Renogy DC DC Charger w/ MPPT

[NelsonB]

Thanks for the info, guys! I re-watched Will's video and realize that part of my confusion stems from the fact that this unit limits the solar array to 25 volts. Since (when the alt. is charging at all) the solar array is limited to input a max of 25 amps - both being 25 - I was confused. Now I understand the 25 (and possibly 50) amp thing, I'm a little disappointed that the PV array is limited to 25v due to the wiring size requirements dictated by this.

 

[Ranger1/75]

Here is a quick diagram of how you would do it. Make sure you have a relay rated for at least 20% more than your max amps. Common "Bocsh" relays are typically 40 amps but have seen some that were 30. Make sure the Ignition switch + is only on when the key is in the Run position, not also in the accessory position.

View attachment 29555

You couldn't have made it more easy for me to understand. Thank you!

 

[UncleTodo]

So after reading through the entire thread, here's my take on the gist:
Unit limits current from one input if any current is sensed from the other input
Can drain starter battery if house battery is low
LFP float voltage is high, adjustable w/BlueTooth module

There were some other things popping up like solar input & wiring etc, but above stood out as feature flaws.
Thanks to ChevyMike, seems all above can be alleviated with either ignition or toggle activated relays, one for solar and one for alternator.
Driving, want full alternator power? Disconnect solar.
Parked, don't want to chance draining starter battery? Disconnect alternator.
House battery fully charged? Disconnect either active input or both to avoid high float and BT purchase.

BT module seems to be wonkily hit or miss at best, plus I'd rather just have a control panel or just switches. I'm fine without something that needs another app.
I wish I could swing a RedArc, but my budget is definitely not robust enough for that.

Also, to clarify, in going with this unit, you need to make sure you're house battery can be charged at 50 amps, and as well your alternator can sustain a 50 amp load, yes?

 

[dvspl]

So after reading through the entire thread, here's my take on the gist:
Unit limits current from one input if any current is sensed from the other input
Can drain starter battery if house battery is low
LFP float voltage is high, adjustable w/BlueTooth module

There were some other things popping up like solar input & wiring etc, but above stood out as feature flaws.
Thanks to ChevyMike, seems all above can be alleviated with either ignition or toggle activated relays, one for solar and one for alternator.
Driving, want full alternator power? Disconnect solar.
Parked, don't want to chance draining starter battery? Disconnect alternator.
House battery fully charged? Disconnect either active input or both to avoid high float and BT purchase.

BT module seems to be wonkily hit or miss at best, plus I'd rather just have a control panel or just switches. I'm fine without something that needs another app.
I wish I could swing a RedArc, but my budget is definitely not robust enough for that.

I think you've summarized the feature flaws very nicely. The BT module is very wonky as you've said, but does allow you to customize some of the settings.

Also, to clarify, in going with this unit, you need to make sure you're house battery can be charged at 50 amps, and as well your alternator can sustain a 50 amp load, yes?

The max charge current can be set lower using the BT module. I have set mine to 30 amps and it did limit the charge correctly.

 

[Orchid]

Will wrote "This charger can handle 600 watts of solar power no problem, but stick with 400 watts so that the mc4 wires and adapters current limitations are not exceeded."
I have 600 watts of solar power, what do I need to know regarding the mc4 wires and adapters?

 

[Reed Cole]

You need to know the ampacity of the wires and adapters and compare that to the current your panels will produce.

 

[Pappion]

Does it boost the alternator voltage to charge the batteries? Specs are not clear.

 

[UncleTodo]

From what I gather It must to be able to charge LiFePO4.

 

[Ranger1/75]

I'm not sure if I have an issue or an unlisted feature. I wanted to run it by you guys. I have my set up wired almost exactly the same as Will has it on his website. Slight variations, but same outcome. When my house battery is fully charged, and the dcc50s is charging the starter battery via solar panels, I am observing current draw from my house battery when there is draw on the starter battery. For example, when I open my door and the interior cab lights come on, I can see the current coming out of my my house battery via Victron bvm712. When I put my foot on the brake pedal and the brake lights come on, when I turn my head lights on, etc., I can see the draw on my house battery. This happens when the truck is in the off, accessory, and on position, but not when the truck is running. When I start my truck, I can see a spike of about 20A drawn from the house battery, then the charger starts charging the house battery from the alternator. The dcc50s seems to be assisting the starter battery with the use of the house battery, when charging the starter battery via Solar (Indicated by the flashing red light next to the alternator symbol). My assumption is that if the draw on the starter battery exceeds what the solar is putting out, it takes power from the house battery. I'm not sure if this is a bad thing or a good thing. Is this a feature, or do I have a bad unit? Technically it is battery isolation, but the charger is charging the starter battery via the house battery. Thoughts?

