## Battery pack question.

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Manoah2u
Manoah2u
399
Joined: Sun Feb 24, 2013 1:07 pm

### Battery pack question.

Though it's somewhat automotive-related (car batteries),
i'm having some questions on battery technology/appliances that you guys might have some answers to.

A 12 Volt battery that delivers an output of 7 ah, am i correct that it delivers 84 Watts per hour?

Now the question that i'm having is, if you would combine 2 of those same batteries,
would you then generate 168 Watts per hour? and would that also double the Voltage? thus 24 volts?

would that then also mean, that if you would put 4 batteries (in series), would that then result in
48 volts of voltage, and 336 watts per hour?

would that - theoretically - mean, that if one were to combine 20 batteries of 12 volts, each 7ah,
it would generate a total of 240 volts and 1.7 kWh ?

I've also seen 12 volts, 100 Ah batteries for about 120 euro's. am i thus correct, such a battery
is able to provide 12v x 100ah = 1200 Watt per hour, thus 1.2 kWh ? which would thus provide
a capacity of 24 kWh if you'd combine 20 of them?

just trying to see whether i'm correct about that.

I'm asking actually because i'm trying to see how many hours one could supply low-consuming
house appliances on a 'classic' gel or lead-acid battery. To see if i can make a testing setup
where i have a solar panel combined with a (12v) battery, and to see how long a laptop, a led 5w light,
and charging a cell phone can last upon such a setup.

in other words - grid free use of daily use appliances that are used 'the most' on a daily basis.
most laptops operate at about 65 watt, and most cell phones charge on about 5 watt.
that would mean 75 watts combined. now, let's add a small 'table lamp' that uses a 5watt light bulb (which provides decent lighting) so would consume 80 watts of power - per hour.

let's say somebody sleeps 8 hours, works 8 hours, thus 'only' uses these appliances during 8 hours a day.
that would thus require 80 x 8 = 160 watts ?
the issue i'd come 'instantly' up with though, would be that a laptop might 'only' use 65 watts, it does use 220 volts of power - when charging, that is. similarly, a cellphone also uses 220 volts when charging, and the same would go for the lightbulb.
which is where i'm getting lost in calculating, and where i expect the 'laptop charging' to go wrong.
any bright minds here can set me free?
Dumpster sounds so much more classy. It's the diamond of the cesspools.

NL_Fer
NL_Fer
66
Joined: Sun Jun 15, 2014 8:48 am

### Re: Battery pack question.

8x80W = 640 Wh = 0,64 Kwh

AJI
AJI
37
Joined: Tue Dec 22, 2015 8:08 am

### Re: Battery pack question.

You're kind of confusing the issue with volts and amps and watts. In short, volts x nothing = nothing, amps x nothing = nothing, but a watt is a combination of volts x amps in any configuration you like (in a theoretically 100% efficient system). So your 65watt computer is using 220volts, but only 0.295 amps.

NathanE
NathanE
1
Joined: Fri Mar 31, 2017 6:49 am

### Re: Battery pack question.

I'm not sure you are quite right.

A 7Ah 12V battery has a theoretical energy storage capacity of 84WH or 84x60x60 J (302 kJ).

The battery chemistry and physical design will determine how much of this is practically usable, lead acid typically c50% and Li c80% which is primarily limited to the point where it becomes impossible to recharge.

So to your question, is this watts per hour - no it is watt hours, a totally different measure - capacity not rate. Given watts are already a time rate measure of energy (J/s) this (your original) would be like a second time derivative of energy, kind of energy acceleration if you like.

