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About four years ago I had new batteries and an MPPT solar charge controller installed in my off grid 48V 580aH set up. They replaced ageing Trojan T105s and an old PWM controller.
The system was installed over 12 years ago by previous owners, and consists of -
- 1280W PV array consisting of 16x80W nominally 12V panels made up in strings of four in series to produce a nominal 48V - all strings connected in parallel;
- a 60A eTracer MPPT cc (new four years ago);
- Eight 12V AGM batteries in two strings of four connected in parallel to double amp hours (installed 4 yrs ago)
- a 3000W inverter to produce 240V for the house.
From day one, the cc has gone into over voltage disconnect mode every time the sun is shining strongly. Everything was installed by professionals and they worked hard to try to stop that happening - reprogrammed the cc several times, changed wiring layout to and from batteries, and the supplier sent a replacement cc which behaved in exactly the same way!
Eventually the supplier suggested that perhaps the cc was designed to work in that way! After a while the installers and supplier stopped answering my emails, so have lived with the set up.
The programming has been checked over and over, and is set within correct parameters - although I cannot recall what they are as I type without looking at the onboard computer on the cc.
One of my concerns is that the cc seldom goes into float mode. The batteries are never discharged enough for a bulk charge to start, so in the morning charging starts at boost, but gets stuck there when the sun is very strong, as the cc works on time in each mode. Each time the cc goes into over voltage disconnect, the computer starts the time count all over again!
It worries me that this could damage my batteries.
Some questions -
1. Do all cc work this way, or are some sophisticated enough to actually control the voltage/amps going to the batteries without disconnecting if the voltages are high? In that regard I note that despite my PV array being nominally 48V, even on a cloudy day the cc read out shows 60V and over. The disconnect happens when the read out shows in excess of 70V coming from the PV array.
2. If there is a better cc on the market, what make is recommended? We are a retired couple on fixed income and have only now recovered financially from the large outlay 4 years ago to consider buying another cc. Locally, the best cc I have seen advertised is a Studer 60A cc at $NZ1100, but the read out display is for remote use only and costs extra, I would prefer a cc with a built in display.
The system was installed over 12 years ago by previous owners, and consists of -
- 1280W PV array consisting of 16x80W nominally 12V panels made up in strings of four in series to produce a nominal 48V - all strings connected in parallel;
- a 60A eTracer MPPT cc (new four years ago);
- Eight 12V AGM batteries in two strings of four connected in parallel to double amp hours (installed 4 yrs ago)
- a 3000W inverter to produce 240V for the house.
From day one, the cc has gone into over voltage disconnect mode every time the sun is shining strongly. Everything was installed by professionals and they worked hard to try to stop that happening - reprogrammed the cc several times, changed wiring layout to and from batteries, and the supplier sent a replacement cc which behaved in exactly the same way!
Eventually the supplier suggested that perhaps the cc was designed to work in that way! After a while the installers and supplier stopped answering my emails, so have lived with the set up.
The programming has been checked over and over, and is set within correct parameters - although I cannot recall what they are as I type without looking at the onboard computer on the cc.
One of my concerns is that the cc seldom goes into float mode. The batteries are never discharged enough for a bulk charge to start, so in the morning charging starts at boost, but gets stuck there when the sun is very strong, as the cc works on time in each mode. Each time the cc goes into over voltage disconnect, the computer starts the time count all over again!
It worries me that this could damage my batteries.
Some questions -
1. Do all cc work this way, or are some sophisticated enough to actually control the voltage/amps going to the batteries without disconnecting if the voltages are high? In that regard I note that despite my PV array being nominally 48V, even on a cloudy day the cc read out shows 60V and over. The disconnect happens when the read out shows in excess of 70V coming from the PV array.
2. If there is a better cc on the market, what make is recommended? We are a retired couple on fixed income and have only now recovered financially from the large outlay 4 years ago to consider buying another cc. Locally, the best cc I have seen advertised is a Studer 60A cc at $NZ1100, but the read out display is for remote use only and costs extra, I would prefer a cc with a built in display.
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