200 amp alternator with dc to dc charger

[Timtoolman]

I have a 2021 f150 Xlt 302a , that has a 200 amp alternator , I have a Renogy 50 amp 12v to 12 v charger that’s adjustable from 10 amp, 20 amp , 30 amp or 40 amp to 50 amps charge for my travel trailer which has 2 dual 88 amp hr batteries for 12 volt refrigerator (that will be bought soon ) . My question is how many amps can I charge with out hurting my alternator ????????? I will be running 4awg cables from truck battery to charger for minimal power drop

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[Rineland]

I have a 2021 f150 Xlt 302a , that has a 200 amp alternator , I have a Renogy 50 amp 12v to 12 v charger that’s adjustable from 10 amp, 20 amp , 30 amp or 40 amp to 50 amps charge for my travel trailer which has 2 dual 88 amp hr batteries for 12 volt refrigerator (that will be bought soon ) . My question is how many amps can I charge with out hurting my alternator ????????? I will be running 4awg cables from truck battery to charger for minimal power drop

I think @HammaMan might be the best resource to answer your question or at least provide guidance. He’s done a lot of experimenting with the charge strategy and alternator output. The only for sure easy way to get a strong charging output from the alternator is by setting the HVAC fan speed to 5. Whichever output you choose I think you’ll have to run that fan speed for the DC-DC charger to actually charge the battery.

 

[Buyer2021]

My question is how many amps can I charge with out hurting my alternator ????????? I will be running 4awg cables from truck battery to charger for minimal power drop

Will your Renology DC-DC charger be mounted in the RV trailer or in the truck (the former being more common practice for RV installations)? What is the one-way cable length from the battery to the Renology unit?

I ask because I suspect your DC-DC charger amps should be limited based on the voltage drop through the 4AWG cable, not the alternator output.

This wire-sizing calculator may be useful. NOTE that the "Length of Conductor" entered in that calculator is the total of supply (+) and return (-), so that's the one-way length x 2.

Just for example, for a nominal 12VDC system, and assuming a one-way run of 25 ft (enter a conductor length of 50ft), we see that a 4AWG cable will support up to 28Amps with 3% voltage loss. If your one-way cable run is 30ft (enter 60ft for conductor length), that drops to 24Amps. And so on for longer cable runs ....

In other words, I think your appropriate Renology DC-DC charger range setting should likely be limited based on the cable-run voltage loss, and that will bring you to a low enough load that the alternator / vehicle charging system capacity won't be a factor.

Just for your consideration, Have Fun!

 

[Timtoolman]

Will your Renology DC-DC charger be mounted in the RV trailer or in the truck (the former being more common practice for RV installations)? What is the one-way cable length from the battery to the Renology unit?

I ask because I suspect your DC-DC charger amps should be limited based on the voltage drop through the 4AWG cable, not the alternator output.

This wire-sizing calculator may be useful. NOTE that the "Length of Conductor" entered in that calculator is the total of supply (+) and return (-), so that's the one-way length x 2.

Just for example, for a nominal 12VDC system, and assuming a one-way run of 25 ft (enter a conductor length of 50ft), we see that a 4AWG cable will support up to 28Amps with 3% voltage loss. If your one-way cable run is 30ft (enter 60ft for conductor length), that drops to 24Amps. And so on for longer cable runs ....

In other words, I think your appropriate Renology DC-DC charger range setting should likely be limited based on the cable-run voltage loss, and that will bring you to a low enough load that the alternator / vehicle charging system capacity won't be a factor.

Just for your consideration, Have Fun!

Charger will be located in front of trailer in fron

Will your Renology DC-DC charger be mounted in the RV trailer or in the truck (the former being more common practice for RV installations)? What is the one-way cable length from the battery to the Renology unit?

I ask because I suspect your DC-DC charger amps should be limited based on the voltage drop through the 4AWG cable, not the alternator output.

This wire-sizing calculator may be useful. NOTE that the "Length of Conductor" entered in that calculator is the total of supply (+) and return (-), so that's the one-way length x 2.

Just for example, for a nominal 12VDC system, and assuming a one-way run of 25 ft (enter a conductor length of 50ft), we see that a 4AWG cable will support up to 28Amps with 3% voltage loss. If your one-way cable run is 30ft (enter 60ft for conductor length), that drops to 24Amps. And so on for longer cable runs ....

In other words, I think your appropriate Renology DC-DC charger range setting should likely be limited based on the cable-run voltage loss, and that will bring you to a low enough load that the alternator / vehicle charging system capacity won't be a factor.

Just for your consideration, Have Fun!

yes the charger will. be in front of trailer in front storage , length of cables ?? Probably 25’ ish total length for each , + and - including truck and trailer runs, I just don’t want to burn up alternator, Isnt the amount of charging regulated to not to running fan to keep charging it’s a higher , doesn’t the smart feature that the D+ wire connected to 12v ignition source control that ???

 

[HammaMan]

If it's a DC-DC it's likely boost converter and incoming voltage is irrelevant as it's not uncommon for the tow vehicle to have inadequate voltage by the time it arrives at the trailer to charge batteries. 4ga is more than adequate for 50a continuous.

As for how much amperage you can pull given it's ICE and an actual alternator, that will vary based on engine RPM. The powerboost on the other hand will output loads of power. I've maxed out a BMS charging up an LFP bank at 150 amps. The power steering and cooling fans are high-draw items. Running max AC for instance will see the truck drawing ~70 amps just for basic systems and fans in that case.

