[Hanidu-Acres]

Good question. Surplus= enough. 1 is none and 2 is one. But at some point it can get to a “too much of a good thing” point.

[MartHale7]

The best time to use energy is at the time you produce it., storing it at present has loss using standard batteries and inverters. Also another factor with solar is the input is about always changing, this is why an mppt for coils is worth the investment. https://www.youtube.com/watch?v=LmMsTN8b9Hg here is one such option.

[BiggKidd]

That’s crazy in my opinion. First you don’t NEED a controller or inverter between solar panels and a heating element. Second why tie your panels to a single job when a simple dump load controller will let them handle their regular chores and dump excess to heating water? Or you can simply straight wire the panels to a heating element, Yes you need to do a little simple math to work out how many panels at what resistance element etc. but it’s not very hard to figure out. I would suggest a simple thermostat so you don’t over heat / boil the water.

[MartHale7]

You can run direct, but you will not be getting as much heat out of the coils in the morning and evening and partly cloudy days. The MPPT tunes the energy for optimal use with the coil just like the MPPT does for a battery. If the voltage coming in does not match the ohms of the load it just does not work very well… I found this out by testing various solar panel configurations with my heating coils, also if you watch David Poz on youtube he shows why you have to match the panels to the ohms of the heating coil for optimal results.

[BiggKidd]

I’ve had mine running for several years as a dump load. I too found wired straight not to be the best but it is the cheapest if you don’t mind tying a set of panels up only for heating water. I am adding solar / hot water heater element to my thermoelectric project. I have 3) 300W panels that aren’t being used I’m planning to straight wire. I may also run a dump load from my house panels, don’t know yet.

• This reply was modified 1 year, 9 months ago by  BiggKidd.

[MartHale7]

Yeah I have 9 extra 220 watt panels and I am experimenting with all kinds of different setups. I am trying to get ahead of what it and EMP would hit and I need to run direct from my panels….

[BiggKidd]

Guys you might want to stretch your thinking out to a year at a time to really take advantage of this method. Just for example say you heat a 5000 gallon tank of water all year long with excess power then use that for space heating all winter………. Or heat 20 tons of sand to do the same thing.

[coyotech]

I go with lots of RV batteries. Then I can run more for longer. I have 4 solar panels charging 12 batteries now, and the panels keep up with the battery charging. Of course batteries can be expensive. I need to set aside a money saving jar just for replacing batteries over time! But so far, so good. I don’t know if I’m maxing out the charging capability of those panels yet. I don’t think so.

[gods-child]

here is a way with break-down of costs over twenty [20] years to save a fortune on batteries and reduce the solar set-up costs

food for thought

12v lead-acid and gel batteries can also be purchased for a fraction of the price of lithium and most folk do not know they can go to vehicle breaker yards also known as scrap yards and get vehicle batteries for a fraction of the cost of a new battery

and you may also save costs on other things such as cables and connectors switches lights fuses and more plus there could be other things and bargains to help save money for your homestead or mobile-home and-such

for example

where i live i can get second-hand 12v vehicle batteries anywhere from £10 ~ £40 each whereas one [1] new lead-acid battery starts at around £90 for a 60ah ~ 70ah wheres the higher the [ah] the higher the price

thereby if you purchase second-hand 12v vehicle batteries you would be saving them going in the landfill and saving lots of money

and

looking at the high and low price scale for 12v second-hand vehicle batteries

lets calculate costs for a single battery

if second-hand only last five [5] years you can weigh them in get a few bob back or could likely do a swap for a good second-hand battery from the breakers yards or scrap yards or even second-hand vehicle dealers

£40 4x over twenty [20] years is equal to £160 v £4,000 a massive saving of £3,840

£10 4x over twenty [20] years is equal to £40 v £4,000 a massive saving of £3,960

the batteries may last longer as i have seen some folk that claim they are still using their 12v vehicle lead-acid batteries nine [9] years on

£40 2x over twenty [20] years is equal to £80 v £2,000 a massive saving of £1,920

