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Santiago
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'nother battery ?
I know this has been hashed out almost as much as tires but once more......into the fray.
Time to replace my battery bank, such as it is. My system is two 12 volt 190 watt panels, going thru a Xantrex 60 amp charge/controller feeding 4
Sam's Club 6-volt golf-cart batteries wired to 12 volts (20 AMP hours of about 410). The battery bank is converted to 120v via a 1500 watt Xantrex
inverter (modified wave) and on to the power center. Pretty simple and low key operation and so far, trouble free. The entire system, including the
batteries, is 4 years old.
I only use the cabin 4 times a year, week at a time at most. During the time I'm gone, the batteries stay connected to the panels. Everytime I come
in October, the batteries need water, a lot of water. The tops of the plates are dry, requiring over a gallon to top off the 12 cells. During the
winter months, this does not seem to be happening; I still need to add water but the plates are still wet. I hear +/- regarding automated watering
systems. At least twice a year I remove all the cables, do the baking soda thing, reconnect the cabling and do the red-spray stuff. As you can tell,
I am not anal about my system and have no intension of being so. I yam what I yam.
My question is this: 4 more golf cart batteries will cost about $367. If I get 4 more years that's $91/year.
Or, go to an AGM system which will run me upwards to $1000 for 420 AMP hours. The missing piece of info is how long will the AGMs last in this
environment (BOLA) and treatment? Is 8 years doable?
By the way, I do not see the need to expand my system's capabilities. I am always 100% full buy 3 or 4 in the afternoon and never below 80% in the
morning. I wash my panels on arrival.
Another question: where is the best place to take off 12volts in my system: at the batteries or at the 12 volt terminals on the in-let side of the
inverter? My water pump is a Whisper King 12v Surflow and I have been running it off a separate battery but want to wire it into the system. I also
want to run a few 12 volt lights for redundancy in case the inverter goes some day.
Donkey Shame
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monoloco
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Location: Pescadero BCS
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What's the maximum length of time that the system sits without being used? You could safely leave those golf cart batteries disconnected for 3-4
months at a time and it would probably be better for them than leaving them charging and gassing out all their electrolytes. I have seen countless
battery banks killed by leaving them charging unattended for months at a time, usually what happens is one or more cells will go bad and cause the
rest of the bank to be ruined by overcharging. I think that it would be better to take your 12v circuit off the inverter terminals so you just have
one set of cables coming off the batteries instead of another set of ring connectors to corrode.
"The future ain't what it used to be"
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Santiago
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Quote: Originally posted by monoloco  | What's the maximum length of time that the system sits without being used?
I think that it would be better to take your 12v circuit off the inverter terminals so you just have one set of cables coming off the batteries
instead of another set of ring connectors to corrode. |
3 months, occasionallyy 4 over the winter.
I was thinking same thing on the 12 volt take-off.
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rts551
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Because I do not wish to bring batteries down anymore, I have switched to LTH 8d 12 volt deep cycle batteries (they are used on barges and big
trucks). Gohner makes them as well. I don't have any more issues with one 6v battery killing the others or nearly the water usage. They do weigh
60 kilo's apiece but are readily available in Mexico.
On edit: Baja Gringo (Ron) turned me on to these.
[Edited on 10-17-2015 by rts551]
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Santiago
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Is this the one you mean?
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micah202
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...would it work to disconnect most of the panels when you're away,,
,,just have a small trickle-charge?
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bkbend
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Posts: 693
Registered: 11-27-2003
Location: central OR or central baja
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I disconnect mine (6V golf cart) while I'm gone and that solves the dry battery issues. However, they will lose about 10% charge/month and it may
take you a couple of days to get them back up to a full charge. If you're there only for a week, that will cut into your time with full power. I
also worried about lights if the inverter craps out so I have bathroom and partial kitchen lights (and the wife's reading light) wired to 12v so the
important things can still get done. I'm not sure if it's the right way to do it or not but I ran a fused 4 gauge wire to + and - bus blocks and then
connected the 12V runs to that.
