SP reading 13 too high??

John XW NY
John XW NY Solar Expert Posts: 50 ✭✭✭✭
I used my hydrometer and my SP reading was 13 is that too high if so what should i do about it?

When i start my system im getting a reading from SCP of 25.7 v 4.3 amps when i begin to charge

also when i read from terminal to terminal i get a reading of 6.3- 6.4 volts, is that accurate or do i have to remove the neg inverter cable to get a accurate reading?

I am using a 24v Xantrex Xw4024 inv with 12 rolls s-530 batteries

low battery cuttoff set to 24.0 volts
grid supply volts= 27.0 v
recharge volts set to 25.4

when i turn loads on it runs for approximately 1 hour at around 500-1000 watts it starts to run down the battery

is this because it is winter and im not getting enough pv to keep it going?
should i hire someone to do a diagnosis on what is going on?

I did a EQ charge for 3 hours 3 days ago as well because the batteries sat for 2 months before i got everything running

ok TY
Jah Bless JDR


  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: SP reading 13 too high??

    John, if you add a description of your installation to your signature line , we might be able to evaluate it to give an answer to your question about 'do I have enough PV'.
    see below for a example

    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: SP reading 13 too high??

    Reading SG can be tricky. For one thing, it's relative. Start with the same hydrometer and compare future readings to the brand-new 'baseline'. For another, it's easy to read them wrong because the lines are pretty small on the bobber. Reading at the right time is important too: immediately after charging you will have a higher than normal reading because the electrolyte hasn't finished 'remixing'. And, since the numbers start out as low at the top and go up as you go down, it's easy to look and see water level at 1.275 and think it shows 1.300. Hydrometers themselves vary in accuracy, but accuracy is always relative to something else.

    The exact numbers aren't as important as having consistent cell-to-cell readings and consistent readings over time.

    So if you start out with 1.300 in every cell and it stays that way over the years (expect some diminishing of course) you're all right.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: SP reading 13 too high??

    Looking over your other question I'd say there's something wrong here.

    Those Surettes should be about 400 Amp/hrs each, and in a three bank configuration you should have 600 Amp/hrs available @ 50 DOD. On 24 Volts that's roughly 14 kW hours - you should be able to run that 1000 Watt load for half a day at least.

    If you do have insufficient PV and the batteries haven't been getting properly re-charged they could already be sulphated and low in actual capacity.

    I think you need to systematically check every aspect of your system. :D

    Incidentally, the Voltage levels I have on my system are:

    Absorb @ 28.8 (temp compensated) for however much time runs up on the MX 60 (up to 4 hours)
    Float @ 27.6 (arbitrarily chosen but is working well)
    EQ@ 31.0

    You would need about 3000 Watts (working, not peak rating) to keep that size bank up.
  • John XW NY
    John XW NY Solar Expert Posts: 50 ✭✭✭✭
    Re: SP reading 13 too high??

    Thanks 4 the advice, I do have enough PV 18 205 evergreen solar panels = 3.7 kw
    I am charging from the Grid and did the EQ from the grid as there was not enough PV to initiate without it.

    I realize we are in Winter and that in the Summer they will be cranking ( as soon as i trim the treeline):-)

  • John XW NY
    John XW NY Solar Expert Posts: 50 ✭✭✭✭
    Re: SP reading 13 too high??

    Yeah well im figuring out that the problem is probably due to sulfation, the dreaded name that no one wants. Im really p***ed at the guy who did my install because he dragged his butt and now my batteries are lame. Which i spent $4000 on. All i can hope is that Rolls will back me up and replace the ones that need replacement.

    What a pain in the neck!! Ive worked so hard to get this right and spent 30k on my system. To think ill have to lug the batteries somewhere and ship them is crazy.
    Each battery weighing 130 lbs. What else can i do?

    In my opinion their should be better options for storage, more reliable and better technology which i am sure exists. All I know is the Good Lord knows ive done everything to try and get it right.