Okay. I need new batteries. What batteries would you recommend?

[Swampy]

Hi there. I have 12, 6 volt 225ah Pow-r-surge flooded lead acid batteries that need replacement. They are wired in a parallel/series configuration.
I have 4 - 85 watt panels, a 25 amp solar boost charge controller and a 2412 Trace DR inverter/charger. Use this to power my cabin/cottage.
Looking for info/recommendations on the best bang for my buck regarding replacement batteries. Thanks.

[inetdog]

You would be better off with a single string of batteries (no parallel), even if you have to go to 2V batteries to get the AH capacity you need.
By rule of thumb you do not have nearly enough panel power for the number of batteries you have (340W of panel would be matched to a total of 340AH of 12V battery or 680 AH of six volt.)
So if you have been running OK for a few years you may not need that big a battery bank in the first place.

Read the sticky threads on system and battery sizing at the top of the Off Grid section and calculate what size battery bank you actually need. Then come back and ask how to put that together.

[Swampy]

Good stuff. I'll check out the sizing stickies.

[Swampy]

Okay.....I used the off-grid calculator and came up with these numbers:

Total daily load (Watt hours)			1530
Inverter efficiency (use midpoint on efficiency curve) ex 80% enter .8			0.9
Total daily load (Watt hours including inverter losses)			1700.00
Maximum load (to inverter)				1365
Lowest daily insolation for area and time of year the system will be used			3.2
Use PV watts to determine insolation or http://www.gaisma.com/en/
	Amp hour capacity	Max charge current FLA	Max charge current AGM
Battery bank @12 V (AH 20% daily DOD)	708.33	88.54	177.08
Battery bank @24 V (AH 20% daily DOD)	354.17	44.27	88.54
Battery bank@48V (AH 20% daily DOD)	177.08	22.14	44.27
		Amp @12V	Amp @24V	Amp@48V
Panel wattage required PWM controller	1062.50	88.5	44.3	22.1
Panel wattage required MPPT controller	796.88	66.41	33.20	16.60

[Sunking]

Panel Wattage = 700 watts.
Battery Capacity = 600 AH @ 12 Volts, 300 AH @ 24 volts, 150 AH @ 48 volts
MPPT Charge Controller = 60 amps @ 12 volts,.30 amps @ 24 volts, 15 amps @ 48 volts.

Ideal configuration is 24 volts using 2 300 watt panels wired in series or 3 200 watt panels wired in series. For a battery look into Trojan LR16RE-A a 6 volt @ 325 AH, a solid 5 to 7 year battery. One of the best on the market.

As for Charge Controller look no further than a MS TS-MPPT-30, or if you expect to grow a MS TS-MPPT-45 will allow to grow to 800 watts @ 24 volt battery.

Last comment, forget 12 volts.

[solarix]

The best "bang for your buck" on batteries depends on how long you want them to last. How long did the last set last? For a small system for a cabin like yours, I generally recommend minimizing your risk by using golf cart batteries. Yes, they don't last real long, but then you don't have much to lose either. If you had good life out of your last pack, I'd say you could justify moving up to some better "solar" type batteries like the Trojan L16RE-B which cost twice as much (per Ah), but should last twice as long.
Me? I'm still waiting for something really good like the Liquid Metal Battery to become available.

[Sunking]

Another decent manufacture and a little less expensive is US Battery. They make or I should say copy cat Trojans Line Ups. Example they make two RE batteries which are

US RE GC2H XC2 (6 volt 242 AH) and US RE L16 XC2 (6 volt 400 AH) . In other words a Trojan T-105RE and LR16RE-B

equivalent

.

[Swampy]

Panel Wattage = 700 watts.
Battery Capacity = 600 AH @ 12 Volts, 300 AH @ 24 volts, 150 AH @ 48 volts
MPPT Charge Controller = 60 amps @ 12 volts,.30 amps @ 24 volts, 15 amps @ 48 volts.

Ideal configuration is 24 volts using 2 300 watt panels wired in series or 3 200 watt panels wired in series. For a battery look into Trojan LR16RE-A a 6 volt @ 325 AH, a solid 5 to 7 year battery. One of the best on the market.

