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absolute noob trying to start

donkey

Feb 26, 2011
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ok so i have an idea but am having problems getting schematics. for starters as i am a hobbyist the design is for a 12volt system. i am hoping to get a tri-power system. I want a 12volt deepcycle battery- which will be charged via a solar panel or mains but this will be controlled via a switch, i will use a secondary solar panel/ wind generator and lastly a 12volt transformer running of our 240volt mains powers, am hoping to run this into a transformer which i can use to select voltages in 1.5volts steps up to 12volts so i can run experiments. I think i have bitten of more than i can chew with desigining it but with luck i will be able to have a good setup that will not raise my electricity bill as i experiment.
oh last thing fuses and lights
need fuses for safety and lights so i can see what power source is being used, hopefully a meter to read power output from solar and wind gen, and power meter to see how full the battery is. i was thinking of trial and error on the 12volt systems which is ok, but the switching and 240v-12v systems are a little beyond my capabilities
 

davenn

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Sep 5, 2009
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ok

as a start for you to plan your system do a block diagram of the system you want,
do that for each section of the system and then work out where each section interacts with another section... I dont want to do the whole thing for you but here is a starting point :)
eg......

Solar panels ---> regulator/charger ---> 12V Battery Bank ---> Variable Regulator ---> Projects
240VAC - 14V DC Charger ------------------------^

240VAC to 1.5 - 12VDC Variable PSU ---> Projects

etc

Lay it out with boxes drawn around each section of text. Once layed, out then you can start looking at each section and decide on what you need to complete them.
eg. decisions of if you will build or buy a regulator/charger unit to go between the solat panels and the batteries etc etc

have a think about the block diag. post it up here and we can then help you through the stages :)
once the major issues are defined, then we can look at the linking/switching between the different charging systems and the batteries etc

Dave
 

donkey

Feb 26, 2011
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thanks dave i have the diagram sorted its easy but the switching and charging is hard


solar panel 24v --> transformer to seperate to 2*12v sources
1st source to charge battery
2nd source to power when battery is too low


2nd hookup is mains 240v - 2* 12v for same reason above

then i want to hook up a switch to alternate between solar/battery and mains
http://img220.imageshack.us/f/design1h.jpg/
in the link i provide switch 1 will select power to charge battery, solar when available

and the transformer at the end will power all experiments and tools

switch 2 will select source battery when charged is primary, solar is secondary and mains teritiary.

with luck these will be automatic
when i talk about mains in this project i am talking about a transormer 240v -12v but as it runs on 240v i labelled it mains
 
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donkey

Feb 26, 2011
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i am hoping to design a workbench this can fit into to run experiments as well as my 12volt tools, (soldering iron, rotary tool, and a few others which are 12volt) the reason i use a stepper is i will also be using this to run simple projects from jaycar/dicksmith etc hopefully. and these are 1.5 to 12volt usually. i hope it to be an all in one unit so it becomes more compact without having to search for items. i was thinking of putting an extension onto this as well to charge 1.5volt batteries (AA, AAA, C, D) and also 9volts but if i can get this part working first then i will be estatic.
 

Resqueline

Jul 31, 2009
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It seems to me to be a too complex setup for the need.
It's common for solar panel regulators to have multiple inputs; why not use them for "automatic" switching? It's just a matter of using diodes anyway.
It's not good to source the power for the projects straight from the solar panel anyway. Check out the (revised) attachment and see if it'll do what you need.
 

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donkey

Feb 26, 2011
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that does look better. much neater too lol.
now i gotta figure out what amps i need to run a light at all times when i am at the desk. also will be using 12volt rotary tool and soldering iron but i thought it out i will be using them OR the experiments so shouldn't be too hard
 

Resqueline

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The battery will be able to supply everything operating at once even if this far exceeds the recharger units ampere-rating.
You just need to estimate the total Ah drain by all appliances during 24 hours and use a battery at least twice as big, preferably three times (for longevity).
The rechargers just needs to be rated 40% higher than the total Ah drain divided by 24h.
 

donkey

Feb 26, 2011
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awesome this is my first post and the info is very precise. YOU GUYS ROCK.
i was expecting things like"dude look up wiki" lol
if I run 2 deep cycle batteries when i get a charger will i treat it as a a single battery for chargin purposes or do i have to charge each individually? they will be 2 deep cycle batteries 12volt run in series. it will cost a heap but thinking this will last way longer than i need them to so will not have to worry about them draining. I read in a jaycar mag that if they get too low for any period they can get damaged so hoping this will also help eliminate that problem.
 

davenn

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awesome this is my first post and the info is very precise. YOU GUYS ROCK.
i was expecting things like"dude look up wiki" lol

well we some times do that when its obvious that the poster has made no effort to at least do some investigations before asking questions ;)

if I run 2 deep cycle batteries when i get a charger will i treat it as a a single battery for chargin purposes or do i have to charge each individually? they will be 2 deep cycle batteries 12volt run in series. it will cost a heap but thinking this will last way longer than i need them to so will not have to worry about them draining. I read in a jaycar mag that if they get too low for any period they can get damaged so hoping this will also help eliminate that problem.