You are correct that you can combine batteries (subject to having appropriate controllers depending on chemistry) to give higher energy storage, voltage or current producing capability. In fact the batteries we use are often already compound architectures of multiple cells designed to give the desired characteristics

Tommy Cookers
Tommy Cookers
517
Joined: Fri Feb 17, 2012 3:55 pm

### Re: Battery pack question.

@ Man

2 of the 3 the devices are supplied with a controlled low DC voltage from a charger/power supply supplied by a 220 V AC main
the controlled low voltage is specific to the devices internal battery type

producing a pseudo mains supply from a battery requires voltage inversion and transformation ie a suitable 'Inverter'
but if the light is a suitably low voltage type we can avoid needing an Inverter

presumably a suitable charger/supply exists - that runs/charges LED lights, laptops and phones from a 12V battery

and
a 12 V 7 A/hr battery will be flat after 1 hr when yielding energy at a rate of 84 W
doubling the battery will yield double the energy yield (eg 168 W for 1 hr or 84 W for 2 hrs) not quadruple it as you ask

Simon520
Simon520
0
Joined: Mon Jun 08, 2015 11:59 pm

### Re: Battery pack quest

Yes you are confusing yourself with your units.

A watt is a measure of POWER in a circuit where 1 ampere of current is delivered at a potential difference of 1 volt.

A watt-hour is a measure of ENERGY.

Your 7 amp hour battery at a nominal voltage of 12 will theoretically deliver 84 watt-hours of energy. Or .084 kilowatt-hours. Theoretically if you pull 84 Watts, you could do this for 1 hour before the battery is depleted. Or you could pull 168 W of power which would only net you 30 minutes of operation. Or, taking it to a ridiculous extreme, if your battery was capable of it, you could get 5,040 Watts for 1 minute.

If you place The batteries in series which would multiply the voltage while keeping the amp-hours the same. 10 batteries wired in series would give you 120 V DC at 7Ahr capacity.

If you wire the batteries in parallel you would increase the capacity while keeping the voltage the same so you would still have 12 V but it would be increasing the energy capacity; I.e. the amp-hours Will increase in multiples of seven amp hours every time you add a battery in parallel.

A Tesla model S 100D Battery pack has over 9000 individual batteries that are wired both in series and parallel. They are the same 18650 lithium batteries that power most laptops with removable batteries and powerful Vapes; only they are built into modules wired to create approximately 400 V at 250 Amp-hr capacity giving 100 KWHr of energy storage.

Here is where things get tricky. In the real world batteries don’t act like the ideal storage unit. They deliver a nominal amount of energy depending on how fast you pull power; it matters how heavy the load is. For example most lead acid batteries that you buy for your car will have a capacity listed on them. This is typically the capacity the battery would have if the power is pulled off at a rate that will discharge the battery in 20 hours. If the power is drawn off at a lesser rate (so that there’s more time involved) you’ll get slightly higher capacity; conversely if you pull the power off more quickly the battery capacity goes down and if you pull it quickly it goes down tremendously. If you drain a lead acid battery over one hour from fully charged to only 20% capacity left you’ll get maybe a third of the rated capacity.

So when you’re trying to decide if a battery will work for your situation one of the first things you have to do is find out what your energy budget is. That means what is the average power you need for however long you need it. Also important is how the power is drawn off. If it’s just a slow constant voltage overtime that’s one thing but if you’re cycling with very high peak power- that’s important too.

Once you have a fair idea of this it’s time to look at battery chemistry.

Lead acid batteries are relatively inexpensive and can deliver decent power but they’re heavy and they come with some important drawbacks. They are very sensitive to rate of energy removal; if you have a heavy load for a short period of time they are poor choices. Additionally if you want your battery to last more than a few cycles you’re going to have to size it so the battery does not discharge more than 50% at any time before being recharged. That concept is called depth of discharge and if you keep it less than 50% your battery will last (depending on its construction) probably 300 cycles or about a year of daily use. If you keep the depth of discharge 20% or less it will last basically indefinitely or about five years for a typical car battery . If it’s a ‘deep cycle’ lead acid battery with a shallow depth of discharge you can go 10-15 years. If you drain a car battery completely (even if it’s brand new) you’ve shortened its life considerably and it probably won’t ever be the same. if you do it two or three times the battery will probably fail .

Lithium ion batteries (and it’s a diverse group- there are lot of different chemistries within the lithium battery class) are much better tolerant of deep discharges without permanent damage and have a better cycle life than lead acid batteries. They can be much more powerful; there are chemistries designed to deliver rated capacity in 1 minute or less. They are much more energy dense; batteries of similar capacity are much lighter than lead acid. However, most are not intrinsically safe like lead acid is and they require electronic monitoring/control of max and min voltage to avoid damage or explosion/fire.

