Installed 400watt Solar on my Toy Hauler, now I want to replace the 6v Lead acids with LiFePO4

[Glamisduner]

Just installed 4 100 watt panels in series on the roof of my toy hauler. My 6V batteries are still working after 8 years (We always leave the trailer plugged in). However I'm sure they have significantly reduced capacity at this point. I ran 4 renology panels in series and connected them to a Victron Energy 100 / 50A MPPT controller. Then the controller to a 4awg distribution block that also powers my 600watt pure sine inverter.

I'm thinking about joining the cool kids with their fancy Lithium batteries and have watched a bunch of youtube videos leading me here.
I would like to purchase something while the black friday deals are active.

Currently I have 2 6v 225ah batteries in series. They are 8+ years old. My Batteries are installed on the tongue of the trailer behind the propane tanks. I do not have a pass through area since we have a front Bathroom Model, so the new battery will need to be located there as well. It's a 28 foot Ragen trailer.

So I am looking at a Watt Cycle 300ah 12v or a Epoch 300ah (or maybe 460ah essential series). Cost is obvioiusy factor but it's ok if I should spend more on the Epoch. I realize if I pay $1800 I can get an Epoch one that will integrate with my solar controller. But is that really necessary $$$?

Epoch 300ah ($850) https://www.epochbatteries.com/products/12v-300ah-heated-bluetooth-lifepo4-battery-epoch-essentials
Watt Cycle 300ah ($499) https://www.wattcycle.com/products/wattcycle-12v-300ah-mini-lifepo4-battery?ref=aaezwkkc

If the battery goes into a metal box, I'm not sure how useful the bluetooth option would be, but I guess you could open the lid to check, and that's probably enough. I don't have a battery box selected yet, so I would appreciate any suggestions.

The cost difference is significant, and I believe I also need to upgrade the charging unit that came with my trailer? Or can I leave it, and just rely on the solar to top off the batteries for now? So if I get the cheaper battery, the money saved could go towards upgrading the charger....

Second I have a couple concerns.

• Since the battery box will essentially be mounted outside on the tongue of the trailer, and we do camp in a few locations where me cooler ice re-freezes overnight I am wondering if I should just spend the extra $350 for the heated battery. Or could I just get something like a Facon RV holding Tank heating pad like this https://www.amazon.com/dp/B01N7QVBJJ? I would wire this to a switch so I could turn it off when not needed event hough it is thermostat controlled.
  In these locations, the temperature is usually only dipping into freezing overnight, and it warms up in the day, and it only gets that cold sometimes. Still I don't want more problems than I have with my 6 volts.
• Second concern is I need the battery to be able to start our generator. Now these all say they are not for starting, but I can't imagine they would work any worse than the 6v's for starting the generator.

TLDR: have 400 watt of solar. I will be mounting the battery on the trailer toungue. Wich Battery should I get? Will the heating pad be enough if I get the cheaper battery? Battery box recommendations? Any Concerns starting an Onan 4000 generator?

Thanks in advance!

Adding Pictures of solar MPPT install just because.

 

[chrisski]

Make life easy on yourself and get the heated battery.

Just read the reviews and tech data to be sure the heater works good for an external storage on the tongue during all times of use including driving home after the coldest night of the year camping.

I’d prefer an internal install of 4 x 280 ah cells made into a battery with a BMS added, but that may not be possible.

 

[Glamisduner]

Make life easy on yourself and get the heated battery.

Just read the reviews and tech data to be sure the heater works good for an external storage on the tongue during all times of use including driving home after the coldest night of the year camping.

I’d prefer an internal install of 4 x 280 ah cells made into a battery with a BMS added, but that may not be possible.

Yea, internal install would be difficult, the trailer is a front bathroom so the only real place they could go would be under the sink next to the water pump, and I would rather avoid putting them there, if they would even fit.
I would splurge for the 460ah, but it won't fit in the amazon battery box I am looking at: https://www.amazon.com/gp/product/B0CH5CHTKC
The 460ah is .1" too wide. E-trailer has some battery boxes that might work, but they want like $400-$500 just for the battery boxes... Not sure what battery box I could get that would fit it.

Reading through the tech data, but I'm not sure how to answer that question about it working when your driving. The heater is only needed for charging though? Not much of a charge comes through the Trailer plug... I'm not even sure I need the self heating feature, it looks like I could get the cheaper battery and a heater for around $40? Maybe add a Victron Battery Smart shunt for $100 and call that setup good enough?

The Watt Cycle says it is rated for 5000-15000 cycles and still have 80% capacity, much better than the more expensive Epoch? So maybe it's actually a better battery, just with no bluetooth monitoring?

Also is their charger worth getting?

12V 15A Battery Charger - Epoch Batteries

Shop the high-performance 12V 15A Battery Charger by Epoch Batteries. With plug and play functionality, lightweight aluminum alloy construction, and IP67 dustproof and waterproof design, it's perfect for RVs and marine applications.

www.epochbatteries.com

 

[chrisski]

Reading through the tech data, but I'm not sure how to answer that question about it working when your driving. The heater is only needed for charging though? Not much of a charge comes through the Trailer plug... I'm not even sure I need the self heating feature, it looks like I could get the cheaper battery and a heater for around $40? Maybe add a Victron Battery Smart shunt for $100 and call that setup good enough?