£10 2x over twenty [20] years is equal to £20 v £2,000 a massive saving of £1,980

lets calculate costs for a battery-bank of ten [10] batteries

£40 10x is equal to £400 v £10,000 a massive saving of £9,600

£10 10x is equal to £100 v £10,000 a massive saving of £9,900

£400 4x over twenty [20] years is equal to £1,600 v £40,000 a massive saving of £38,400

£100 4x over twenty [20] years is equal to £400 v £40,000 a massive saving of £39,600

£400 2x over twenty [20] years is equal to £800 v £20,000 a massive saving of £19,200

£100 2x over twenty [20] years is equal to £200 v £20,000 a massive saving of £19,800

lest calculate a new lower end lead-acid 60ah ~ 70ah battery at an average £90 each

£90 is equal to £1,000 a massive saving of £910

£90 4x over twenty [20] years is equal to £360 v £4,000 a massive saving of £3,640

£90 2x over twenty [20] years is equal to £180 v £2,000 a massive saving of £1,820

lest calculate a new lower end [ah] lead-acid 60ah ~ 70ah battery at an average £90 each for a battery bank of ten [10]

£90 10x is equal to £900 v £10,000 a massive saving of £9,100

£900 4x over twenty [20] years is equal to £3,600 v £40,000 a massive saving of £36,400

£900 2x over twenty [20] years is equal to £1,800 v £20,000 a massive saving of £18,200

lets calculate a 240ah new leisure battery at average price of £390

£390 is equal to £390 v £1,000 a massive saving of £610

£390 4x over twenty [20] years is equal to £1,560 v £4,000 a massive saving of £2,440

£390 2x over twenty [20] years is equal to £780 v £2,000 a massive saving of £1,220

lets calculate a 240ah new leisure battery at average price of £390 for a battery bank of ten [10]

£3,900 is equal to £3,900 v £10,000 a massive saving of £6,100

£3,900 4x over twenty [20] years is equal to £15,600 v £40,000 a massive saving of £24,400

£3,900 2x over twenty [20] years is equal to £7,800 v £20,000 a massive saving of £12,200

the costs will vary for area to area country to country thus this is only a guide based on my sources and first hand knowledge

also cheaper quicker more environmentally friendly to replace for most and makes connections with those in breakers yards or scrap yards or even second-hand vehicle dealers

for those in remote areas you may be able to purchase online on places like ebay and have them shipped to you

open for discussion

does this make sense to you or do you have a different point of view…??

p.s

if my calculations are off please correct me as i am not good with math

bona-fide

[BiggKidd]

I’ve been using used UPS batteries since going off grid 15 years ago. The set I have now were back up power for an operating room. Insurance makes them change them out every three years no matter if they’ve been used or not.

[MartHale7]

I am in Florida, golf cart central 😉 I spent about 5 years making my own battery chargers to desulfate lead acid batteries. When I came to Florida, I started my solar system by getting trojan 8v batteries for $16 each. This was the scrap value then these were batteries that were old and were on their last leg. It was from this system, I learned solar. I topped up lots of electrolyte in these batteries. From there I moved to Electric Vehicle lithium batteries. I buy slightly used lithium batteries for $100 a KWH, I have over 25 KWH of storage now in a 24v, and 36v systems. I have done lots of research on lithium batteries and I treat them very well, and they have treated me awesome for running my AC, my well pump, and my table saw.

For me lithiums well managed is the way to go as I have large capacity, and can take the batteries much lower than you can with lead acid batteries. Lead acid batteries do work, but I am glad to get away from filling electrolyte in those batteries.

Lithims have to be kept warm to charge them, and you have to think about possiblity of fire, but so far, they have done me right, others may choose a different route…. I am interested in the new lead – carbon foam batteries. They can be taken to zero volts and they keep right on going with no degradation. So much battery tech coming out hard to know what is real, and what is scams.

[BiggKidd]

I went LifePO4 on my golf cart as a test bed before trying to get new batteries for the house. Didn’t work out to well in the long run BUT that was MY screw up not the cells! I let dust get between them and it rubbed them raw and they shorted out between the cases.