 

[Reed Cole]

I'm not sure if I have an issue or an unlisted feature. I wanted to run it by you guys. I have my set up wired almost exactly the same as Will has it on his website. Slight variations, but same outcome. When my house battery is fully charged, and the dcc50s is charging the starter battery via solar panels, I am observing current draw from my house battery when there is draw on the starter battery. For example, when I open my door and the interior cab lights come on, I can see the current coming out of my my house battery via Victron bvm712. When I put my foot on the brake pedal and the brake lights come on, when I turn my head lights on, etc., I can see the draw on my house battery. This happens when the truck is in the off, accessory, and on position, but not when the truck is running. When I start my truck, I can see a spike of about 20A drawn from the house battery, then the charger starts charging the house battery from the alternator. The dcc50s seems to be assisting the starter battery with the use of the house battery, when charging the starter battery via Solar (Indicated by the flashing red light next to the alternator symbol). My assumption is that if the draw on the starter battery exceeds what the solar is putting out, it takes power from the house battery. I'm not sure if this is a bad thing or a good thing. Is this a feature, or do I have a bad unit? Technically it is battery isolation, but the charger is charging the starter battery via the house battery. Thoughts?

View attachment 30843

I don't have one of those units but if we assume the charger is connecting the starter battery to the house battery in parallel in order to charge the starter battery then it makes sense that current would be drawn from both batteries.

It would be nice if turning the ignition on would disconnect the batteries, with the ability to connect if desired for a jump start. But it sounds like the batteries are disconnected when the starter battery reaches a high enough voltage.

 

[UncleTodo]

Not necessarily, in the case of a previous post, dude had his starter battery drain attempting to charge the house battery.
While the system seems to be generally decent, if you look above at my previous post 503 you'll see a quick rundown.
I myself haven't purchased yet and am thinking I'll try the Kisae DMT1250 over this.

 

[Ranger1/75]

I think you've summarized the feature flaws very nicely. The BT module is very wonky as you've said, but does allow you to customize some of the settings.

The max charge current can be set lower using the BT module. I have set mine to 30 amps and it did limit the charge correctly.

I have the Renogy BT-2 module paired with the DCC50S & previously the DCC30S. Where did you find a setting for altering the charging current (Amps). Attached is a screen shot from the "Renogy BT" App. I also have the Renogy "DC Home" app. All the settings are based on volts, not Amps. If you can point me to additional settings I'd appreciate it.

 

[Ranger1/75]

I have some clarification on what you've read/watched based on my experience with these units. I had the dcc30s previously, dcc50s currently.

So after reading through the entire thread, here's my take on the gist:
Unit limits current from one input if any current is sensed from the other input

The unit limits current from the alternator to 25A if any solar input is detected or 15A with the dcc30s. Nothing is reduced from the solar input.

Can drain starter battery if house battery is low

If the ignition signal input (IGN) wire is wired into your fuse box using an add a fuse, on a circuit that is ONLY hot when the car is in the on position, you will not discharger your starter battery unless you are sitting parked, engine not running, with the key in the ignition on position. That would kill anyones battery. That's the same as leaving any accessory on while the car isn't running. That only applies to newer vehicles with smart alternators. I can not speak to a old school alternator setup, not using the (IGN) wire. Don't confuse ignition on with a circuit that is hot when in the accessory position. Otherwise you can't sit in your car and listen the radio while sitting in the car without the charger draining your starter battery.

LFP float voltage is high, adjustable w/BlueTooth module

This is correct. You can adjust many charging parameters with the BT-2. It's pretty worthless for monitoring the battery. You need a true battery monitor for that purpose.

There were some other things popping up like solar input & wiring etc, but above stood out as feature flaws.
Thanks to ChevyMike, seems all above can be alleviated with either ignition or toggle activated relays, one for solar and one for alternator.
Driving, want full alternator power? Disconnect solar.

Correct. Or drive at night

Parked, don't want to chance draining starter battery? Disconnect alternator.