As for Charge Controller look no further than a MS TS-MPPT-30, or if you expect to grow a MS TS-MPPT-45 will allow to grow to 800 watts @ 24 volt battery.

Last comment, forget 12 volts.

Thanks for the reply and recommendation. Could I keep my Trace 2412 DR Inverter/charger and stay with 12V using the LR16RE batteries?

[Sunking]

Putting a 2 Kw Inverter on a 12 volt battery is pushing your luck as that requires up to 200 amps on the DC side to produce the full 2400 watts the Inverter is capable of. Lot larger than you really need. The trouble with that is getting 200 amps from the Battery Term Post to the Input of the Inverter. without a lot of voltage loss, heat, and fire potential. I hold the line at 100 Amps recommendation as that is doable, less expensive, and much easier to work with 4 AWG vs 1/0. 4 AWG stranded copper cable is about as large as a DIY can handle with tools and skill available. The higgher currents require larger cables and terminals.

But can you make it work to save some coins? For a Cabin system I think you can if you follow some strict procedures to ensure your safety, willing to take the risk and the expense of high current. . One of those conditions is how the heck you can terminate a 1/0 AWG copper cable? Have you ever seen or know what 1/0 AWG cable is.

If I were in your shoes I would look around at Electric and Motor Shops that can make you a set of cables with the exact length and compression fitting made to fit the battery and Inverter Termination Point. Keep the cables as short as possible, no longer than 5 feet -1-Way. Be sure to use factory recommended Torque and check it frequently with use. Additional you can find factory made cables on the internet. Heck if I were still in the states I could make a living making cables and selling them to you and others like you. I got everything it takes including the 16-Ton Press and Dies. Be prepared to spend $100 or more. The compression connectors are $10 to $20 each and you need 4 of them plus the cable that sells for $8/ft.

As for the battery changes things a bit as you need 12 volts @ 600 AH, and LR16RE-B is only 370 AH. But let's discuss this a bit. You said Cabin right. How many days a week do you use it and how frequently? Normally we would recommend 5 day reserve for a daily use system. Not so for a occasional use and we can lower that to 3 days and with a genny no sweat as your Inverter Charger already has th ebattery charger. Just need a genny to back it up.

So do you have a genny and infrequent use?

I am thinking 500 watts, 40 amp MPPT, 12 volt 400 to 500 AH battery using your Inverter on a Vacation System if my hunch is right. Washes out like this:

• Panel Wattage = 500 Watts using 2 x 250 watt panels wired in series. $600 to $750
• Morningstar TS MPPT 45 Amp. Charge Controller = $380 to $420
• Battery = 2 x US Battery model US L16HC XC2 a 6-Volt 420 AH $450 to $600 for a pair. That is less than the Trojan with more capacity. Naturally not the same quality, but good for the money and respected in the industry as a quality product offering. They are Trojans only direct competitor. . With Proper care 4 or 5 years vs 5-8 with Trojan. Makes for a better starter battery. In a few years when replacement comes up take another look and move up to a Trojan or whatever emerges.

Ball is in your court.

[Swampy]

Hi Sunking and thanks for the reply. I am a bit confused as my system today has a 2412 inverter charger on it now and has worked for 11 years. Here are some pics of my setup. 1932.JPG

[Sunking]

I do not doubt you one bit. Looks like it was installed correctly. But if by 11 years you mean the batteries lasted 11 years is not really correct. It may have taken 11 years for the batteries to degrade to the point they would not last a full day or two is way over due for replacement. Batteries are consider expired at 80% rated capacity, not with only 20% left in them. Think of it like a car engine, If your power was down to 80% you would notice and look at replacement. At 20% would be unusable.

It is understandable a 12 volt system was selected 11 years ago. That was really the only option with off the shelf stuff. The battery selection did not exist or the equipment. They took it out of the RV and moved indoors. Modern indoor systems start at 24 volts and go up. There is no down side to moving up in voltage.If you want to stay at 12 volts to save coins, by all means do so. At least upgrade and use a single string battery as that is an improvement and enhances efficiency and cycle life.