Regarding your project; let’s assume your max power draw is 100w and that’s pretty continuous; it may drop down to say 20 W if you just power and lights but most the time it’s 100 W .

The most flexible solution would be using a decent sine wave inverter and a large battery. There would be significant inefficiencies because you’re going from your battery voltage to household current then using a wall wart transformer to charge your laptop battery which is them being used by your laptop.

(I would make a comment that you don’t want to use a battery to charge a battery; you’d be better off devising a DC 18 V system using 3x 6V lead acid batteries or better yet 6 lithium cells to power the device directly through the charge port; you could use a DC to DC converter to safeguard your equipment but good ones are costly.)

If you’re using 100 W received 12 hours at a time that’s 1.2 kWh of energy. You’re going to need a larger lead acid battery to keep < 50% depth of discharge; And a 12 hour rate will basically give you close to the battery’s rated capacity- let’s say you’ll need 2.4 kilowatt hours of energy.

2400 watt hours/12v= 200 amp hours. Conveniently, that’s basically the amp hours in a 6 V golf cart battery so you could go to Costco and get yourself two of those wired in series to double the volts to 12v. A good sine wave inverter won’t be terribly expensive for only 180 Watts or so.

Lithium batteries in that size are harder to find. You could go with Chinese LiFePO4 200 AH modules; wire 4 in series but a decent battery management system and charger is pricy. 200 amp hours via 18650 batteries is roughly 60 to 100 of them; you’d need 4x100 since they are 3.7v nominal and you’d need >12v for an inverter.

I’d suggest some Chevrolet Volt battery modules. They are relatively inexpensive for what you get and a 2.4 kwhr module is available; though it’s 36 volts nominal.

Or you could get a few extra laptop batteries to run the computer for 12 hours...

Manoah2u
Manoah2u
399
Joined: Sun Feb 24, 2013 1:07 pm

### Re: Battery pack question.

Wow, thanks for the info, gonna have to process it

I was actually investigating as i'm looking to see if i can move to Spain (Alicante area, Costa Blanca) in a few year's time,
and am looking to see if i can power the most 'off-grid' through Solar Power and energy storage. I'll need to stay below 10kW a day to avoid getting fines or actually recieving (hefty) taxes. It still remains to see if it's actually worth the investment, but i have noticed you can buy a set of 4 solar panels of about 275 wP each that would generate about 1 kW together and that would provide about 3000 kW a year. cost would be about € 1100,- eur (including VAT) for a set.

So i've started putting numbers and figures together to see if when able to pair that to a battery system, i might be able to harvest enough energy to theoretically live off-grid. If i could / and would, it might be worth the investment, taking into account a 20 year lifespan of materials used (including wear).

Obviously power supply needs to be sufficient, so i'm gonna need some clear data for that, so thanks for the above.

but i'm curious to see to start small already
Dumpster sounds so much more classy. It's the diamond of the cesspools.

Big Tea
84
Joined: Sun Dec 24, 2017 7:57 pm

### Re: Battery pack question.

Manoah2u wrote:
Wed Apr 25, 2018 9:07 pm
Wow, thanks for the info, gonna have to process it

I was actually investigating as i'm looking to see if i can move to Spain (Alicante area, Costa Blanca) in a few year's time,
and am looking to see if i can power the most 'off-grid' through Solar Power and energy storage. I'll need to stay below 10kW a day to avoid getting fines or actually recieving (hefty) taxes. It still remains to see if it's actually worth the investment, but i have noticed you can buy a set of 4 solar panels of about 275 wP each that would generate about 1 kW together and that would provide about 3000 kW a year. cost would be about € 1100,- eur (including VAT) for a set.

So i've started putting numbers and figures together to see if when able to pair that to a battery system, i might be able to harvest enough energy to theoretically live off-grid. If i could / and would, it might be worth the investment, taking into account a 20 year lifespan of materials used (including wear).

