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  1. Hi Alistair, I would not mix charged batteries with uncharged or low charged in a bank of batteries. But if you do not have another choice then it is better than leaving the batteries without a charge. Please remember to increase your charge current if you do. You should also not run the inverter on the batteries only, until the bank is fully charged. The Optimate-6 looks fine. Edit: If you choose to add the other batteries then yes use Mike's diagram for the connections.
  2. That is why I asked if DB9 is completely off-grid. This setup cannot work otherwise. 3 phase gives 380 Volt between phases and 220 Volt from phase to neutral. That is why the inverter can be connected in this way as long as there is no 3 phase equipment connected and no 3 phase grid connection. With this setup you will still get 220 Volt from phase to neutral but your phase to phase voltage will now be 0 Volt. If Jaco_n wants to still feed his inverter with the grid, he can disconnect 2 phases and just feed his inverter with one phase and neutral, and with DB9's setup feed the house.
  3. Hi Alistair. Pitty the Axpert does not have a 25 amp charge current setting. It will affect your charge times as follows 100% discharged will now take 15 hours and 50% will now take 7.5 hours. On solar only you can discharge 33% if you want it charged back in one day of 5 hours sunshine. Reading the Axpert Manual, option 29's default setting is 21.0 volts which gives 1.75 Volts per cell. This value is when the battery is considered 100% discharged. I guess this is when the inverter will switch off. It does not seem that you can set a DoD of 50% or less. But as I said I do not have
  4. DB9 Are you still connected to 3 phase Grid with this setup or are you completely off-grid?
  5. On more expensive inverters you will see sense wires running to the battery pack specifically to compensate for the voltage that was selected on the inverter and the actual voltage at the battery pack. Also there is temperature sensors placed at the battery pack to compensate the charging voltage according the current temperature.
  6. Hi Alistair. I would increase float to 2.3 Volts i.e. 27.6 Volts. Better yet. Increase the float voltage until the value measured with your multimeter over the battery with the lowest voltage (Battery D) is 2.28 Volts i.e. 13.68 Volts. Please make sure that the voltage on Battery C stays within the Float range and do not exceed 2.31 volts i.e. 13.86 Volts. Bulk charge will be fine seeing that you can not change it any further. Yes give Battery D more time. Please set your charge current to be no more than 25 amps. For one bank of two batteries in series the max charge current is 25 am
  7. Hi Alistair, Out of your measurement you can see that there is a problem. The average voltages range from 2.25 to 2.22 Volt per cell. Normally for SLA at 20 Degrees C Float is 2.26 - 2.31 and Bulk is 2.43 - 2.53. The only Stride datasheet that I could get is for a N100MF Battery. The Float on the datasheet is 2.30 Volt and max charge current is 0.25C which is 25 Amps. Unfortunately the data sheet does not give a Bulk charge voltage. It seems that the Axpert is giving the voltage that you selected. Does the Axpert indicate that it is Float charging? (4 bars on in the battery symbol wit
  8. Hi Alistair. Gel has more advantages than flooded but more expensive to buy. Also charging voltage is more critical. Gel will give better service life which makes it cheaper in the end. Other than that it is still a lead acid battery.
  9. Some nice to read stuff. https://www.cdtechno.com/pdf/ref/41_2128_0212.pdf
  10. Hi Alistair. If they are sealed batteries, how are you using a hydrometer on them? It is also sounding more like an under charge problem to me. Can you confirm that it is the older batteries giving the problems. Also make the changes Carl has suggested to the Axpert and then measure with a multimeter the voltage over each battery while they are charging and report it here if you can. Please measure as Carl said to at least 2 decimal points.
  11. Hi Dope. I would recommend NARADA REX-C 12volt 200a/h. They will be more pricey than you are willing to spend but they have good specifications. http://philsolar.ph/wp-content/uploads/2014/05/REXC-Series-Lead-Carbon-Battery.pdf
  12. When you buy batteries they could be from different batches and the batches could differ in manufacturing dates. This will give you different SOC on the batteries due to internal resistances discharging the batteries while they are awaiting installation. It is therefore good practice to get the batteries as close as possible to the same SOC before you connect them into a battery pack. After they are connected in a pack it is not needed to individually adjust there SOC as you can then do an equalising charge to level things out. Just remember you would not like to do this regularly as an equ
  13. Alistair, What is important about a battery bank is that each battery is balanced. Each battery must have the same potential across it when charging and must be discharged with the same current draw. That is why it is important to have all the batteries at the same (SOC) State Of Charge before they are connected in a battery bank. Maybe that particular battery that failed was at a lower SOC when you connected it in your bank. This battery could be at a different SOC because it is from a different batch or manufacturing problem. Did you charge all the batteries individually before you conne
  14. Batteries in series will not double the current. Batteries in parallel will. Therefore each series string will be limited to 30 amps. The two series strings in parallel will therefore be limited to 60 amps. Thus 720 watts. EDIT: 720 watts per string which will be 1440 watts for two strings in parallel.
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