New to off-grid; need help to fix/upgrade existing system

706jim · October 2019

Lots of comments here. Having a place on an island for years, I would stay away from propane for refrigeration. The fridges are more expensive and use a lot of propane.....when YOU have to lug the tanks!
This was the main reason I've increased my system size and gone to electric.
Propane fridges also require periodic maintenance of the chimney and burner. Here in Canada, they must be vented out of an exterior wall and that may cause them to blow out in high winds.
Additionally, they do NOT self defrost so you will need to put your food into coolers for defrosting at least monthly.
If you decide to increase your system capacity, I would also go with a 1500 watt inverter. A unit of this size can usually run one of anything you would normally plug into a wall outlet.

Photowhit · October 2019

Marc Kurth said:

Be sure to have your supplier CLEARLY indicate "Solar Batteries" on your invoice. This is standard procedure when shipping to many countries.

Marc has been selling batteries for many years, incase you just read through the remark. We are gifted to have experts in several fields here!

raindog · October 2019

Yes, thanks so much for your suggestions!

@softdown : Actually, I started having computers built to my specs because the limitations built in by manufacturers irked me beyond measure.

I know someone who will carry stuff over, but he has friends on another island, and, because of the Hurricane, he will be going there this year ... in December. It would be a very long wait and a lot of ice 'til then in any case.... No boaters are around this time of year; they typically arrive later in the season, after all threat of hurricane has passed.

As mentioned above, I am having a pallet with dog food and other things shipped over (which I need very soon!)
It's a good idea to go private for the future shipments, though, when I have more time to plan. I think the freight shipping by sea is not charged by weight for the sort of items I am shipping; instead charged by pallet/handling. I've been shipping dog food, etc. by air before this ($$$ <-- pampered pet). Still have a 5x10' storage unit in FL to move as well.

It's a lot of transitions; my last adventure.

This has been a crash course in learning about solar power in the real world. From the outside it looks like it's mostly about the panels, how they are getting cheaper, etc., etc., but the batteries and other stuff on the inside, off-grid, are the heart & soul.

I'm working on the load requirements for the new system and will open another thread (?? here, or in another category ??) as mcgivor suggested.

BB. · October 2019

Here is fine... The history will bring others up to speed--And it is helpful when folks look stuff up in the future and can read from the begining in a single discussion/thread.

-Bill

spacebass · November 2019

softdown said:

spacebass said:

You must somehow buy an 'Inverter' fridge though I understand from Bill on here such technology is scarce in th U.S. An inverter fridge uses less electricity generally and does not have the start up constant big peak in electricity demand .
I would not believe per gospel exactly what is promoted by industry moguls as You have already noted re batteries.
I am in the process of buying 4 x 110 ah lithium battery packs , I will post my experience .I have one already , the built in BMS limits charge to. 12.6 volts , I am also using a 100 ah Hitachi sealed car battery which I can charge to. 14.3 volts. the lithium goes down to 9.9 volts and the car battery goes down to 11.2 so I gain on downside with Lithium but also gain on the upside with lead acid, so not overjoyed with my first lithium analysis. If I had to choose which battery gives me the longest output / utility it woul be the Hitachi. Car battery.
You will know that lead acid batteries are heavy I would not think You could move this 100 ah battery, so this may be the deciding factor.
My experience as a novice is You should go for 2 x 220 ah or 4 x 110ah lithium , as I am now moving to from 2x 220 ah lead acid , which just does not do 1700 hours to 0800 hours without any solar input .(I Do have a big inverter fridge) I am moving to the lithium not because I am convinced it will deliver. on it's promise but because I am getting batteries nearly half price.

Typo?

raindog said:

@spacebass : Hi and thanks! I ran searches looking for an inverter compressor fridge. It seems they are only available in the USA in the very large, ~22 cu. ft. models from makers like Samsung and LG. Such a shame -- the people who would most benefit from them are denied the option. I will check in Nassau, but appliances here mostly come from the US.

I'm still trying to determine my needs re: the batteries, etc. Actually, this setup worked for a year for me without much issue, but it is not really sufficient for full-time living. The batteries are old (~ 5 years -- longer than most last in this climate according to neighbors), and, I believe, I drained the last life out of them during Hurricane Dorian, online, trying to keep tract of the storm.

I'll get help to move the batteries from the boat to the car and car to house; after that, I don't plan on moving them.

How much sun do you get in your location?

