drafts:mppt_faq
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drafts:mppt_faq [2016-12-02 06:01] – [I want to over dimension the PV array, how can I calculate the maximum?] mvader | drafts:mppt_faq [2019-03-06 12:04] – [Q7: Can I use the MPPT Solar Charger as DC-DC charger?] bob | ||
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====== MPPT FAQ ====== | ====== MPPT FAQ ====== | ||
- | ==== 75/15 and 100/15 cannot be controlled by a BMS, what now? ==== | + | See also [[victronconnect: |
+ | ==== Q1: I want to size or oversize my PV array, how can I do this? ==== | ||
- | The reason is that the RX pin is already used to the battery life on/off selection with the jumper. So therefore it is unfortunately not possible to control these two models with the VE.Direct .. remote on/off cable [link]. The solutions is buy the next model in line: the MPPT 100/30. | + | See the blogpost [[https://www.victronenergy.com/blog/ |
- | ==== Can the output of the MPPT be used as a power supply, thus without batteries? ==== | + | ==== Q2: 75/10, 75/15 and 100/15 cannot be controlled by a BMS, what now? ==== |
+ | |||
+ | By default the RX pin is already used to control the battery life on/off selection with the jumper. Use VictronConnect to change the function of the RX pin to remote on/off to enable BMS control. See | ||
+ | [[https:// | ||
+ | |||
+ | ==== Q3: My MPPT is only showing voltage readings, not currents and also no Watts? ==== | ||
+ | Make sure to *not* connect PV minus to the battery. See the manual. | ||
+ | |||
+ | ==== Q4: Can the output of the MPPT be used as a power supply, thus without batteries? ==== | ||
The answer is; it depends on the type of load. | The answer is; it depends on the type of load. | ||
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Loads where under voltage does not apply, like light globes, can be operated without any problems. | Loads where under voltage does not apply, like light globes, can be operated without any problems. | ||
- | ==== I want to over dimension | + | ==== Q5: What about grounding one of the PV array poles? ==== |
+ | |||
+ | The MPPT is non isolated, meaning that the minus of the PV input is at the same potential as the minus of the battery output. | ||
+ | |||
+ | Grounding is always done at one point only, to avoid ground currents. For a battery system, grounding must be done at the battery. | ||
+ | |||
+ | ==== Q6: The Solar Charger is not working | ||
- | Over dimensioning a PV array is installing more Watt peak than the maximum charge power of the chosen MPPT charge controller. A common reason to over dimension is winter time. | + | 1. Check that the PV voltage |
- | As an example, | + | Or measure |
- | To get less difference between summer and winter, you can install | + | 2. For models with a Remote on/off switch (a green two pole connector, labelled Remote L H), check that the jumper is in. L and H need to be shorted |
- | How to determine | + | 3. Check that the battery voltage is set properly in the settings (12/24/48). |
- | There are two limits, when determining the maximum array size that can be connected to an MPPT: | + | 4. Check for [[:mppt-error-codes|error codes]]. |
- | - The Maximum PV open circuit voltage | + | If all above is fine, and still the unit does not operate, contact a dealer to have the unit tested. |
- | - The Maximum PV short circuit current | + | ==== Q7: Can I use the MPPT Solar Charger as DC-DC charger? ==== |
- | Both values are specified in the datasheets of all our MPPT Solar Chargers. | + | For example to charge a 12 Volt battery from a 24V battery bank? |
- | The ratings of the array must not exceed these maximum limits of the MPPT. | + | No. |
- | Note that you cannot multiply these values | + | ==== Q8: Can I connect different panels |
- | And same for the Maximum PV open circuit voltage, and then do not forget to take the coldest expected temperature into account. Because the colder it is, the higher the max voltage. | + | No. Under no circumstances. |
- | ===== DISQUS Comments ===== | ||
+ | ===== DISQUS ===== | ||
~~DISQUS~~ | ~~DISQUS~~ | ||
drafts/mppt_faq.txt · Last modified: 2021-09-30 07:18 by guystewart