Lithium safe converter

[RickLight]

I think Jim may be correct on the wire gauge being the throttle/bottleneck on reaching anywhere close to fuse rating on charging the trailer battery from the TV alternator.

Unfortunately that's not the way electricity works. If too much current goes down a wire it will heat up, until it melts. A fuse is just an easily replaceable piece of wire that's skinnier than the rest of the wire.

[Guest]

Rick,

Agree if the load is excessive the wire would heat up (hopefully the fuse would blow first) but a wire that's small and excessively long will still have a larger voltage drop than a larger diameter cable of the same length.

Since the voltage from the TV can vary from 12V to 15V, charging from a straight connection at the 7 pin is not very robust.

Jim

[John303]

Thanks Guys,

It will be interesting to see what the 20amp Renogy will do while connected to my 7 pin connector. Its fused to 35amps. I'm getting close to installing the battery and chargers but its going to be a deep freeze in Michigan tomorrow night. And I de-winterized. LOL.
Honestly even if I only obtain 10 amps I would still be ok since my goal is to be able to control the charge rather than to rely on the battery BMS. I trust the BMS but like the idea of using it as a redundant system. Something else that I did not mention is how the TV can sometimes exhibit voltages over the 14.6V maximum for lithium charging and is another reason for the charger.......to keep the peak voltage to the battery at the 14.1V setting I am using.

Jim

Jim, did you ever get the 20 amp Renogy installed with your stock 7-pin connector? I too am venturing down this road and want to avoid running a huge charge cable from the truck battery back to the RV.

[Guest]

John303 John,

I did and it works perfectly. I wired in the ignition activation wire (referred to as D+) to the trailer marker light circuit to activate the charger. I did look into the wiring diagrams for my GMC truck and this showed my battery feed on the 7 pin connector was 35 amp. When I looked at the fuse that was installed it was 30 amp. I suspect the circuit is capable of 35 amp and protected to 30 amp? So the Renogy is running fine with the 30 amp fuse even though I had seen it peak at 27 amps on the input side when first activated. The Renogy from what I remember put out slightly more than 21 amps on a 50% discharged Lithium battery. I'm using the truck fuse for the entire circuit since this would be at the source and a 25amp fuse on the Renogy output. The ignition circuit or D+ is also fused at the truck on the marker or running lights fuse.
This has all been integrated along with the AC DC charger in the passthrough docking station.

Jim

[John303]

John303 John,

I did and it works perfectly. I wired in the ignition activation wire (referred to as D+) to the trailer marker light circuit to activate the charger. I did look into the wiring diagrams for my GMC truck and this showed my battery feed on the 7 pin connector was 35 amp. When I looked at the fuse that was installed it was 30 amp. I suspect the circuit is capable of 35 amp and protected to 30 amp? So the Renogy is running fine with the 30 amp fuse even though I had seen it peak at 27 amps on the input side when first activated. The Renogy from what I remember put out slightly more than 21 amps on a 50% discharged Lithium battery. I'm using the truck fuse for the entire circuit since this would be at the source and a 25amp fuse on the Renogy output. The ignition circuit or D+ is also fused at the truck on the marker or running lights fuse.
This has all been integrated along with the AC DC charger in the passthrough docking station.

Jim

Jim,

A question for you. When I look at the Renogy installation manual it seems they are calling for some good size wires even for the 20 amp model. From the front of my truck to the basement of the 303 must be 25-30ft, so it appears to call for something between 8 and 4 awg wire. My "trailer receptacle" fuse is 30 amp also. I just wanted to confirm that you made no modifications to the truck or trailer wiring, other than redirecting the current charge wire to the Renogy, and from the Renogy to the battery? I also see from the manual that you can modify the charge voltage from 14.0-14.6, which I am guessing would would also affect the current to the battery, as well as current from truck. What did you set your voltage to?

Thanks in advance.

[Guest]

Jim,

A question for you. When I look at the Renogy installation manual it seems they are calling for some good size wires even for the 20 amp model. From the front of my truck to the basement of the 303 must be 25-30ft, so it appears to call for something between 8 and 4 awg wire. My "trailer receptacle" fuse is 30 amp also. I just wanted to confirm that you made no modifications to the truck or trailer wiring, other than redirecting the current charge wire to the Renogy, and from the Renogy to the battery? I also see from the manual that you can modify the charge voltage from 14.0-14.6, which I am guessing would would also affect the current to the battery, as well as current from truck. What did you set your voltage to?

Thanks in advance.