Funny the U.S. so far behind the rest of the world must be making $$$$$ out of it part of the con like batteries, manipulating the matket. Here in Thailand I would say 7 cubic feet up 50/50 availability.
Batteries are the problem they are just too expensive to be viable and in practice everything ends up less , plus in the tropics I am in Thailand it is dark at six pm and output from panels not up to much after 4 pm , Batteries go out 2am am to 4am and back charged 8 to 10 am depending on cloud I am, sure when the sun is blazing down at midday my batteries are full and the controller is limiting the charge rate, which means to benefit from maximum sun You need more batteries !
I have only had the solar for 3 months and the worst time here for sun I hope for better in our winter !
You must get inverter products I also have an inverter washing machine.Toshiba.Probably save on DC inverter.
In summary I would say I have to run everything from 4pm to 9am on battery that is 17 hours actually quite s demand so double whatever your analysis reckons your battery requirement is for 'full time living'. x.

Dear @softdown the lithium battery pack stops charging at 12.6 volts which is what is written on the dedicated charger and the light on the charger turns from red to blue (fully charged) , maybe the charger stops charging at 12.6 volts not the BMS limiting?

softdown · November 2019

spacebass said:

softdown said:

spacebass said:

You must somehow buy an 'Inverter' fridge though I understand from Bill on here such technology is scarce in th U.S. An inverter fridge uses less electricity generally and does not have the start up constant big peak in electricity demand .
I would not believe per gospel exactly what is promoted by industry moguls as You have already noted re batteries.
I am in the process of buying 4 x 110 ah lithium battery packs , I will post my experience .I have one already , the built in BMS limits charge to. 12.6 volts , I am also using a 100 ah Hitachi sealed car battery which I can charge to. 14.3 volts. the lithium goes down to 9.9 volts and the car battery goes down to 11.2 so I gain on downside with Lithium but also gain on the upside with lead acid, so not overjoyed with my first lithium analysis. If I had to choose which battery gives me the longest output / utility it woul be the Hitachi. Car battery.
You will know that lead acid batteries are heavy I would not think You could move this 100 ah battery, so this may be the deciding factor.
My experience as a novice is You should go for 2 x 220 ah or 4 x 110ah lithium , as I am now moving to from 2x 220 ah lead acid , which just does not do 1700 hours to 0800 hours without any solar input .(I Do have a big inverter fridge) I am moving to the lithium not because I am convinced it will deliver. on it's promise but because I am getting batteries nearly half price.

Typo?

raindog said:

@spacebass : Hi and thanks! I ran searches looking for an inverter compressor fridge. It seems they are only available in the USA in the very large, ~22 cu. ft. models from makers like Samsung and LG. Such a shame -- the people who would most benefit from them are denied the option. I will check in Nassau, but appliances here mostly come from the US.

I'm still trying to determine my needs re: the batteries, etc. Actually, this setup worked for a year for me without much issue, but it is not really sufficient for full-time living. The batteries are old (~ 5 years -- longer than most last in this climate according to neighbors), and, I believe, I drained the last life out of them during Hurricane Dorian, online, trying to keep tract of the storm.

I'll get help to move the batteries from the boat to the car and car to house; after that, I don't plan on moving them.

How much sun do you get in your location?

Funny the U.S. so far behind the rest of the world must be making $$$$$ out of it part of the con like batteries, manipulating the matket. Here in Thailand I would say 7 cubic feet up 50/50 availability.
Batteries are the problem they are just too expensive to be viable and in practice everything ends up less , plus in the tropics I am in Thailand it is dark at six pm and output from panels not up to much after 4 pm , Batteries go out 2am am to 4am and back charged 8 to 10 am depending on cloud I am, sure when the sun is blazing down at midday my batteries are full and the controller is limiting the charge rate, which means to benefit from maximum sun You need more batteries !
I have only had the solar for 3 months and the worst time here for sun I hope for better in our winter !
You must get inverter products I also have an inverter washing machine.Toshiba.Probably save on DC inverter.
In summary I would say I have to run everything from 4pm to 9am on battery that is 17 hours actually quite s demand so double whatever your analysis reckons your battery requirement is for 'full time living'. x.

Dear @softdown the lithium battery pack stops charging at 12.6 volts which is what is written on the dedicated charger and the light on the charger turns from red to blue (fully charged) , maybe the charger stops charging at 12.6 volts not the BMS limiting?

Sounds quite odd to me. Fully charged lead acids show 12.8 volts when healthy. My latest Duracell battery charger uses a higher charging voltage when in lithium mode. Maybe 14.2 for lead acid and guessing 14.6ish for lithium. Most of us guys are lead acid dinosaurs. Mark K and David A and BB would likely know for sure.

