Marine batteries for backup power.

[lkruper]

Hands down, the smartest of the bunch for floating for those batteries would have to be the Tecmate-Optimate 6. 240ah is the end of it's spec for maintaining. A 50% duty cycle in float (30mins on, 30 mins test, repeat - at 13.6v). This will take place AFTER it finishes the 12-hour long-term test. Some users forget this. Floodies won't overflow, and agm's that have dried out from prior abuse or age are given time to cool in between. Real-world smarts, not just hype.

Still, for BIG batteries, use a proper amperage charger for bulk at least. ALL low-amperage chargers are not ideal for bulk charging big batteries. In your instance, for just maintaining a large one, the Optimate 6 is my recommendation for an inexpensive yet truly smart charge.

At last count I've tested / own about 25 or so chargers. Many are GOOD, but the Optimate is the wisest of the bunch.

I have been meaning to ask you about the Optimate 6 for 24v banks. I presume it won't work because it is for 12v batteries, correct? However since I am so inexperienced with batteries, I would feel much better checking out my new batteries right away.
And if it can be used for an active float, that means it does double duty.

If there is no way to use the Optimate for 24v, this charger might sway me towards my first batteries being two golf cart batteries instead of Marine.

[PNjunction]

I have the TV on power save, but have not played with the backlighting yet. I will do that. Can you recommend an inexpensive active float charger that would maximize the life of batteries in float/backup most of the time?

Hands down, the smartest of the bunch for floating for those batteries would have to be the Tecmate-Optimate 6. 240ah is the end of it's spec for maintaining. A 50% duty cycle in float (30mins on, 30 mins test, repeat - at 13.6v). This will take place AFTER it finishes the 12-hour long-term test. Some users forget this. Floodies won't overflow, and agm's that have dried out from prior abuse or age are given time to cool in between. Real-world smarts, not just hype.

Still, for BIG batteries, use a proper amperage charger for bulk at least. ALL low-amperage chargers are not ideal for bulk charging big batteries. In your instance, for just maintaining a large one, the Optimate 6 is my recommendation for an inexpensive yet truly smart charge.

At last count I've tested / own about 25 or so chargers. Many are GOOD, but the Optimate is the wisest of the bunch.

[lkruper]

My comments are general and broad. Just remember battery manufactures are not created equal. In general terms a Deep Cycle will last about twice as long as Hybrid. But you cannot compare say a Wally World Golf Cart battery with Trojan RE as you are now comparing a 1-2 year battery to a 5 to 7 year battery. The take away is if you compare Acme Battery Company Hybrid and Deep Cycle battery line, the Deep Cycle is going to last roughly twice as long, bu thas some current limitations.

As to daily cycle vs Emergency or infrequent cycle you are now working on Calendar Life. Batteries have both Cycle and Calendar life, which ever comes first. Cycle every day, and much shorter than Calander life. With Emergency Stand-By use, you can use a smaller battery and discharge to 50 to 80% DOD. But there is a catch with the smaller battery. You are much more likely to exceed the maximum Discharge Rate on a smaller battery. In which case you are now looking for Hybrid or AGM. Like I have always said Hybrids have a place, but a niche place.

You are on the right path, keep it up. Its YOUR MONEY. Spend it wisely. Don't be like the 95% of those who come here after the fact wondering what went wrong.

Thanks. One of the reasons I wanted flooded batteries is to get some real experience with measuring SG and adding water, etc. I really don't care if they don't last that long, and to be honest, when I get tired of them I will likely re-purpose them to be used as backup for something at home and get something else to learn from.

[lkruper]

You may also want to look into a smaller ac/dc fridge/freezer like an A.R.B. and see if the efficiency is worth using these smaller units as compared to your original plan. At least in the case of critical items like prescription meds and other things that really need tending to. It isn't large, but perhaps worth a look. ARB's are pretty bulletproof, although it is more of a camping-style setup.

I spent a long time comparing Engel, ARB, and others like them. Bottom line was I could not justify spending that kind of money and ended up buying a traditional Energy Saver 14.5 Frigidaire for the cabin basement for 1/3 to 1/2 the cost of the good AC/DC brands with much more storage space and even an icemaker.

The small Supentown 3.2 in the kitchen is 95w and 1.3 amps and about 5 years old. If that one dies, I will consider an AC/DC model in its place. Fact is, I am not off-grid and don't really think I will have extended outages. However I am planning for El Nino just in case. If the outage happens in the wintertime, my basement acts like a root cellar and outside would be a freezer.

I also have a good stock of Mountain House, just in case.

[lkruper]

Tip: If you didn't actually measure the wattage of the TV, just know that the sticker is a worst-case scenario of full backlighting. If you are just going by the sticker, that's great for your calculations since it is unlikely you are using 100% full backlighting in the first place leading to a larger power hedge. I'm talking the typical lcd tv.

