battery questions

[TitanMike]

Originally Posted by chriscowles

Nice setup. I'd have to relocate the stuff I keep there now, such as chocks and bars, as you did. I'll buy a locking hitch pin and store my 3P stinger in the back accessory hitch to get it out of that space, as well.

Since you're charging from your vehicle, did you supplement the wiring there, too?

I started at the truck battery. Installed an ANL type fuse (50 amp) inline with some #8-2 marine type wire, running from battery to an Anderson connector at the hitch. I then ran some of the same wire from the Anderson connector to the lower right front of the compartment (you'll the large romex type wire in the previous pic. It then connects to the input of the DC-DC charger (far end in the pic). I use the regular power lead from the TV to control the DC-DC charger as that line is only hot when the ignition is on. Nothing else on that line, all charge current comes from #8-2 auxiliary wire I added. Trailer part of the auxiliary wire is zip tied to umbilical cable and the truck portion just zip tied along the bottom of the truck to the OEM wire loom leading from engine compartment power distribution box to the rear trailer connector. I encased the marine type wire in some wire loom for extra protection. I only draw 27 amp from the alternator when charge current is full but rather than a 30 amp ANL fuse I went to the 50 amp due to the higher heat. 40 amp is supposed to be max current for a # 8 wire but I figure any problem will come in the form of a short and the fuse should blow instantly. (tried a circuit breaker initially but under-hood heat tripped it and I would have had to go to a 100 amp breaker to deal with the heat de-rate so I settled on a fuse. The ANL fuses are also available at just about any autoparts store as they're popular for the ear damaging stereo systems.

[chriscowles]

Originally Posted by babock

Yes...hinged at the bottom.

This is what it looks like when tilted up.



It was my first electrical engineering job after I retired from EE.

What are the 3 gauges? Source? What does the rotary switch control?

[chriscowles]

Originally Posted by TitanMike

... I use the regular power lead from the TV to control the DC-DC charger as that line is only hot when the ignition is on. Nothing else on that line, all charge current comes from #8-2 auxiliary wire I added. ...

So power to the regular lead acts as an on/off switch for the charger?

[babock]

Originally Posted by chriscowles

What are the 3 gauges? Source? What does the rotary switch control?

The rotary switch is the main battery switch. The 3 items on the left are circuit breakers. The gauge on the upper right is the Victron BMV-712.

[Half Ton Heavy]

Originally Posted by babock

Yes...hinged at the bottom.


This is what it looks like when tilted up.





It was my first electrical engineering job after I retired from EE.

Very nice!

[TitanMike]

Originally Posted by chriscowles

So power to the regular lead acts as an on/off switch for the charger?

Yes. The Renogy DCC 1212-20 (and -40) use the "IGN" signal from the tow vehicle or coach to switch on/off the unit. Otherwise the starting battery would be run down as the DC-DC charger would continue to try and charge the auxiliary batteries, in my case the Lithium's.

Rather than run a separate wire I figured that this would do the job the same way.

BTW, I also use this voltage source to turn on/off the volt/amp meter as I don't really need it when the TV is not hooked up and charging.

All trailer use and charging, both Converter and Solar is monitored by my Victron monitor.

[TitanMike]

Originally Posted by babock

So are power posts. Done in industrial applications ALL the time. I would never use anything that didn't use ring connectors.


I used a couple power posts in my build to transition wire sizes.

I notice a couple of "muffin fans" mounted on the hinged panel. What are you using to control them and how much power do they consume?

At first glance I thought that the Solar Controller, Converter, and Inverter were all a little "cozy" but then I noticed the fans. Do they exhaust from the area behind the hinged panel or blow into it?

[Half Ton Heavy]

Originally Posted by TitanMike

Forward compartment curb side.

Here's pic

The meter on back wall is volt/ammeter that shows current flowing into lithiums from tow vehicle. Just a cheapo from Amazon. Necessary? Maybe no but for less than the price of lunch i just felt like tossing it in[emoji16]

Battery mount is a floor mount that holds two grp 27's and rather than the usual j-hooks a nylon strap holds them down.Attachment 230883

I now have a light aluminum storage box on tongue wher batteries used to be that i store chocks and the like when underway and spring bars when setup.

Maybe I missed it, but 20 or 40 amp renogy charger?