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Santiago
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| Quote: Originally posted by soulpatch | If that is the C60 you should be able to easily adjust your float charge down to 12.5 V while you are gone.
Do you know what you have it set at?
Can I assume you disconnect your inverter so it isn't drawing current?
[Edited on 10-17-2015 by soulpatch] |
It is the C60 and I left the jumpers and adjusting wheels at the factory setting, whatever that was.
Yes, the inverter is turned off. Here is a picture of my board, please do not laugh with earshot. Only two batteries in the test, but there are
four.
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rts551
Elite Nomad
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Yes
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landyacht318
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Ideal float voltage is just high enough to prevent discharge.
Ideal float voltage changes with battery temperature, the higher the temperature, the lower the voltage required.
A battery which is not discharged the night before does not need to spend 2 hours in the mid 14s the next morning.
Batteries whose plates get exposed rarely provide adequate service after refilling..
Lower float voltage to 12.9 when you leave in summer, allow 14.5v absorption voltage for no more than 15 minutes when you are away.
A daily deeply cycled battery does not need the same voltage regimen as one which was not cycled.
Your charge controller seems to allow different settings. YOu have just not chosen them right when you leave.
Batteries self discharge more in hot weather. I would not recommend leaving them for 3 to 4 months in 80F average without a charging source.
Sams club 6v GC batteries are No trojan T-105, but way better than 99.98% of 12v flooded batteries in deep cycle duties.
AGM batteries are great and give great service, but only when their specific recharging demands are met. Their price does not make them immune from
chronic under or overcharging.
AGMS do not make great solar only batteries as they like higher amp recharging, upto 30% for lesser $$ AGMS and no less than 20% for high$$ AGMSlike
Lifeline, and Odyssey requiring 40% when deep cycled.
I'd recommend more Wet GC batteries and learn how to lower the voltage on your charge controller for when you leave and know how to bump it back upto
14.6 to .8 for 3 to 4 hours when you actually cycle the batteries daily. If it can accommodate a battery temperature sensor, all the better.
One battery guru I highly respect claims than no wet/flooded 4d or 8d battery has plates as thick as a T-105 GC-2 battery. That they are basically
starting batteries, marine/dual purpose at best. Nowhere near the construction of a true deep cycle battery.
http://www.pbase.com/mainecruising/deep_cycle_battery
Positive plate thickness defines a quality deep cycle battery, though Odyssey and Northstar AGMS tout their thin plate pure lead technology, and I
have to say my Northstar AGM is Effing impressive in deep cycle as well as engine starting duty, as long as it is charged truly fully after every
depletion( when amps taper to 0.5% of capacity at 14.4v), and recharged regularly at a very high rate.. 40 amps or more for a 90AH battery. Ignore
the trickle charger mentality with AGM batteries, and on flooded batteries deeply cycled daily.
If one PSOC's their battery, partial state of charge cycling, then the battery gets peeed off and sulfates. Flooded batteries get less peeed off than
AGM in PSOC usage.
AGM batteries need to be installed as a system. The charging currents need to be tailored to their petulance, and the petulance varies between AGM
brands.
I'd say that they need a high charge rate every 7 to 10 cycles when low and slow solaar only recharged.
Beware of blinking green lights on charge controllers. When A charge controller drops to float voltage, it does not mean the battery is fully
charged, it ONLY means that absorption voltage was held as long as it was programmed to do so.
Ideal Absorption voltage and duration at which it is held is moving target that wanders with temperature, depth of discharge, charge rate.
Those who use a hydrometer compensated for temperature will find their charge controller is a effing liar, that Absorption voltage, perhaps a higher
ABSV) needs to be held for much longer before specific gravity maxes out.
When a heavily cycled battery does not regularly have its specific gravity maxed out in the 1.275+ range, the battery is losing capacity faster than
if it were.
Lead Acid Batteries are murdered by ignorance of their requirements, 99% of the time.
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Santiago
Ultra Nomad
Posts: 3500
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Assuming four 6volt GC batteries:
So, first I find out from the battery manufacturer what their recommended settings are and these I use when I'm there.
