Need a charge controller that DOES NOT power from battery

[bigbfan]

Hello,

We are doing a project at a farm that pumps rain out from a barrel into drip irrigation. Project works well except that we are finding that due to cloudy weather our battery is draining pretty often, and since the charge controller we are using powers from the battery, we are in catch22 as it never starts even when the sun is out. We used car battery starter to jump start the battery and then everything works until next time the battery drains. We are looking at getting bigger batteries but I feel we should also invest in a charge controller that powers form the panel instead , else we are always chasing our tail. Or a charge controller that can be run from an alternate source. Any pointers ?


Below is our charge controller that we are hoping to replace: it’s a 10A charger .

SUNER POWER Waterproof 10A Solar Charge Controller - Intelligent 12V/24V Solar Panel Battery Regulator https://a.co/d/bs3cydq
Our batterry is a standard lead acid rechargeable 35Ah battery
Our panel is a 50W panel: Suner Power panel.

Thanks

 

[Bud Martin]

May be should stick to just one thread otherwise it will hard to keep track on answers and questions.

Looking for 10-20A charge controller that runs from panel instead of battery

Hello, This is my first ever solar project. Pls bear with me. We are doing a project at a farm that pumps rain out from a barrel into drip irrigation. Project works well except that we are finding that due to cloudy weather our battery is draining pretty often, and since the charge controller...

diysolarforum.com

 

[WindWizard]

Your probably not charging your battery with the 50 watt panel. Doing the math it would take at least 8 or 9 hours to charge the battery. 35X12 = 420 watts. 420 divided by 50 . That is in a perfect world. A 50 watt panel usually puts out a whole lot less and then using a pwm charge controller further reduces what your are putting in the battery. You could get a clamp meter and measure how many amps you are putting in the battery. You probably want to keep it cheap but you most likely need a larger solar panel and a decent mppt controller to make it work. Most pumps take at least 8-10 amps so the battery is weak as well.

 

[bigbfan]

May be should stick to just one thread otherwise it will hard to keep track on answers and questions.

Looking for 10-20A charge controller that runs from panel instead of battery

Hello, This is my first ever solar project. Pls bear with me. We are doing a project at a farm that pumps rain out from a barrel into drip irrigation. Project works well except that we are finding that due to cloudy weather our battery is draining pretty often, and since the charge controller...

diysolarforum.com

Sorrry will take care next time.

 

[bigbfan]

Your probably not charging your battery with the 50 watt panel. Doing the math it would take at least 8 or 9 hours to charge the battery. 35X12 = 420 watts. 420 divided by 50 . That is in a perfect world. A 50 watt panel usually puts out a whole lot less and then using a pwm charge controller further reduces what your are putting in the battery. You could get a clamp meter and measure how many amps you are putting in the battery. You probably want to keep it cheap but you most likely need a larger solar panel and a decent mppt controller to make it work. Most pumps take at least 8-10 amps so the battery is weak as well.

I am looking at adding another 35Ah battery in parallel. When the battery jump starts, I have seen the battery charge from 10% to 60% (controller LEDs indicate that) in about 3-4 hours on a Sunny day (so yes , I feel the panel is charging). However can you suggest a better controller which can take the initial surge as well as some under charge protection for the battery ?

Here is my pump :

BACOENG DC 12V Farm & Ranch Solar... https://www.amazon.com/dp/B016VX8XBW?ref=ppx_pop_mob_ap_share

 

[WindWizard]

Just what I suspected. A 10 Amp pump. You need to break out your wallet and purchase a bigger panel or panels and upgrade your battery and also a Mppt charge controller.

 

[Mattb4]

... When the battery jump starts, I have seen the battery charge from 10% to 60% (controller LEDs indicate that) in about 3-4 hours on a Sunny day (so yes , I feel the panel is charging). ...

The controllers indication of charge is highly inaccurate. It is based on voltage and during charging the voltage is higher than actual battery resting voltage. All you have to do is the math. A 35ah battery at 10% would mean it has used 31.5ah with 3.5ah remaining. To get back to 60% charged it has to reach the 21ah level. Therefore it takes 21ah - 3.5ah = 17.5ah at 12v = 210w

3-4 hours of sun on a 50w panel that likely only generates 40w an hour average = 120w to 160w Therefore at best your battery has added only 16ah back instead of 17.5ah. or 56% charged.

All of this is not taking into account conversion loss for charging, lets say 10%. Thus your 56% charge is closer to only 50%.

 

[WindWizard]

I look at your situation like having a sink with the water running part way and your sink stopper is open to the point where the water goes down the drain faster than you are filling it. You never do fill up the sink. The water in the sink is your battery. The stopper is your pump. The water running into the sink is your solar. You are putting into the battery maybe 3 amps and drawing out 10 amps for the pump. It just does not work. You need to be putting at least 10 amps into the battery just to break even. Purchase the following items to make it work.

1-300 watt or higher solar panel
2-30 amp MPPT solar controller (depending on the solar panel)
3-Deep Cycle battery rated at least 100 amps. Two 6 volt golf cart batteries work great.

Solar does cost a lot of money but it is very rewarding and satisfying to see how much freedom from the electric company it brings.

 

[Doggydogworld]

Hello,

We are doing a project at a farm that pumps rain out from a barrel into drip irrigation.

Does the pump run 24x7? If not, how much does it run and what turns it off and on (timer, photocell, manual, etc.)?

Project works well except that we are finding that due to cloudy weather our battery is draining pretty often, and since the charge controller we are using powers from the battery, we are in catch22 as it never starts even when the sun is out.

Almost all SCCs use battery power for internal circuits which need clean, stable voltage. It's hard to use highly variable power from a panel to control that same panel.

I've heard of SCCs with small internal batteries so they can work with a dead external battery (or none at all). They aren't common, though, because it's bad to drain a battery all the way to zero. As such engineers assume a dead battery requires operator attention.

I'd get a bigger panel to handle cloudy stretches and use your SCC's low voltage cutoff to protect the battery from completely discharging. You can power small loads (e.g. a string of LEDs) directly from your SCC's load port and get battery protection automatically. If the pump is too much draw for the load port to handle directly you can instead use the load port to control a relay that shuts down the pump.