Could I use the stock converter on my 2017 trailer to charge LifePo4 batteries?

[eric_h]

Hi,

I have a Passport 153ML travel trailer with a stock converter and a wet cell battery. I would like to replace the battery with a pair of LifePO4 batteries and install a solar + inverter system with an automated switch for shore power. That said, when connected to shore power, the stock converter will charge the batteries, as it does today. I doubt that this old charger was meant for LifePO4 batteries (trailer documentation does not mention that).

My question is, then- could the stock converter charge the LifePO4 batteries and how efficiently?
More important- could it damage the batteries? Would I need another component?
Or must I disable the stock converter and get a dedicated charger that supports LifePO4 batteries for more $$?

I searched through the forum and could not find a definitive answer, although one might certainly be hiding here somewhere I would appreciate your help clarifying this one.

Thank you!
Eric

 

[MisterSandals]

that this old charger

What charger do you have?

 

[time2roll]

Generally the original converter will be fine. None are perfect. Some of the "lithium" converters are even worse.
Best to post the converter model number for specific answers.

 

[eric_h]

Thank you both.

I'd have to get hold of the trailer (which is in storage for the winter, until mid-April) to get the converter model number. Cannot find that data online. Owner's manual just mentions that it could be either Hengs or WFCO, which is no help...
I wrote to Keystone customer service and hoping to get a response soon.

My main question would then be if, in such charger could damage such batteries, which already come with an integrated BMS.

Thanks again!

 

[time2roll]

Keystone is probably a WFCO and will charge at a steady 13.6 volts. If lucky it will drop to float after several days to 13.2. In the rare instance the WFCO decides to boost charge the battery at 14.4 volts all is still fine for the LFP battery. Depending on use, individual needs and travel experience a different charging system can be installed.

Many that camp off grid install solar and the converter is mostly unused.

 

[eric_h]

Keystone is probably a WFCO and will charge at a steady 13.6 volts. If lucky it will drop to float after several days to 13.2. In the rare instance the WFCO decides to boost charge the battery at 14.4 volts all is still fine for the LFP battery. Depending on use, individual needs and travel experience a different charging system can be installed.

Many that camp off grid install solar and the converter is mostly unused.

Thank you! That really helped me set my path forward.

 

[John Frum]

I suggest you get an inverter/charger and disable the converter.
Leave the converter in place though as an emergency backup.
An inverter/charger is an inverter, charger and automatic transfer switch.
If you need any two of the functions I suggest you get an inverter/charger.

 

[rickst29]

If the Keystone power center is WFCO and you do want to stay with the current WFCO charger, I would switch the Converter battery profile to AGM/GEL mode. That prevents the converter from inflicting possibly harmful "anti-sulfation" cycles on the LFP batteries.

The WFCO Converters (they call them "main board assembly", or "MBA') are generally too fast to drop into a low-voltage "Float" or "Storage" mode. Float if maintained for a long time, can charge LFP battery banks pretty decently. But if you want to charge quickly more quickly (from a generator) you might want higher "Boost" Voltage to be maintained for longer time period, and you might want a method to force "Boost mode" even when the WFCO thinks that the battery (assumed by a WFCO MBA to be lead-acid) is at an adequate State of Charge already.

LFP "12V" batteries will not test, at tiny discharge current values, much below 12.8V for most of the State-of-Charge range. Their Voltage only begin to fall off, when less than 20% of battery capacity remains. WFCO believes the batteries, perhaps only 25% full, to be nearly 100% as lead-acid batteries.

Those WFCO "MBA" units which offer a Lithium switch will, like many others, push almost 14.6V whenever they are plugged in. This will push your battery to 100% capacity (unless the BMS charge circuit shuts down "charging" at a somewhat lower voltage). Lead-Acid batteries love to be stored at 100% SOC for as long as possible, but that's very bad for LFP cells. My advice is to NEVER use the "Lithium" setting on a WFCO converter board, and I also apply that advice to US-built and somewhat better 'Progressive Dynamics' main board assemblies.

In my own Travel Trailer, I have one of those Progressive Dynamics Converters. I have it set for "AGM/GEL" batteries, preventing anti-sulfation cycles. The PD Converters offer a controller pendant with a button, with which you can forcibly switch the operating mode from "float" 13.6V or "storage" 13.1V to "Boost mode" voltage. Following "boost mode", the PD Converters will maintain "float voltage" for about a week. If your trip is longer than a week, you need only press the button to invoke "Boost" Voltage for another short period of time.

