Advice with adding solar panels and 240v to charge lithium batteries on renogy dc-dc system

[caz]

Advice with adding solar panels and 240v to charge lithium batteries on renogy dc-dc system

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• Start dateToday at 9:20 AM

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caz​

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Hi guys, I have just recently purchased a ute with a dc-dc system. Unfortunately the owner could not give me much information on the set up. I am trying to work out alternative ways to charge my batteries while not driving or only driving short distances as I do not have solar yet. I'm running two lithium batteries in parallel (260ah) through a renogy 30ah dc-dc which I am pretty certain has a built in regulator and input for solar. Does this mean that if I attach a solar panel it should be one without its own regulator? Unless I attach it directly to the batteries then it should have its own regulator? I do also have two batteries under my bonnet, my starter battery and a deep cycle. The deep cycle apparently powers all the extra lights etc around the ute and switch in the cab.

I also have an Anderson plug coming off the back of the ute, how can I tell if I can attach a solar panel via Anderson plug to that? Alsof I buy a 240v battery charger what amperage would I need? And any recommendations on brand etc. I have a few more questions regarding solar and my set up but would be great to get some comments on these initial queries cheers and thanks

 

[Rocketman]

No one here can tell for sure the way your system is wired. Yes we will have guesses, if it was wired as expected…, etc.

You will need to get a DMM digital multimeter and “trace” wires. Also get the owners manual for each piece of equipment and understand it.

Draw yourself a diagram for the way your system is wired to refer to in the future.

My guess - you can attach _____w of solar to the Renogy dc-dc charger (look the watts up). It is a SCC (solar charge controller). If you want to add more solar you can add another SCC to your system.

Once you tell me where the Anderson Plug wires goes then we will both know what it is for. Some people will use those plugs for ground mounted solar - other people use it as a power plug - so it has 12v pos &neg.

Good Luck

 

[caz]

No one here can tell for sure the way your system is wired. Yes we will have guesses, if it was wired as expected…, etc.

You will need to get a DMM digital multimeter and “trace” wires. Also get the owners manual for each piece of equipment and understand it.

Draw yourself a diagram for the way your system is wired to refer to in the future.

My guess - you can attach _____w of solar to the Renogy dc-dc charger (look the watts up). It is a SCC (solar charge controller). If you want to add more solar you can add another SCC to your system.

Once you tell me where the Anderson Plug wires goes then we will both know what it is for. Some people will use those plugs for ground mounted solar - other people use it as a power plug - so it has 12v pos &neg.

Good Luck

Thankyou for you reply. If the Anderson plug in question is for ground mounted solar, would I be correct in assuming that, if within the correct wattage, that panel would not require it's own SCC?

 

[Rocketman]

My GUESS is because they did not put solar panels on the roof - they ran the solar wires from the Renogy Dc-dc charger to the Anderson connector for ground mounted solar.

Could I be wrong - 50-50 chance…

Trace the wires from the Renogy charger (solar input and see where they go.

Now IF they go to the Anderson plug, then you need to look in the manual of the Renogy charger to see what specs of panels it can handle.

I put panels on the roof of my RV - they are always there collecting the sun rays. So that’s where I would put panels first. But grind mounts are nice because you can move them as the sun moves.

 

[caz]

My GUESS is because they did not put solar panels on the roof - they ran the solar wires from the Renogy Dc-dc charger to the Anderson connector for ground mounted solar.

Could I be wrong - 50-50 chance…

Trace the wires from the Renogy charger (solar input and see where they go.

Now IF they go to the Anderson plug, then you need to look in the manual of the Renogy charger to see what specs of panels it can handle.

I put panels on the roof of my RV - they are always there collecting the sun rays. So that’s where I would put panels first. But grind mounts are nice because you can move them as the sun moves.

I will see if I can trace the wires back. I believe you can remove the side panels of the renogy to see where the wires run to, but the whole system is built into a protective box and I can't trace the cables in behind the dcdc. Would I be able to check which cables connected to the dc-dc are from the Anderson, by connecting a long bit of wire from the Anderson and doing a continuity check on my dmm at the dc-dc connection?

