Solar Output (with Wapda at night) and Battery Sizing Recommendations Needed

Before I ask for help, here is what I did and what I lost.

In April 2015, I installed this setup at my home.

  1. 2 x 180watts Yingli solar panels
  2. 40A Ep solar MPPT charge Controller (CC)
  3. 1 Osaka IPS 800 battery
  4. Homage 1000VA ups

Exactly after 8 months the battery was dead. The dealer, who knows nothing about solar etc, told me that one cell was dead and another one was also dying. He recommended not to replace the cell but get a new battery. According to him, the battery died due to over-charging.

Well, it seems true to me. Usually I turn off WAPDA to UPS at day time and turn it on at night, but this doesn't happen always. So when the WAPDA to UPS is on all day long, the battery used to get about 30A (10 from UPS and 20 from MPPT at mid-day). This might be one of reasons due to which battery was dead so early. In fact I was expecting above 2 years life of battery due to Solar at day time.

What I have concluded is there might be two reasons due to which battery dies so early.

  1. The battery was getting high current during charging.
  2. The CC was chargeing the battery till 14.4volts. Then it keeps the battery at that volts for exactly 2 hours and then return to 13.8 volts (floating charging). I think Osaka IPS 800 was not made to be charged till 14.4 volts.

Now I need to know what should I do??

  • Should I get a battery of ~200AH so that it is not damaged by the solar 20A current??
  • Or should I replace the MPPT CC with simple PWM CC, so that it doesn't charge the battery up to 14.4v for two hours?

I have read in the forums that Millat batteries can be charged up to 14.4V. If it is so, then should I get this battery for my current setup??

1 - Battery failure is not always due to overcharging.. there are many other reasons as well.

2 - wet batteries arent capable of being used with solar, but we have no choice. after wasting 4x huge dry batteries, i am back to AGS set, since dry are extremely expensive.

3 - the CC has adjustable charging volts, you can change all values in the CC itslef, to stop charging at specified lower volts..

4 - the proper method of charging is indeed going to 14.2V for boost charge for a few hours till battery is full and then come back to float value of 13.75. in this regard, your CC is fine.

5 - if you are getting 20A+ power from your CC, then you should turn of your ups in morning times to allow only 1 charging source to charge. homage and other systek so called hybrid ups are CRAP. and they are mostly responsible for battery failures than anything else.

6 - if you can afford and you wont use dual charging, then AGS is better.. Millat also can go to 14.4V, and it seems good too.. however, in both cases, you need to lower your CC charging values.

7 - in case you plan to change your CC to PWM, do let me know via PM ..

[quote=“farhan_ds, post:2, topic:22491”]

2 - wet batteries arent capable of being used with solar, but we have no choice. after wasting 4x huge dry batteries, i am back to AGS set, since dry are extremely expensive.

[/quote]

Farhan,

The above is alarming. I remember you had put in sacred sun batteries about a year ago. Are you telling us that those have been trashed. #$%#. That’s bad. Share your diagnosis please.

Aurangzeb

Usman

Your problem is probably because of deep discharge of the battery- not overcharging.

Aurangzeb