Reasons to NOT go with cheaper / chinese parts & devices - & a Genset QN

Nila

Hi All,

I have been off this forum for some time as I was busy with my other business.

So the story is : I had a nice PV setup going in my home
http://forum.solar-electric.com/showthread.php?18362-PV-Setup-success-Want-to-see-how-it-fares has all the info.

I should thank the admins here who helped a lot , BB helped a lot in particular.

The Story:

Now I am posting this so it is a lesson to be learnt for others haha.

This setup was working fine for some time then it started having issues and a year later it nearly gave up entirely.

1. The chinese pwm charge controller always measured the battery voltage and Pv voltage with -1 to -1.5 V inaccuracy so it tried to always overcharge batteries. Its error was always there but the level was NOT high so batteries will get warm but will complete the charge.

2. I had issue with my cheap 3.5KW Microtek Inverter (48v) (about 400$) which was working nice for months then it failed with its circuitry blowing which I believe may be due to extended usage of a domestic inverter that is not designed to be On for like 10-12 hours a day.

Service personnel replaced it as it was under warrenty for free but then the new circuit started reading battery with inaccuracy of over 2.5V lol.. I didn't notice it initially.

It nearly BURNT the batteries once by over charging at hell of voltages , It tried to charge batteries until it said 56V or more.
I found it very late.. may be it took 1 of my 4 batteries..entirely and I didnt realize it.

I replaced the inverter with another cheaper one 3.5k Lumnious which is more like 250-300$ but worked better than the other one.
I was able to get some PV charging and the inverter would top off,etc.

but now It was too late because the battery set had issues and I had issues with backups slowly.

Another battery failed and I had not time to attend to these.
Being lead acid batteries I had to water them all regularly which was a pain too.

So I just took 2 of those batteries with a smaller 24V inverter from a friend and had a smaller backup time without any PV.
Now I believe they are dead too .

3. For me I had a switch on the electricity line that goes to the Inverter which had to be switched OFF in morning and back ON in evening. This way I can prevent the Inverter's charging function to activate during the day time when my PWM is also charging the batteries also to activate the Inverter function in daytime when i had sun.

People in my home kept forgetting to turn the switch back on in evening so causing Inverter to drain batteries to 5% on few instances.

4. I read from some where in the forum that every newbie here kills their first battery string and I think i Just completed it
I was able to get about 2.5 years though. I had them for a year without panels just with inverters .


LESSONS:
1. Dont use cheaper parts
2. Monitor the system all the time
3. Try to automate , not use Human solutions like I tried.

However Biggest take away from all this is that I have learnt a lot about Electrical stuff from this and in internet generally .
and I was trying to create a battery monitor myself for this setup and I found about Arduino/Raspberry Pis and I was able to learn a LOT about electronics as well Now I can create small gadgets myself.

Loss is a 300$ Inverter ( which still works and may have to find a ways to turn off its charger ) and a
750$ worth of batteries ( I might have to replace them anyway in a year and these were cheaper ones as well , Chinese made with local label )

New system
As my system went bad, power situation on our city improved so i was in no rush to do anything about it.. I just disconnected the system.
Now the power situation is again coming back

so I am planning for future to do everything right again with
Xantrex 6048/ 60AMP MPPT and 8 Tall Tubular batteries.

Xantrex/Schneider has some support in India I dont know about MidNite,etc.
6048 is actually cheaper in India than other countries.

but this is going to cost me like atleast 8000$ I believe ,
I will make a new post about this plan to get your advice.

I would like to do the new solar PV setup again in my new home which I am moving at May and not in this current home.

Posted my generator qn here: http://forum.solar-electric.com/showthread.php?24811-Help-me-choose-the-generator&p=202312#post202312

I would need this as a 3rd backup anyway just in case.

vtmaps

Re: Reasons to NOT go with cheaper / chinese parts & devices - & a Genset QN

Nila wrote: »

It nearly BURNT the batteries once by over charging at hell of voltages , It tried to charge batteries until it said 56V or more.
I found it very late.. may be it took 1 of my 4 batteries..entirely and I didnt realize it.

