why battery voltage drop much at bigining ?

[Matrix]

I had to back door onto this thread this morning too. Got here now thru "Today's Posts". System would not let me onto this thread via my subscribed threads page.

[zolar]

hi all and thanks again suneagle and welcome back matrix,,, and yes its strange I started that topic but I can't see it again ,,, strange , although since last visit to it I didn't add something

[zolar]

suneagle , matrix ,,, what your openion about this calculator for the system ( I mean there is difference between it and altestore ) , so which one better to use plz?
cuz its faster and easy.

https://www.renogy.com/calculators

[Matrix]

I ran my personal numbers thru it and it seemed under powered Calculators are basically just guesstimaters

[zolar]

ah , thanks brother
1 more question please: is there an ammeter I can put it in my system so I can read the battery bank capacity just to compare between the ammeter reading and the controlar reading?
any names plz,

[SunEagle]

ah , thanks brother
1 more question please: is there an ammeter I can put it in my system so I can read the battery bank capacity just to compare between the ammeter reading and the controlar reading?
any names plz,

I would rather use a clamp on DC ammeter then a permanent one using a shunt & meter.

You can find a number of different types for different prices. Mine is a Uni-T UT202 which is inexpensive and provides what I need when I use it.

[Amy@altE]

Hi, I've been away from this forum for a while, but happened to pop by today. In Abu Dhabi, if you have the panels tilted at 40 degrees off horizontal, you will get 5.1 sun hours in July, the worst month. December is close at 5.2 sun hours. 600W lights x 8 hours = 4800Wh. I tend to calculate more conservatively than our calculator, I'd rather size it a little bigger. 4800Wh loads / 5.1 sun hours / .65 losses = 1447W of solar needed. In our calculator, if you enter 5.1 sun hours, it comes up with 1223W of solar, so it is using .77 as the losses instead of my .65. I know SunKing would rather use .50, so you will get a different answer depending on who you ask.

[Sunking]

Zolar what you have been suckered into is quite common. On-Line calculators at places that sell or advocated Solar are going to bait you with over conservative estimates. What that does gets you exactly what you got, a grossly undersized system. By the time you discover it, too late, they already got your money, and ready to sell you more stuff to make it work second time around. If the calculators used standardized engineering practices and principles, the results would likely scare you away and they loose business. So they bait and trap you. Unfortunately you got caught in the trap.

[zolar]

thanks a lot suneagle but can I check battery capacity with that and if yes , is there any video to watch please?
,thanks alot amy@alte for explaination,
thanks a lot sunking for the advice and I think yes that's what I got in .

and guys what about fuses or breakers ( I attend to use between panels and charger ,,, and between charger and battery ,,, also between battery and inverter )
so what about values?

[Mike90250]

....so what about values?

All that comes up when the system is engineered, and length of cable runs, system voltages, and power requirements are calculated.

I can tell you to put a 20A breaker on a 10 ga wire, but I cannot account for if it's a long 12V DC run or a short 240V run.

[zolar]

thanks mike90250 I am happy see you again,,,
and for the second system I am attending to make its :
24 v system , connecting 4 panels parallel with Y connector each 24v 320watt about 7 meters to the 60amps charger ,from charger to batteries about 3 meters cable long about 2 meter from batteries to a3kw inverter which output is 220v ac .
( NOW about the AWG actually I don't know , cuz here we are using mm , and when I compare between them in internet tables its not as we used to know it .
BTW mike and all expert PLEASE I know I shouldn't ask this Q,,, specially after all this time and some few information I got BUT :
as we know to find the amps is watt divided by voltage , but in solar people divide the load watt by system voltage ,, WHY NOT divide it by ac voltage since its fitted now after the inverter and working on 220 v. ( don't tell me cuz its the amps storage )

[Mike90250]

.....I know I shouldn't ask this Q,,, specially after all this time and some few information I got BUT :
as we know to find the amps is watt divided by voltage , but in solar people divide the load watt by system voltage ,, WHY NOT divide it by ac voltage since its fitted now after the inverter and working on 220 v. ( don't tell me cuz its the amps storage )

Because the amps at the 220VAC is generally small and does not matter much. Your 500W Klieg light only takes 2.3A @ 220VAC. But your 12V battery has to supply both the 500w the lamp uses, and maybe 10% more for inverter self-consumption - and now we are pulling 46A out of the battery and have to use a very heavy (and expensive) wire to carry that much current. And the battery terminals have to carry that power for a long time, and they start to heat up too. All that heating is more losses. If it was a 24V system, that 46A instantly becomes 23A, and the wire can be half the size ( and weight and cost) , and even 48V can be just 12A. Voltage is much easier to transport than amps.

[zolar]

let me have a chance to understand it.
but on my old 12v system I started a heater gun at 1kw for about 20min works on 220v out from an inverter 2k watt and the cables didn't come hot and cable size was 12 mm as we normally deal with , I think it equal to 6 AWG or 7 AWG .

[zolar]

suneagle I am going to buy UNI-T UT210E , but what I need actually a meter or any tool with ascreen to show the capacity % of my battery bank

[SunEagle]

suneagle I am going to buy UNI-T UT210E , but what I need actually a meter or any tool with ascreen to show the capacity % of my battery bank

Well the only meter that will provide some battery information is a voltmeter and that is not an accurate way to determine the % SOC. A battery may show 100% SOC or > 13V yet it may get quickly drained due to it's age and usage.

The clamp on meter will hopefully provide similar information of the CC showing how many amps are going into the battery while it is charging. I would not trust any "meter" that shows me the % SOC of a battery. Best way is to measure the Specific Gravity using a temperature compensated hydrometer. But if the battery is sealed you really have no way of knowing exactly what condition it is in.