You saying Jaycar means you must be in Australia, maybe New Zealand, I think they are over there now too.
I'm also looking at doing a serious battery backup system at home here in Sydney.
A mate just got me 3 x 12V 100A/H (used) batteries that still have plenty of life in them.
I have also been looking through the Jaycar and Altronics catalogs to determine charging systems. I cant afford the solar panels that would be needed to charge those batteries, the panels would be in the order of $1000 each :(
So I'm more looking at charging from the mains and will most likely run the gear off the batteries contineously, so that when the mains supply drops out there s no switchover pause between switching from a mains supply to a battery supply system.
I would run my amateur radio gear direct from the batteries. The 240V gear (computers etc) would be run from the batteries via an inverter, ~ 600-800W contineous rating 1000W peak (burst).

DONT let the batteries drop below 10V. Any deep cycle sealed lead acid battery will need to be constant voltage charged at 13 - 14 Volts.
Putting your batteries in series means you will need a 24V charger.

cheers
Dave
 

donkey

Feb 26, 2011
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ok awesome just a few things. is that 1000 for the complete solar panel setup or 1k per bettery charging solar? and as you have 3 that would be 3000. both expensive however i could justify 1k not 3k lol.
and yes australia brisbane to be precise however I have heard that jaycar has an international site for america.
also altronics I have not heard of but will start looking at them
also i messed up... this is for a 12volt system i meant parrllel not series. I am assuming to do this will up my amps thus making the charger needed still 12volt but higher amp.
I am sorry there will be times I mess up like that.
 
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davenn

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ok awesome just a few things. is that 1000 for the complete solar panel setup or 1k per bettery charging solar? and as you have 3 that would be 3000. both expensive however i could justify 1k not 3k lol.

yeah, thats per panel which would all feed into a single regulator/charger
The prob is you have to decide on what the total Amp/Hr capability of your battery system is and be able to provide the very sizeable current that will be required to charge the battery bank

and yes australia brisbane to be precise however I have heard that jaycar has an international site for america
also altronics I have not heard of but will start looking at them

Altronics have a Brissy office, do a google search dont know if Im allowed to put their 1300 phone number on the forum, dunno if it breaks the rules
They have been around for many years, very similar to Jaycar but often easier to deal with, the company I work for buys 100's of thousands of $$ from them each yr

also i messed up... this is for a 12volt system i meant parrllel not series. I am assuming to do this will up my amps thus making the charger needed still 12volt but higher amp.
I am sorry there will be times I mess up like that.

Thats ok, I suspected that but let you clarify :)

Dave
 

hevans1944

Hop - AC8NS
Jun 21, 2012
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I may be a little out-of-date on this, but a battery management system (BMS), especially when two or more rechargeable batteries are involved, will more than pay for itself in extending the usable life of a lead-acid (sealed or not) battery. At a minimum, the BMS will keep track of how much charge (in AHrs) is added to or taken from a battery and then adjust the charging rate from either mains or a solar panel array to optimize the battery life without the necessity to EVER "deep discharge" a (usually) marine-rated battery. As @davenn said NEVER discharge a lead-acid battery to less than 10 vdc open-circuit voltage. Doing so will irreversibly damage the battery chemistry.

Also, even though you want to use two 12 vdc batteries in parallel, I would suggest that they be recharged individually, perhaps from mains power overnight, and using a BMS to regulate the charging rate. That will allow you to always have a fully-charged battery available for experiments. Even if you use a SEALED lead-acid battery, it is a good idea to locate batteries in a ventilated, but heated area, of your residence or garage or workshop. ALL batteries lose capacity when they become cold, so keep 'em toasty!
 

hevans1944

Hop - AC8NS
Jun 21, 2012
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Yes Hop, about 11 years :) :)
What I meant was, I don't know what the state-of-the-art is in BMS today. Clearly, not even Elon Musk could build a Tesla (or any other practical EV) using hundreds (if not thousands) of individual cells without battery management technology appropriate to the battery chemistry. I am pretty sure that Western Electric (the R&D side of AT&T, prior to the Government bustin' up the telephone company monopoly) used some form of BMS to keep all those lead-acid batteries properly charged up. Or doesn't anybody still remember "land line" telephones and those little brick buildings that housed batteries and telephone switchgear (stepper relays and such)? Does anybody here remember when you had to call the Operator to schedule a Long Distance telephone call, courtesy of AT&T's Long Lines Division? Of course, given how archaic the "telephone company" used to be (remember the Carterfone debacle?) they probably hired someone with a hydrometer to check each battery for charge on a daily basis.
 

Martaine2005

May 12, 2015
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Yes, I realised what you meant but I couldn’t resist it:)
I have the old telephone exchange building in my road. It’s still full of the old equipment. Incidentally, my uncle was the area manager for BT (British Telecom) and was given his golden handshake retirement from that very building.


Martin
 
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