choice of 2 batteries

[Zambian Kid]

hello everyone. This is my first post, been lurking around for the last few days.

I live in zambia, here everyone is starting to sell solar on the local market. Unfortunately there items are the lower quality stuff which we still pay top dollar for as its got to be imported and taxed, then there is markup and all that goes with it.

i have bit the bullet and ordered myself a kid. should be here this week 

I have a choice of 2 batteries.

1 powersafe v 12V190F made in EU
2 Su-Kam      12V200AH/10HR made in India

basically id like to buy 2 batteries and store them then get a 24V inverter. think it would be a good starting point.

hope someone can tell me which would be the better option.

thanks in advance!!

[ClassicCrazy]

If you aren't going to use the batteries for awhile, you shouldn't get them until plan on using them. For lead acid batteries their lifespan starts counting down the time the acid is put in them.

I did not look up the exact specs on your battery choices. But in general it is better to get the flooded type lead acid - the kind you can look at the electroyte and add distilled water to for maintenance. It is easier to know what they are doing by being able to take specific gravity readings for each cell when you need to .

The sealed type of  AGM batteries just do not have as long of a life time  ( the amount of cycles they will discharge ) as the flooded type. And they get difficult to diagnose when they have problems since you can't check each cell on them.

With any of the batteries there are date codes of manufacture stamped in the plastic case. I wouldn't buy any that are older than 6 months if possible because you don't know if they have been maintained properly and you may be getting a new battery that is already starting to have sulfated plates in it.

With any of the batteries if you are storing them, you need to keep a charge on them. Not sure what you meant by storing them ?

Lithium are a lot more expensive but have some long term advantages over lead acid. But like any battery you need to really understand them so you don't ruin them by over or under charging or depleting them beyond their capacity.

Hope that helps some !

Larry

[ClassicCrazy]

A good battery type to begin solar with might be the 6v golf cart type - usually rated about 215 amp hour or so and around here they cost around $100 each.  So if you wanted to have 24v system you would need 4 in series.  It is always better to have batteries in series if possible than paralleled since then the same amount of current goes through each cell. 

It really isn't good to add extra batteries of different ages later on - so make your choice correctly in the first place to match the amount of power you want to draw out with an inverter to what the specs on the battery are rated for.  In general you don't want to take more than 50 percent capacity out of lead acid batteries to get maximum lifespan.

The other consideration is for whatever kind of battery you have you want to have enough solar panels to charge it back up but perhaps where you are it is sunny more than not and that won't be as big as a consideration as it is up north where I live !

Larry 

[Zambian Kid]

Thanks Larry for the good advice.

I understand that adding batteries to a bank already in use is a no go. So the reason I wanna store them disconnected is so I can get 4 over the time of 2 months. Golf cart batteries would be awesome as many ppl use them on the forum here. But unfortunately here it's not as easy as there. First off nobody imports the 6v here as all they know here is buy an inverter and a battery of 12v so they can have some lights and watch tv for an hour.

I'm basically looking toward the future and wanna go offgrid basically. I'm paying double here for anything u get there and nowhere near the quality. It's tough in the tropics.

Yes here we have plenty sun. Our Sumer is 40celcius and our winter is around 7celcius. So sun is not a problem. I'm leaning toward the EU ones which is option number 1. And to be honest any battery we buy here is over 6 months old.

Thanks again

Mike

[ClassicCrazy]

Even if you don't start using the batteries right away it is a good idea to keep a trickle charge on them because they self discharge over time just sitting around.

Get a volt meter - even one of the very cheap ones, and when you go to buy the batteries check the voltage on them. Don't take any that are too low - they are already bad ( under 12v for sure is not good ) . I wouldn't want any flooded types that are lower than 12.4 v . The AGM types can show a good voltage even if they are kind of bad so not sure what to tell you there unless you do a load test on them .

Guess we are lucky to have so many choices and demand quality here !

Larry

[Westbranch]

I note one small point that may have been missed so far, that is, you want all your batteries to be from the same production run (lot). Then you have the best chance of them all having the same performance characteristics, ie how they recharge and discharge.

hth

[Zambian Kid]

Thanks hth. I have read that along the line somewhere.

