Solar Brainiacs Needed! I got a question....

[Jim SoG]

I bought a flexopower lithium 444 power station which can be charged by solar with a max of 120w. So my question is, if I wanted to charge a regular battery and this Lithium, could I use larger panel, say 2oow and get a charge controller?

Jim
solar thinking makes my head hurt...LOL

 

[old_man]

Let me shed some light on this...ha ha. A charge controller does nothing to change the solar panel output. It only limits the maximum voltage that could applied to the battery and limits the current allowed to flow into the batteries. Charging two batteries of different types and charge parameters at the same time off of the controller will not work. You might get by with two charge controllers, but I foresee problems getting them to play well together. I say, either charge one until fully charged, then switch to the other, along with changing any needed parameters, or do two separate systems. I guess in a poor mans solution, you could run a battery charger for the second battery, from an inverter connected to the first battery, while it was being charged. You would waste a lot of power in all of the conversions, but it would work.

 

[old_man]

Yes you can charge a battery directly from a solar panel. You can also overcharge a battery directly from a solar panel, destroying it. Also, if you don't at least put a diode in series with the panel, you can also discharge a battery directly to a solar panel.

Charge controllers can be had for less than $30.

 

[old_man]

Let me shed some light on this...ha ha. A charge controller does nothing to change the solar panel output. It only limits the maximum voltage that could applied to the battery and limits the current allowed to flow into the batteries. Charging two batteries of different types and charge parameters at the same time off of the controller will not work. You might get by with two charge controllers, but I foresee problems getting them to play well together. I say, either charge one until fully charged, then switch to the other, along with changing any needed parameters, or do two separate systems. I guess in a poor mans solution, you could run a battery charger for the second battery, from an inverter connected to the first battery, while it was being charged. You would waste a lot of power in all of the conversions, but it would work.

The root problem here is that the two batteries have different chemistries, voltages, and charge profiles.

 

[Roam_CO85]

Would it be like tying a couple batteries together? Making a bigger battery cell? Like a tractor or a diesel pickup or someone adding another cell

 

[Roam_CO85]

So if you had 3 batteries tied together on a inverter and had solar recharging those deep cell batteries you could cook those batteries?

I bet having two different types that would throw a chink in the chain

 

[Jim SoG]

Ok I think I am getting it, I will need to do 2 systems or do 1 battery at a time to be safe....

Appreciate the brain cells guys!

Jim

 

[Mogwai]

Ok I think I am getting it, I will need to do 2 systems or do 1 battery at a time to be safe....

Appreciate the brain cells guys!

Jim

I wouldn't give up that easy. Try the Redarc, not cheap but should do the trick. Will take input from an alternator and/or solar, and has the ability to charge different battery types at the same time, each with the proper charge profiles. Dual Input 25A In-vehicle DC Battery Charger

 

[Jim SoG]

Ok now I got another related question just to be clear about what I read above.......

My Litium444 has a max of 120w input so I can get say a 180w panel and a charge controller that will limit the watts going to my 444 down to 120? Am I getting that correct? If so then I can use the panel for other solar charging (no 444 battery hooked up) jobs and that would be cool.....

Appreciate all you guys trying to educate me, I am a bit slow........LOL


Jim

 

[Mogwai]

Ok now I got another related question just to be clear about what I read above.......

My Litium444 has a max of 120w input so I can get say a 180w panel and a charge controller that will limit the watts going to my 444 down to 120? Am I getting that correct? If so then I can use the panel for other solar charging (no 444 battery hooked up) jobs and that would be cool.....

Appreciate all you guys trying to educate me, I am a bit slow........LOL


Jim

I don't think you need to worry about the 120W input if you use a smart controller like posted above, or this one.

Edit: I don't know why the link won't work but search this on Amazon: Renogy 20A DC to DC Battery Charger for Flooded, Gel, AGM, and Lithium Batteries Using Multi-stage Charging


If you had more solar than you needed you could could be simultaneously charging main car battery, etc... If the battery doesn't need a charge the charge controller should cut the charge.

 

[old_man]

Ok now I got another related question just to be clear about what I read above.......

My Litium444 has a max of 120w input so I can get say a 180w panel and a charge controller that will limit the watts going to my 444 down to 120? Am I getting that correct? If so then I can use the panel for other solar charging (no 444 battery hooked up) jobs and that would be cool.....

Appreciate all you guys trying to educate me, I am a bit slow........LOL


Jim

Pretty much. Charge controllers should be able to limit the charge current. Just beware, the panel says 180W. That is in ideal conditions rarely seen outside the lab. Over a days sunlight time, you will be lucky to average 100W.