Obviously power supply needs to be sufficient, so i'm gonna need some clear data for that, so thanks for the above.

but i'm curious to see to start small already
You may be interested in this (sorry, ot not F1)
One test is worth a thousand expert opinions

Manoah2u
Manoah2u
399
Joined: Sun Feb 24, 2013 1:07 pm

### Re: Battery pack question.

Big Tea wrote:
Wed Apr 25, 2018 9:31 pm
Manoah2u wrote:
Wed Apr 25, 2018 9:07 pm
Wow, thanks for the info, gonna have to process it

I was actually investigating as i'm looking to see if i can move to Spain (Alicante area, Costa Blanca) in a few year's time,
and am looking to see if i can power the most 'off-grid' through Solar Power and energy storage. I'll need to stay below 10kW a day to avoid getting fines or actually recieving (hefty) taxes. It still remains to see if it's actually worth the investment, but i have noticed you can buy a set of 4 solar panels of about 275 wP each that would generate about 1 kW together and that would provide about 3000 kW a year. cost would be about € 1100,- eur (including VAT) for a set.

So i've started putting numbers and figures together to see if when able to pair that to a battery system, i might be able to harvest enough energy to theoretically live off-grid. If i could / and would, it might be worth the investment, taking into account a 20 year lifespan of materials used (including wear).

Obviously power supply needs to be sufficient, so i'm gonna need some clear data for that, so thanks for the above.

but i'm curious to see to start small already
You may be interested in this (sorry, ot not F1)

I'm aware btw over the Spanish gov'ment's 'stance towards civilian solar power usage.
Interestingly, there's a lot of 'scare' but really little actual result.
People were (and are still) screaming blood and murder over the decision a few years back to tax Solar Power users and to fine those who have not put in the correct administrative work for their solar installation with very high fines.
Bureaucracy is in fact a rather 'painful' process in Spain (well it always is, but cases like these are making it hard), so that would be the 'hardest' part.

However, the EU has already slapped Spain on it's fingers in regards to it's 'Impuesto del Sol' tax, so there's definately progress.

also, there's a 10kW 'treshold' - below 10kW you are essentially 'free as you wish'. (per day or per hour i'm not certain any more). That should be fine. Additionally, i've been told - don't take that as church though - that as long as you stay below that figure, you don't even need to manage proper 'bureaucratic' work that you have such a thing installed.
fully off-grid, you don't need to anyway if i'm correct. just as long as you don't generate more than 10kW AND/OR that you keep it for personal usage. in other words, you cannot 'become' a commercial power supplier.

in regards to the negative comments (not here obviously) in regards to Spain's stance towards private solar power usage, and the complicated and costly process to get the right papers and administrative work done to actually have such an installation, there is some defense - apart from the fact Spain has quite a big 'debt' of energy and needs to pay this off - what you don't want is that you run into the risk of damaging the infrastructure by people doing half-assed jobs of installing power supplies they have no idea of what they're doing or what the risks are.
if done half-arsed, there are a variety of risks - fires and explosions, and then haven't delved into the potential dangers of improper usage/storage/handling of leadacid batteries or batteries / condensators in general.
especially in a country where draught can cause much more negative side-effects.

also, i've read about people going berserk on the government over this winter's energy bills, but i don't see the reports of the moments when there was plenty of wind and storms in the country which saw kWh price drop towards 0,02 eur compared to the 0,25 price it had temporarily. which is, in fact, around the same price energy costs in the NL's at this moment more or less.

but i'm wandering far off.

can somebody also tell me about those batteries used for energy storage situations?
for example, what battery or what system would be preferred?
I've read sitations where people had 2v (yes, 2v) with 2000 Ah capacity,
also 12 v sitations with 1100 a, etc.
Dumpster sounds so much more classy. It's the diamond of the cesspools.

NL_Fer
NL_Fer
66
Joined: Sun Jun 15, 2014 8:48 am

### Re: Battery pack question.

Batteries are actually the biggest problem.

Most used are leadacid deep cycle (semi-traction / AGM) type. But they wear more when discharged deed. Discharge to 50% of capacity is recommended as the maximum limit, less discharge will increase the life of the battery. Lifespan 3-5 years in most situations.

