to believe that the common 1400 CCA 125 pound 8D is pretty suitable for deep cycling.

    http://www.napaonline.com/Catalog/CatalogItemDetail.aspx/Battery-Marine-RV-Deep-Cycle-Universal-BCI-8D-NAPA-Batteries/_/R-NBE8276_0006559833
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,728 ✭✭✭✭✭✭
    softdown wrote: »
    This info leads one to believe that the common 1400 CCA 125 pound 8D is pretty suitable for deep cycling.

    http://www.napaonline.com/Catalog/Ca...276_0006559833


    People have been trying to use 8D batteries offgrid at least 23 years ago when I started. If you take (2) L16 6 volt batteries 400 AH at the 20 hour rate, at around $650 cost for both L16's.
    The 8D is not going to compare price wise, spec wise, warranty, and will fail long before the L16's. I remember old hippies down by the river doing this with wires running everywhere.

    Look a little deeper into the number of cycles, the amp hours at the 20 hour rate, and warranty. A good battery will have a manual ! Take a look at Surrette, Trojan, Crown, and US battery in this price range. AGM's will be more money and probably not last as long if maintenance is done correctly with liquid electrolyte batteries.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

  • softdown
    softdown Solar Expert Posts: 3,812 ✭✭✭✭
    All true.....but we are trying to address the viability of deep cycle 8Ds.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • Mountain Don
    Mountain Don Solar Expert Posts: 494 ✭✭✭
    softdown wrote: »
    the 8Ds that I have seen are ~20x10x10. 20" from front to back

    ... which is why they are called 8D. The battery group number is a standard, agreed on by the Battery Council International. The idea being that a brand "XYZ" bought in the USA could be replaced with a brand "ABC" bought in Mongolia and it would fit, right down to the placement of the positive and negative terminals.

    FWIW, and this is an opinion, I believe if 8D's were a truly good RE choice we would see the major battery brands selling 8D's labeled as suitable for RE use. I can't find any of those. I do see a number of 8D's that along with the words "deep cycle" have the word "marine" included in the description. My experiences with batteries that include that Marine word have been poor when battery longevity is a main criteria. That experience goes back to the late 60's with batteries intended to run camping refrigeration through an assortment of RV's and for the past half dozen years off grid use. Call me biased if you wish, but I don't feel like trying to reinvent the RE wheel, if you understand what I mean. I have had good experiences with GC-2 group batteries; stationary and mobile. That 40+ years does NOT make me an expert on batteries. I do think the overall experiences comparing marine/deep cycle to GC-2 is very meaningful though.
    Northern NM, 624 watts PV, The Kid CC, GC-2 batteries @ 24 VDC, Outback VFX3524M
  • H2SO4_guy
    H2SO4_guy Solar Expert Posts: 213 ✭✭✭
    Up until a month ago I was running 3 strings of 8D batteries of assorted manufacturer. Most of them I got a couple of years ago used for $60 each and I did get a blem set for $75 each. That put me at $780 in 3 strings for about 500 AH @ 48 volts. I figure if I use the 8 hour rate it may be more accurate on used batteries. One died so now I have 2 strings with 3 spares that I will keep charged monthly.

    They work pretty well, but when you have six cells tied together when any one fails, the unit is now scrap. I use them during the day while the big AGM’s charge with no load whatsoever…..usually. I don’t run them down too far usually because they are not matched, but they will scrap for around $30 or so each, so I don’t have that much into them.

    They don’t seem to like to be hit really hard (Like 70 amps or so) but for run of the mill usage they work very well and I feel they will extend the life of the larger AGM’s by taking some of the load off of them.

    I would buy them again if I could get them cheap, but they have limitations. I used to get them for $25 each, but that deal went away.