 

[old_man]

I don't think you need to worry about the 120W input if you use a smart controller like posted above, or this one.

Edit: I don't know why the link won't work but search this on Amazon: Renogy 20A DC to DC Battery Charger for Flooded, Gel, AGM, and Lithium Batteries Using Multi-stage Charging


If you had more solar than you needed you could could be simultaneously charging main car battery, etc... If the battery doesn't need a charge the charge controller should cut the charge.

The issue with this is that you have to set the battery type with the dip switch. Both batteries would have to be the same.

 

[bmwguru]

I bought a flexopower lithium 444 power station which can be charged by solar with a max of 120w. So my question is, if I wanted to charge a regular battery and this Lithium, could I use larger panel, say 2oow and get a charge controller?

Jim
solar thinking makes my head hurt...LOL

A lot of good info can be found here. DIY Solar Power with Will Prowse

 

[Jim SoG]

That is a great series, thanks!

Jim

 

[Jim SoG]

Just got my Power pack, found iut it has a built in MPPT controller already....

Jim

 

[old_man]

So if you had 3 batteries tied together on a inverter and had solar recharging those deep cell batteries you could cook those batteries?

I didn't say that exactly. I said that tying a solar panel directly to a battery or multiple batteries can lead to problems. If you use a cheap charge controller, it solves the overcharge and discharge issue.

If you are tying multiple batteries in parallel, they all need to be of similar type. A normal wet cell automotive battery has a slightly different voltage than a lithium battery, or even an AGM in some instances. That means that due to the differences in voltage, the charge current will not be equally divided between the batteries.

Unequal charge current happens even with batteries having the same nominal voltage (battery type). The key there is that the one that has less charge will hog the current until the voltage of each battery becomes equal and then they will more or less equally share the current. This is a simplification but should suffice for this discussion.

This is exactly what happens when you jump start a battery. Both batteries have a voltage (related to the amount of charge) and since the "dead" battery has a lower voltage, it will actually get current from the fully charged battery. Ever wonder why starting the car with a good battery helps do the jump start faster? Think about what I have said. When a battery is being charged, you do that by hooking it to a voltage higher than itself, causing current to flow. The greater the difference in voltage the greater the current. So instead of the source battery having a nominal voltage of around 12 volts, when it is being charged, the alternator is actually boosting the voltage across the battery to between 13 and 15 volts. That higher charge voltage is then applied the dead battery and more current will flow.

A solar charge controller is very similar to the voltage regulator in your car. If any of you have had the voltage regulator fail, in one mode it can lead to overcharging and will boil (ruin) the battery.

 

[Roam_CO85]

I didn't say that exactly. I said that tying a solar panel directly to a battery or multiple batteries can lead to problems. If you use a cheap charge controller, it solves the overcharge and discharge issue.

If you are tying multiple batteries in parallel, they all need to be of similar type. A normal wet cell automotive battery has a slightly different voltage than a lithium battery, or even an AGM in some instances. That means that due to the differences in voltage, the charge current will not be equally divided between the batteries.

Unequal charge current happens even with batteries having the same nominal voltage (battery type). The key there is that the one that has less charge will hog the current until the voltage of each battery becomes equal and then they will more or less equally share the current. This is a simplification but should suffice for this discussion.

This is exactly what happens when you jump start a battery. Both batteries have a voltage (related to the amount of charge) and since the "dead" battery has a lower voltage, it will actually get current from the fully charged battery. Ever wonder why starting the car with a good battery helps do the jump start faster? Think about what I have said. When a battery is being charged, you do that by hooking it to a voltage higher than itself, causing current to flow. The greater the difference in voltage the greater the current. So instead of the source battery having a nominal voltage of around 12 volts, when it is being charged, the alternator is actually boosting the voltage across the battery to between 13 and 15 volts. That higher charge voltage is then applied the dead battery and more current will flow.

A solar charge controller is very similar to the voltage regulator in your car. If any of you have had the voltage regulator fail, in one mode it can lead to overcharging and will boil (ruin) the battery.

I see what your saying. You are talking about it being tied straight to a battery vs having a controller attached the circuit. .

This is one thing I know nothing about...glad there are people out there to ask. Ive had a voltage regulator fail and boil one before. I had my semi almost burn up because of that. Cooked all four of them. Also know if one of those terminals on all four batteries is loose the whole set up wont work properly

I have a trailer that has a winch that runs off a battery thats hooked to a solar panel that works really well but has a regulator on it.

I was just wondering if that was a realistic thing with a solar panel. I know the OP was talking about a normal battery and a lithium battery.

Learned a lot in this threat and thank you for explaining it.

 

[Jim SoG]

All great info here!

Jim