 

[caz]

I will see if I can trace the wires back. I believe you can remove the side panels of the renogy to see where the wires run to. Would I be able to check which cables connected to the dc-dc are from the Anderson, by connecting a long bit of wire from the Anderson and doing a continuity check on my dmm at the dc-dc connection?

Apparently the guy who owed the ute previously, just connected a panel directly to the batteries

 

[Rocketman]

Apparently the guy who owed the ute previously, just connected a panel directly to the batteries

That is not a practice I would do.

Also you will need to get comfortable opening the panel to figure stuff out & to attach solar wires to the Renogy dc-dc charger to connect to your panels. If a human put it together another can pull it apart to fix it and figure it out. Yes a long wire to verify that a wire goes where you think it does is a good practice. (Just make sure there is no voltage on that wire)

Also, above you asked about buying a battery charger…. Make sure it is a lithium charger.

As for how many amps- your choice. (Do You have two lithium batteries at 260ah each - for a total of 520ah - or two batteries that together have 260ah?). The max you want to charge a battery bank is .2C (20% of the amp hour limit) - unless your bms limits you to less than that. That’s a max rate of either 52 amps or 104amps.

Either way that’s a big charger. So you will probably be getting a smaller one than that. The only difference will be how long it takes to put energy into the battery- a 40a will go 2x as fast as a 20a - which will be much faster than a 10a. A lot depends on when you will use the charger.

On the road trying to get as much juice into the battery as fast as possible - get the bigger charger.
At home when it will sit for a week in between weekend trips - save money get the smaller charger.

 

[caz]

That is not a practice I would do.

Also you will need to get comfortable opening the panel to figure stuff out & to attach solar wires to the Renogy dc-dc charger to connect to your panels. If a human put it together another can pull it apart to fix it and figure it out. Yes a long wire to verify that a wire goes where you think it does is a good practice. (Just make sure there is no voltage on that wire)

Also, above you asked about buying a battery charger…. Make sure it is a lithium charger.

As for how many amps- your choice. (Do You have two lithium batteries at 260ah each - for a total of 520ah - or two batteries that together have 260ah?). The max you want to charge a battery bank is .2C (20% of the amp hour limit) - unless your bms limits you to less than that. That’s a max rate of either 52 amps or 104amps.

Either way that’s a big charger. So you will probably be getting a smaller one than that. The only difference will be how long it takes to put energy into the battery- a 40a will go 2x as fast as a 20a - which will be much faster than a 10a. A lot depends on when you will use the charger.

On the road trying to get as much juice into the battery as fast as possible - get the bigger charger.
At home when it will sit for a week in between weekend trips - save money get the smaller charger.

Thanks again for your reply. I took the side panel of the dcdc and there actually isn't a cable attached to the PV connection

 

[caz]

That is not a practice I would do.

Also you will need to get comfortable opening the panel to figure stuff out & to attach solar wires to the Renogy dc-dc charger to connect to your panels. If a human put it together another can pull it apart to fix it and figure it out. Yes a long wire to verify that a wire goes where you think it does is a good practice. (Just make sure there is no voltage on that wire)

Also, above you asked about buying a battery charger…. Make sure it is a lithium charger.

As for how many amps- your choice. (Do You have two lithium batteries at 260ah each - for a total of 520ah - or two batteries that together have 260ah?). The max you want to charge a battery bank is .2C (20% of the amp hour limit) - unless your bms limits you to less than that. That’s a max rate of either 52 amps or 104amps.

Either way that’s a big charger. So you will probably be getting a smaller one than that. The only difference will be how long it takes to put energy into the battery- a 40a will go 2x as fast as a 20a - which will be much faster than a 10a. A lot depends on when you will use the charger.

On the road trying to get as much juice into the battery as fast as possible - get the bigger charger.
At home when it will sit for a week in between weekend trips - save money get the smaller charger.

The lithium batteries are 260ah in Total. I am pretty remote at the moment in Australia being 4.5 hours return from the closet auto store. But will look at all my options for PV and 240v chargers during the silly season sales. Thanks for your advice Rocketman

 

[Rocketman]

Just make sure you understand the constraints of the solar part of your DcDc charger - and buy accordingly. If unsure ask a question here…