On leaving for 3-4 months, I need to change the float setting to it's lowest point: 12.5. Should the Bulk setting be reduced as well? During these
months away, it should never go into Bulk, correct?
I can change the equalization charge from auto to manual: auto is every 30 days. Factory setting is manual and I suspect that is what it is set at. I
seem to recall once doing an equalization charge a few years ago. How often, given my usage, should I do one?
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rts551
Elite Nomad
Posts: 6699
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| Quote: Originally posted by landyacht318 | Ideal float voltage is just high enough to prevent discharge.
Ideal float voltage changes with battery temperature, the higher the temperature, the lower the voltage required.
A battery which is not discharged the night before does not need to spend 2 hours in the mid 14s the next morning.
Batteries whose plates get exposed rarely provide adequate service after refilling..
Lower float voltage to 12.9 when you leave in summer, allow 14.5v absorption voltage for no more than 15 minutes when you are away.
A daily deeply cycled battery does not need the same voltage regimen as one which was not cycled.
Your charge controller seems to allow different settings. YOu have just not chosen them right when you leave.
Batteries self discharge more in hot weather. I would not recommend leaving them for 3 to 4 months in 80F average without a charging source.
Sams club 6v GC batteries are No trojan T-105, but way better than 99.98% of 12v flooded batteries in deep cycle duties.
AGM batteries are great and give great service, but only when their specific recharging demands are met. Their price does not make them immune from
chronic under or overcharging.
AGMS do not make great solar only batteries as they like higher amp recharging, upto 30% for lesser $$ AGMS and no less than 20% for high$$ AGMSlike
Lifeline, and Odyssey requiring 40% when deep cycled.
I'd recommend more Wet GC batteries and learn how to lower the voltage on your charge controller for when you leave and know how to bump it back upto
14.6 to .8 for 3 to 4 hours when you actually cycle the batteries daily. If it can accommodate a battery temperature sensor, all the better.
One battery guru I highly respect claims than no wet/flooded 4d or 8d battery has plates as thick as a T-105 GC-2 battery. That they are basically
starting batteries, marine/dual purpose at best. Nowhere near the construction of a true deep cycle battery.
http://www.pbase.com/mainecruising/deep_cycle_battery
Positive plate thickness defines a quality deep cycle battery, though Odyssey and Northstar AGMS tout their thin plate pure lead technology, and I
have to say my Northstar AGM is Effing impressive in deep cycle as well as engine starting duty, as long as it is charged truly fully after every
depletion( when amps taper to 0.5% of capacity at 14.4v), and recharged regularly at a very high rate.. 40 amps or more for a 90AH battery. Ignore
the trickle charger mentality with AGM batteries, and on flooded batteries deeply cycled daily.
If one PSOC's their battery, partial state of charge cycling, then the battery gets peeed off and sulfates. Flooded batteries get less peeed off than
AGM in PSOC usage.
AGM batteries need to be installed as a system. The charging currents need to be tailored to their petulance, and the petulance varies between AGM
brands.
I'd say that they need a high charge rate every 7 to 10 cycles when low and slow solaar only recharged.
Beware of blinking green lights on charge controllers. When A charge controller drops to float voltage, it does not mean the battery is fully
charged, it ONLY means that absorption voltage was held as long as it was programmed to do so.
Ideal Absorption voltage and duration at which it is held is moving target that wanders with temperature, depth of discharge, charge rate.
Those who use a hydrometer compensated for temperature will find their charge controller is a effing liar, that Absorption voltage, perhaps a higher
ABSV) needs to be held for much longer before specific gravity maxes out.
When a heavily cycled battery does not regularly have its specific gravity maxed out in the 1.275+ range, the battery is losing capacity faster than
if it were.
Lead Acid Batteries are murdered by ignorance of their requirements, 99% of the time. |
What kind of batteries do you use, and what are you charge rates set for?
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landyacht318
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Posts: 247
Registered: 7-28-2007
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My Solar/battery/electrical System is in A campervan.