Perhaps I am completely wrong...

mcgivor · November 2019

@softdown said
Sounds quite odd to me. Fully charged lead acids show 12.8 volts when healthy. My latest Duracell battery charger uses a higher charging voltage when in lithium mode. Maybe 14.2 for lead acid and guessing 14.6ish for lithium

Because there are different chemistries within the lithium umbrella, voltages per cell differ, 12.6V maximum charging would be consistent with a 3 cell series LiPo or similar with maximum of 4.2V per cell to make a 12V nominal battery, 4 cell series LiFePo4 on the other hand has a maximum 3.6V per cell so 14.4V maximum charging voltage for 12V nominal.

softdown · November 2019

An important distinction when discussing the merits of Lithium technology. It seems the 12.6 max charging current represents a smaller minority.

spacebass · November 2019

mcgivor said: Thank You Mcgivor for your interesting insight, mcgivor said:

@softdown said
Sounds quite odd to me. Fully charged lead acids show 12.8 volts when healthy. My latest Duracell battery charger uses a higher charging voltage when in lithium mode. Maybe 14.2 for lead acid and guessing 14.6ish for lithium

Because there are different chemistries within the lithium umbrella, voltages per cell differ, 12.6V maximum charging would be consistent with a 3 cell series LiPo or similar with maximum of 4.2V per cell to make a 12V nominal battery, 4 cell series LiFePo4 on the other hand has a maximum 3.6V per cell so 14.4V maximum charging voltage for 12V nominal.

Thank You @mcgivor for your interesting comment I have not documented exactly how I have been charging the Hitachi lead acid battery but lately I have been finishing it off with a small 5 amp foxsur electronic charger after old style 30 amp charger I try and keep around 20 amps on meter which I have a feeling gets it up to 14.3 volts.

The 12.6 volts on the lithium which I believe is polymer. Is the rating of the charger which says the battery is full at 12.6 volts and stops charging .
The battery pack is rated at 110 ah is that possible with 3 cells. ? I am about to buy 3 more for 48 volt system they are new out of China from Thai person bringing them in.
Thanks again.

mcgivor · November 2019

@spacebass

When building a lithium bank the method is to parrallel first then series, multiple cells are connected in parallel to create cell blocks, theroitically there is no limit to the number of parallel cells to gain capacity. The cells, or cell blocks are then connected in series to achieve the nominal voltage required, so yes it is possible to have 110 Ah parrallel in a 3 series configuration, you could even build 1100Ah at 12V nominal if desired.

Tesla do exactly this using thousands of cells a little larger than AA size to achieve capacity then series connecting to achieve the desired voltage. There are advantages to doing this is specifically related to high charge and discharge rates needed for EV applications which is not generally applicable to stationary off grid where endurance is required. Cooling of the cells in EV applications is utilized to prevent thermal runaway but generally not required in low demand situations.

The benifits of modular batteries is it reduces the complexity of having to actually designing a system, if parrallel series is approved, each will have its own BMS, the trade off is it doesn't allow custom expansion that is possible with a single BMS. There are some LiFePo4 batteries which each have internal electronics combined with an external BMS but I'm not familiar with them, though it it is an interesting concept.

The one thing to remember with LiPo is they are very sensitive to overcharging, physical damage and short circuit often resulting in spontaneous combination, not to mention gasses related to such failure, although probably not common with a well designed BMS, they do exist.

spacebass · November 2019

mcgivor said:

@spacebass

When building a lithium bank the method is to parrallel first then series, multiple cells are connected in parallel to create cell blocks, theroitically there is no limit to the number of parallel cells to gain capacity. The cells, or cell blocks are then connected in series to achieve the nominal voltage required, so yes it is possible to have 110 Ah parrallel in a 3 series configuration, you could even build 1100Ah at 12V nominal if desired.

Tesla do exactly this using thousands of cells a little larger than AA size to achieve capacity then series connecting to achieve the desired voltage. There are advantages to doing this is specifically related to high charge and discharge rates needed for EV applications which is not generally applicable to stationary off grid where endurance is required. Cooling of the cells in EV applications is utilized to prevent thermal runaway but generally not required in low demand situations.

The benifits of modular batteries is it reduces the complexity of having to actually designing a system, if parrallel series is approved, each will have its own BMS, the trade off is it doesn't allow custom expansion that is possible with a single BMS. There are some LiFePo4 batteries which each have internal electronics combined with an external BMS but I'm not familiar with them, though it it is an interesting concept.

The one thing to remember with LiPo is they are very sensitive to overcharging, physical damage and short circuit often resulting in spontaneous combination, not to mention gasses related to such failure, although probably not common with a well designed BMS, they do exist.

@mcgivor my batteries have arrived I believe they are now Lipo4 as the charge is 14..6 volts and 6 amp charger I am reading a photograph the vendor sent me, 6 amp is a bit different to 15 amp of the lipo unit ? which he is swoppng for a new one. I believe these batteries are not 110ah according to charger , they arecquiteca bit bigger than the original 110ah believed to be Lipo.
Well all installed and ticking over ,Interestingly just found in one of the boxes the bill for this order and it states 12 v 120 ah x 4 !!! So Looks like they shipped with lesser charger in the box for some no doubt dodgy reason and I am now going to up the amps to charge from 6 to 10 amps as per instruction leaflet ! Happy happy !!

New to off-grid; need help to fix/upgrade existing system

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