Better is lithium, li-on, lipo, lifepo, etc. Discharge till 20-30% is possible without any wear. Lifetime with good battery management can exceed 10 years. Low weight. Downside is very expensive to buy, altough the longer lifetime will make up for it.

AJI
AJI
37
Joined: Tue Dec 22, 2015 8:08 am

### Re: Battery pack question.

Manoah2u wrote:
Wed Apr 25, 2018 9:07 pm
I'll need to stay below 10kW a day to avoid getting fines or actually recieving (hefty) taxes.
Is that 10kW a day for panels or storage or both? If you're 100% off the grid there's no way they can tell how much storage you have, but they can estimate how much you can collect via aerial photography.

Manoah2u
Manoah2u
399
Joined: Sun Feb 24, 2013 1:07 pm

### Re: Battery pack question.

AJI wrote:
Wed Apr 25, 2018 11:00 pm
Manoah2u wrote:
Wed Apr 25, 2018 9:07 pm
I'll need to stay below 10kW a day to avoid getting fines or actually recieving (hefty) taxes.
Is that 10kW a day for panels or storage or both? If you're 100% off the grid there's no way they can tell how much storage you have, but they can estimate how much you can collect via aerial photography.
that's what confuses me too, but info is too scarce too make sense of for me atleast.
In any case though - from what i've read atleast - you're oblidged to 'return' any excess of power generated
to the grid, though you won't get compensation for that. Obviously, you need to be actually 'connected' to
the grid for that to happen. What i don't know however if that that happens from 10kW+ or less even.

As for living off grid, indeed they can't tell, only estimate. Unless - and this i haven't figured out properly yet -
they base their information on the data you are mandated to hand to them by the administration required to
send to the gov'ment for owning or placing solar power equipment.

If you are connected to the grid, you're obviously using or making an impact on the infrastructure. Hence their defense that you need to pay extra taxes even though you're not fully using the grid's power supply.
Personally - but that's my personal interpretation - i am of opinion that if you are disconnected from the grid,
then you are not making an impact on the infrastructure. Offcourse we can only talk about the infrastructure of power supply and/or usage. Water supply for example and Gas usage is a total different story alltogether.
But, again, in my opinion, if you are not connected to the grid - disconnected - then you make no impact on the infrastructure and as such, i do not personally believe you are oblidged or that the government is in the position to mandate anything or tax you anything over your own way of providing energy.

For example, i know of some buildings/houses that are in mountaineous areas in Spain, that literally have no connection to the electricity grid, or water grid for that matter. First and foremost because there literally is no supply. These houses are provided their heating through a fireplace running on wood, for example. Also through use of bottles of gas. lighting through candles. and water through a private well and a huge water tank that stores rain water, and buying bottled water in the supermarkets.
there is no way the government can tax or fine these people, who are literally living off-grid. Obviously, everybody has to pay taxes, but that's another story.

So, likewise, i assume that if you are disconnected from the grid, you cannot be fined or taxed. but again, i don't make or invent the rules. i've seen suggestions or even applications where there's a 'protection' installed that doesn't allow excess of power to be 'returned' to the grid. if your personal power supply (solar power) exceeds that of the current used by appliances and the storage capability of batteries, then a relay switch will interrupt the current from the solar power supply and hence no excess can be generated.

likewise, one can 'easily' install a 10kW 'kill switch' which simply stops power supply from solar panels if that number is reached, and then you would need to run on battery stored energy.

for example, you might have 4 solar panels each generating 275 Wp (peak watts), which would combined supply you with 1.1 kW (per hour). If the sun would shine for 9 hours straight during the day, and everything would work maxed out, you'd be supplied with 9.9 kW total during the time the sun shines. If i'm correct you should calculate a 90% realistic power supply (without wearing down), even with rather positive estimates, so you'd end up with 8.91 kW anyway ( or, 8910 watts). so with that amount of supply, one would, during sunlight, charge the batteries, aswell as provide energy to the appliances in use during the same time.

