I need a 150 watt solar panel battery charger circuit?

[gary350]

Harbor Freight had a special on solar panel kits with NO battery charger circuit. I think the factory battery chargers was bad so customers returned the panels for a refund. These are sold as 45 watt kits. I bought 9 solar panels with no battery charger circuit.

I would like to connect all 9 panels together to charge a car battery. Then I can use a DC/AC inverter to take power from the battery. My meter shows no load voltage on the panels is 18.5 vdc and 14 vdc when connected to a car battery. 9 panels in parallel will give be 135 watts this should charge a 1000 amp battery no trouble at all with 14 hours of sun every day.

I need a circuit that will charge the battery then stop charging when the battery is fully charged. I have no clue how this is done? This is the only ideas I have?

**broken link removed**?

 

[MikeMl]

Go buy a commercial solar charger. Your batteries will thank you.

 

[gary350]

Go buy a commercial solar charger. Your batteries will thank you.

I spent an hour searching for one. I guess I dont know the official correct name. I keep finding 1000s of cell phone solar chargers, ipod solar chargers, car battery cigerette lighter solar charger, laptop solar charger, tablet solar charger, every thing under the sun but what I want. Maybe it is called solar voltage regulator or solar voltage controller?

**broken link removed**

 

[tronitech]

Try searching "Solar Panel Regulator Charge Controller". I think this is what you seek?

 

[k7elp60]

Or use solar charge controller. Here is a link
https://www.amazon.com/XCSOURCE®-In...7&sr=8-1&keywords=12v+solar+charge+controller

 

[rfranzk]

I agree with Mike, commercial charge controllers are constantly improving and with MPPT (Multi Point Power Tracking) are very efficient even on low sun days. They are relatively inexpensive considering the features included like low voltage load disconnect. MPPT allows for a higher voltage input so you could wire the panels in a combination series parallel configuration for a higher voltage input then the controller will maximize the watts available for the most efficient use depending on needs and available sun. With lower voltage panels in low sun they cannot develop the needed voltage to effectively charge batteries. I have used a couple of different Morning Star controllers with good success. Something like this. https://www.morningstarcorp.com/product_category/mppt-charge-controllers/
It wouldn't hurt to purchase a higher watt controller for potential upgrades to your system in the future. Have fun with your project.

 

[crutschow]

........................
.................. 9 panels in parallel will give be 135 watts this should charge a 1000 amp battery no trouble at all with 14 hours of sun every day.
.........................

What is this 1000 amp battery?
Standard automobile types have a storage rating of around 100AH to 200AH.

 

[Nigel Goodwin]

What is this 1000 amp battery?
Standard automobile types have a storage rating of around 100AH to 200AH.

Fairly obviously not just ONE battery, but a bank of them - standard practice for solar arrays.

However, as usual, his imagined output from the panels is probably rather optimistic - but I presume he is from a fairly sunny place?.

 

[Tony Stewart]

I was assuming the 1000 A battery was just CCA rating for a starter battery for cars , in other words the Cold Cranking Amp rating.
These are not suitable for many long cycles of charge discharge due to the thin plate design , but are cheap and dirty.
The weight of a dry battery will tell you something about its plate lead content.

For a 135 W charger @ 14.2V max or 10A, and 14.2 being 77% of the 18.5 Voc, it is already well matched for MPT. Cloudy day Voc will drop to 17.5V then this ratio of 81% is still well within MPT range.

Generally chargers are CV limiters like alternators in cars set to 14.2V since the 1000 CCA rating far exceeds the 10A capacity of source.

You don't want to discharge your battery less than 11.5V for low current load voltage but startup surge from the SS inverter is allowed drag it down ( 7V for 1000A or much lower A if discharged or 0% SoC)

These are the general rules around a good battery charger, in addition to protection for reverse voltage, shorts and load dumps.

When the charger is switched off the float voltage will drop 1.7V so you need hysteresis in sensing if you choose a cheap relay On-OFF control method.
A linear method at 10A and 2.5V drop will not work well as it dissipates 25W.
The better approach used in regulators is a hysteretic PWM voltage regulator or a SMPS.

You can buy a board off EBAY for $10~$30 or roll your own for giggles and kicks for $10 if you know how. More if you don't.

https://www.ebay.ca/itm/10A-Solar-C...619?pt=LH_DefaultDomain_0&hash=item2c99a41223
https://www.ebay.ca/itm/10A-12V-24V...253?pt=LH_DefaultDomain_0&hash=item1c46aae565

Note that these cheap regulators don't use any magnetics or MPPT, so the current will be pulsed, EMI may be abundant in the AM band but it works hey for $8 ~$12 + shipping and has digital features.

 

[shokjok]

You'll find solar recharging circuits at **broken link removed** .
My bike trailer uses a single 25W solar panel ( from Princess Auto stores in Canada) to recharge a 235 CA gel cell, that keeps the radio alive for about five hours before the radio acts up or fades away.

 

[Tony Stewart]

I used to love PrincessAuto. It's like a testosterone store for gadgets.
**broken link removed** has many interesting circuits, but nothing useful > 6A/

 

[gary350]

This one will probably work it is only $10 with free postage from china.