My most recent flooded battery was a USbattery, group31. 130AH capacity.
With lots of experimenting with a hydrometer and changing my solar settings, I found 14.9v absorption voltage with a 15.3v float voltage for the
remainder of afternoon, In daily usage cycling 45 to 60AH overnight, was required for Specific gravity to stay above 1.265 after 10 to 14 deep cycles.
Every 14 to 16 days It would require 45 to 120 minutes being held at 16v after a normal absorption cycle.
This battery's performance Absolutely tanked if it did not receive these practically obscene voltages daily and EQ charges every 2 weeks. If I let
it walk down in capacity too far, then even more time at 16v, 4 to 5 hours, was required to get the specific gravity up to 1.280. 15.5v would not do
it, 15.7v would not do it, 16v would.
When the alternator contributed heavily to charging in the early morning when the battery was most depleted, the total time at which it needed to be
held at 14.9v and 15.3v was reduced. My alternator would do 32 amps minimum and as much as 85 into this USbattery group31. It would always start at
62 amps Into the battery but fade to 32 amps when hot and idle speed slowed by 375 rpm.
This battery lasted nearly 500 deep cycles, which is pretty good for such a battery. When I was Not cycling the battery nightly, I reprogrammed float
voltage to 13.1v, and also lowered absorption voltage to 14.1v for 30 minutes or 1 amp taper point, No automatic equalize allowed, basically it would
rise to absorption voltage quickly early morning and drop to 13.1float voltage right after. Water loss in this regimen is minimal, barely perceptible
in 3.5 weeks the system was left alone over the holidays.
I have not replaced it. My other battery which Was more for engine starting purposes only, is a Northstar AGM battery, group 27, 930CCA, 90 AH
capacity. Right now My solar settings are 14.4v, absorption voltage set for 3.5 hours or when current required to hold 14.4v drops below 0.4 amps.
Float voltage 13.6v. Bulk charge is just maximum amps available until 14.4 is attained, and is highly variable depending on day.
I pull 40 to 65 AH from this battery 4 to 5 nights a week. it still easily pulls 70 to 80 amps from the alternator whose voltage regulator allows a
maximum of 14.9v. or 0.5v higher than recommended by Northstar.
This AGM battery loves huge recharging currents, and then to be top charged to 100% by 200 watts of solar. After 4 to 5 solar only recharge cycles
after 50% deep cycles, it requires a high amp recharge from its most depleted state or performance tanks.
This battery is my only battery at the moment. I have tremendous confidence in its abilities as at nearly 2 years old and closing in on 200 Deep
cycles, It can hold the same voltages under the same loads with the same amount of capacity Removed from it, compared to when it was brand spanking
new.
It can easily and quickly start my Engine, even when depleted to 50%. When fully charged, it hold 13.06v for 3 weeks with no load on it. Very low
self discharge.
All previous Flooded batteries had obviously degraded by 200 deep cycles, but they were all the quasi deep cycles, Crown and USbattery brand, in the
group 27 and group31 size 12v format. The wally world marine/dual purpose batteries in group 27 size were lucky to last 300 cycles total at a no more
than 65% depth of discharge, but these did not receive proper voltages or durations and sulfated prematurely and shorted cells easily.
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BigWooo
Senior Nomad
Posts: 579
Registered: 1-2-2007
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I'm posting without reading the replies (didn't have time) so I may be repeating some info. When we had a vacation home we spent about equal amount
of time in Baja as you do. We used Concorde AGM batteries and shut down the solar when we were not there. AGM batteries can sit up to 9 months
without a charge. The batteries were still good when we sold our place after being used for over 10 years!
On our new home we also use Concorde AGM's. They get daily use now and I'm getting about 8 years out of them. I'm very careful to be sure I have
proper absorb time and I have a big enough bank so I don't discharge them more than 25% daily (usually about 20%). though.
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woody with a view
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Posts: 15938
Registered: 11-8-2004
Location: Looking at the Coronado Islands
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Mood: Everchangin'
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thanks for bringing this up Santiago, i'm learning as well.
