Charge Lithium Battery With Shore Power

[hovr]

Hi,
I have been learning a lot about LiPo4 batteries, BMS, MPPT charge controllers and solar panels in past week or so. One topic I have not found much information on is how batteries are charged (with protection) when it's hooked up with shore power. I have not seen any wiring schematics that shows what's between 110v/30A and battery, all the wiring schematics posted by folks shows that the solar charge controller isn't used. I know some folks with good roof estate only use solar to charge their batteries, but my 16 caravel only have enough space for 180w or so, and in PNW, in most of months of the year, it would likely take a week to fully charge a 200A battery. It would be great if I can hook up to shore power and get the battery charged overnight.

So what's needed to charge LiPo4 batteries with shore power? there should be a 110vAC -> 12v DC converter that charges the factory installed lead acid battery, but Lithium batteries requires temp protection - charge controller has temp sensor but if it's not used for shore power.

Thanks,

-Hovr

[fran&frank]

You are correct, you need some type of charger with an appropriate charge profile for a lithium battery. It could be a converter/charger or an inverter charger depending on how you are configuring your system. Some lithium batteries have a bms with a built in low temperature disconnect. My system consists of a Victron Multiplus inverter/charger, and Victron battery monitor, and a temperature probe and I programed the Multiplus to not charge the battery when its below 35 degrees.-- Frank

[hovr]

Originally Posted by fran&frank

You are correct, you need some type of charger with an appropriate charge profile for a lithium battery. It could be a converter/charger or an inverter charger depending on how you are configuring your system. Some lithium batteries have a bms with a built in low temperature disconnect. My system consists of a Victron Multiplus inverter/charger, and Victron battery monitor, and a temperature probe and I programed the Multiplus to not charge the battery when its below 35 degrees.-- Frank

Thank you, I feel like I am going down a rabbit hole with this DIY solar/battery project , hopefully this is the last component I didn't plan for.

[PB_NB]

I ordered a new charger for my new lithium battery. I will disable the charger built into the fuse panel and install the new unit with an on off switch. Then I will use my battery monitor to keep tabs on the SOC. When the trailer is parked at the house, I have it plugged in but don't want to run the charger all the time. The setting for lithium charge demands are slightly different from AGM or Lead Acid and this charger will allow my to set the charge voltage.

The lithium batteries usually have a BMS to control overcharging and overheating but better to be safe rather than kill an expensive battery.

[ROBERT CROSS]

Rabbit Hole...maybe.
Money pit...not necessarily.


I went with a Boondocker Lithium charger.

Our 2 Battleborn batteries have a built in battery management system,(BMS)

Bob
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[PB_NB]

My convertor is "B" coming off my Circuit number 2. Should be straight forward to isolate it and delete it.

[PKI]

Stop - you need a converter, either with the solar charge control or as a separate component that delivers the 14.4volts to charge the Lithium bank. We used the PD4655LI converter. Others are out there. The PD was installed in the original position with the jumper set to the LI voltage. However, there are some folks who recommend the original version of the PD with the dongle that pushes up charge voltage for a short period and then drops back to 13.7 volts. We just turned off the use/store switch when more charge was not needed. Not sure what your '16 has for circuits. Check manual and verify what you have. Then call your lithium cell provider for guidance. BattleBorn was very helpful when we installed ours. Note - a battery management system that measures use and charging status is very helpful. Would not be without one. Pat

Note - how is battery charged on shore power - 120v goes from pedestal to the converter. 12v goes from converter to the battery bank. Works as it does in your original circuits. Difference is higher voltage.

Note - the Sports have different, less complicated, circuits, so verify what you have first.

[PB_NB]

Hi Pat, the convertor onboard provides a charge to the Lead Acid battery. If I was to stop it from charging the battery by disconnecting it, would I be disabling other functions in the trailer?

I know that the automatic function would be lost with a separate charger rather than one always on.

My understanding is that the converter just charges the battery by converting 120AC to 12DC. This could be achieved with a lithium battery charger as well.

If I am missing something, please advise.

Thanks, PB

[ROBERT CROSS]

What is important with Lithium batteries...using a charger that will provide the correct charge profile, you achieve that by upgrading the current converter/charger or replacing it.
Ours could not be converted to the lithium profile and had to be replaced.

Bob
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[hovr]

Thanks folks, after a bit more research I found this in the Caravel manual, converter charger section -

Automatic Micro-Controller Operation
The power converters 3-stage switch mode is fully automatic. The converter senses which mode it needs to be in by checking the condition of the battery. The three modes include:
Absorption Mode: During this mode the converter output is in the 13.6 VDC range. This is the mode that the converter will function at normally. This mode provides the 12 VDC and the current required by the trailer.
Bulk Mode: In this mode, the output voltage of the converter will switch to 14.4 VDC range for a maximum of four hours. If the converter cycles between “Absorption and Bulk modes”, there could be a shorted battery cell or other issues.
Float Mode: If the trailer has not been used for a period of time and the shore power has been left plugged in, the converter will automatically go into float mode with a voltage of 13.2. When the converter senses a demand, by turning on lights, the converter automatically returns to absorption mode.

This should work well with the LiPo4 battery as is right, the 14.4 is a bit lower than 14.6 for 100% capacity, but I think the solar charger should have no problem top that off - seems like I don't need anything additional except to make sure the battery BMS has low temp shutoff, right?

[ROBERT CROSS]

I have 360w of solar...it has never charged to 100%, 14.2v

Shore power maintains 100% at 14.2v.

Bob
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[PB_NB]

Originally Posted by ROBERT CROSS

What is important with Lithium batteries...using a charger that will provide the correct charge profile, you achieve that by upgrading the current converter/charger or replacing it.
Ours could not be converted to the lithium profile and had to be replaced.