Victron makes a great little 120-VAC Converter, but it maxes out at only 15A. To go bigger with a superior Victron product (with full programming and monitoring via bluetooth) you would need to switch to a full Inverter/Charger/Power Distribution unit, as smoothJoey recommended in the previous post.
- - -
If you go "my way", keeping the current WFCO load center, you have new and separate costs (plus installation hassles) for the new Inverter and transfer switch. The fantastic Victron "all-in one' units performs all 3 jobs, you would need only a cheap (and small) DC-12v distribtuion panel for the fuses and downstream "12 VDC" circuits in your RV Trailer. Progressive Dynamics makes a very good and small unit for that DC 12v Power Distribution job.

I know a couple of people who use the bigger Victron units in travel trailers of my own type ("Trailmanor" aluminum pop-up Travel Trailers, they're not cheap), and I'm very jealous of their upgrades. With a Victron load center, you would also have the option of configuring the battery pack at 24V, or even 48V - while still providing "+12V" to the output power port for your 12V load circuits.

 

[eric_h]

I suggest you get an inverter/charger and disable the converter.
Leave the converter in place though as an emergency backup.
An inverter/charger is an inverter, charger and automatic transfer switch.
If you need any two of the functions I suggest you get an inverter/charger.

That's a good point, actually. I do need all three, and looking for a solution that will also allow me to charge with my towing car's alternator.
I could go with such an inverter/charger and add a separate dedicated dc-dc charger for the alternator charge.

Thank you!

 

[John Frum]

That's a good point, actually. I do need all three, and looking for a solution that will also allow me to charge with my towing car's alternator.
I could go with such an inverter/charger and add a separate dedicated dc-dc charger for the alternator charge.

Thank you!

Dc2dc chargers have a lot of hidden gotchas to navigate.
If you open a new thread on the subject I would be glad to share what I have learned.

 

[eric_h]

If the Keystone power center is WFCO and you do want to stay with the current WFCO charger, I would switch the Converter battery profile to AGM/GEL mode. That prevents the converter from inflicting possibly harmful "anti-sulfation" cycles on the LFP batteries.

The WFCO Converters (they call them "main board assembly", or "MBA') are generally too fast to drop into a low-voltage "Float" or "Storage" mode. Float if maintained for a long time, can charge LFP battery banks pretty decently. But if you want to charge quickly more quickly (from a generator) you might want higher "Boost" Voltage to be maintained for longer time period, and you might want a method to force "Boost mode" even when the WFCO thinks that the battery (assumed by a WFCO MBA to be lead-acid) is at an adequate State of Charge already.

LFP "12V" batteries will not test, at tiny discharge current values, much below 12.8V for most of the State-of-Charge range. Their Voltage only begin to fall off, when less than 20% of battery capacity remains. WFCO believes the batteries, perhaps only 25% full, to be nearly 100% as lead-acid batteries.

Those WFCO "MBA" units which offer a Lithium switch will, like many others, push almost 14.6V whenever they are plugged in. This will push your battery to 100% capacity (unless the BMS charge circuit shuts down "charging" at a somewhat lower voltage). Lead-Acid batteries love to be stored at 100% SOC for as long as possible, but that's very bad for LFP cells. My advice is to NEVER use the "Lithium" setting on a WFCO converter board, and I also apply that advice to US-built and somewhat better 'Progressive Dynamics' main board assemblies.

In my own Travel Trailer, I have one of those Progressive Dynamics Converters. I have it set for "AGM/GEL" batteries, preventing anti-sulfation cycles. The PD Converters offer a controller pendant with a button, with which you can forcibly switch the operating mode from "float" 13.6V or "storage" 13.1V to "Boost mode" voltage. Following "boost mode", the PD Converters will maintain "float voltage" for about a week. If your trip is longer than a week, you need only press the button to invoke "Boost" Voltage for another short period of time.

