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  1. Mwater

    best 12 Volt bettery in the heat

    I think will be fine if the max consecutive days without sun is 3 days. even the 3-day will rarely happens. so to have more than one 4-days in 12 days is almost impossible. its almost a desert so the problem is more the heat than sunshine.
  2. Mwater

    best 12 Volt bettery in the heat

    first I wanna make sure that the calculation for the battery size is right. The battery are charged by a solar panel the maximum amp is 4.8 amps, the minimum hours of charging per day is 4, Number of consecutive days without sun is 3. the battery will power a system that has a continuous Dc load...
  3. Mwater

    best 12 Volt bettery in the heat

    For the lead acid batteries the problem in temperature and where this batteries will be in an ambient temperature that could reach 60 C (140F) Following scottyUK advice I dug more about lithium batteries. I found some information about lithium ion phosphate. Valence batteries are not bad; I...
  4. Mwater

    best 12 Volt bettery in the heat

    IRstuff, the system will be used for more than 5 years. the ALCAD ni-cd battery can last for 20 years but the unit price is $2000 for multiple batteries that's a lot. ScottyUK you are right about the size range. my idea is to have 12 volt pack (10 ah) in parallel; I don't know if this will...
  5. Mwater

    best 12 Volt bettery in the heat

    the discharge is for measurement instrument with a continuous load of 20 watt. I think the 100 amp-hr battery is what I need. I checked the ni-cd batteries and they are around $2000. from my research the ni-cd are indicated as best solution. For low maintenance lead-acid batteries the...
  6. Mwater

    best 12 Volt bettery in the heat

    We are looking for 12 V batteries in the 80-120 amp/hour range that have minimal maintenance, the battery will be used with solar systems. The systems will be installed in the desert in South California, where the temperature in summer can reach 50C or 125F .since, the temperature reduces the...
  7. Mwater

    Bearing failure, motor or pump?

    thanks mbensema it is very helpful. I was not very clear before; the myth is not about the electrical fluting but about insulating the bearing to solve the problem. I think the dealer agree with you that is better to prevent the problem with good grounding and electrical installation than...
  8. Mwater

    Bearing failure, motor or pump?

    If you have a centrifugal pump, inverter duty motor and VFD, which bearings has the highest risk of failure(motor or pump), what kind of failures is expected and what are the steps needed to prevent these type of failures. Are there any features that can be added when ordering the motor and...
  9. Mwater

    Inverter duty

    Thanks for the advice
  10. Mwater

    Inverter duty

    motor losses are fixed losses + variable losses (I2R). I have around 100 amps output current from the VFD at different motor frequency. the current output from the VFD is equal to the current drawn by the motor? thus the heat generated at the motor is almost the same at different motor speed...
  11. Mwater

    Motor cooling & VFD

    first I want to thank you for your assistance. DickDV, how we can evaluate how much heat or efficiency loss we will get by looking at the amps. when the problem that we are having is how much ventilation we need. we use VFDs to control pumps in canals and we don't want to have motor failure so...
  12. Mwater

    Motor cooling & VFD

    I have a question about part 3; the data that I have shows that at specific speed, voltage, and frequency the VFD horse power and current increases as the water horse power (output) decrease. this true for low speed (50, 40, 30% reduction)but for higher speed (10%, 20% reduction) the VFD's hp...
  13. Mwater

    Motor cooling & VFD

    I am interested in motor cooling. 1) What's the key component in motor (induction motor) heat generation? is it the current (amps) or the input horse power and efficiency at a specific point. I read different articles and they all mention current losses in the motor (stator and Rotor), but...

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