Battery system w/o Solar for Island cottage questions.

[wired1]

Hi All,
I have a beach cottage in the Bahamas that is tied to the grid and we have rolling blackouts, as well as unannounced outages weekly. Last time we had one I plugged in a 100 watt inverter to my car and had fans and lights for the 4 hours it was out. My battery started my car the next morning, so now I want to expand on this.!!!

I already in my excitement purchased a 1000 watt Renogy inverter to get me started. Now I'm not sure where to take this. I'm not there for months at a time, and I think for now Solar panels are out because of the hurricane situation there and lack of space to put them safely.

I want to buy the right batteries to power my fridge and a few fans a TV and lights for 8 hours until the power comes back, or I could run my generator to recharge the batteries for the next night if it doesn't.

I was all set to buy 8 AGM 100AH batteries and a Pal said to go with Lithium instead. I don't want to spend more than $1500 on my batteries though. There will be a lot of time these are not needed also.

I may even just go with 2 extension cords off the inverter in the beginning, I'm not sure about the size and type of charger either or whether I need a special charge controller or battery monitor or not.

I plan on perhaps installing a manual transfer switch run to a critical load panel in the future to keep costs low and I don't mind the manual part of this. My main concern is I keep it safe and affordable.

I would appreciate any direction. I have spent months reading and watching battery testing, solar installs and all kinds of articles, but not sure of the right answers to my dilemma?

Thanks

 

[iamrich]

Not sure how much you want to spend, but a simple all in one unit plugged into a battery would probably do it. Most all in ones have Grid in, so you basically put the unit in between your grid in and the cottage. You can set the unit to run on grid first which will both charge the batteries and run the house. When the power goes out, the unit will switch to the batteries. If you could mount at least one panel on the roof, it would likely take care of the power used by the inverter itself and reduce the grid usage. Then you could add panels later if possible. Four panels on the roof would net you a lot of power in your part of the world.

 

[HOU_Castle]

Hi All,
I have a beach cottage in the Bahamas that is tied to the grid and we have rolling blackouts, as well as unannounced outages weekly. Last time we had one I plugged in a 100 watt inverter to my car and had fans and lights for the 4 hours it was out. My battery started my car the next morning, so now I want to expand on this.!!!

I already in my excitement purchased a 1000 watt Renogy inverter to get me started. Now I'm not sure where to take this. I'm not there for months at a time, and I think for now Solar panels are out because of the hurricane situation there and lack of space to put them safely.

I want to buy the right batteries to power my fridge and a few fans a TV and lights for 8 hours until the power comes back, or I could run my generator to recharge the batteries for the next night if it doesn't.

I was all set to buy 8 AGM 100AH batteries and a Pal said to go with Lithium instead. I don't want to spend more than $1500 on my batteries though. There will be a lot of time these are not needed also.

I may even just go with 2 extension cords off the inverter in the beginning, I'm not sure about the size and type of charger either or whether I need a special charge controller or battery monitor or not.

I plan on perhaps installing a manual transfer switch run to a critical load panel in the future to keep costs low and I don't mind the manual part of this. My main concern is I keep it safe and affordable.

I would appreciate any direction. I have spent months reading and watching battery testing, solar installs and all kinds of articles, but not sure of the right answers to my dilemma?

Thanks

Assuming: staying only 1-2 months in a year, low power consumption (1000W), probability of power outage 50%, and gasoline is available), I would rather go with gen-set. Simple, cheap, and less maintenance, other than oil change every/other year (depending on hours of operation)?

With battery, you need to maintain it regardless AGM or LiFePo4 type.

 

[45North]

Off the shelf ups. Uninterruptible power supply does exactly this.
Why reinvent the wheel?

 

[Jasgeer]

I would think a gas generator (like a Honda i2200) would be the simplest and most cost effective considering the yearly usage. I keep one around for such emergencies.

 

[wired1]

Assuming: staying only 1-2 months in a year, low power consumption (1000W), probability of power outage 50%, and gasoline is available), I would rather go with gen-set. Simple, cheap, and less maintenance, other than oil change every/other year (depending on hours of operation)?

With battery, you need to maintain it regardless AGM or LiFePo4 type.

I would think a gas generator (like a Honda i2200) would be the simplest and most cost effective considering the yearly usage. I keep one around for such emergencies.

First of all, thank you all for the input. I do have a Honda I2200 and just don't want to have it running at night as it would be sooo noticeable there! It's pretty quiet and we like it that way

I think we go at least 6-8 times a year, sometimes for 2 weeks and sometimes for 2 months. (Not this last year though, sadly).

