Connecting 2 regulators to the same battery bank?

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Re: Connecting 2 regulators to the same battery bank?

Postby livin_amuk » Wed May 04, 2016 12:56 pm

Thanks for the suggestion, but the 3KW model is $5000, combined with $700 for a Midnite and I may as well just run a generator for 10 years. I don't have a job, and survive on Centrelink being creative and frugal, this is out of my price range. I'm sitting on around $2000 atm and really hope to upgrade my system and incorporate my four 250w panels before winter hits.

I've heard a lot of good things about the Plasmatronics PL60. Are you familiar with it?

Code: Select all
System Voltage         12-48V
Rated Solar Current    60A
Rated Charge Current   60A
Rated Load Current     30A
Max Solar Voltage      70V/80V/100V

I'm a little confused by the specs, but as a 24v system this will fit my purpose right?
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Re: Connecting 2 regulators to the same battery bank?

Postby Gordon-Loomberah » Wed May 04, 2016 1:45 pm

$5K for a 3kW inverter is quite expensive, you should be able to pick up a decent quality 2nd hand Latronics or Selectronics 24V 2-3kW inverter for well under $2K.

You'd have to run all 4 250W panels in parallel with the PL60, which is a good reliable Australian made unit. Make sure you size your wires suitably to avoid too much line loss between panel and regulator though.
However, in hot weather you may struggle to get your batteries to full charge with the PL60 if you have many loads running, as Vmp will be in the order of 25V for those panels, whereas your battery will need charging to over something over 28V.
Depending on whether or not the 200W panels are 60 cell, you may be able to run them in parallel as well, perhaps in a different orientation to spread out your power production.
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Re: Connecting 2 regulators to the same battery bank?

Postby APR » Wed May 04, 2016 3:00 pm

I have an Outback FX2548 inverter/charger, an Outback FM60 charge controller, and a Mate 2 system controller and display that I could be incited to offload for $2,000. The inverter/charger and charge controller are s/h, the Mate 2 is new.

If the OP shops around he will find S/H gear available with a few months warranty for competivive pricing.

Personally, I think if your current inverter provides enough power to meet your needs and it is only the ability to keep your batteries charged over a couple of days of use that is posing a problem, I would get more panels and another charge controller so you can harvest more solar energy each day.
2 x Goodwe GW5048D-ES Hybrid inverters, 13kW panels, 20kWh LiFePO4
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Re: Connecting 2 regulators to the same battery bank?

Postby new to solar power » Wed May 04, 2016 6:16 pm

If you are going to go a 48v system check out this controller.

http://www.ebay.com.au/itm/new-5kva-400 ... SwsB9WBmJ~

From reading Offgrid's posts Kurt has been using one like this for a few years now without any problem.
I know you can't better the rolls royce type equipment but if you are short on dollars then maybe this could be an option.
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Re: Connecting 2 regulators to the same battery bank?

Postby Smurf1976 » Wed May 04, 2016 7:08 pm

FWIW - 7 years ago I built a system with 2 x small 12V PWM regulators (separate panels) connected to a common battery bank at work. It's still running today with no problems or changes in that time.

So it can certainly be done, you just need to make sure that both regulators are set identically.
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Re: Connecting 2 regulators to the same battery bank?

Postby Whitespeed » Wed May 04, 2016 7:10 pm

livin_amuk wrote:
davidg wrote: I'd suggest a Midnite Classic 150.

I looked it up, was hard to find any opinions on it that weren't sponsored.


For what it is worth, I run a midnight classic and I am very happy with it, I have found factory backed advise and warranty excellent.

While the PL 60 would be a good unit (I have had the pl20 for many years now used as a remote machinery batt charger) I think for a little extra the classic will give better power returns from your panels, give better feedback on what it's doing and be more flexible in how you can configure your other components around it.

I am not sponsored, I work in healthcare and have no affiliation with the solar industry... except for handing over sums of money to retail stores :lol:
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Re: Connecting 2 regulators to the same battery bank?

Postby jules » Thu May 05, 2016 8:30 am

Well I also live deep in a forest and have a small system that's been running without fault for many years, so I'm happy to add support to Plasmatronics regulators such as the PL60. In my experience totally reliable, very adjustable to suit different circumstances and NO FAN. The PL60 can work with 12, 24 or 48V I believe, so depending on the arrangement of your batteries you could set it to suit.

I'm wondering if you're planning to run everything from the inverter or if you might use 12, 24 or 48V for powering lighting directly? There's some advantages to doing it this way as inverters are less efficient when they're at the low end of their power output. To follow on a theme from above, I also prefer an inverter that doesn't need to run it's fan at the slightest whiff of a load. I suspect, from its design, that the Victron referred to above might like to have its fan running.

As with other posts above I recommend either a Selectronic or Latronics inverter.

The reason for running batteries in series is that it helps keep all the batteries in balance because all the power has to flow through the whole line of batteries whereas if you have batteries in parallel you're much more likely to develop unevenness which can leave a battery in a backwater, to use the well loved water analogy, so its performance progressively goes downhill, to use a physical analogy.

Your battery bank looks a bit small to run a 3kW inverter, partly because you'd flatten the batteries very fast if you use anything close to capacity for long. A lot depends on what your long term plans are.
Primary system: .8KW Trina panels; Plasmatronics PL40; 1,000Ah VRLA 12X2V battery bank; 1.7KW Selectronic inverter. Off grid for 30 years.

Spares; 5 x 12V, 1,000 Ah batteries plus a couple of regulators
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Re: Connecting 2 regulators to the same battery bank?

Postby Whitespeed » Thu May 05, 2016 10:01 am

I will add a vote for the Latronics as well. Mine is a LS3548. Only had it for a couple of years so can't speak for reliability, but frequently gets run fairly hard with no complaints.

As for fan noise, I can run 3kw out of it at ~15 c ambient before fan starts. Fans start at 2.5kw @~25c. 2kw @ ~30c and 1.5kw @ ~35c. All of these are for contious load running.
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Re: Connecting 2 regulators to the same battery bank?

Postby jules » Thu May 05, 2016 12:06 pm

The "rated load current" of 30 amp in the chart above is the maximum current that can be passed through the regulator as load. The "load" terminal of a PL regulator is only intended for light duties. An inverter for example, should never be connected to the load terminals. There's plenty of wiring advice in manuals. Heavier loads are normally carried via a shunt which, with an extra black box, can allow the PL to give you accurate readings of current in and out.

Are the other figures in the chart self explanatory?
Primary system: .8KW Trina panels; Plasmatronics PL40; 1,000Ah VRLA 12X2V battery bank; 1.7KW Selectronic inverter. Off grid for 30 years.

Spares; 5 x 12V, 1,000 Ah batteries plus a couple of regulators
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