There's nothing wrong with charging lead acid batteries to 56 volts... most types of lead acid batteries need more than 56 volts to be charged properly. Some of your problems have more to do with poor battery management than with cheap equipment. You can just as easily ruin your batteries with expensive, high quality electronics as with cheap chinese parts and equipment.

--vtMaps

Nila

Re: Reasons to NOT go with cheaper / chinese parts & devices - & a Genset QN

I should have been more clear, It was charging with 58-60V charging voltage but I was talking about the resting voltage.. it wanted the batteries to attain 56-57V stable before It will let it off hook.

I believe 54 is the resting voltage for 100% charged state.. I may be incorrect.

vtmaps wrote: »

There's nothing wrong with charging lead acid batteries to 56 volts... most types of lead acid batteries need more than 56 volts to be charged properly. Some of your problems have more to do with poor battery management than with cheap equipment. You can just as easily ruin your batteries with expensive, high quality electronics as with cheap chinese parts and equipment.

--vtMaps

Cariboocoot

Re: Reasons to NOT go with cheaper / chinese parts & devices - & a Genset QN

Nila wrote: »

I should have been more clear, It was charging with 58-60V charging voltage but I was talking about the resting voltage.. it wanted the batteries to attain 56-57V stable before It will let it off hook.

I believe 54 is the resting voltage for 100% charged state.. I may be incorrect.

Actually it's even lower: true resting Voltage on a 48 Volt system is typically 50.8 Volts.
You may be thinking of Float Voltage, which could be 54. They are not the same thing.

Nila

Re: Reasons to NOT go with cheaper / chinese parts & devices - & a Genset QN

Yeah correct, I was out of touch with these voltages

Anyways I wanted this a lesson to anyone who like me wondered why should we pay like 2-3k$ for an inverter or 500$ for a charge controller whist there are very cheap alternatives.

Cariboocoot wrote: »

Actually it's even lower: true resting Voltage on a 48 Volt system is typically 50.8 Volts.
You may be thinking of Float Voltage, which could be 54. They are not the same thing.

PNjunction

Re: Reasons to NOT go with cheaper / chinese parts & devices - & a Genset QN

Yessir - going cheap usually means you buy things twice or more. Since the charge controller is the "heart" of your system, I don't understand those that will spend bucks on other infrastructure, and then cheap-out on the heart of the system.

That being said, did the pwm controller have ANY form of temperature-compensation? Ambient is better than nothing, but of course remote "on-the-battery-terminals" is better. In your location, this would be crucial. Of course one wants to place the controller as close to the batteries as possible.

What are your cabling runs like? What gauge of wire and what lengths are involved?

Nila

Re: Reasons to NOT go with cheaper / chinese parts & devices - & a Genset QN

PWM did have wired temperature sensor and I had it glued to a terminal of a battery. PWM was/is still working however it just reads the battery voltages/PV voltages slightly wrong ( not sure how big an error 1.5V is when system Voltage is 48V)

Dont expect remote sensors for a 100$ charge controller lol.


Cables were 4mm for interbattery connections just for 2 feet lengths.
16mm for PV to Battery which is about 25 Feet. .

I consulted here in this forum before wiring so I m sure they were all fine.

PNjunction wrote: »

Yessir - going cheap usually means you buy things twice or more. Since the charge controller is the "heart" of your system, I don't understand those that will spend bucks on other infrastructure, and then cheap-out on the heart of the system.

That being said, did the pwm controller have ANY form of temperature-compensation? Ambient is better than nothing, but of course remote "on-the-battery-terminals" is better. In your location, this would be crucial. Of course one wants to place the controller as close to the batteries as possible.

What are your cabling runs like? What gauge of wire and what lengths are involved?