[TitanMike]

Originally Posted by Half Ton Heavy

Maybe I missed it, but 20 or 40 amp renogy charger?

I am using the 20 amp. Older truck, smaller alternator.

[Half Ton Heavy]

I have a 2019 f150 with the built in (crappy square wave) inverter, which got a slightly larger alternator - maybe 210 amp? Pondering the wire requirements for that, looks like they recommend a 2 gauge with possibly 4 gauge sufficing. And a 60 amp fuse iirc. Gets pricey using decent wire and whatnots. Since I will have 280 ah of battery I should go for it. I worry about heating up the alternator at a campsite however. My goal is solar plus that equals no generator ever. Since we will be at wooded state parks, solar maybe touch and go. I doubt however, that we will consume much electricity either. Dunno, all new to this!

[TitanMike]

Originally Posted by Half Ton Heavy

I have a 2019 f150 with the built in (crappy square wave) inverter, which got a slightly larger alternator - maybe 210 amp? Pondering the wire requirements for that, looks like they recommend a 2 gauge with possibly 4 gauge sufficing. And a 60 amp fuse iirc. Gets pricey using decent wire and whatnots. Since I will have 280 ah of battery I should go for it. I worry about heating up the alternator at a campsite however. My goal is solar plus that equals no generator ever. Since we will be at wooded state parks, solar maybe touch and go. I doubt however, that we will consume much electricity either. Dunno, all new to this!

I often find myself camping in the woods which is why i have a solar suitcase and a long, heavy gauge, extension cord for it. I can follow the patches of sun that come through the trees and usually get enough solar power to charge the batteries.

Another of the many advantages of LiFePo batteries. Very, very, little charging current is wasted with them. With lead acid chemistry it takes significantly longer to replace consumed energy due to the need for long absorbtion times.

[chriscowles]

Originally Posted by TitanMike

I often find myself camping in the woods which is why i have a solar suitcase and a long, heavy gauge, extension cord for it. ...

Another of the many advantages of LiFePo batteries. ...

How long is your cord, and what gauge? Do I assume correctly that you plug it into the charge controller shown in the picture?

The charge speed of LiFePo and the ability to use more of their capacity is nice but I don't think I'll ever be able to rationalize spending $1K on a battery.

[chriscowles]

Originally Posted by Half Ton Heavy

I have a 2019 f150 with the built in (crappy square wave) inverter, which got a slightly larger alternator - maybe 210 amp? ...

There are projects on F150forum.com to replace the crappy stock inverter with a decent pure sine wave inverter, if you're interested. The OP's goal was to reuse the stock connectors so it could be swapped back out when sold, and to not exceed the wattage labeling or the capacity of related circuits.

[TitanMike]

Originally Posted by chriscowles

How long is your cord, and what gauge? Do I assume correctly that you plug it into the charge controller shown in the picture?

The charge speed of LiFePo and the ability to use more of their capacity is nice but I don't think I'll ever be able to rationalize spending $1K on a battery.

I had a 40 some foot piece of 10-4 SO cord I had scavanged years ago. I paired wires so it essentially became jusdt two conductors and it does plug into the controller via the factory installed "port". I further enhanced performance by wiring my two panels in series and the controller is a Smart MPPT unit.

On a good "solar day" I've recorded over 1.1 kwh of harvested solar energy with just a 160 watt "suitcase." That works out to about what i use in an average high use day or 40% of my battery capacity. Most days my batteries are fully recharged by 3PM on just an average "solar day".

[chriscowles]

Originally Posted by TitanMike

I had a 40 some foot piece of 10-4 SO cord I had scavanged years ago. I paired wires so it essentially became jusdt two conductors and it does plug into the controller via the factory installed "port". I further enhanced performance by wiring my two panels in series and the controller is a Smart MPPT unit.

On a good "solar day" I've recorded over 1.1 kwh of harvested solar energy with just a 160 watt "suitcase." That works out to about what i use in an average high use day or 40% of my battery capacity. Most days my batteries are fully recharged by 3PM on just an average "solar day".

Perhaps a dumb question but what is "SO" cord?

Regarding withing the panels in series, does that make it 24V? If so, does the charge controller automatically change the 24V input to 12V output to the batteries and trailer?