In normal use, you can save a LOT of power by running a lower backlight. Do NOT confuse this with "brightness". In my case, I reduced the power draw to HALF of the sticker rating by reducing the backlight (again, NOT brightness) to a very low level.

You may want to experiment and see just what your level of tolerable backlight reduction is. How low can you go before it becomes unusable? Saving up to 25% or more of the sticker value should be very easy. You may not want to use a low level backlight all the time under normal grid-power, but when the juice goes out and the batteries kick in, just remember to reduce the backlight as much as comfortable. When testing, give yourself some time to get adjusted to it before making a decision as the abrupt change can sway your decision too soon. When you see the power savings, that might be the arbiter instead!

A kill-a-watt ac meter or clamp-on dc ammeter at the battery terminals will reflect just how fast that power requirement goes down with even moderate reductions in backlighting.



The Stanley may actually do a better job if it offers a standard 13.6v float. The NOCO doesn't really do an active float, but "float monitoring", designed for guarding against parasitic loads and long-term self discharge. Even though it has a "trickle" stage, (version 1's, version 2 have a different optimization technique) there is not much trickling at all taking place. Thus, your batteries are just going to self-discharge until they reach a trigger point or a high parasitic load occurs. This may not be desirable if you desire true active float instead.

I have the TV on power save, but have not played with the backlighting yet. I will do that. Can you recommend an inexpensive active float charger that would maximize the life of batteries in float/backup most of the time?

[lkruper]

You should consider the golf cart batteries at Costco instead of the marine ones. They are around the same price but will last longer. The biggest issue would be that they are 6v, so you would need 4 to get a 24v system.

I did not notice this right away, but the link Sunking gave with cycle curves does show the difference between the two Signature lines, one with Marine (24, 28, 31) and other Signature including T105. (http://www.trojanbattery.com/markets...ble-energy-re/)

Looks like Trojan T105 have double the cycles as their Marine.

But, the caveat here is that we don't really know about Costco's golf cart batteries. They are Interstate and I did not find any cycle data on Interstate.

[PNjunction]

I am not planning on powering my two refrigerators (95w 3.2 cu ft, 700w Energy efficient) with batteries but will power them doing the day while running on generator.

You may also want to look into a smaller ac/dc fridge/freezer like an A.R.B. and see if the efficiency is worth using these smaller units as compared to your original plan. At least in the case of critical items like prescription meds and other things that really need tending to. It isn't large, but perhaps worth a look. ARB's are pretty bulletproof, although it is more of a camping-style setup.

[PNjunction]

My design specifications are to have enough power to keep my TV, satellite receiver, DSL modem, laptop computer and security cameras on over night so as not to need to listen to the noise of the generator. I would also likely use the battery initially if power goes out and when we are not sure when power will be restored. These devices add up to 113 watts if they are all on at once and a total of 138 AH @ 12v for one "overnight" time-period.

Tip: If you didn't actually measure the wattage of the TV, just know that the sticker is a worst-case scenario of full backlighting. If you are just going by the sticker, that's great for your calculations since it is unlikely you are using 100% full backlighting in the first place leading to a larger power hedge. I'm talking the typical lcd tv.

In normal use, you can save a LOT of power by running a lower backlight. Do NOT confuse this with "brightness". In my case, I reduced the power draw to HALF of the sticker rating by reducing the backlight (again, NOT brightness) to a very low level.

You may want to experiment and see just what your level of tolerable backlight reduction is. How low can you go before it becomes unusable? Saving up to 25% or more of the sticker value should be very easy. You may not want to use a low level backlight all the time under normal grid-power, but when the juice goes out and the batteries kick in, just remember to reduce the backlight as much as comfortable. When testing, give yourself some time to get adjusted to it before making a decision as the abrupt change can sway your decision too soon. When you see the power savings, that might be the arbiter instead!

A kill-a-watt ac meter or clamp-on dc ammeter at the battery terminals will reflect just how fast that power requirement goes down with even moderate reductions in backlighting.

I have a 3.5 amp NOCO charger that I plan to use to float these two batteries after they are charged with the Stanley.

The Stanley may actually do a better job if it offers a standard 13.6v float. The NOCO doesn't really do an active float, but "float monitoring", designed for guarding against parasitic loads and long-term self discharge. Even though it has a "trickle" stage, (version 1's, version 2 have a different optimization technique) there is not much trickling at all taking place. Thus, your batteries are just going to self-discharge until they reach a trigger point or a high parasitic load occurs. This may not be desirable if you desire true active float instead.

[lkruper]

With a 113w load a 12v system would be fine, so just two batteries would work. They can cycle more times than the marine ones. As for a time limit on batteries that are lightly cycled I don't know how that compares.