Victron makes a great little 120-VAC Converter, but it maxes out at only 15A. To go bigger with a superior Victron product (with full programming and monitoring via bluetooth) you would need to switch to a full Inverter/Charger/Power Distribution unit, as smoothJoey recommended in the previous post.
- - -
If you go "my way", keeping the current WFCO load center, you have new and separate costs (plus installation hassles) for the new Inverter and transfer switch. The fantastic Victron "all-in one' units performs all 3 jobs, you would need only a cheap (and small) DC-12v distribtuion panel for the fuses and downstream "12 VDC" circuits in your RV Trailer. Progressive Dynamics makes a very good and small unit for that DC 12v Power Distribution job.

I know a couple of people who use the bigger Victron units in travel trailers of my own type ("Trailmanor" aluminum pop-up Travel Trailers, they're not cheap), and I'm very jealous of their upgrades. With a Victron load center, you would also have the option of configuring the battery pack at 24V, or even 48V - while still providing "+12V" to the output power port for your 12V load circuits.

Thank you for the elaborate explanation!

I'm leaning towards an all-in-one solution and bypassing the stock converter.
I'm not sure I would need the more expensive solutions, though, as my calculation shows that a 1000w solution should be more than enough for my needs. There is this solution: https://watts247.com/product/pip-1012lv-ms/
RE the DC-to-DC charger, as suggested- I'll start a new thread about it.

Eric

 

[rickst29]

Thank you for the elaborate explanation!

I'm leaning towards an all-in-one solution and bypassing the stock converter.
I'm not sure I would need the more expensive solutions, though, as my calculation shows that a 1000w solution should be more than enough for my needs. There is this solution: https://watts247.com/product/pip-1012lv-ms/
RE the DC-to-DC charger, as suggested- I'll start a new thread about it.

Eric

Thanks for your link. When you refer to a "1000w solution", are you talking about the maximum continuous power through the Inverter (pulling from DC batteries alone)?
You should note that reactive 120-VAC loads (e.g. a microwave oven) will need an Inverter rated at roughly 2x the RMS power of the Inverter, with around 4x the peak power. (Generally speaking, a "1000 watt" microwave creates too much stress on the components of a smaller Inverter, and will cause it to die at a young age. Reactive loads require more headroom, in this case a 2000/4000 Inverter would be the minimum size you would want to have running that microwave unit.)sing it to die young. simply puts "simple resistance" DC loads, such as a USA household toaster or a coffee maker, generally consume more than 1000 watts.

For both of those reasons, I have personally just upgraded from an overrated "1500 watt Inverter" (which, in actuality, can can only do about 1000 watts into a resistive load) into a so-called 3000/6000 watt inverter. Being another piece of off-brand made-in-China junk, I'm anticipating (and will accept) an over-rating by a similar factor. It arrives for testing today or tomorrow. (If it really does more than 1900 watts continuous into resistive loads, then I'm keeping it. If it can't do that much, I'll return it). The point of this story is the fact that many Chinese-built "1500 watt" Inverters iare NOT capable of running a household 'Mr. Coffee' machine.

Victron products, in contrast, nearly perform within a gnat's eyelash of their stated specifications. They cost much more, but I'd work extra hours to spring for the $1300 Victron, rather than the $425 PIP.

 

[eric_h]

Thanks for your link. When you refer to a "1000w solution", are you talking about the maximum continuous power through the Inverter (pulling from DC batteries alone)?
You should note that reactive 120-VAC loads (e.g. a microwave oven) will need an Inverter rated at roughly 2x the RMS power of the Inverter, with around 4x the peak power. (Generally speaking, a "1000 watt" microwave creates too much stress on the components of a smaller Inverter, and will cause it to die at a young age. Reactive loads require more headroom, in this case a 2000/4000 Inverter would be the minimum size you would want to have running that microwave unit.)sing it to die young. simply puts "simple resistance" DC loads, such as a USA household toaster or a coffee maker, generally consume more than 1000 watts.

I actually calculated that I would need about 500w and that's why I went for the 1000w solution. I'm not a microwave person (planning to pull it out and gain the storage space and weight), and prefers my propane stove any day of the week for anything (including hot drinks)
I also heat (the trailer and shower water) with propane (and a few amps for the fan), but do keep a small 400w-500w convection heater as backup, and I despise the noise the AC makes, so really never use it and resorts to fans.
Other requirements could be my laptops, which won't go over 130w each, TV, some led lights etc.

I did have the intention of giving my inverter 50% slack, and my calculations seem to show that I do.

For both of those reasons, I have personally just upgraded from an overrated "1500 watt Inverter" (which, in actuality, can can only do about 1000 watts into a resistive load) into a so-called 3000/6000 watt inverter. Being another piece of off-brand made-in-China junk, I'm anticipating (and will accept) an over-rating by a similar factor. It arrives for testing today or tomorrow. (If it really does more than 1900 watts continuous into resistive loads, then I'm keeping it. If it can't do that much, I'll return it). The point of this story is the fact that many Chinese-built "1500 watt" Inverters iare NOT capable of running a household 'Mr. Coffee' machine.

All that said, with your input- and thinking about getting a 2000w inverter- if I'm to go for an all-in-one solution, I'm not sure it would still be cost effective to go to a higher wattage one, or to revert to the idea of separate devices. I have a challenge in finding space for all of these devices in my trailer.

PIP was recommended in this channel, but I'm open to other options, of course.
Any suggestions?

Thank you!

 

[time2roll]

Most items will run on 300w inverter and is far easier to install. If going much larger I recommend going all the way to 2000w as it will run anything with a regular plug. Forget about resistance space heaters and use an electric blanket if something is needed.

 

[eric_h]

Let me ask that in another way: if I follow Will Prowse's blueprint here: https://www.mobile-solarpower.com/the-classic-400-watt-rvs-vans-buses.html, and due to the lack of space in my trailer, I wonder if there's a good all-on-one solution that will cover at least the MPPT controller+Inverter+ATS parts of it, and that are still 12V?

 

[eric_h]

If the Keystone power center is WFCO and you do want to stay with the current WFCO charger, I would switch the Converter battery profile to AGM/GEL mode. That prevents the converter from inflicting possibly harmful "anti-sulfation" cycles on the LFP batteries.

The WFCO Converters (they call them "main board assembly", or "MBA') are generally too fast to drop into a low-voltage "Float" or "Storage" mode. Float if maintained for a long time, can charge LFP battery banks pretty decently. But if you want to charge quickly more quickly (from a generator) you might want higher "Boost" Voltage to be maintained for longer time period, and you might want a method to force "Boost mode" even when the WFCO thinks that the battery (assumed by a WFCO MBA to be lead-acid) is at an adequate State of Charge already.

LFP "12V" batteries will not test, at tiny discharge current values, much below 12.8V for most of the State-of-Charge range. Their Voltage only begin to fall off, when less than 20% of battery capacity remains. WFCO believes the batteries, perhaps only 25% full, to be nearly 100% as lead-acid batteries.

Those WFCO "MBA" units which offer a Lithium switch will, like many others, push almost 14.6V whenever they are plugged in. This will push your battery to 100% capacity (unless the BMS charge circuit shuts down "charging" at a somewhat lower voltage). Lead-Acid batteries love to be stored at 100% SOC for as long as possible, but that's very bad for LFP cells. My advice is to NEVER use the "Lithium" setting on a WFCO converter board, and I also apply that advice to US-built and somewhat better 'Progressive Dynamics' main board assemblies.

In my own Travel Trailer, I have one of those Progressive Dynamics Converters. I have it set for "AGM/GEL" batteries, preventing anti-sulfation cycles. The PD Converters offer a controller pendant with a button, with which you can forcibly switch the operating mode from "float" 13.6V or "storage" 13.1V to "Boost mode" voltage. Following "boost mode", the PD Converters will maintain "float voltage" for about a week. If your trip is longer than a week, you need only press the button to invoke "Boost" Voltage for another short period of time.

Victron makes a great little 120-VAC Converter, but it maxes out at only 15A. To go bigger with a superior Victron product (with full programming and monitoring via bluetooth) you would need to switch to a full Inverter/Charger/Power Distribution unit, as smoothJoey recommended in the previous post.
- - -
If you go "my way", keeping the current WFCO load center, you have new and separate costs (plus installation hassles) for the new Inverter and transfer switch. The fantastic Victron "all-in one' units performs all 3 jobs, you would need only a cheap (and small) DC-12v distribtuion panel for the fuses and downstream "12 VDC" circuits in your RV Trailer. Progressive Dynamics makes a very good and small unit for that DC 12v Power Distribution job.

I know a couple of people who use the bigger Victron units in travel trailers of my own type ("Trailmanor" aluminum pop-up Travel Trailers, they're not cheap), and I'm very jealous of their upgrades. With a Victron load center, you would also have the option of configuring the battery pack at 24V, or even 48V - while still providing "+12V" to the output power port for your 12V load circuits.

OK. It took a week but I finally got the exact model: WFCO WF8955PEC.
Specs say:

Converter Type	Three-Stage Converter Charger
Output Current	55 A
Voltage Output	13.2 – 14.4V DC Range
Absorption Mode (Nominal Voltage)	13.6V DC (nominal voltage)
Bulk Mode (Quick Charging Voltage)	14.4V DC (quick charging voltage)
Float Mode (Trickle Charge Voltage)	13.2V DC (trickle charge voltage)

So, if I understand correctly, for my 200ah LFP batteries, once it detects "fully charged", it will not actually charge again until the batteries reach below around 20%, right?
Btw, their page claim that: "Our standard products will charge your lithium-ion battery, without damage or excessive heat so you will not have to worry about where your power supply will be coming from", including the 8900 series.

Btw- they are offering the "WF-8950L2-MBA" that changes the motherboard to support LFO, but seems that it would be more cost-effective to get an inverter/charger instead, that supports both...

Also:

Output Power	940 W

Is that also the maximum power the board can take or just the maximum output coming from the converter? I was planning to route my 2KW inverter directly via the circuit board (via ATS) to the trailer. Should that pose a problem, with the inverter ability to produce more than 940W?

Thank you!

 

[jbird526]

Dc2dc chargers have a lot of hidden gotchas to navigate.
If you open a new thread on the subject I would be glad to share what I have learned.

@smoothJoey Would it be possible for you to post a sticky or resource with the gotcha's at some point? I think a lot of people would be interested.

 

[time2roll]

OK. It took a week but I finally got the exact model: WFCO WF8955PEC.
Specs say:

Converter Type	Three-Stage Converter Charger
Output Current	55 A
Voltage Output	13.2 – 14.4V DC Range
Absorption Mode (Nominal Voltage)	13.6V DC (nominal voltage)
Bulk Mode (Quick Charging Voltage)	14.4V DC (quick charging voltage)
Float Mode (Trickle Charge Voltage)	13.2V DC (trickle charge voltage)

So, if I understand correctly, for my 200ah LFP batteries, once it detects "fully charged", it will not actually charge again until the batteries reach below around 20%, right?
Btw, their page claim that: "Our standard products will charge your lithium-ion battery, without damage or excessive heat so you will not have to worry about where your power supply will be coming from", including the 8900 series.

Btw- they are offering the "WF-8950L2-MBA" that changes the motherboard to support LFO, but seems that it would be more cost-effective to get an inverter/charger instead, that supports both...

Also:

Output Power	940 W

Is that also the maximum power the board can take or just the maximum output coming from the converter? I was planning to route my 2KW inverter directly via the circuit board (via ATS) to the trailer. Should that pose a problem, with the inverter ability to produce more than 940W?

Thank you!

No detection of charge level. Most likely never see 14.4 volts. Just charge away at 13.6 indefinitely. Possibly drop to float (13.2v) after several days or a week of non use. Nothing "smart" here. Mostly just a timer.

I would stay away from the 8950L2-MBA as it runs at a higher voltage that is unnecessary.

940w is the max power of the converter. Can feed the 120v side with 2kW as the normal input is 3.6kW, unless it is 50 amp then 12kW.

 

[eric_h]

No detection of charge level. Most likely never see 14.4 volts. Just charge away at 13.6 indefinitely. Possibly drop to float (13.2v) after several days or a week of non use. Nothing "smart" here. Mostly just a timer.

I would stay away from the 8950L2-MBA as it runs at a higher voltage that is unnecessary.

940w is the max power of the converter. Can feed the 120v side with 2kW as the normal input is 3.6kW, unless it is 50 amp then 12kW.

Thank you!

 

[eric_h]

@smoothJoey Would it be possible for you to post a sticky or resource with the gotcha's at some point? I think a lot of people would be interested.

You could see the discussion @smoothJoey, others and I had here