House Power

[MesaJohn]

Because of a smoking Black Friday sale before Christmas, I purchased a 12V, 200 AH LiFePO4 battery and a 2000 watt inverter. I have plenty of room for it in the back of the FJ Cruiser, but here is my question.....

I watched a couple of YouTubes on guys charging their LiFePO4 batteries from the alternator on the vehicles engine. They were both very concerned that their alternator would be overloaded, so they used a 12V DC to DC charger that maxed at 20 amps and was rated for Lithium batteries. Has anyone done this with your rig and has it been successful and do you have any tips, tricks and advice?

When we travel, we do a lot of mileage per day, running the vehicle many, many hours. We don't set up camp and sit there for 3 days. We tend to travel point to point every day. Now if we were sitting for days, I would want couple of solar panels to charge the batter, but for now, I am just interested in the alternator doing the charging every day.

Running 24 hours a day will be our 54qt frig/freezer and in the evenings and mornings the Starlink Mini.

What's your thoughts?

Here are some pics....

 

[MidOH]

Had one on my previous work truck. Primary purpose was to send clean power, and protect the lithium battery.

My tablets mount had a small DC to DC charger as well.

Now we're lead acid, with no converters. No reason why. Likely just cost. (And tougher tablets)

 

[reaver]

I have two of the dc-dc chargers you show. One in my Xterra, and one in my trailer. Both work great.

Now, according to the image above, the battery bms supports 100A max output, which is a theoretical limit of 1340W (based on a typical charge of 13.4V for LiFePO4 batteries) not taking effeciency loss in the conversion.

I wouldn't run a load of more than 1000w off that battery.

 

[Dave in AZ]

Yah. I have stopped carrying my 450W of panels, totally not needed now. I have dcdc charger intended for powerstations, so output is boosted to 42V to allow fast charging through the mppt solar charge controller on powerstation.

If going direct to LFP battery, then normal dcdc charger is desired. However, I wouldnt buy that Renogy, there are endless posts at diysolarforum.com Mobile/vehicle subforum, about these not working or issues.

Get a Victron, or a Kisae, many options. My dcdc is a Pecron 500w car charger, I can set it to 200w, 300w, 400w, 500w, whatever I feel my alternator can support with its load. So 500w in dayti.w good weather, 200 to 300W or off in rain at night (hibeams, wipers, airco, turn signals, braking and lights etc.)

Definitely the way to go if you drive every other day or more.

 

[reaver]

Yah. I have stopped carrying my 450W of panels, totally not needed now. I have dcdc charger intended for powerstations, so output is boosted to 42V to allow fast charging through the mppt solar charge controller on powerstation.

If going direct to LFP battery, then normal dcdc charger is desired. However, I wouldnt buy that Renogy, there are endless posts at diysolarforum.com Mobile/vehicle subforum, about these not working or issues.

Get a Victron, or a Kisae, many options. My dcdc is a Pecron 500w car charger, I can set it to 200w, 300w, 400w, 500w, whatever I feel my alternator can support with its load. So 500w in dayti.w good weather, 200 to 300W or off in rain at night (hibeams, wipers, airco, turn signals, braking and lights etc.)

Definitely the way to go if you drive every other day or more.

So, I've read the same thing. I still have two of them. One is still going strong after 3 years, and the other is going strong after a year. I realize I may be an outlier here. Personally, I've had great luck with renogy products so far.

 

[K12]

If you are in the move every day and doesnt sound like you will be using much power at all a dc-dc charger is great. I have a victron 30a that goes from my truck battery to the trailer battery compartment when i plug it in. Biggest thing is to make sure you use the right cable size for accomodate for current and voltage drop (shouldnt be an issue if qll in the same vehicle). I as well have heard not so good about renogy, I love victron my entire system is based on it. I will be selling my 12v victron orion-tr soon as im going to be going to a 24v system if you are interested DM me and we can work something out. It has bluetooth monitoring which makes it easy.

 

[MesaJohn]

In full disclosure, I don't have the exact battery above.

I wouldn't run a load of more than 1000w off that battery.

Agree. I have very, very little load on all the things I would ever use. #1 is my Frig/Freezer...... On 12v it is stupid low at around 50 watts with a max startup peak around 100 watts. #2 is the Starlink Mini and it is about 60 watts max on 12v. #3. Would be recharging devices and batteries (camera, drone, radios, etc.)

 

[Viking1204]

I installed a Redarc DC to DC charger on my truck to maintain my 138ah lithium battery and it was a game changer. With the battery depleted below 50% it could charge it back up to 100% in 30 minutes!