I was thinking after taking measurements with my Kill a watt, I would need about 300-400 watts per hour and would like to get somewhere between 6-10 hours without starting the generator. If I went with AGM's, and they were only used say once per month, could I expect a really long life with them?

Not sure how much you want to spend, but a simple all in one unit plugged into a battery would probably do it. Most all in ones have Grid in, so you basically put the unit in between your grid in and the cottage. You can set the unit to run on grid first which will both charge the batteries and run the house. When the power goes out, the unit will switch to the batteries. If you could mount at least one panel on the roof, it would likely take care of the power used by the inverter itself and reduce the grid usage. Then you could add panels later if possible. Four panels on the roof would net you a lot of power in your part of the world.

What is a decent "all in one" and how much do they cost? My budget is under $1800, give or take.

Also, am I correct that with Lithium ion batteries I would need only 1/2 the AH? And given my small usage would any of the less expensive ones be worth it over the AGM's, which are $190 for the Renogy 100AH?

 

[wired1]

First of all, thank you all for the input. I do have a Honda I2200 and just don't want to have it running at night as it would be sooo noticeable there! It's pretty quiet and we like it that way

I think we go at least 6-8 times a year, sometimes for 2 weeks and sometimes for 2 months. (Not this last year though, sadly).

I was thinking after taking measurements with my Kill a watt, I would need about 300-400 watts per hour and would like to get somewhere between 6-10 hours without starting the generator. If I went with AGM's, and they were only used say once per month, could I expect a really long life with them?


What is a decent "all in one" and how much do they cost? My budget is under $1800, give or take.

Also, am I correct that with Lithium ion batteries I would need only 1/2 the AH? And given my small usage would any of the less expensive ones be worth it over the AGM's, which are $190 for the Renogy 100AH?

Oh, almost forgot. Gasoline is $6.85 per gallon and it's not ethanol or water free!! Not to mention 10% is "invisible"!!! No weights and measures people here.....

 

[Jasgeer]

First of all, thank you all for the input. I do have a Honda I2200 and just don't want to have it running at night as it would be sooo noticeable there! It's pretty quiet and we like it that way

I think we go at least 6-8 times a year, sometimes for 2 weeks and sometimes for 2 months. (Not this last year though, sadly).

I was thinking after taking measurements with my Kill a watt, I would need about 300-400 watts per hour and would like to get somewhere between 6-10 hours without starting the generator. If I went with AGM's, and they were only used say once per month, could I expect a really long life with them?


What is a decent "all in one" and how much do they cost? My budget is under $1800, give or take.

Also, am I correct that with Lithium ion batteries I would need only 1/2 the AH? And given my small usage would any of the less expensive ones be worth it over the AGM's, which are $190 for the Renogy 100AH?

The cheapest AGMs I have found are the Duracell auto/truck batteries sold by Sam's Club. People seem to like them but as with any AGM you shouldn't discharge more than 50% which might be why you quote "I would need only 1/2 the AH" with Li. Being a camper, I know that AGMs are good but 5-6 years of use seems to be a realistic limit.

 

[iamrich]

What is a decent "all in one" and how much do they cost? My budget is under $1800, give or take.

Also, am I correct that with Lithium ion batteries I would need only 1/2 the AH? And given my small usage would any of the less expensive ones be worth it over the AGM's, which are $190 for the Renogy 100AH?

I actually don't think an all in one has much value for you unless you plan to run solar. You are basically paying for a charge controller for nothing, but assuming 120v 60hz single phase, I would go with either the green MPP solar LV2424 https://watts247.com/product/hybrid-lv2424/ or the Growatt https://watts247.com/product/spf-3000tl-lvm-24p/. If you could mount two panels on the roof (250wx2) you would probably generate enough power when the sun is up to offset your usage and charge the batteries. Even if you are worried about hurricanes, just mount the panels on the roof with rails and take them down before hurricane season starts. I assume you are not there for that anyway? That would probably take care of you from mid morning to almost sundown, and then the batteries might get you through the rest of the night. Assuming your grid power only stays off for 8 hours you should be fine. 400wh x 10 hours is 4000wh, so at 24v you are going to need 200ah LiFePo4 (using ~80%) or 400ah of Lead acid (using ~50%).

All in One $750 shipped
Batteries $1520 ($190x8) local?
Wiring/fuses/connects/etc. $100
Solar panels (no clue if they are available in the Bahamas)?