A 24V charge system can significantly reduce wire size needs (saving $$) and allow the controller to have higher power output, since the limiting factor is current, if I understand correctly.

[babock]

Originally Posted by TitanMike

I notice a couple of "muffin fans" mounted on the hinged panel. What are you using to control them and how much power do they consume?

At first glance I thought that the Solar Controller, Converter, and Inverter were all a little "cozy" but then I noticed the fans. Do they exhaust from the area behind the hinged panel or blow into it?

They are currently not in operation but they get their power straight from the solar panels through a buck converter so they only run when the sun is out. I really don't need them at all so they are disconnected. The bottom one forced air in and the top one forced air out.

[babock]

Originally Posted by chriscowles

Perhaps a dumb question but what is "SO" cord?

Regarding withing the panels in series, does that make it 24V? If so, does the charge controller automatically change the 24V input to 12V output to the batteries and trailer?

A 24V charge system can significantly reduce wire size needs (saving $$) and allow the controller to have higher power output, since the limiting factor is current, if I understand correctly.

When using an MPPT controller you can have any voltage panels and the controller does a DC to DC conversion down to charge voltage. The voltage of the array just has to be below the max voltage input of the controller.


24V systems are good when you need a lot of power for running air conditioning. Running a 3000W inverter or smaller is a waste since you still have to use a 24V to 12V converter to run everything in the RV.

[TheTichenors]

I am using a 200 watt solar suitcase with 2 100 amp AGM batteries and thinking about switching to single 120amp lithium battery. My main concern is the charger in the RV (2020 FR 272FLS). I doubt it is compatible with lithium chemistry. What do I do about replacing that converter/charger with something lithium compatible?

[chriscowles]

Originally Posted by TheTichenors

I am using a 200 watt solar suitcase with 2 100 amp AGM batteries and thinking about switching to single 120amp lithium battery. My main concern is the charger in the RV (2020 FR 272FLS). I doubt it is compatible with lithium chemistry. What do I do about replacing that converter/charger with something lithium compatible?

Drop-in Li-compatible replacements exist, such as those from Progressive Dynamics, a reputable and popular manufacturer. Having said that, I'll ask our more experienced friends whether Li-compatible models are backwards compatible with FLA batteries?

If upgrading the conductors from the stock WF8955 converter to my FLA 6V batteries do not result in charging ideally, I'll consider upgrading the converter to a drop-in PD model. If doing that, I should include a Li-compatible version in that consideration, in anticipation of possibly upgrading the batteries in the future. I can do that only if the Li-compatible charger is also backwards-compatible with FLA batteries. (I would upgrade the conductors accordingly.) Will the converter recognize it's connected to FLA batteries rather than Li batteries, or can it be set accordingly?

NB: PD may not honor warranties if not purchased from "authorized" sources. Read Amazon reviews for that issue before purchasing there.

Edit: I seem to have found my answer here: http://www.progressivedyn.com/wp-con...al-english.pdf

"... CAUTION The 9100L series converter/chargers are designed to recharge lithium iron phosphate batteries. DO NOT USE TO RECHARGE LEAD/ACID BATTERIES! ..."
(Emphasis from original source.)

[chriscowles]

Originally Posted by babock

When using an MPPT controller you can have any voltage panels and the controller does a DC to DC conversion down to charge voltage. The voltage of the array just has to be below the max voltage input of the controller.

24V systems are good when you need a lot of power for running air conditioning. Running a 3000W inverter or smaller is a waste since you still have to use a 24V to 12V converter to run everything in the RV.

Thanks for the explanation. I know of the requirement to step down from 24V back to 12V for the standard RV components. What I did not know was that MPPT controllers manage variable voltage input, nor the threshold of system capacity that makes 24V economically advantageous.

I doubt I'll ever have enough battery capacity to run our 15K BTU air conditioner. I'd rather camp where I don't need air conditioning that badly, or stay where we have shore power.

My use of a future solar system will be to minimize the need to run my generator to maintain my batteries for traditional 12V loads. That includes powering 2 CPAPs without humidifiers on 12V converters, plus running the furnace as much as is required to keep my Caribbean wife happy. If we can use the microwave briefly on occasion, that would be nice, but certainly not essential. I can make Jiffy Pop on the propane stove.