Yes I know they still make 12 Volt equipment for home inverters. They also sell Ganja and Boose does not make it right. That logic applies and spills over to the equipment size. Example the largest CC you can buy is 80 to 96 amps. Well at a given battery voltage the maximum panel wattage is:

1000 watts @ 12
2000 watts @ 24
4000 watts @ 48

Same logic applies to discharge side o Inverter size is the same 1000 wattts @ 12 volts and on up to 48 volts. The limiting factor? 80 to 100 Amps. At 2400 watts @ 12 volts with efficiency accounted for is 220 amps. At 24 that drops to 110 amps, and 55 amps at 48 volts.

There is a reason they quit making 2412's. It is outdated and dangerous.

[Swampy]

Panel Wattage = 700 watts.
Battery Capacity = 600 AH @ 12 Volts, 300 AH @ 24 volts, 150 AH @ 48 volts
MPPT Charge Controller = 60 amps @ 12 volts,.30 amps @ 24 volts, 15 amps @ 48 volts.

Ideal configuration is 24 volts using 2 300 watt panels wired in series or 3 200 watt panels wired in series. For a battery look into Trojan LR16RE-A a 6 volt @ 325 AH, a solid 5 to 7 year battery. One of the best on the market.

As for Charge Controller look no further than a MS TS-MPPT-30, or if you expect to grow a MS TS-MPPT-45 will allow to grow to 800 watts @ 24 volt battery.

Last comment, forget 12 volts.

I know you are saying forget 12 volts but.....trying to keep the budget in check, what if I went with a single string of new batteries in series of 6, Trojan 2V 1110 ah L16RE's, upgraded my panels to 700 watts, upgraded charge controller to the MS TS-MPPT-30 and kept my DR 2412 inverter/charger ?

[Mike90250]

Compare these 2 budgets

trying to keep the budget in check, what if I went with a single string of new batteries in series of
6, Trojan 2V 1110 ah L16RE's, $2100
upgraded my panels to 700 watts,
upgraded charge controller to the MS TS-MPPT-30

kept DR 2412 inv/chg
[ = 13320 watt hours of battery ]

or

8ea, 6v 200ah Golf Cart batteries in series for 48V [ 9600 watt hours of battery ] $800
700w of PV
2Kw inv/chg (PICOGLF20W48V120VR ) $700 or 3Kw Outback FXR3048A $1,700
Midnight solar KID 30A MPPT Charge Controller $300

[Logan5]

I know you are saying forget 12 volts but.....trying to keep the budget in check, what if I went with a single string of new batteries in series of 6, Trojan 2V 1110 ah L16RE's, upgraded my panels to 700 watts, upgraded charge controller to the MS TS-MPPT-30 and kept my DR 2412 inverter/charger ?

12 volts will not keep your budget in check, but rather keep stressing your budget, 12 volts is for Cars and Toys. Not suitable for off grid solar. in 6 months a 12 volt system will cost you twice as much and still need an expensive 24/48 volt upgrade. 12 volt inverters are good for a 400 to 700 watts, Use less than ideal wiring, start a fire.

[karrak]

I know you are saying forget 12 volts but.....trying to keep the budget in check, what if I went with a single string of new batteries in series of 6, Trojan 2V 1110 ah L16RE's, upgraded my panels to 700 watts, upgraded charge controller to the MS TS-MPPT-30 and kept my DR 2412 inverter/charger ?

If your system has worked well up to now and you have done very well with getting 11 years out of your battery why not just replace the batteries with something similar. All you should have to do is unbolt the current cables from the battery and bolt them on to the new one. If you want to increase the size of your inverter then sure you need to look at a higher voltage.

Another battery option that you might look at is a 12V LiFePO4 battery with inbuilt BMS. Because of the much higher charge and discharge rating of these batteries you could probably get by with around a 140Ah-200Ah @12V battery. It depends on how much reserve power you want and whether you want to run a generator.

As for the safety aspect your system looks well built with the correct size cable and cable terminations. My car's starter motor is 2kW and if I had a larger motor could be 3kWs. There are millions of cars out there that have cabling capable of running 200-300+A.

Simon