So I must test voltage and make sure it's above 12.4v and get the same production run. Good advice there guys.

I'm hoping to collect my kid today. Really can't wait 

Anyone else running a kid on 12v bank? If so I wouldn't mind some info on there setup. As u know I'm in the middle of nowhere without anyone to help lol.

[ClassicCrazy]

You didn't say which kind of panels or how many you will be using.
Basically you will put your panels in series and get a higher voltage and set up the kid to charge at 12v using the battery manufacturers specifications for the absorb and float setpoints - as well as equalize setpoints depending on what type of battery you have.

If you have the Whizbang Jr you will also enter the battery capacity so you can get an idea of state of charge in a percentage value known as SOC . 

Not sure if the temperature compensation probe comes with your the Kid you ordered or not - You may not need one if your batteries do not get too hot or too cold . The temperature compensation adjusts the battery charging setpoints according to the battery temperature.

The Kid user manual has pretty good instructions and pictorials on setup .
Larry

[Zambian Kid]

Hi Larry.

Well I got my kid in hand. Very nice piece of kit. I ordered the shunt and the whiz bang. No temp sensor as I will get one further down the line. But scared to set it up as its a lot of money for a mistake on my behalf.

I can give u my battery specs and I'm wondering if u can help me with all my value inputs. I not the sharpest tool in the shed when it comes to electronics and perameter settings.

I have 2x ollandia HP12-100DG (12V100AH GEL DC) setup I'm parallel

Constant voltage charge
Cycle use: 14.2-14.4V
Standby use: 13.6-13.8V
Initial current Less than 20A

That's all the info on the batteries

[Zambian Kid]

Sorry, these are my panels. Have 6. Not sure how is the best way to connect them to the kid

[ClassicCrazy]

You have a few options on how you set up your system.
You can connect all  your panels together in series for a higher voltage to the Kid - and then the Kid will drop it to 12v.

You could do the same thing but connect your two 12v batteries in series and make a 24v system instead.
Advantage of that is you can get more efficiency from the Kid and with 12v I think you may be at limit of 30 amp limit where at 24v you won't be.  With 24v you can also use smaller wire to batteries for charging and also from batteries to inverter. You would of course need to get a 24v inverter and wouldn't be able to use 12v appliances unless they can also handle 12v.

You would use the 14.2 setting for Absorb and the 13.6v for Float. Double those values if you set it up as 24v.
For the Absorb time you will have to kind of watch your system awhile to figure out how much time you need to fill the batteries before it goes to float. 

I guess it says to limit the charging current so there is a setting on the Kid to limit current - guess you would want to set that to 20amps output . But that will limit the current available from the panels if you are using a load more than 20 amps when the sun is out .

Your batteries are rated 100 AH so if you put them in series for 24v  you will have 100 AH capacity and double that if you wire them as 12v parallel  . Use those numbers in the SOC setup menu , use about 92 % efficiency in that menu.
 
Larry

[ClassicCrazy]

Consider getting one of the Midnite Mini DC boxes with breakers when you get an inverter ( or before). Makes it a lot easier to wire everything and has the large inverter breaker you need. Then you just get a few more breakers for the input from panels, output to batteries , and for DC loads if you have any. There is place for those breakers and spot in the box for mounting the shunt and whizbang.

http://www.midnitesolar.com/products.php?menuItem=products&productCat_ID=8&productCatName=Mini%20%20DC%20Disconnect

[ClassicCrazy]

Midnite has a string calculator on their site somewhere  - it is made for the Classic but you can use the data from it for the Kid too. Not sure if they have string calculator for the Kid specifically .   When you determine your voltages and currents you can then use that info to size your wiring for low voltage drop and also size the breakers.

Larry

[Westbranch]

Your batteries are rated 100 AH so if you put them in series for 24v  you will have 100 AH capacity and double that if you wire them as 12v parallel  . Use those numbers in the SOC setup menu , use about 92 % efficiency in that menu.

Same number of Watts though, no matter which config you use... you will have to figure out which config (12 or  24V) gives you the best overall efficiency.  don't forget the inverters efficiency...

[ClassicCrazy]

Well  - actually the Kid will do double the number of watts out at 24v than 12v - right ?

12 x 30 = 360 watts
24 x 30 = 720  watts