Solar Controller for Prado's 2nd battery for fridge

I have 2 x 85 Watt solar panels on my Prado, a second 100 AH deep cycle battery and a Morningstar Prostar PWM solar regulator with meter and have probably had it for nearly 10 years and it has been great. I really like the functions of this regulator as you can see exactly what is going in and out and the current voltage very easily, but it "appears" to me that it might be getting a little worn with age, because the 3 voltage lights don't seem to be operating like they used to. Eg. Yellow light comes on sometimes when voltage is around 12.8 which never used to happen at that voltage.

My question is: What is the best value for money solar regulator for my situation. I prefer a good quality regulator, but some of the prices on Ebay are very expensive for my needs, but I also realise that battery replacement is also expensive if they are not charged correctly. Brian DJ

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Reply By: GerryG - Saturday, May 25, 2019 at 19:12

Saturday, May 25, 2019 at 19:12
I just bought a Powertech unit from Jaycar today for $149. It can be used on 12 or 24 volt systems, is 15 amp MPPT that will accept up to 50 VDC. I think this means that most grid panels, that usually produce around 48 volts and can be bought cheaply can be used with this unit.
It's quite a heavy unit and the "box info" reads well. The max panel size on 12v is 180w and on 24v is 360w. I haven't hooked it up yet but I have used a number of Powertech units before. Its a MP-3739 model.
AnswerID: 625742

Reply By: RMD - Saturday, May 25, 2019 at 20:23

Saturday, May 25, 2019 at 20:23
G'day Brian DJ

I purchased an Ecoworthy solar reg which has a clear easy to read and programme screen. It can handle 20 amps and 300w input when running a 12v battery. Since most panels do not put out their stated/rated current you are well below that. The reg can be used for either 12v or 24v systems, settable. Max panel voltage is 50v input.
Since it has 50v solar input I had used two folding panels in parallel 18v to 20v, but now in winter when the sun is less I have both panels in series, ie, double the volts to 39v, so it begins to charge earlier and stop later, because of the, now half amps flowing but the voltage is doubled, it gives a decent amount of harvest because the MPPT BULK stage utilizes the voltage/amps available.
Absorb and float stages alter to PWM mode as it claims a more accurate control of set voltage. The Float voltage is settable (very handy)as is the Load cutoff voltage and resume voltage, if you use that feature. Some do use it for fridge battery discharge level safety At $104 delivered it seemed good value and works well.

The regulator when using MPPT for Bulk takes advantage of the maximum panel energy which a PWM doesn't do as well. It has a demo mode which, when pressed, shows the percentage of MPPT gathering above what the PWM mode will provide. Mine does test with meters to show, more amps entering the battery than is flowing in the panel to regulator line. MPPT at work.
Many other regs will probably perform in a similar way, this is just what I have.
AnswerID: 625744

Reply By: arofs1 - Sunday, May 26, 2019 at 12:47

Sunday, May 26, 2019 at 12:47
Thanks Gerry and RMD for your information, it will assist me with my eventual purchase. Brian DJ
AnswerID: 625754

Reply By: Swaggie - Monday, May 27, 2019 at 09:09

Monday, May 27, 2019 at 09:09
I would suggest you try Victron,a 20amp should be around $169 and it has Bluetooth. They make an app so you can watch on your mobile if you wish..

AnswerID: 625772

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