3 days of rain squalls did a number on my system last time. i left two of these plugged in to the controller with the inverter off to give them a good
soak: http://deepcyclebatterystore.com/solar-battery-back-up/
looks like i need another couple of them though. like i said, i brought them WAY down and they had trouble getting back to full each day due to
weather. BTW, my total draw is 4.5A when everything is on, which is almost never.
[Edited on 10-19-2015 by woody with a view]
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Santiago
Ultra Nomad
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| Quote: Originally posted by BigWooo | I'm posting without reading the replies (didn't have time) so I may be repeating some info. When we had a vacation home we spent about equal amount
of time in Baja as you do. We used Concorde AGM batteries and shut down the solar when we were not there. AGM batteries can sit up to 9 months
without a charge. The batteries were still good when we sold our place after being used for over 10 years!
On our new home we also use Concorde AGM's. They get daily use now and I'm getting about 8 years out of them. I'm very careful to be sure I have
proper absorb time and I have a big enough bank so I don't discharge them more than 25% daily (usually about 20%). though. |
Did you use the 12v or the 6v?
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rts551
Elite Nomad
Posts: 6699
Registered: 9-5-2003
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We have apples and oranges going on here. I have a wind generator, 6 100 watt panels, 2 150 watt panels, use to use12 6v gc batteries , now use
6 8d batteries. But I run a full house (tv, frig, freezer, fans, etc). My grid tie inverter charvers the batteries if I do have to run the
generator (which is not often).
I DO NOT run my batteries down every day. So I think the requirements for a household are very different than a camper or vacation lights only
home.
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monoloco
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Posts: 6667
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Location: Pescadero BCS
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| Quote: Originally posted by Santiago | | Quote: Originally posted by BigWooo | I'm posting without reading the replies (didn't have time) so I may be repeating some info. When we had a vacation home we spent about equal amount
of time in Baja as you do. We used Concorde AGM batteries and shut down the solar when we were not there. AGM batteries can sit up to 9 months
without a charge. The batteries were still good when we sold our place after being used for over 10 years!
On our new home we also use Concorde AGM's. They get daily use now and I'm getting about 8 years out of them. I'm very careful to be sure I have
proper absorb time and I have a big enough bank so I don't discharge them more than 25% daily (usually about 20%). though. |
Did you use the 12v or the 6v? |
If you need more capacity in a 12v system than you can get with 2 6v
batteries, you are better off using 6 2v batteries to avoid parallel strings. I am using 8 6v Concorde AGM's for a 24v system and have had some issues
with uneven charging, and wish that I would have bought 12 2v batteries instead. Considering how little that you use your system, it's probably not
worth spending double the money on AGM's. Maybe keep an eye out for some used 2v AGM telecom batteries.
"The future ain't what it used to be"
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captkw
Ultra Nomad
Posts: 3850
Registered: 10-19-2010
Location: el charro b.c.s.
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Mood: new dog/missing the old 1
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Carbon Foam AGM
Being I do batt/pwr systems in my line of work I have to stay on top of my game and was wondering if anyone here is using them in a system and their
thought's...from what I have learned is they are showing a bright future..pun intended !!
[Edited on 10-20-2015 by captkw]
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BigWooo
Senior Nomad
Posts: 579
Registered: 1-2-2007
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12volt
| Quote: Originally posted by Santiago | | Quote: Originally posted by BigWooo | I'm posting without reading the replies (didn't have time) so I may be repeating some info. When we had a vacation home we spent about equal amount
of time in Baja as you do. We used Concorde AGM batteries and shut down the solar when we were not there. AGM batteries can sit up to 9 months
without a charge. The batteries were still good when we sold our place after being used for over 10 years!
On our new home we also use Concorde AGM's. They get daily use now and I'm getting about 8 years out of them. I'm very careful to be sure I have
proper absorb time and I have a big enough bank so I don't discharge them more than 25% daily (usually about 20%). though. |
Did you use the 12v or the 6v? |
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