    Good luck and let us know how it works out
    12K asst panels charging through Midnite Classic 150's, powering Exeltechs and Outback VFX-3648 inverter at 12 and 48 volts.  2080 AH @ 48 VDC of Panasonic Stationary batteries (2 strings of 1040 AH each) purchased for slightly over scrap, installed August 2013.  Outback PSX-240X for 220 volt duties.  No genny usage since 2014. 
  • softdown
    softdown Solar Expert Posts: 3,812 ✭✭✭✭
    Dang....is there a reliable way to find such deals as you found?All I can think of is Craigslist so far.
    H2SO4_guy wrote: »
    Up until a month ago I was running 3 strings of 8D batteries of assorted manufacturer. Most of them I got a couple of years ago used for $60 each and I did get a blem set for $75 each. That put me at $780 in 3 strings for about 500 AH @ 48 volts. I figure if I use the 8 hour rate it may be more accurate on used batteries. One died so now I have 2 strings with 3 spares that I will keep charged monthly.

    They work pretty well, but when you have six cells tied together when any one fails, the unit is now scrap. I use them during the day while the big AGM’s charge with no load whatsoever…..usually. I don’t run them down too far usually because they are not matched, but they will scrap for around $30 or so each, so I don’t have that much into them.

    They don’t seem to like to be hit really hard (Like 70 amps or so) but for run of the mill usage they work very well and I feel they will extend the life of the larger AGM’s by taking some of the load off of them.

    I would buy them again if I could get them cheap, but they have limitations. I used to get them for $25 each, but that deal went away.

    Good luck and let us know how it works out

    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • softdown
    softdown Solar Expert Posts: 3,812 ✭✭✭✭
    I believe this is correct. The Deep Cycles are pretty likely to be "Marine" batteries whatever that means. Once read that one can expect approx. the following longevity:
    Auto battery: 1 year
    Marine battery: 2 year
    Golf cart battery: 5 year
    Solar battery: 7-15 years

    So....marine batteries really are not very special at all.

    ... which is why they are called 8D. The battery group number is a standard, agreed on by the Battery Council International. The idea being that a brand "XYZ" bought in the USA could be replaced with a brand "ABC" bought in Mongolia and it would fit, right down to the placement of the positive and negative terminals.

    FWIW, and this is an opinion, I believe if 8D's were a truly good RE choice we would see the major battery brands selling 8D's labeled as suitable for RE use. I can't find any of those. I do see a number of 8D's that along with the words "deep cycle" have the word "marine" included in the description. My experiences with batteries that include that Marine word have been poor when battery longevity is a main criteria. That experience goes back to the late 60's with batteries intended to run camping refrigeration through an assortment of RV's and for the past half dozen years off grid use. Call me biased if you wish, but I don't feel like trying to reinvent the RE wheel, if you understand what I mean. I have had good experiences with GC-2 group batteries; stationary and mobile. That 40+ years does NOT make me an expert on batteries. I do think the overall experiences comparing marine/deep cycle to GC-2 is very meaningful though.

    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,728 ✭✭✭✭✭✭
    The 8D is basically a truck battery. 18 wheeler's. Marine batteries and truck batteries are built to take vibration which is not an issue in RE batteries. The really good marine batteries like the Surrettes can sit right next to a diesel engine for 5 years in a sailboat and operate upside down for some time when it is upside down. Probably long enough to dive inside the boat and find something you need. The Surrette warranty is quite long and is a much better battery than a marine battery from Napa, Auto Zone or....
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

  • softdown
    softdown Solar Expert Posts: 3,812 ✭✭✭✭
    They are not always built tough. I know of two that sprung a leak quite easily. Mine slid forward upon braking and cracked badly when it impacted the side of a pole a couple feet away. Replaced the acid, sanded the crack and epoxied. Seems fine now. But I thought it broke quite easily.
    The 8D is basically a truck battery. 18 wheeler's. Marine batteries and truck batteries are built to take vibration which is not an issue in RE batteries. The really good marine batteries like the Surrettes can sit right next to a diesel engine for 5 years in a sailboat and operate upside down for some time when it is upside down. Probably long enough to dive inside the boat and find something you need. The Surrette warranty is quite long and is a much better battery than a marine battery from Napa, Auto Zone or....

    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,728 ✭✭✭✭✭✭
    softdown wrote: »
    They are not always built tough. I know of two that sprung a leak quite easily. Mine slid forward upon braking and cracked badly when it impacted the side of a pole a couple feet away. Replaced the acid, sanded the crack and epoxied. Seems fine now. But I thought it broke quite easily.