Bob
🇺🇸

Hi Bob, do you know if there are systems that rely on the converter for 12V DC rather than from the battery?

I tried the battery disconnect and all the 12V devices seemed to stop running except the propane monitor. even when sore power was still active. Airstream may have done some hidden wiring to pull 12V DC for some underlying system that I can't see in the drawings.

The charger I am getting is a GP 55A MAX Smart Charger. I was told by GP that I need to set the initial output voltage on the charger to match the battery. Then it is able to adjust the output mode automatically.

I have no problem disconnecting the supplied converter and running this GP unit but I was concerned that I might be disconnecting something else in the process. If we ever sell the trailer to get an extra two feet more down the road, I can just reconnect the converter and put the lead acid battery back in.

I think the term might be confusing the discussion when I refer to "charger" or "converter" but they are effectively doing the same thing.

[PB_NB]

Originally Posted by ROBERT CROSS

I have 360w of solar...it has never charged to 100%, 14.2v

Shore power maintains 100% at 14.2v.

Bob
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Are you using the same converter that is part of your fuse panel or a separate added charger? I have the same verbiage as Hovr in my manual. The GP unit is adjustable to 14.6V, and the BMS built into the battery has a max charge rate of 14.6V before cutoff, if that really makes a difference.

[ROBERT CROSS]

Originally Posted by PB_NB

Are you using the same converter that is part of your fuse panel or a separate added charger? I have the same verbiage as Hovr in my manual. The GP unit is adjustable to 14.6V, and the BMS built into the battery has a max charge rate of 14.6V before cutoff, if that really makes a difference.

Our stock Converter was a stand alone model mounted under the front couch.
The Boondocker just replaced it.

On our '06 Classic...the converter will power all AC & DC with the batteries removed, I'm not sure if the same applies to the newer AS's.

Bob
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[PB_NB]

Thanks, I think both hovr and I are on the right track with slight differences in the deployment but with similar end results, I hope!

[PKI]

Originally Posted by PB_NB

-- snip --would I be disabling other functions in the trailer? -- snip --

The DC electrical circuit schematic should detail all of the system connections. Pat

[uncle_bob]

Hi

Protection wise, your lithium's *should* have a built in BMS. In this day and age, if they don't ... buy another brand. That BMS does a lot of the management and protection stuff on the battery.

Lead acid charge profiles are different from lithium charge profiles. If you go from lead acid to lithium, you need to swap out the converter charger. The only exception is if you have a fully programable unit (not what comes stock) and can change all of it's parameters when you make the switch.

Ideally, you want to go up around 14.6V (but not over) when charging lithium. On a lead acid, this is not the case. You *do* equalize lead acid at this sort of voltage, but that is a different thing than routine / every time charging.

Once up to charge voltage, you want to cut back to around 13.5 to 13.8V on lithium. Again, not the same as the 13.2 that lead acid is looking for. Lithiums are well into discharge by the time they get to 13.2V.

Lithium's will "accept" a lot of current at full charge voltage. Lead acid ... not so much. The people who design lead acid chargers understand this. Their chargers often don't put out a lot of current at the high end voltage as a result. This means your lithiums take *way* longer to charge than they should.

Finally, not all "lithium" chargers are created equal. From what I've seen, it's a "get what you pay for" kind of deal. The Victron stuff is expensive, but it works well ....

Bob

[ROBERT CROSS]

ummm....from BB
"There is a wide variation among values for charging algorithms for lead acid batteries. The bulk and absorption voltages typically vary between 14.0 and 14.8 V, and the float can vary between 13.2 and 13.8 V. The 12 V Battle Born batteries sit comfortably right in the middle of these ranges. We recommend a bulk and absorption voltage of 14.4 V. A float is unnecessary, since li-ion batteries do not leak charge, but a floating voltage under 13.6 V is fine."

I'm sitting at 14.4 on SP.
What am I reading rong?
Is 13.2 well into discharge but nowhere near complete discharge?
OF needs to know.🥴

Bob
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[jimdelane]

Unless you are dealing with a home built battery, lithium batteries come with a BMS. The cells need protection to prevent overheating, overcharging, overvoltage, etc. That is why a BMS is necessary. Most smaller lithium batteries (100Ah) come with a 100A BMS. That means that it can take a 100A charge or discharge. However, for maximum life, a 25-30% charge is usually recommended. Larger lithium batteries are available (200ah, 300Ah and 400Ah and they offer BMS from 150A to 300A.
Unlike lead acid/AGM, each lithium battery acts as a standalone - in other words, when a lithium battery is fully charged, the BMS will cut off the incoming charge regardless of any other batteries in parallel.
The solution to your question is to purchase a lithium compatible charger/converter. I like Progressive Dynamics. For a 200Ah system, you might consider their 45A charger.
You will need a separate charger/converter for your lead acid battery. This charger will put out 45A at 14.5V continuous. You can also use the 30A also - it will increase charge time but not by much.
The BMS will protect you from overheating. You need to avoid charging the lithium battery if the battery is below 32F or freezing. The easiest way to avoid this is to have a heating pad in the battery box.

Suppliers of 200Ah, 300Ah and 400Ah batteries include

AMPS
https://lithiummarinebattery.com/

LiFeBlue
http://www.lifebluebattery.com/rv-bo...ion-batteries/

ReLion
https://relionbattery.com/products/lithium

[ROBERT CROSS]

The BB BMS has Temp control.
"Temperature. An internal battery management system (BMS) allows you to safely charge between 25°F-135°F (-4°C-57°C) and discharge between -4°F-135°F (-20°C-57°C).Nov 21, 2019"

Our BB's remain in the AS all year here in WNY.
Bob
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