[gods-child]

quote “Lithims have to be kept warm to charge them, and you have to think about possiblity of fire” end-quote

therein lays the problems for me apart from the expense, as you said $100 per KWH with these risks are a no-no a big juicy no-no for me

for me less risk of fire suits me my family and neighbours and fire-department

less risk of fire does-not suit hospital or funeral-parlor or morgue

still factoring in the cost of battery-acid and routine maintenance and desulfator is far less risk of fire and far economical and more financially viable for most folk in my humble opinion

desulfator UK made selling on ebay £20 and change

hydrometer £4

25L Battery-acid £85 and change

free-will and good-luck for those who know the risks of fire associated with lithium-batteries and want to put themselves and others at harms way, not to mention property damage and loss, which would add to more costs either medical funeral or replacement costs thereof

bona-fide

[MartHale7]

Yep. I have played with alum batteries as well, but if I was going back to lead acid I would consider carbon foam… They look amazing.

I do respect your choice. Lead acids do have a proven history.

https://www.youtube.com/watch?v=PrhapRFkt7o

[Hippocrates_Garden]

I’m pretty much all in on Lithium. I’m in Arkansas and it doesn’t take a lot to keep them above freezing if inside a structure, for mobile (say golfcart/side by side) I’d likely add the extra for self heating, as it would only be one or two batteries not a full property system. To the degree I already have over $8k of EG4 batteries yet to be installed. Once those are in and running, if I need to expand, haven’t decided if just get another rack, or build from cells mainly for the experience and flexability.

If I’m going to depend on them, and hope to get 20+ years without having to change (which would put me in my 70s or later) I just don’t see the weight, work, frequent expense and (low but still there) explosive risk of lead acid and space. They just take up twice the space and weight.

But that’s just me

[BiggKidd]

I loved my Li batteries until the dust got them and again it was MY fault. I’m the idiot that put a fan through the case instead of making it airtight!

[gods-child]

quote “(low but still there) explosive risk of lead acid and space. They just take up twice the space and weight.” end-quote

at least when a lead-acid battery explodes they do not catch on fire like the lithium batteries do and all you need is water to neutralise the already weakened by deionised-water and battery-acid solution

as for 12v car/van/leisure batteries they are significantly smaller and lighter than the lithium batteries

[Hippocrates_Garden]

For the energy potential per volume, these “leisure” batteries are lighter? Are they lead based? I’m not sure what you are calling “leisure” batteries. Can you point me toward one?

[gods-child]

leisure batteries come in

lead-acid

agm

gel

and new technologies according to https://advancedbatterysupplies.co.uk/blog/2016/02/leisure-battery-information/

[Hippocrates_Garden]

so they are all lead-based. I don’t see how they can be “lighter” than lithium. Remember a 100ah lead-based battery doesn’t need to be discharged much below 50% at most, and recharged as quickly as possible to prevent early degradation. Even a well-maintained lead-based battery may begin experiencing degradation after 500-700 “cycles”,

Lithium can be discharged to 20% without degradation, can be left discharged say 50% without degradation for an extended time, can be expected to go 3000-7000 cycles before significant degradation

meaning, a single 100ah lithium = two 100ah lead-based batteries in useful energy per cycle.

That single 100ah Lithium battery is half the weight of one lead-based battery of the same rating (or 1/4 the weight of equivalent energy availability (meaning two 100ah lead-based batteries) which now take up twice the space.

And the lead-based battery bank (two 100ah lead based to equal one 100ah lithium) will need to be replaced at least once, maybe 2-3 times before the lithium requires replacement as far as we can tell so far.

It’s always up to the person, the situation and such, but as I grow older, and having no idea what will happen re: materials and components. I personally would rather bite the bullet now, fill whatever space I have available with storage that gives me the longest life, least maintenance and most available energy per cycle possible. The less I tinker with batteries, the more time doing other stuff.

Thank goodness, there are so many options, and people that understand and are willing to use and share information on all of them. Options, Diversity, freedom.. kinda the point right?

[BiggKidd]

Good thought!