John,

From the trailer wire connections at the frame of the trailer, I ran a dedicated 8 AWG marine grade tinned copper wire to the docking station and to the Renogy. If you want to do a test outside the rig, cut enough wire such as the 8 AWG, that would be able to connect to where your planning to mount the charger. Disconnect the trailer battery feed wire at the trailer frame and connect this to the 8 AWG and then to the Renogy. From the Renogy connect the output to a battery sitting on the ground and outside the rig. Run a jumper to the D+ terminal while monitoring the input current from the truck. Do this with the Lithium battery at 50% SOC or less so the Renogy will operate at its full 20 amp output.

I performed this driveaway test before installing my charger and wiring since the input current will be slightly higher than the output. Once I was convinced the 30 amp fused circuit could handle the load, the charger was installed with loomed 8 AWG wire.

I made no modification to the truck wiring. Also while I tested this with the truck running as well as off, I will use this charger only while running and underway. This way, as the truck is running, higher voltage will be provided which will lower the current demand to the Renogy and the alternator will have airflow while moving. I'm activating the Renogy with the trailer running lights which can be found in the docking station of the Imagine. White wire with blue stripe.

It is so cool to observe the Victron app on my phone while underway and to watch the charger kick in when I turn on the running lights. My Victron BMV712 is mounted in the front panel of the docking station and the reception from inside the truck has been good.


Jim

[FindingMyPlace]

Question to all in this thread: Has anybody looked into or tried to use the Tow Vehicle Alternator Charger Kit (Drop-In Lithium) that AMSolar have? I am still getting caught up on this overall challenge but it would seem that this would allow for drop in and negate any risk of power draw or strain on the TV. It won't charge as well as the DC to DC gear but might be a low budget way to ensure a good charge?
https://amsolar.com/rv-battery-accessories/98-altclitow

[howson]

Question to all in this thread: Has anybody looked into or tried to use the Tow Vehicle Alternator Charger Kit (Drop-In Lithium) that AMSolar have? I am still getting caught up on this overall challenge but it would seem that this would allow for drop in and negate any risk of power draw or strain on the TV. It won't charge as well as the DC to DC gear but might be a low budget way to ensure a good charge?
https://amsolar.com/rv-battery-accessories/98-altclitow

To directly answer your question: no. From my brief read of AMSolar's description of this setup it is more about isolating the two battery systems than it is charging the lithium. (I could be wrong.)

I tackled this issue by installing a DC-DC Charger. Long thread, but it has a lot of details: https://gdrvowners.com/forum/operati...e-battle-borns

Guest installed a 20A Renogy using the vehicle's 7-pin wiring (much less complicated). His information is also in that same thread but he may be able to provide more information if you're interested.

[Guest]

Battery manufacturers opinions will vary where its not a good idea to mix battery types in parallel IMO. Flooded lead acid batteries and Lithium batteries require different voltages where the Lithium battery will need a 14.3V input at the final stages of charging to properly balance the batteries cells.
Lithium batteries with their low internal resistance will accept high charge currents where this can put a much higher load on the vehicles alternator. This would not ordinarily be an issue except a high load at idle and just after cranking the TV can create a great deal of heat on the alternators diodes at idle.

To get around both cases, its best to use a DC DC charger such as the Renogy or other brand which will provide separation. This way, the TV lead acid battery is being handled through the ECU and TV alternator which will control the voltage levels for flooded lead acid batteries while the Renogy will simultaneously control the voltage levels that would be dedicated for lithium charging.
For system overheating, the engines control system will monitor alternator loads and will work to recover the lost energy from engine cranking and to also run accessories. The system can respond in several ways to protect the system but applying a large load such as charging a lithium battery bank and after an initial crank event can put undo stress on the alternator since airflow in minimized at idle. To handle this case, it would be best to activate the Renogys' D+ or ignition circuit by connecting to the RV running lights. This way the driver can activate the Renogy when the vehicle is in motion which will provide adequate cooling that would be provided at higher RPM and vehicle speed.

Jim

[Bupboy]

I have a Solitude 310GK-R with the solar option on order and am ordering two battleborn batteries to start. In emailing with battleborn, I asked for converter recommendation and they asked for the existing WFCO model number. Does anyone know or where I can find out?

Thanks, Jon

[bertschb]

I have a Solitude 310GK-R with the solar option on order and am ordering two battleborn batteries to start. In emailing with battleborn, I asked for converter recommendation and they asked for the existing WFCO model number. Does anyone know or where I can find out?

Thanks, Jon

Unless Grand Design has changed models, it's most likely a WF-9855. Many people who replace their two lead acid batteries with LiFePO4 batteries replace their WFCO charger/converter with the Progressive Dynamics PD-9160ALV. People who move to large battery banks will often get larger Victron units.