It probably thus would be better to have a 5th solar panel installed, 5 (panels) x 275 (wattpeaks) x 0,9 (efficiency) x 8 solar hours tops = 9.9 kw, or 9900 watts. obviously this is the total generated amount of watts, not the amount of watts provided in 1 hour for example. in other words, there is 9900 watts available to be consumed.
from those 9900 watts, again, you'd obviously need to supply the batteries, aswell as the consuming appliances during the day. so one (me) should calculate the total amount all the appliances would consume, and at which hours they would consume, and how much time and energy it takes for the batteries to be fully charged.

in a 'perfect' situation, i would need to make sure the solar panels are both able to charge the batteries, aswell as the appliances, to a solar power supply limit of 10kW, yet make sure i never ever reach that amount of power need, so i can actually have an excess of battery supply so if the sun doesn't shine, is blocked, or/and during winter period, i don't run into power shortage (offcourse an option would be a diesel generator).

As far as i'm understanding, the treshold is for 10kW solar power. I don't see how battery supply would be included in that, as quite frankly, if you are connected to the grid, AND have a battery supply, and charge your batteries with gridpower, there is not a law or tax against that. so honestly, i think that if you could have plenty of batteries available, and you could manage to 'daily' charge those batteries with 10kW max, and theoretically only consume about 3 to 5 kw a day, you would be able to 'store' 7 to 5 kw a day extra in your batteries, a day.

which again, brings me back to the batteries, and which is why i want to see how much 'power' can be stored in the batteries, and how much actual 'power' they can supply.

so perhaps my right question would then be :

what battery power (volts, amps, and all that is needed to know) would i need to simultaneously use all my home appliances together :

- washing machine ( saw a eco Zanussi that runs on 800 watts, buying price only 300 euros)
- salora 32" Led TV + soundbar ( 30 watts + 30 watts = 60 watts )
- AEG table-sized refrigerator ( 7 watts with 70 watts peak )
- Exquisit freezer table model ( 11 wats with 90 watts peak )
- ECO fan (40 watts)
- HP 17 inch laptop (45 watts)
- ECO coffee machine (450 watts)
- Microwave (600 watts)

i haven't been able to find actual information about A++ energy efficient central heating systems. i've seen very, very economic ones but i can't find just how much they use in real-time, only annual usage and that is open to a lot of interpretation. same would go for airconditioning, but i've read operating consumption is about 1kWh, but that remains something optional. also swimming pool water pump and filters, though i've found very economic ones, i still need to find the actualy real-time consumption of that, so i'll need to keep those out.
same goes for ovens.

i'm planning to buy gas bottles for the stove.

so that would make estimated power consumption - if all is on together - 2.1 kW on peak power.
that's rather a hefty amount, especially concidering a microwave runs for a few minutes tops, same for a coffee machine even though those are used more regularly ( i drink a good amount of coffee ), and a washing machine is on only during about 1,5 hours tops each cycle. also, both refrigerator and freezer both are calculated peak watt usage, but that also only is during momentary cooling neccesity, outside that, they run mostly on 7 and 11 watts.
nevertheless, if all is running at the same time (i'd like that possibility anyway), that means 2.1 kW is used.
but again, only for about an hour.

if i'd look into non-peak power, then i would be seeing a figure of about 120 to 200 watts, which is offcourse peanuts. (thanks to energy-efficient technology!). if those would be on for a full day it would be a lot, even concidering the fridge etc, tv and laptops never are on all day long.

ok, that is too without lighting, but those are leds anyway. i've got leds of 2 watts that are mood lighting, and a couple of 3 watt very bright leds that provide actual lighting if needed. let's say i've got 8 of those on at the very same time, then i'm running more or less 24 watts tops, so not really a big deal, and if those would be on for 12 hours a day it would be rather long. so so let's say 300 watts tops for a whole day.

so i might concider that a figure between 3 and 4 kW a day - again, with very economic appliances - is reasonable, but let's add some space and make it 5kW.

now that, offcourse still, is without battery charging. some random google searches for a 100 amps battery of 12 volts with 8 amps charging would result in the need of about 1,7 kwh of power usage, during 13 hours charging time. i still thoroughly have to calculate the above, but let's say thus for 2 batteries, one would need 3,4 or 3,5 kW. i might concider that i'd prefer to have the battery charged in half that time tops, so let's say 7 kW's needed to charge the batteries. that then would make the total about 12 kW's of consumption, and thus would not provide enough, i'd have a minimal defecit of 2 kW of power supply like that.

but again, i might be completely off in my calculations. especially with the batteries and the efficiency of charging those.
Dumpster sounds so much more classy. It's the diamond of the cesspools.

