24v Bank Dead - upgrade to 24v LiFe or scrap system for 48v - WANTED recommendations

[robbertwilliams]

Hi,

Current system:
Solar array 1700w wired s/p to get about 60v at the charge controller
8 L16 FLA Batteries wired s/p to get 740ah (installed in 2013)
Midnite Solar Classic 150
Schneider Electric SW2524 Inverter

Situation:
Off grid yurt - we consume about 2-2.5 kwh/day and hope to use more in future (add full size fridge) The batteries are pretty much toast - cases are deforming and low voltage shutoff happening when running coffee kettle next morning after a previous day of full charge. This is more or less a somewhat temporary living situation we are currently in but if an actual structure is built - we will remain off grid here for years to come. There is also an electronics smell - I have not been able to isolate it to the inverter or charge controller - so quite possible one of the two are on their way out.

Been looking at replacing with (2) eg4 24v 200ah (version 2). But I don't see too much of a future with 24v options in the solar market - so I'd hate to get these batteries and have the inverter die on me and be limited with replacement options in the future.

Looking for some perspective...different than mine - it seems I get my blinders on when researching this on the laptop...not quite the same as in person shopping nor does it appear that there's a one stop shop to view/analyze all the options. Anyways, would love recommendations - should I stick with the 24v current setup w/new batteries (also, if someone has another battery to recommend for same price point? not going to DIY it)? Or make switch to 48v and have to get batteries, charge controller, inverter (suggestions please on all)?

I'm sure I've left out some necessary details.

Thanks

 

[chrisski]

-batteries-FLA
————-
When have you equalized last?

-lithium
———-
I’d do this, provided the batteries can be kept from freezing AND the BMS meets highest current/amo requirements without tripping a BMS.

A coffee maker takes up a lot, but you do have a lot of battery and it should be good. Depending on the setup, a coffee maker and microwave may not.

Voltage
———-
Depends on usage requirements and what you equipment need to upgrade. I don’t think you need a 48 volt system.

I upgraded from 12 volts to 24 volts and NOT 48 volts because my MPPTs, switches, and fuses were not rated up to 48 volts, but already installed were able to handle 24 volts.

 

[Q-Dog]

I'm happy with 24 volts. It does all we need - running a full size refrigerator full time and has enough spare capacity to run a space heater or window air conditioner.

 

[HRTKD]

The upgrade to 48 volt would likely require a change of more equipment than you might think. A number of components that are fine for 24 volt are not rated for 48 volt, which lives most of its life well above 48 volts.

 

[JRH]

I like 24……it’s easy …it’s fun…it’s hard to get shocked….I don’t have lots of of power needs in the RV as many do with a real house or whatever…
I’m in the minority of opinion here I know , but ….

Simple,clean lighter, less complex , easy to throw together with a few batts if need be…
It does everything I need for a 35 ft Rv and more…

 

[alcook62]

I like 24……it’s easy …it’s fun…it’s hard to get shocked….I don’t have lots of of power needs in the RV as many do with a real house or whatever…
I’m in the minority of i opinion here I know , but ….

Simple,clean lighter, less complex , easy to throw together with a few bats if need be…
It does everything I need for a 35 ft Rv and more…

Yeah, me too. I've been this way for going on six years now. No problems and I just upgraded to my third battery (now 17.76 kwh)

 

[740GLE]

I’m more interested in how you’re using 2-3kwhr a day in a yurt?

I thought the whole idea of one of those would be to spend more time away from electricity and it’s cruel comforts.

 

[seneysolar]

Does that inverter power all your needs? If so then i would agree to stay 24V.

Id recommend Trojan SPRE-06-415 for replacements. Besides if you get 8 batteries now, they could do either 24v or 48V all the same.

The Midnite Classic will do both voltages.

The big decision comes if you ever buy a new inverter...

 

[yodamota]

24v for 8 years now, meets all our requirements.

 

[Rednecktek]

If it ain't broke, don't fix it. If you went to 48v, you'd need to replace the inverter, the fuses, breakers, probably charge controller, possibly rewire your solar array to get the higher voltages you'll need, and any converters you might have running 12v stuff.

The 24v just needs to stay warm.

 

[Q-Dog]

4 of these will be around $2000 with the 5% discount, plus tax. On sale because they changed their name from AmpereTime to LiTime. They make other sizes, but these are the cheapest at 24 volt.

Ampere Time 24V 100Ah, 2560Wh Lithium LiFePO4 Battery & Built in 100A

2.56kWh | Best for Your Home System: One Ampere Time 24V 100Ah lithium battery equals two 12V 100Ah lithium batteries, 24V higher - Amperetime-US

www.litime.com

 

[Steve_S]

I run my home with everything off 24V and have done so for 7 years. I use an average of 3.5-4.0kWh per year year round.
Currently there are several great deal on 24V LFP Packs and remember that if you get a 200AH LFP, you can actually get that 200AH out of it. You can also add more battery later without any bad side effects (unlike lead).

Unless you "need" 240V greater than 25A the "need" for 48V is can be argued.

 

[Zwy]

I run my home with everything off 24V and have done so for 7 years. I use an average of 3.5-4.0kWh per year year round.

Per day year round?

3.5-4.0 Kwh per year year round sounds like some Caveman ##it.

Currently there are several great deal on 24V LFP Packs and remember that if you get a 200AH LFP, you can actually get that 200AH out of it. You can also add more battery later without any bad side effects (unlike lead).