[Bupboy]

Thanks Brian

[John303]

John,

From the trailer wire connections at the frame of the trailer, I ran a dedicated 8 AWG marine grade tinned copper wire to the docking station and to the Renogy. If you want to do a test outside the rig, cut enough wire such as the 8 AWG, that would be able to connect to where your planning to mount the charger. Disconnect the trailer battery feed wire at the trailer frame and connect this to the 8 AWG and then to the Renogy. From the Renogy connect the output to a battery sitting on the ground and outside the rig. Run a jumper to the D+ terminal while monitoring the input current from the truck. Do this with the Lithium battery at 50% SOC or less so the Renogy will operate at its full 20 amp output.

I performed this driveaway test before installing my charger and wiring since the input current will be slightly higher than the output. Once I was convinced the 30 amp fused circuit could handle the load, the charger was installed with loomed 8 AWG wire.

I made no modification to the truck wiring. Also while I tested this with the truck running as well as off, I will use this charger only while running and underway. This way, as the truck is running, higher voltage will be provided which will lower the current demand to the Renogy and the alternator will have airflow while moving. I'm activating the Renogy with the trailer running lights which can be found in the docking station of the Imagine. White wire with blue stripe.

It is so cool to observe the Victron app on my phone while underway and to watch the charger kick in when I turn on the running lights. My Victron BMV712 is mounted in the front panel of the docking station and the reception from inside the truck has been good.


Jim

Well, it has been an interesting day. I decided to install the Victron Smart Isolated Tr 12-12/18 DC-DC charger https://www.victronenergy.com/dc-dc-converters/orion-tr%20smart. My thinking was that if you made a 20 amp charger work then an 18amp charger should be no problem. I made no changes to truck or trailer wiring, thinking that 10 gauge should be more than adequate. Even though truck/trailer do not have isolated grounds, from my research it should work without issue, just no isolation. The Victron model has bluetooth built in and lets you select various voltages to detect whether the truck is running. Right away I ran into issues where if the charger switched on the input voltage would drop to 8.6 volts and then lockout. In all my troubleshooting I discovered some interesting things.

1. Voltage of 13.8 at the battery
2. Voltage of 12.8 at the 7-pin connector in the truck. I was surprised that I lost a volt from the front of the truck to 7-pin, with the trailer disconnected.
3. Where I put my grounds from the Victron seemed to matter. Grounded at the thermal fuse on the basement wall my voltage was 10. Put the grounds on the battery terminal, and it was 12.8.
4. I could fiddle with the settings and force the charger to charge, giving me 21 amps from the truck, but 8.6 volts at the input. The Victron app lets you see voltages.

So Jim, when you were checking amps, did you by any chance happen to check voltage at the input to your Renogy? I think I can wire the Victron to turn on from the running lights, but I bought it thinking I would not have to do that. I have put about 6 hours into this trying to figure it out, and I am thinking that the 10awg just has to much voltage drop to use the "smarts" in the way it was intended.

If anybody has any insights, I would like to hear them.

Thanks.

[gbkims]

Well, it has been an interesting day. I decided to install the Victron Smart Isolated Tr 12-12/18 DC-DC charger https://www.victronenergy.com/dc-dc-converters/orion-tr%20smart. My thinking was that if you made a 20 amp charger work then an 18amp charger should be no problem. I made no changes to truck or trailer wiring, thinking that 10 gauge should be more than adequate. Even though truck/trailer do not have isolated grounds, from my research it should work without issue, just no isolation. The Victron model has bluetooth built in and lets you select various voltages to detect whether the truck is running. Right away I ran into issues where if the charger switched on the input voltage would drop to 8.6 volts and then lockout. In all my troubleshooting I discovered some interesting things.

1. Voltage of 13.8 at the battery
2. Voltage of 12.8 at the 7-pin connector in the truck. I was surprised that I lost a volt from the front of the truck to 7-pin, with the trailer disconnected.
3. Where I put my grounds from the Victron seemed to matter. Grounded at the thermal fuse on the basement wall my voltage was 10. Put the grounds on the battery terminal, and it was 12.8.
4. I could fiddle with the settings and force the charger to charge, giving me 21 amps from the truck, but 8.6 volts at the input. The Victron app lets you see voltages.

So Jim, when you were checking amps, did you by any chance happen to check voltage at the input to your Renogy? I think I can wire the Victron to turn on from the running lights, but I bought it thinking I would not have to do that. I have put about 6 hours into this trying to figure it out, and I am thinking that the 10awg just has to much voltage drop to use the "smarts" in the way it was intended.

If anybody has any insights, I would like to hear them.

Thanks.

Truck wiring differences?
My truck only has 14 Awg for +12 running from it's fuse box to 7-pin connector.

[John303]

Truck wiring differences?
My truck only has 14 Awg for +12 running from it's fuse box to 7-pin connector.

My truck has a 30 amp fuse. I think it has 10awg based on comparing to other 10awg wiring, and the fuse size.