Are you wondering can you charge a lithium ion battery with a solar panel? As usual this brings up many other questions such as; What type of solar panel can charge the battery? Or What is a lithium ion battery? And do I need a solar charge controller to charge it?
You might want to swap out your existing lead acid battery bank with a LiFePO4 alternative. But you are unsure if your existing solar panels will work. Or you might be contemplating a new installation but are used to working with lead acid. And want to know if a different type of solar panel should be used with lithium.
You might have an existing installation. But you want to know if a lithium battery will slip in right next to an existing lead acid battery bank. Let’s see if we can answer some of these questions
Can You Charge A Lithium Ion Battery With A Solar Panel?
“Yes, any solar panel can charge a lithium ion battery and what’s more, charging will be quicker. This is because compared to lead acid batteries it is up to five times faster. Not only is the charge rate quicker, the whole capacity rating is usable. A lead acid battery can only be discharged to 50%. If it is discharged below that regularly it will become damaged and it’s lifespan will be shortened”
Take a 60Ah hour lead acid battery for example. Because of the 50% rule it would only be able to use half of it’s amp hours. In this case that would be 30Ah otherwise you would risk damaging the battery. But if it were a lithium ion battery the full 60Ah would be available to use with no adverse effects.
Then there is the whole life cycle thing. I know there is a big price difference between lead acids and lithium batteries. But 500 cycles for some lead acid compared to 4,500 plus for lithium batteries has got to make you think. Am I throwing money down the drain buying new lead acid batteries?
I know this might be a problem if you have an existing lead acid battery bank. Because a LiFePO4 might not be the best replacement battery idea to drop into your battery bank. When lots of manufacturers do not recommend it.
Do I Need A Solar Charge Controller To Charge A Lithium Ion Battery?
Absolutely yes you do need a solar charge controller to charge any 12V battery with a solar panel. Except for a portable power station/generator as it should have one built-in along with an inverter. Even completely off-grid residential installations need a solar charge controller.
Charging a battery without a controller will put your expensive battery at risk. Leaving your pocket feeling extremely painful. Not only can you damage the cells you can completely destroy the battery.
Fortunately lithium ion batteries have a battery management system (BMS) to prevent overcharge. But I have heard the odd horror story. A solar charge controller is a must-have piece of kit in any solar setup.
A good quality solar controller will help keep a lithium ion battery safe. And will make the charging process more efficient
What types of solar charge controllers are there?
The general types of solar charge controllers are;
PWM – Pulse-Width Modulation and MPPT – Maximum Power Point Tracking
I am not going to go into the ins and outs of each type here.
But MPPT are the most efficient type of controllers. They do cost more than PWM controllers but are better used with lithium ion batteries. This is because you will want to achieve the most efficient performance you can.
What sort of protection can I expect from a solar charge controller?
You will need to check if the controller will charge a lithium ion battery. Some do not. But you can usually find this information in the manufacturer’s specifications.
A typical controller will provide protection such as;
- Low Voltage
- Over- Discharging
- Reverse Polarity
- Reverse Current
Do not be tempted to buy a cheap controller because lithium ion batteries are expensive. You do not want to be left out of pocket by using an inferior controller to save a few dollars.
What Type Of Solar Panel Can Charge A Lithium Ion Battery?
Any type of solar panel will charge a lithium ion battery as long as you use a charge controller. (Sorry there I go again banging on about controllers).
They can be used with;
- Rigid solar panels
- Flexible solar panels
- Portable solar panels (briefcase/suitcase)
- Bifacial solar panels
The solar panel wattage doesn’t matter. But the higher the solar panel wattage the faster they will charge a lithium ion battery. The higher the wattage of a solar panel array the faster it will charge a lithium ion battery bank.
So there isn’t any different type of solar panel that will perform better with lithium batteries than another. Apart from the solar panels wattage output and efficiency. As far as that goes monocrystalline is the obvious choice.
Although at the time of writing recent developments in solar cell and material technology have put that in doubt. These developments might make monocrystalline panels obsolete because of Perovskite solar cells. Some tests have reported efficiency of up to 30%.
Will Perovskite solar panels make monocrystalline the polycrystalline panels of the future? Only time will tell.
What Is A Lithium Ion Battery?
Lithium Iron Phosphate (LiFePO4) is a naturally occurring mineral. It has great thermal stability, high energy density and is non-toxic. Lithium ion batteries come in all different shapes, sizes and amp hour (Ah) capacities. But they all have things in common which are big advantages over lead acid types.
- Their life cycles are higher
- They have battery management systems
- They can be installed horizontally or vertically
- They are lighter
- They can charge up to 5 times faster
- They are stable at high temperatures
- They are more environmentally friendly
What are the uses of a lithium ion battery?
Lithium ion batteries can be used to power almost anything from the coffee maker in your RV to a forklift truck. I doubt you will be powering a forklift truck anytime soon. Unless you are a lift truck driver of course.
The main uses you would use them for are;
- In an recreational vehicle
- A motorhome
- A camper van
- A Trailer or caravan
- A boat
- A yacht
- An outbuilding such as a shed or garage
- A holiday chalet or cabin
- A home where there isn’t enough roof space for large residential solar panels
- If you are renting and want to reduce your power bills
- If you want your business to become more energy self-sufficient
- If you want to be generally more environmentally friendly
The batteries usually have capacities between 50Ah and 300Ah. (I know there are larger batteries but these are normally reserved for household use). Depending on the manufacturer they can be connected together in series or parallel. This enables you to put together a pretty powerful battery bank.
But best of all because the battery life cycle is 4000 plus. The battery bank is going to last a long long time. For example a 400Ah battery bank with a usage (discharge) of 200Ah 365 days per year. Would be expected to work efficiently for 10 years plus. If you used it for half of that time it would be 20 years plus.
And because they are virtually maintenance free. You will only have to give them the once over now and again. Just to check the wiring and for corrosion at the terminals. Together with the appropriate solar panel wattage output, solar charge controller and inverter. A complete self sustaining, eco-friendly and energy bill reducing system can be put together.
My Closing Thoughts
I hope I managed to answer some of your questions about charging a lithium ion battery with solar panels. Their long lifespan and advantages over lead acid batteries make their choice a no-brainer. The only thing that might put you off is the cost.
But if you weigh it up dollar for dollar. I think you will find if it is within your budget lithium batteries are a sensible choice. There is nothing more tiresome than having to change batteries. Even having to do so for your TV remote can drive you nuts. I always try to use a certain make of lithium battery to save the pain ha ha
For further reading take a look at my
The review includes; How the 12V 100Ah battery works, pros and cons, other LiFePO4 batteries in Renogy’s range. And comparison with the Battle Born GC2 100Ah
I hope you enjoyed this post and have found it helpful. If you have any questions about charging a lithium ion phosphate battery with a solar panel. Or want to leave your own personal review, please feel free to leave a comment below.