Unless you "need" 240V greater than 25A the "need" for 48V is can be argued.

 

[Brucey]

4 of these will be around $2000 with the 5% discount, plus tax. On sale because they changed their name from AmpereTime to LiTime. They make other sizes, but these are the cheapest at 24 volt.

Ampere Time 24V 100Ah, 2560Wh Lithium LiFePO4 Battery & Built in 100A

2.56kWh | Best for Your Home System: One Ampere Time 24V 100Ah lithium battery equals two 12V 100Ah lithium batteries, 24V higher - Amperetime-US

www.litime.com

I would suggest the DJLB 24V 100Ahs instead, $1756+tax for four. I have two in series for 48V they work great.

Amazon.com

 

[seneysolar]

There is also an electronics smell - I have not been able to isolate it to the inverter or charge controller - so quite possible one of the two are on their way out.

I would assume the batteries are the smell, especially if you are charging a bad one

 

[Steve_S]

Per day year round?

3.5-4.0 Kwh per year year round sounds like some Caveman ##it.

Yes but you have to understand that I designed & built my home and did so with Efficiency in mind because right from the start (even before buying my land) I knew I was going offgrid solar powered with this build... It's my final build and my Bucket List item I wanted to do and I had a lot of time to plan & implement it.

• 1 bedroom, Full Bath, 2nd story loft, 9/12 pitch roof (Cathedral Ceilings)
• FPSF Slab Foundation R-20 HD-Foam Insulation under it & up the sides.
• Radiant Heating in floor with 7/8" Pex
• Cool Roof System (saved 25-30% of Heating & Cooling costs and is incredible ! (Thermally Broken Roof)
• Rain Screen Siding method (used Live Edge White Cedar as my finish) (Thermally Broken Walls)
• INSULATION: (All obtained from Commercial Roofers - not available in retail land)
• -- 4" XPS Under the FPSF Slab and out the sides (wings) 24" providing R20, double code requirement.
• -- 5.25" High Density EPS-2 Foam between 2x6 studs R32)
• -- 7,5" Paper Faced PolyISO between Rafters (Cathedral Ceiling, roof is 9/12 Pitch)

There is a lot more info but it does not belong in this thread. Bottom Line, is that a well-built efficient home that uses Passive Technologies to maintain its livability is far cheaper than Generation & Storage and has an immediate payback in comfort & affordable livability. The passive airflow between the RainScreen Siding & venting through the cool roof via natural convective forces os not new and is extremely effective.

Fact is, my Heating System runs for 4 hours per day to keep 25C/77F Temp in house even when it is -30C/-22F. Additionally, during summer the Radiant Slab is a Thermal Regulator which never goes over 19C/62F and therefore keeps the home cool which the Thermally Broken structure which prevents heat transfer into the house from outside.

 

[pollenface]

If nothing else is broken I would just build a 24v battery.

 

[OzSolar]

Off grid yurt - we consume about 2-2.5 kwh/day and hope to use more in future (add full size fridge)

Random thoughts:

Have you eliminated every issue with the current FLA. What's the specific gravity of each cell? Have you equalized? A failing battery connection would cause a LVD when running the kettle but do fine the rest of time. Have you measured the actual battery voltage with a meter when the kettle is running?

A full size fridge will almost double your daily kWh usage but will be a wonderful upgrade to your life.

You've got plenty of inverter to start and run a fridge.

I'd stick with the smallest system I could today and when the big system is needed in the future you can design specifically for it.

Because LFP batteries are more efficient than FLA you'll have noticeable more usable daily kWh out of your current solar array.

Sounds like you've got a little bit of time so I'd start looking at Battery Hookup for a battery that suits your needs. They randomly get all sorts of batteries.

For example they currently have this 12v 100 AH battery for $150. They state it can be put series up to 48v but you still might want to get a balancer. I'd have to let others comment on that.

Not saying this is good idea, rather just trying to introduce you another way to do it. You could do this battery in a 2S4P configuration for 400AH at 24V. If you ever need to go to 48v you could change to a 4S2P configuration.

 

[robbertwilliams]

-batteries-FLA
————-
When have you equalized last?

-lithium
———-
I’d do this, provided the batteries can be kept from freezing AND the BMS meets highest current/amo requirements without tripping a BMS.

A coffee maker takes up a lot, but you do have a lot of battery and it should be good. Depending on the setup, a coffee maker and microwave may not.

Voltage
———-
Depends on usage requirements and what you equipment need to upgrade. I don’t think you need a 48 volt system.

I upgraded from 12 volts to 24 volts and NOT 48 volts because my MPPTs, switches, and fuses were not rated up to 48 volts, but already installed were able to handle 24 volts.

Equalized a month ago...did not check individual cell voltages afterwards - the batteries are 10+ yrs old now, surprised I got 10 out of them. Thanks for your reply.

 

[robbertwilliams]

Does that inverter power all your needs? If so then i would agree to stay 24V.

Id recommend Trojan SPRE-06-415 for replacements. Besides if you get 8 batteries now, they could do either 24v or 48V all the same.

The Midnite Classic will do both voltages.

The big decision comes if you ever buy a new inverter...

The inverter has worked fine for our needs. Obviously, it takes some work to realize you can't run the instant pot, vacuum, and tea kettle all at the same time but for what we have it's fine. Thanks for the reply.