Thoughs on my new Renogy Solar Panel System

[LenS]

Has had my new 200 watt Renogy Premium MPPT polycrystalline system working for 3 days now w/o the van plugged in. Results:

1. House batteries stay charged. Running 48Ah per 24 hour day of refrigerator/inverter. Have about 1.5 hours (11AM to 12:30Pm) of direct 100% sun light. Rest of time shade.

2. The readout/display TM-5 is of little value. House batteries are 100% charged at ~13 volts but the thing is programmed for fully charged to be 14.3 volts. So when house batteries ARE charged the TM-5 shows ~75% charged. The current displayed going into the house batteries while charging has to be completely wrong and makes no sense.

3. TM-5 is good only for showing solar panel voltage and house battery voltage. Cost $39.99

My batteries are fully charged by noon. Batteries are about 85% charged at 8-9 AM. So panels work great. Glad I got 200w's.

[Bbasso]

Maybe I missed it but what type of house batteries do you have? Also what type of controller are you using? The reason I ask is because most batteries are full at 12.7 to 12.8 so I don't know why you would want it programmed so high unless its some special battery.

I too have a renogy 100 watt panel with a Sunforce 30 amp solar controller and loving it. But once I have some money I'll invest in the second panel so I can charge a little bit faster I didn't realize my useage was so high... opps.

[Viva]

Originally Posted by LenS

2. The readout/display TM-5 is of little value. House batteries are 100% charged at ~13 volts but the thing is programmed for fully charged to be 14.3 volts. So when house batteries ARE charged the TM-5 shows ~75% charged. The current displayed going into the house batteries while charging has to be completely wrong and makes no sense.

I may be off base here, but is the solar controller a smart charger? I think most are? If so, 14.3 wouldn't be an unusual value for the absorption stage (Stage 2), and then 13.6 for the float stage (Stage 3) (Stage 1 is bulk, where you are throwing everything you can at them.)

I have two different solar controllers, and have helped a friend program a third type. All three of them had a few "standard" settings for absorption and float. They vary slightly by battery type, but 14.3 and 13.6 are typical values. I have used the custom settings to program the values for my Lifeline AGMs because they have a slightly atypically low float charge spec (13.3v IIRC).

If you're talking about something different, then please ignore.

[LenS]

Originally Posted by Bbasso

Maybe I missed it but what type of house batteries do you have? Also what type of controller are you using? The reason I ask is because most batteries are full at 12.7 to 12.8 so I don't know why you would want it programmed so high unless its some special battery.

I too have a renogy 100 watt panel with a Sunforce 30 amp solar controller and loving it. But once I have some money I'll invest in the second panel so I can charge a little bit faster I didn't realize my useage was so high... opps.

Correct. I figure my two Interstate gulf cart 6v wet cell batteries are 100% charged at 12.9 volts. I also do not know why the Renogy controller is set for 14.3 volts. It is a fixed value in the controller, not a programmed value. And yes most batteries are full around 12.8v.

the Renogy Premium MPPT polycrystalline system uses the Renogy 20 Amp MPPT Solar Charge Controller.

[Viva]

Originally Posted by LenS

I also do not know why the Renogy controller is set for 14.3 volts. It is a fixed value in the controller, not a programmed value. And yes most batteries are full around 12.8v.

I haven't owned a controller with only one fixed value, but for my batteries (I have two different brands in different vehicles, although both are AGM), 14.3 would be in - or very close to - the proper range for absorption charging. So I'd be happy with that setting. Don't most batteries want 14.x volts for absorption charge? (I'm most familiar with AGM these days, so don't know if flooded batteries call for less/more.)

For example, my Lifelines call for the following at 77º Fahrenheit:
Absorption - 14.3 volts
Float - 13.3 volts

I have a Full River AGM battery elswhere, and it calls for the following at 77º F:
Absorption 14.4 - 14.9 volts
Float 13.6 - 13.8 volts

I find that the latter corresponds to many solar controllers' standard settings; I had to go into the custom settings for the Lifelines because their Float value is lower than typical (apparently) at 13.3.

As per usual these voltages go up when batteries are cooler, and down when they are warmer (hence temperature compensation), but these are the 77º specs, which are the ones usually specified as default (and what I think controllers without temperature compensation default to.

Edited to add:
I looked and see you have two Costco GC2 golf cart batteries (6 volt in series to make 12 volts). I couldn't find the charging specs on these, but I did look up the specs on Trojan T-105's, which are also flooded 6 volt Golf Cart batteries. Here is what they specify at 77º:

Absorption: 14.8 volts

Float: 13.2 volts

(Equalize: 15.5 volts)

For temperatures, they specify the following:
.028 VPC for every 10°F (5.55°C) above or below 77°F (25°C) (add .028 VPC for every 10°F (5.55°C) below 77°F and subtract .028 VPC for every 10°C above 77°F).

I'm going to guess your controller doesn't have temperature compensation (given that the charge settings are not adjustable), so the closer you keep the batteries to 77º the better, as that is what the controller is going to "assume" (I would think).

One note is that even though your controller is not programmable, does it have a few "stock" settings? If so, you could try to use one that would give you a higher absorption voltage (presuming the Costcos are anything like the T-105's which want 14.8 volts)

******
Where I am right now, for example, the ambient temperature is 75º. The batteries are at 64ºF. And my solar controller is putting 14.55 volts into the batteries (temp compensated absorption voltage). The batteries aren't particularly low, but I'm using power, and so I think the controller goes into the absorption stage. I expect it will be in float before too long. (I have 200 watts of Grape Solar semi-flexible panels out on the ground, in series, and a Sunsaver MPPT 15 controller hooked up to them.)