    Agree that very few things in life are always. I did the same repair on an island in the Pacific. They are not suppose to move around you know? I did not think mine would, but I was wrong.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

  • H2SO4_guy
    H2SO4_guy Solar Expert Posts: 213 ✭✭✭
    I found the $25 group 8D's off of a local Craigslist ad. They had been running 2 for each diesel engines for backup gennys and replace some every 18 months, but I can't get those anymore. There is a place here that I was getting $60 8D's with trade in of lead for weight. It is always a crap-shoot on what they have in stock. It is the last place before batteries go to the smelter. I brought them cookies for 12 weeks in a row to get really good deals. They let me nose around with a volt meter and buy whatever I want for a great price. The cat's meow was getting 56 cells of 2 volt Panasonic cells @ 1040 AH each. These things are working great and I can't hit them with enough load to ever wear them down. Went 17 days with very little sunshine never went below 49 volts under load.

    Check your area for who sends batteries directly to the smelter. The trucks carry about 44,000 pounds of batteries, so it has to be a shop doing some volume.

    Good luck and let us know
    12K asst panels charging through Midnite Classic 150's, powering Exeltechs and Outback VFX-3648 inverter at 12 and 48 volts.  2080 AH @ 48 VDC of Panasonic Stationary batteries (2 strings of 1040 AH each) purchased for slightly over scrap, installed August 2013.  Outback PSX-240X for 220 volt duties.  No genny usage since 2014. 
  • softdown
    softdown Solar Expert Posts: 3,812 ✭✭✭✭
    How about simply placing an ad offering 10% more per pound for batteries than the smelter does. Plus you pick them up? Would need to qualify it so you weren't buying junk somehow. I know a guy who placed an ad offering to buy batteries. Good some good ones and some bad ones.
    H2SO4_guy wrote: »
    I found the $25 group 8D's off of a local Craigslist ad. They had been running 2 for each diesel engines for backup gennys and replace some every 18 months, but I can't get those anymore. There is a place here that I was getting $60 8D's with trade in of lead for weight. It is always a crap-shoot on what they have in stock. It is the last place before batteries go to the smelter. I brought them cookies for 12 weeks in a row to get really good deals. They let me nose around with a volt meter and buy whatever I want for a great price. The cat's meow was getting 56 cells of 2 volt Panasonic cells @ 1040 AH each. These things are working great and I can't hit them with enough load to ever wear them down. Went 17 days with very little sunshine never went below 49 volts under load.

    Check your area for who sends batteries directly to the smelter. The trucks carry about 44,000 pounds of batteries, so it has to be a shop doing some volume.

    Good luck and let us know

    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • H2SO4_guy
    H2SO4_guy Solar Expert Posts: 213 ✭✭✭
    I started on searching on Craigslist, but there is something weird on there about used batteries. Don't know exactly, but not too many ads there for them. I would usually search for industrial batteries. I once found 3 T185 (Or was it T165???) Anyway they are 12 volts and about 165 AH. I got 3 for $25 each, and they were out of a battery operated 36 volt lift. They ran my refrigeration for awhile and now they are worth about $80 or so in scrap. How do you go wrong when you get to use them for very little? I just purchase the battery ends brand new in bulk, sometimes for a fraction of new, and make my own cables, mostly from used wire I got cheap. I have also purchased many cable ends from our gracious host NAWS. I try to always let them know that the reason I am buying from them is due to the forum here.

    I would run an ad for industrial batteries or a forktruck battery. The challenge is getting enough of the same age, size, and condition to work in an RE system. That's why when I buy I try to buy spares at the same time from the same lot. Lots of ways to do this stuff on the cheap if motivated!

    Good luck
    12K asst panels charging through Midnite Classic 150's, powering Exeltechs and Outback VFX-3648 inverter at 12 and 48 volts.  2080 AH @ 48 VDC of Panasonic Stationary batteries (2 strings of 1040 AH each) purchased for slightly over scrap, installed August 2013.  Outback PSX-240X for 220 volt duties.  No genny usage since 2014. 
  • softdown
    softdown Solar Expert Posts: 3,812 ✭✭✭✭
    Scrounging your way up to 12K in solar power. World class I'll bet.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • softdown
    softdown Solar Expert Posts: 3,812 ✭✭✭✭
    Found a better way to scrounge than Craigslist and Ebay?
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries