Switch to Lithium?

[splitting_lanes]

The WF-8955PEC has a 14.4 v bulk mode charging, it’s unclear how that mode is activated from the manual I read.

14.4 volts is enough to charge a lithium and balance it.

It’s possible to have multiple chargers hooked up to a battery, as long as at least one can provide the higher voltage a lithium needs to top off and balance, it should be ok.

For my trailer, I had to shorten and double up the 8 awg wires to get it to charge at a high rate. So, I suggest you try your existing converter and if it doesn’t give you a 14.4v 55a charge, try modifying the wiring next. If that still doesn’t do it, then look at replacing the converter. As I recall, some of the converters have a jumper to switch to make it go into a higher voltage bulk mode…. Check for that also…

 

[John in Santa Cruz]

if there's two chargers, and one outputs a higher voltage, than that one will supply the charging current. if the charging load drags the voltage down to the range of the 2nd 'lower voltage' charger, then they both will provide current.

 

[John in Santa Cruz]

oh, and 190+190 watts is 380 watts peak, if the sun is direct on and its a totally clear day. realistically, you'll probably get 300-320 watts in the summer, and maybe 200 in the winter, IF both panels are not partially shaded. My single 360W panel can generate 2000-2400 watt*hours on a clear summer day if my battery is discharged enough to need that much. most camping days, my actually usage is 700 WH or so. IF my batteries are really deeply run down, it could take two sunny days to fully charge them, but I have 5200 WH of battery capacity (2 x 206AH)

 

[CE Vogel]

Lots of questions here! I'll try to answer them clearly.
I looked up your converter specs. It does NOT provide an Equalization stage, which is good. Equalization applies 15 volts or more to the batteries periodically to reduce sulfation. This is good for FLA/AGM batteries, but bad for Lithium batteries. You can safely connect lithium batteries to your WF-8955PEC converter.

Your converter does provide a 14.4V 'Boost' function, which is time and current limited. I don't know if the Boost function will engage with lithium batteries, but if it does, it will bring the batteries a little above the 80% charge a non-boost non-lithium converter would provide.

It is OK to mix lithium compatible and non-lithium charge sources. The non-lithium charge sources will charge to their FLA/AGM voltage setting, then taper off their current as the lithium compatible charge sources keep going. If the batteries are discharged below the FLA/AGM charge voltage, all chargers will operate simultaneously for a while. This is not a problem. You can operate as many charge sources simultaneously as you'd like (converter, solar, truck), and as long as none of the exceed 14.6 volts, no harm will occur.

If you do not install a DC-DC converter between your tow vehicle and trailer batteries, you can install a diode as others suggested, or disconnect the tow vehicle charge line. If you install a DC-DC converter, it is a one-way device and will act as a diode when the trailer batteries are charging and the tow vehicle is connected but not running. In ALL of the above scenarios, you need to verify your breakaway switch (and power jack if you have one) still have power with the tow vehicle disconnected. You may need to run a new wire from the battery to the breakaway switch (and jack) to ensure they always have power.

It is hard to estimate how many daily amp-hours to expect from your 380W of solar panels. Variables include solar panel Vmp specification, sun angle, length of day, shading, ambient temperature, how clean they are, and the solar charge controller. A PWM solar charge controller will not provide any charge current until the solar panel voltage rises several volts above the battery voltage. A MPPT controller starts charging just slightly above battery voltage and provides more charging hours per day. Some MPPT charger controllers, such as my Redarc unit, have a built-in DC-DC converter and start charging when the solar panels reach 9V. There are not many watts generated, but it does allow charging much earlier in the morning and later in the evening. The 9V capability is useful in the shade; I don't get much charging, but I get more than zero.

Some people are concerned about the higher operating voltage of lithium vs FLA/AGM batteries damaging their appliances. It is true some people with older trailers had MaxxFan problems after converting. It appears MaxxFan did some updates to their control boards about 2019 which solved the problem. My 2020 trailer has three MaxxFans, and they are all working perfectly. All the other 12V appliances also work perfectly, even though my trailer was originally delivered with FLA batteries. There seems to be no 'load side' issues with the higher voltage lithium batteries in trailers delivered recently. It is only the charge side that can get involved.

I hope this helps

 

[brroberts]

I don’t remember which WFCO models are which, but the oldest did not support lithium. Next came models like mine that support lithium with a switch. My 6v GC’s came with it set to li and I had to change it. More recently the model is one that is supposed to auto detect flooded or li battery.

 

[Shiny]

The WF-8955PEC has a 14.4 v bulk mode charging, it’s unclear how that mode is activated from the manual I read.

14.4 volts is enough to charge a lithium and balance it.

It’s possible to have multiple chargers hooked up to a battery, as long as at least one can provide the higher voltage a lithium needs to top off and balance, it should be ok.

For my trailer, I had to shorten and double up the 8 awg wires to get it to charge at a high rate. So, I suggest you try your existing converter and if it doesn’t give you a 14.4v 55a charge, try modifying the wiring next. If that still doesn’t do it, then look at replacing the converter. As I recall, some of the converters have a jumper to switch to make it go into a higher voltage bulk mode…. Check for that also…

Thank you!

Yes I saw the "bulk mode" and interpreted it as only active when it senses a very low SOC.

To me, this meant that voltage would not be "held", and practically, the current draw from a low SOC lithium battery would probably max out the current from the converter, preventing it from actually reaching 14.4V.

 

[Shiny]

if there's two chargers, and one outputs a higher voltage, than that one will supply the charging current. if the charging load drags the voltage down to the range of the 2nd 'lower voltage' charger, then they both will provide current.

oh, and 190+190 watts is 380 watts peak, if the sun is direct on and its a totally clear day. realistically, you'll probably get 300-320 watts in the summer, and maybe 200 in the winter, IF both panels are not partially shaded. My single 360W panel can generate 2000-2400 watt*hours on a clear summer day if my battery is discharged enough to need that much. most camping days, my actually usage is 700 WH or so. IF my batteries are really deeply run down, it could take two sunny days to fully charge them, but I have 5200 WH of battery capacity (2 x 206AH)

Thanks again.

I appreciate the time you have taken to help me.

I looked at one of my downloaded Thornwood logs and the max current off the panels was about 18 but I don't know how that compares with other days.

I do know we typically consume 70 to 80 AH per day, but that is being conservative and if we buy lithium, we should be able to stop worrying about it.

Mike

 

[Shiny]

Lots of questions here! I'll try to answer them clearly.
I looked up your converter specs. It does NOT provide an Equalization stage, which is good. Equalization applies 15 volts or more to the batteries periodically to reduce sulfation. This is good for FLA/AGM batteries, but bad for Lithium batteries. You can safely connect lithium batteries to your WF-8955PEC converter.

Your converter does provide a 14.4V 'Boost' function, which is time and current limited. I don't know if the Boost function will engage with lithium batteries, but if it does, it will bring the batteries a little above the 80% charge a non-boost non-lithium converter would provide.

It is OK to mix lithium compatible and non-lithium charge sources. The non-lithium charge sources will charge to their FLA/AGM voltage setting, then taper off their current as the lithium compatible charge sources keep going. If the batteries are discharged below the FLA/AGM charge voltage, all chargers will operate simultaneously for a while. This is not a problem. You can operate as many charge sources simultaneously as you'd like (converter, solar, truck), and as long as none of the exceed 14.6 volts, no harm will occur.

If you do not install a DC-DC converter between your tow vehicle and trailer batteries, you can install a diode as others suggested, or disconnect the tow vehicle charge line. If you install a DC-DC converter, it is a one-way device and will act as a diode when the trailer batteries are charging and the tow vehicle is connected but not running. In ALL of the above scenarios, you need to verify your breakaway switch (and power jack if you have one) still have power with the tow vehicle disconnected. You may need to run a new wire from the battery to the breakaway switch (and jack) to ensure they always have power.

It is hard to estimate how many daily amp-hours to expect from your 380W of solar panels. Variables include solar panel Vmp specification, sun angle, length of day, shading, ambient temperature, how clean they are, and the solar charge controller. A PWM solar charge controller will not provide any charge current until the solar panel voltage rises several volts above the battery voltage. A MPPT controller starts charging just slightly above battery voltage and provides more charging hours per day. Some MPPT charger controllers, such as my Redarc unit, have a built-in DC-DC converter and start charging when the solar panels reach 9V. There are not many watts generated, but it does allow charging much earlier in the morning and later in the evening. The 9V capability is useful in the shade; I don't get much charging, but I get more than zero.

Some people are concerned about the higher operating voltage of lithium vs FLA/AGM batteries damaging their appliances. It is true some people with older trailers had MaxxFan problems after converting. It appears MaxxFan did some updates to their control boards about 2019 which solved the problem. My 2020 trailer has three MaxxFans, and they are all working perfectly. All the other 12V appliances also work perfectly, even though my trailer was originally delivered with FLA batteries. There seems to be no 'load side' issues with the higher voltage lithium batteries in trailers delivered recently. It is only the charge side that can get involved.

I hope this helps

Very helpful again, thank you for taking so much time!

Great to hear the higher voltage did not cause issues for you. Ours is also a 2020 so hopefully the fan will be the same.

I may call WFCO and ask if there's a way to "force" the 14.4V mode but even if not, the 55A output should get lithium batteries a long way toward full if we deplete them and the solar proves inadequate to keep them full.

Mike

 

[alanmalk]

I do know we typically consume 70 to 80 AH per day, but that is being conservative and if we buy lithium, we should be able to stop worrying about it.

That was my approach.

When I switched from an propane fridge to a compressor fridge two seasons ago, my first week-long trip was to a very shady campground in Wyoming. My batteries at the time were 2X100AH Lithium - very abused the previous winter. I was seriously worried but never ran out of power. Charging consisted of the stock 160 Watt flat-on-the-roof plus a portable 150 that got 3? hours of sun. Add in a couple of cloudy days to boot and no battery monitor. Much relief that the ice cream never melted.

Fast forward a year and I have upgraded to 2X300AH and 350 Watts of portable panels. I in fact have stopped worrying (and still don't have a monitor).

 

[Shiny]

I don’t remember which WFCO models are which, but the oldest did not support lithium. Next came models like mine that support lithium with a switch. My 6v GC’s came with it set to li and I had to change it. More recently the model is one that is supposed to auto detect flooded or li battery.

Thank you!

I read the owner's manual and didn't see mention of a switch but I may reach out to WFCO.

Mike

 

[nepaweb]

Thank you!

I read the owner's manual and didn't see mention of a switch but I may reach out to WFCO.

Mike

Here's a picture of the switch on the WFCO panel. This came standard on our 2020 Escape.

 

[Shiny]

Here's a picture of the switch on the WFCO panel. This came standard on our 2020 Escape.

That's encouraging and very helpful, thank you!

I will look for this next time I go to check on the camper at the storage lot.

Mike

 

[fudge_brownie]

In the Will Prowess reviews he makes frequent mention of putting a 250 AMP fuse on each battery. For my upgrade I am doing exactly as you but with a 280 AMP Li Time. I plan to add the following two items.

Blue Sea Systems 5191 Fuse Block Terminal 30-300 AMP​

Blue Sea Systems Terminal Fuses​

Finally, he felt any battery in an RV should have LTCP - Load Temperature Charging Protection

 

[Shiny]

In the Will Prowess reviews he makes frequent mention of putting a 250 AMP fuse on each battery. For my upgrade I am doing exactly as you but with a 280 AMP Li Time. I plan to add the following two items.

Blue Sea Systems 5191 Fuse Block Terminal 30-300 AMP​

Blue Sea Systems Terminal Fuses​

Finally, he felt any battery in an RV should have LTCP - Load Temperature Charging Protection

Thank you for the links. I also think individual fuses are wise.

That 280 AH battery looks like a great value. Hope it goes smoothly for you. We are sticking with two smaller to make it easier to pull in and out of the camper, but we will pay more for that.

Low temp protection is definitely smart, but seems to be incorporated in most of the batteries I have considered. I have concluded heaters are probably not needed for us, given we don't camp outside in winter and when it's freezing outside, the batteries will be inside our heated camper.