With the all in one you could just run passthrough AC off the grid until the power goes out and then switch on the inverter (or just leave it on and eat the ~40wh it uses when idle).

 

[wired1]

I actually don't think an all in one has much value for you unless you plan to run solar. You are basically paying for a charge controller for nothing, but assuming 120v 60hz single phase, I would go with either the green MPP solar LV2424 https://watts247.com/product/hybrid-lv2424/ or the Growatt https://watts247.com/product/spf-3000tl-lvm-24p/. If you could mount two panels on the roof (250wx2) you would probably generate enough power when the sun is up to offset your usage and charge the batteries. Even if you are worried about hurricanes, just mount the panels on the roof with rails and take them down before hurricane season starts. I assume you are not there for that anyway? That would probably take care of you from mid morning to almost sundown, and then the batteries might get you through the rest of the night. Assuming your grid power only stays off for 8 hours you should be fine. 400wh x 10 hours is 4000wh, so at 24v you are going to need 200ah LiFePo4 (using ~80%) or 400ah of Lead acid (using ~50%).

All in One $750 shipped
Batteries $1520 ($190x8) local?
Wiring/fuses/connects/etc. $100
Solar panels (no clue if they are available in the Bahamas)?

With the all in one you could just run passthrough AC off the grid until the power goes out and then switch on the inverter (or just leave it on and eat the ~40wh it uses when idle).

Thank you!!
I've always wanted to put up panels. I surely will when I am done building my garage and apartment but there's so much traffic and underground work, driveway, septic, power lines and water lines all over, it's just too much right now. I'm guessing 1 year and I'll want to add them for sure. I added another thread about helping me choose batteries and the right inverter and someone mentioned Chins batteries. I guess there's no way around learning everything but I'm getting old and can't remember shit ) I also have so much going on right now, I need it to be fairly simple for now.

 

[wired1]

The cheapest AGMs I have found are the Duracell auto/truck batteries sold by Sam's Club. People seem to like them but as with any AGM you shouldn't discharge more than 50% which might be why you quote "I would need only 1/2 the AH" with Li. Being a camper, I know that AGMs are good but 5-6 years of use seems to be a realistic limit.

Thanks! I just bought 3 of those for my oat and they're a great deal!

 

[wired1]

Thanks! I just bought 3 of those for my oat and they're a great deal!

Sorry, I meant my Boat, Ha

 

[wired1]

400wh x 10 hours is 4000wh, so at 24v you are going to need 200ah LiFePo4 (using ~80%) or 400ah of Lead acid (using ~50%).

So Rich, to get 400 usable AH at 24 volts, would I need 16 x 100 AH lead acid?

You also have me thinking a lot more now that I do want and will be adding solar panels to this in the future. I didn't realize how the prices have come down in the last few years. But that is still at least a year away. For now trying to decide lead AGM of Lithium and at what voltage is making me crazy as I want to be prepared for panels and growing in the future. We pay .32 per Kwh there so Hmmm...So much to learn

 

[iamrich]

You would need x8 12v 100ah batteries to get to 24v 400ah. You would parallel four sets of two in series.

 

[wired1]

You would need x8 12v 100ah batteries to get to 24v 400ah. You would parallel four sets of two in series.

Thanks, How many usable 120 volt watts should I expect from that? Also, which is better for $1600., This

24V HAWK - LIFEPO4 - 170AH - 4.3KWH​

or 8 of these?

Renogy Deep Cycle AGM Battery 12 Volt 100Ah​

 

[HOU_Castle]

Thanks, How many usable 120 volt watts should I expect from that?

With AGM battery, ~4800W. LiFePo4 battery about 7700W.

 

[iamrich]

24v x 400ah / 2 (50% discharge) = 4800wh You could run the inverter at 110v and maybe net a few more watt hours, especially for lights and fans.

 

[wired1]

With AGM battery, ~4800W. LiFePo4 battery about 7700W.

What would I be spending for the LiFePo4 battery to get 7700W.?

 

[HOU_Castle]

I bought mine back in March 2021, CHINS 24V-200Ah about $1500 plus tax (each). I heard nowadays, everything goes up in pricing.

 

[wired1]

I bought mine back in March 2021, CHINS 24V-200Ah about $1500 plus tax (each). I heard nowadays, everything goes up in pricing.

Wow, I wish I understood how the 7700 watts comes from 24V-200AH? I'm missing something I though that would give me 4800 watts to use??