I did not necessarily mean just driving. Any time the panels are connected and the SCC on and its daylight, the batteries will be charging unless some sort of intervention happens like the SCC shutting off at a temp or the BMS shutting off at a temp.

For me, those times I forget to manually check tend to be early in the morning when the sun comes out and when I leave and drive away.

I am in sunny AZ, so my batteries are not likely to dip down to 32. For your heater, if you are far north, driving down the road in 0 temps, I don’t know when the heater stops working.

I use the Victron Smart Shunt with optional temp sensor as primary shut the SCCs off at around 36 F and as last resort, the BMS is set to shut off at 34 F. You don’t have control of the BMS.

What I mentioned with the shunt will stop charging from teh SCC, not from my converter. I could still accidentally turn my converter on if I forget to check. In this case, the BMS will not allow the charge. Not sure of your though.

For the charger you linked, I did not see the charge profile. I don’t like to charge my lithiums above 14.1, so without knowing the profile, I would not get it.

I can’t speak to the heated option, but there are a few threads on here that people have been using for years.

 

[Glamisduner]

It decided to get the larger 460 battery, but i still can't find a battery box to fit it. Also camping with the nearly dead six volts so that makes it harder lol

 

[mikefitz]

I ran 4 renology panels in series and connected them to a Victron Energy 100 / 50A MPPT controller

The Renogy panels available may have a Voc of 24.3 volts, in cold conditions the series volts may exceed the controller 100 volt limit.
With a typical 0.3% / degC increase for every deg below 25C Voc will increase, example, at 25 degC series volts is 97.2, at 0 deg C series volts is 104.5. ( based on a guess of Voc and temp coefficient, research the values for your panels)

 

[Glamisduner]

The Renogy panels available may have a Voc of 24.3 volts, in cold conditions the series volts may exceed the controller 100 volt limit.
With a typical 0.3% / degC increase for every deg below 25C Voc will increase, example, at 25 degC series volts is 97.2, at 0 deg C series volts is 104.5. ( based on a guess of Voc and temp coefficient, research the values for your panels)

What happens if I hit 104v? Should I buy different panels? Wire 2 of them in parallel? I

I don't think they will be seeing 0 degrees in the daytime but I guess it could happen. So far V Max is 95v... Renology website says they are up to 24.3v each. But I haven't tested them in really cold conditions. I suppose I could always go out in the roof and unplug one.

Still need suggestions on a box. Haven't found anything. Might have to go with the smaller battery. The 6v are not working well this trip... Also parked facing a bad direction for the array this trip.

 

[chrisski]

What happens if I hit 104v? Should I buy different panels? Wire 2 of them in parallel? I ordered them from Amazon I don't remember seeing additional information.

I don't think they will be seeing 0 degrees in the daytime but I guess it could happen. So far V Max is 95v...

Still need suggestions on a box. Haven't found anything. Might have to go with the smaller battery. The 6v are not working well this trip...

Yes Wire them 2S2P. That will still get enough to charge 24 volt batteries. An MPPT is very forgiving to input voltage, until it exceeds the max and you reach an up in smoke thing. Ideally would be 3S2P if you could find 100 watt panels where voltages and amperages matched to fit in the jigsaw puzzle..

I Bought a century plastic GC2-4 box for my four golf cart batteries when I had lead acid. There are a variety of sizes:

https://www.centuryplastics.ca/images/stories/pdfs/Battery_Boxes_Containment_Boxes.pdf

I found nothing else that fit four golf cart batteries.

 

[Glamisduner]

Yes Wire them 2S2P. That will still get enough to charge 24 volt batteries. An MPPT is very forgiving to input voltage, until it exceeds the max and you reach an up in smoke thing. Ideally would be 3S2P if you could find 100 watt panels where voltages and amperages matched to fit in the jigsaw puzzle..

I Bought a century plastic GC2-4 box for my four golf cart batteries when I had lead acid. There are a variety of sizes:

https://www.centuryplastics.ca/images/stories/pdfs/Battery_Boxes_Containment_Boxes.pdf

I found nothing else that fit four golf cart batteries.

Does this mean with 2 pairs of panels in parallel, then put those together in series? I have about 30ft of 10 awg wire to get to the inverter so I though having all of them in series would be better to reduce losses?

 

[Glamisduner]

Posting this here because I have been searching for many hours and have not been able to come up with a box to fit the 460ah EPOCH Essentials:
20.55"L x 9.45"W x 8.6"H Battery.

This is the only box I can find and it is sold out: https://www.rvlockbox.com/shop/wm2hpudc062mxdqhuq668h4yecujge
RV Lockbox 23" Wide Mouth
But maybe it will help someone else. Right now it looks like I may have to get the smaller battery just because no one seems to make a box to fit the large one.
I'm not sure on the waterproofness of that one either...