What I do know is that I have Costco golf cart batteries in our weekend cabin. They see 20 to 25 weekends a year of use and have been doing the job for 5.5 years so far. The way they get used, they spend most of their time in float and occasionally get drawn down past 50%.

From the link Sunking provided (http://www.trojanbattery.com/markets...ble-energy-re/) you will get 600 cycles if you don't abuse the batteries and 1200 if you baby them.

At 25 2-day weekends per year you have 7 more years life in those batteries and 18 more years with good care.

Good choice!

[Sunking]

Thanks for that link to the comparison of cycles including the t105 signature line. That was very informative. When you say last twice as long that is based on frequent cycles, correct? What about a backup battery on float most of the time?

My comments are general and broad. Just remember battery manufactures are not created equal. In general terms a Deep Cycle will last about twice as long as Hybrid. But you cannot compare say a Wally World Golf Cart battery with Trojan RE as you are now comparing a 1-2 year battery to a 5 to 7 year battery. The take away is if you compare Acme Battery Company Hybrid and Deep Cycle battery line, the Deep Cycle is going to last roughly twice as long, bu thas some current limitations.

As to daily cycle vs Emergency or infrequent cycle you are now working on Calendar Life. Batteries have both Cycle and Calendar life, which ever comes first. Cycle every day, and much shorter than Calander life. With Emergency Stand-By use, you can use a smaller battery and discharge to 50 to 80% DOD. But there is a catch with the smaller battery. You are much more likely to exceed the maximum Discharge Rate on a smaller battery. In which case you are now looking for Hybrid or AGM. Like I have always said Hybrids have a place, but a niche place.

You are on the right path, keep it up. Its YOUR MONEY. Spend it wisely. Don't be like the 95% of those who come here after the fact wondering what went wrong.

[lkruper]

Hybrid batteries have many Marketing names, like Marine, Golf Cart, RV, Trolling, Leisure and the list goes on.

The Trojan T-105 is a good example of a high end battery. There are two, T-105 and T-105RE. The T-105 does have discharge curves, just gotta know where to look. T-105 is Signature Line and RE is Premium Line. Industrial is Top Dog in Trojan line. . The main difference you will find are two fold. The RE is 5 pounds heavier with lead, and Carbon-Lead Alloy.

The T-105 is a 3-4 year battery, the T-105RE is a 5-7 year battery. You can see this reflected in WARRANTY and Cycle Life. The RE is about 15% higher in cost and well worth it considering it should last twice as long.

Bottom line you get what you pay for.

Thanks for that link to the comparison of cycles including the t105 signature line. That was very informative. When you say last twice as long that is based on frequent cycles, correct? What about a backup battery on float most of the time?

[Sunking]

But not necessarily the best choice for a first system, since new owners tend to do other things to murder their first battery bank in only a couple of years.
"Are you feeling lucky?"

True for most folks. But some people are just smart. They know to listen to those who have gone before them, and learn from others mistakes and does not repeat them. The majority prefer to do it their way, the HARD WAY and can only learn by loosing their money and that is an excellent teacher as well, just not too smart.

I gotta feeling Lurker is on the smarter side and doing homework. Wished more would do that.

[Sunking]

Sunking, you are right about one thing. The hard part about tracing through my spreadsheet is the conversion between AH and WH.

AH is just an end result. WATT HOURS is a constant and equal at any voltage. 100 wh can be at 10 or 100 volts. Last thing you need to know is Amp Hours and is just a resultant product of Watt Hours and Battery Voltage.

If you work in AH, can be done, but opens you up to all kinds of conversion errors and jus tmakes it more complicated then need be. . You eliminate that possibility using Watt Hours. Last step is finding Amp Hours.

I am a simple man and KISS it. Keep It Simple Stupid.

[inetdog]

The T-105 is a 3-4 year battery, the T-105RE is a 5-7 year battery. You can see this reflected in WARRANTY and Cycle Life. The RE is about 15% higher in cost and well worth it considering it should last twice as long.

But not necessarily the best choice for a first system, since new owners tend to do other things to murder their first battery bank in only a couple of years.
"Are you feeling lucky?"

[Sunking]

Hybrid batteries have many Marketing names, like Marine, Golf Cart, RV, Trolling, Leisure and the list goes on.

The Trojan T-105 is a good example of a high end battery. There are two, T-105 and T-105RE. The T-105 does have discharge curves, just gotta know where to look. T-105 is Signature Line and RE is Premium Line. Industrial is Top Dog in Trojan line. . The main difference you will find are two fold. The RE is 5 pounds heavier with lead, and Carbon-Lead Alloy.

The T-105 is a 3-4 year battery, the T-105RE is a 5-7 year battery. You can see this reflected in WARRANTY and Cycle Life. The RE is about 15% higher in cost and well worth it considering it should last twice as long.

Bottom line you get what you pay for.