 

[Timtoolman]

If it's a DC-DC it's likely boost converter and incoming voltage is irrelevant as it's not uncommon for the tow vehicle to have inadequate voltage by the time it arrives at the trailer to charge batteries. 4ga is more than adequate for 50a continuous.

As for how much amperage you can pull given it's ICE and an actual alternator, that will vary based on engine RPM. The powerboost on the other hand will output loads of power. I've maxed out a BMS charging up an LFP bank at 150 amps. The power steering and cooling fans are high-draw items. Running max AC for instance will see the truck drawing ~70 amps just for basic systems and fans in that case.

I should be ok at 20 amps for just the refrigerator ??? T
I’d be happy with that , even happier with 30 but don’t want to get greedy

 

[Buyer2021]

@Timtoolman , just curious, what's the chemistry of your dual (presumably 12V parallel wired) 88AH batteries? FLA, LFP, or ....?

 

[Timtoolman]

@Timtoolman , just curious, what's the chemistry of your dual (presumably 12V parallel wired) 88AH batteries? FLA, LFP, or ....?

Wet cell grp -27 interstates for now I may get 100amphr ones in spring

 

[Babbage]

https://custombatterycables.com/custom-made-battery-cable/

If you will need new cables the above site has some good items, custom made cable any length, soldered with hd heat shrink sealed jackets and any ends you choose.

I replaced a cable once - like the black one see the green copper peaking out? lol - with one of theirs (red), for a new HD alternator that I had on another Ford, they have good stuff.

Edit: If you are hooking up new runs to the battery direct, perhaps upgrade the alternator output and or ground cables as well like below? Not sure how easy this would be.

 

[Timtoolman]

@Timtoolman , just curious, what's the chemistry of your dual (presumably 12V parallel wired) 88AH batteries? FLA, LFP, or ....?

Wet cell 89 amp hrs

https://custombatterycables.com/custom-made-battery-cable/

If you will need new cables the above site has some good items, custom made cable any length, soldered with hd heat shrink sealed jackets and any ends you choose.

I replaced a cable once - like the black one see the green copper peaking out? lol - with one of theirs (red), for a new HD alternator that I had on another Ford, they have good stuff.

Edit: If you are hooking up new runs to the battery direct, perhaps upgrade the alternator output and or ground cables as well like below? Not sure how easy this would be.

Thanks I will check them out , I’d like to up grade to a higher alternator, that may be a future up grade if I don’t get another truck , I did just have to get a new 800 cca battery thank to Ford

 

[Timtoolman]

https://custombatterycables.com/custom-made-battery-cable/

If you will need new cables the above site has some good items, custom made cable any length, soldered with hd heat shrink sealed jackets and any ends you choose.

I replaced a cable once - like the black one see the green copper peaking out? lol - with one of theirs (red), for a new HD alternator that I had on another Ford, they have good stuff.

Edit: If you are hooking up new runs to the battery direct, perhaps upgrade the alternator output and or ground cables as well like below? Not sure how easy this would be.

What size alternator should I get if I up grade from 200 amp factory ?? 2021 f150 xlt 302a

 

[Babbage]

What size alternator should I get if I up grade from 200 amp factory ?? 2021 f150 xlt 302a

This one (370 AMP) looks good to me! Heck I might get it to help my pro power.... You can't really go higher safely. I have not bought from here but it looks good to me.

https://www.dcpowerinc.com/products...5l?rq=yr_2021~mk_ford~md_f-150-raptor~le_3-5l

 

[Timtoolman]

This one (370 AMP) looks good to me! Heck I might get it to help my pro power.... You can't really go higher safely. I have not bought from here but it looks good to me.

https://www.dcpowerinc.com/products...5l?rq=yr_2021~mk_ford~md_f-150-raptor~le_3-5l

I just ordered 2 lithium 100 amp hr batteries so that should help get rid of the small wet cell batteries that are also much heavier

 

[Babbage]

I just ordered 2 lithium 100 amp hr batteries so that should help get rid of the small wet cell batteries that are also much heavier

Are you looking at this, what does everyone else think about this alternator:

" Our XP series high-output alternators are the ultimate upgrade when you need the absolute biggest and most sophisticated high output alternator on the planet. All of our XP series alternators are designed for one purpose, brute force idle output. When you need the most extreme idle output with the most sophisticated integrated alternator-monitoring system to prevent thermal failures is where the XP alternator delivers. Every DC Power product we sell is held to the strictest quality standards in the industry. We only use 100% brand new USA made components along with one of the most rigorous testing before each individual alternator leaves our shop. Each XP series alternator comes standard with our custom hard-anodized billet aluminum pulley and 2-year replacement warranty. If you're looking for a significant overall increase in top end and idle output, the XP series alternator is your solution. "​

 

[Timtoolman]

Are you looking at this, what does everyone else think about this alternator:

" Our XP series high-output alternators are the ultimate upgrade when you need the absolute biggest and most sophisticated high output alternator on the planet. All of our XP series alternators are designed for one purpose, brute force idle output. When you need the most extreme idle output with the most sophisticated integrated alternator-monitoring system to prevent thermal failures is where the XP alternator delivers. Every DC Power product we sell is held to the strictest quality standards in the industry. We only use 100% brand new USA made components along with one of the most rigorous testing before each individual alternator leaves our shop. Each XP series alternator comes standard with our custom hard-anodized billet aluminum pulley and 2-year replacement warranty. If you're looking for a significant overall increase in top end and idle output, the XP series alternator is your solution. "​

I saw that , that one pricey alternator

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