Andres125sx
329
Joined: Tue Aug 13, 2013 9:15 am

### Re: Battery pack quest

Simon, I´ve copy-pasted your entire post for future reference!

Simon520 wrote:
Wed Apr 25, 2018 10:31 am
Here is where things get tricky. In the real world batteries don’t act like the ideal storage unit. They deliver a nominal amount of energy depending on how fast you pull power; it matters how heavy the load is. For example most lead acid batteries that you buy for your car will have a capacity listed on them. This is typically the capacity the battery would have if the power is pulled off at a rate that will discharge the battery in 20 hours. If the power is drawn off at a lesser rate (so that there’s more time involved) you’ll get slightly higher capacity; conversely if you pull the power off more quickly the battery capacity goes down and if you pull it quickly it goes down tremendously. If you drain a lead acid battery over one hour from fully charged to only 20% capacity left you’ll get maybe a third of the rated capacity.

I guess it´s different for each chemistry, isn´t it?

Simon520 wrote:
Wed Apr 25, 2018 10:31 am
Once you have a fair idea of this it’s time to look at battery chemistry.
What are the real posibilities for this? Some time ago I read about flow batteries, but I have no idea if that was just a project or they´re real

Andres125sx
329
Joined: Tue Aug 13, 2013 9:15 am

### Re: Battery pack question.

Manoah2u, it looks like you´re read a lot more than me about the subject, but what I remember is if you´re self-suficient and have no connection to to the grid, you´re free to pay any tax or comply with any requirement. But this does increase significantly your storage requirements to be safe, so I´m not sure if it´s worth

I´ve tried to find it, but it´s too long and I don´t have enough time right now, but just in case you can read spanish, this is the actual law

https://www.boe.es/buscar/act.php?id=BOE-A-2015-10927

I´ll try to find it tomorrow, if I can help you some way just tell me, I´m also very interested on this

Manoah2u
Manoah2u
399
Joined: Sun Feb 24, 2013 1:07 pm

### Re: Battery pack question.

Andres125sx wrote:
Thu Apr 26, 2018 7:28 pm
Manoah2u, it looks like you´re read a lot more than me about the subject, but what I remember is if you´re self-suficient and have no connection to to the grid, you´re free to pay any tax or comply with any requirement. But this does increase significantly your storage requirements to be safe, so I´m not sure if it´s worth

I´ve tried to find it, but it´s too long and I don´t have enough time right now, but just in case you can read spanish, this is the actual law

https://www.boe.es/buscar/act.php?id=BOE-A-2015-10927

I´ll try to find it tomorrow, if I can help you some way just tell me, I´m also very interested on this
i'll see what i have found, i've got some stuff saved so i'll put it together and share (here publically).
i was actually about to write you to see if you know more lol!
anyway, definately will share soon. i'm calculating a zillion of things.

after hard work and studying i've managed to have a new job now as airport security officer, and will be starting soon, i'm very excited! i've already written some airports in spain and i'm excited to say that there's possibility for me to get a job there once i've completed a year here and have all the neccesary final degrees under my belt, which i should be able to get within a year. going to work my ass off and put a lot of it in savings so i can invest it in the type of house i'm really, really excited to snatch. wish i had everything sorted out already today, as i've ran into a very interesting house but reality simply makes it so that there is no way i am able to fund it right now, so i'm gonna have to be patient and i'm sure something similar or even better will pop up when the time is right.

but thanks for your reaction, appreciate it a lot!

enjoying this thread a lot guys thanks so much
Dumpster sounds so much more classy. It's the diamond of the cesspools.