This should not happen if you wire the (IGN) wire into a circuit that is only hot when the vehicle is On/running.

House battery fully charged? Disconnect either active input or both to avoid high float and BT purchase.

For me the BT was a must for lowering the voltage for float and boost. I keep them both at 14V.

BT module seems to be wonkily hit or miss at best, plus I'd rather just have a control panel or just switches. I'm fine without something that needs another app.
I wish I could swing a RedArc, but my budget is definitely not robust enough for that.

I'm not pushing for this unit at all, but you only need the app to adjust your charging settings. Once you find your sweet spot, you won't open the app again. Set it and forget it. Now my victron BVM-712. That's another story. I constantly use the victron connect app. It would be nice if there was a display, or some dip switches to be able to make adjustments on the unit, but the way it is currently made, does lower the cost for the average person who is ok with the default battery type parameters.

Also, to clarify, in going with this unit, you need to make sure you're house battery can be charged at 50 amps, and as well your alternator can sustain a 50 amp load, yes?

This makes sense, however my battery can accept 50A. So I don't know if the charger would auto detect the resistance and adjust to a battery that can't, or if the battery's BMS would just shut down to protect the battery.

 

[Ranger1/75]

I don't have one of those units but if we assume the charger is connecting the starter battery to the house battery in parallel in order to charge the starter battery then it makes sense that current would be drawn from both batteries.

It would be nice if turning the ignition on would disconnect the batteries, with the ability to connect if desired for a jump start. But it sounds like the batteries are disconnected when the starter battery reaches a high enough voltage.

The batteries are isolated from one another. Not in parallel. There is a charger between them in this system.

 

[Reed Cole]

Not necessarily, in the case of a previous post, dude had his starter battery drain attempting to charge the house battery.
While the system seems to be generally decent, if you look above at my previous post 503 you'll see a quick rundown.
I myself haven't purchased yet and am thinking I'll try the Kisae DMT1250 over this.

Sounds like a smart choice.

 

[Reed Cole]

The batteries are isolated from one another. Not in parallel. There is a charger between them in this system.

Yeah, but it sounds like the charger connects the two batteries in parallel WHEN the house battery is full in order to charge the starter battery.

Can't imagine any other explanation for why your house battery monitor would detect current drawn by circuits connected to your starter battery.

 

[dvspl]

I have the Renogy BT-2 module paired with the DCC50S & previously the DCC30S. Where did you find a setting for altering the charging current (Amps). Attached is a screen shot from the "Renogy BT" App. I also have the Renogy "DC Home" app. All the settings are based on volts, not Amps. If you can point me to additional settings I'd appreciate it.

Well, I don't currently have access to the unit to look for how I set that max charging current. But I set it using the DC Home app connected to the BT-2 module while the alternator was charging the house batteries. I should be able to look again during the week after Christmas so will post another reply after I have a chance to look.

 

[linkcat]

Hi, I have a Sprinter 2016 with smart alternator (E33 Battery management on VIM datacard). I know I have to install it with the ignition wire to a positive (only on when the engine is running), my question is:

1. If I put a switch inline the smart alternator wire to the DCC50S, in theory I will be able to disconnect the alternator charging (what I want to be able to make). What I'm thinking is, if the DCC50S detects no volts on the wire (ignition wire) but detects an increase of the voltage of the main battery, it can "think" that I don't have a smart alternator and start charging the leisure battery even with the ignition wire OFF?

 

[Reed Cole]

Hi, I have a Sprinter 2016 with smart alternator (E33 Battery management on VIM datacard). I know I have to install it with the ignition wire to a positive (only on when the engine is running), my question is:

1. If I put a switch inline the smart alternator wire to the DCC50S, in theory I will be able to disconnect the alternator charging (what I want to be able to make). What I'm thinking is, if the DCC50S detects no volts on the wire (ignition wire) but detects an increase of the voltage of the main battery, it can "think" that I don't have a smart alternator and start charging the leisure battery even with the ignition wire OFF?

Yes it should begin charging whenever it senses a high enough voltage from the starter battery. A switch or relay on the positive wire from the starter battery to the input of the charger would work though.

 

[Ranger1/75]

I found it. Thanks for bringing its existence to light.

Well, I don't currently have access to the unit to look for how I set that max charging current. But I set it using the DC Home app connected to the BT-2 module while the alternator was charging the house batteries. I should be able to look again during the week after Christmas so will post another reply after I have a chance to look.