I'm more worried about damage to batteries in storage, so will just have to pull them inside when we think there is risk for damage. Where we live, below zero is unlikely before November and we are finished camping then.

Mike

 

[John in Santa Cruz]

the main battery fuse should be scaled for the main battery cables. if your cables are only suitable for 200A, you do NOT put a 250A fuse on a battery! Me, I have 125W fuses on each of my two batteries, and don't expect the load to ever be much over 200A peak for my inverter starting up a heavy load.

 

[Shiny]

Here's a picture of the switch on the WFCO panel. This came standard on our 2020 Escape.

Just talked to WFCO and unfortunately, we have the "first" design and do NOT have this switch.

The tech support person (great experience BTW) did say I can order just the board assembly to upgrade to the "AD" function and fully support lithium.

He did say our PEC converter will effectively shut off and go into a rest mode when the converter "senses" the solar charge. I assume this means if the battery/solar charger voltage exceeds the 13.6 V absorption setting, the converter just rests. If there is something else going on here, let me know!

He warned we may need to shut off the solar if we want to take advantage of the higher charge current provided by the converter. As I understand, our converter can deliver 55 A but our solar panels won't get close to that. So if the converter shuts down, we will greatly reduce charge time, assuming we had access to shore power. I don't see this as an issue, since we won't deplete the batteries if we have shore power. But I think I may install a solar disconnect just to isolate in case I am guessing wrong.

I suspect I will want an MPPT solar controller before I will want a lithium-supporting converter upgrade.

For now, I will see how it all behaves before making any decisions on converters and solar chargers.

Thanks to you on this forum, I am confident I can basically switch to lithium as a "drop-in" without risk of harming the batteries, even if the charge efficiency is lower than it could be with a lithium converter and MPPT solar charger.

Fingers crossed!

Mike

 

[BobG-ESC]

...........
He warned we may need to shut off the solar if we want to take advantage of the higher charge current provided by the converter. As I understand, our converter can deliver 55 A but our solar panels won't get close to that. So if the converter shuts down, we will greatly reduce charge time, assuming we had access to shore power. I don't see this as an issue, since we won't deplete the batteries if we have shore power. But I think I may install a solar disconnect just to isolate in case I am guessing wrong.

...............

You should already have a disconnect between the solar charge controller and the solar panels. If you don't and you want to add one, make sure it is rated for the DC volts of the solar panels. If you are thinking about adding any panels in series to what you have, the switch should be sized for the total voltage. I ended up getting a DC breaker/switch that was rated for the DC voltage because I couldn't find a reasonably priced switch that rated for the voltage from the solar panels.

You don't need a switch between the solar charge controller and the battery. There should be a fuse in the line though. If you ever want to disconnect the solar charge controller, just remove the fuse. I haven't disconnected my solar charge controller from the battery since I installed it over 4 years ago. I do use the solar panel disconnect though.

 

[Shiny]

...............

You should already have a disconnect between the solar charge controller and the solar panels. If you don't and you want to add one, make sure it is rated for the DC volts of the solar panels. If you are thinking about adding any panels in series to what you have, the switch should be sized for the total voltage. I ended up getting a DC breaker/switch that was rated for the DC voltage because I couldn't find a reasonably priced switch that rated for the voltage from the solar panels.

You don't need a switch between the solar charge controller and the battery. There should be a fuse in the line though. If you ever want to disconnect the solar charge controller, just remove the fuse. I haven't disconnected my solar charge controller from the battery since I installed it over 4 years ago. I do use the solar panel disconnect though.

Thank you!

I'll look for an existing cutoff and if not, I appreciate the guidance on a switch.

I've never thought about disconnecting the solar panels but see how it could make sense when the converter is available.... I have more to learn!

 

[Shiny]

Are my "stock" solar panels (installed by Escape on our 2020 5.0) likely to be GoPower GP-PV-190M ??

 

[John in Santa Cruz]

FWIW, there was no solar panel cutoff on my 2014, with the stock Escape 160W panel of that era. The panel was hard wired to a GoPower GP-PWM-30 "30 AMP PWM DIGITAL SOLAR CONTROLLER", and that in turn was hard wired to the battery such that it would charge the battery even if the battery disconnect switch was flipped.