Lithium BMS Question

[TitanMike]

I've not heard of landing gear motors exceeding the 100a start-up BMS threshold and as you've mentioned, so far, no one has responded they have.
Nor have I ever seen landing gear circuits fused that high. 'Some' hydraulic units that control hydraulic Level-up and hydraulic slides are fused higher but you did not specify you had that system.
I'm wondering your concern or what made you believe the landing gear motor would be an issue?

I did some quick research. Replacement nkn-hydraulic landjng gear motors i looked at all have 12v-30 amp labels on them. Some landing gears have dual motors for independent operation of the legs.

Max current should be 30 amps for single and 60 amps for dual motor type. One hp Hydraulic pump 12v permanent magnet motors generally draw <75 amps.

Far less than the 100 amp bms in many, if not most, lifepo4 100 ah sized batteries.

Once again, for the benefit of anyone who missed it earlier, if the fuse protecting the motor(s) isn't blowing why should a 100 amp rated BMS shut battery down?

 

[richp-FRF]

I have pretty well decided what I'm going to do and I appreciate all of the help provided here. I believe I'm going to go with their 140 amp hour, 150 amp BMS model. I think the comment about the fusing on that circuit pretty well answered it for me, and that choice gives me a nice increase over what I have been comfortable living with for years.

For sort of a bit of clarity in closure, these are one motor electric landing jacks, not hydraulic. It's an older unit without a leveling system, hydraulic jacks, residential refrigerator, and some of the other stuff that people are taking for granted these days.

 

[richp-FRF]

Hi Jim,

Thanks for your additional comments.

Because the motor has functioned flawlessly for 10 years on a 30 amp fuse, I'm not concerned there is any thing unusual going on there.

I know the electrical characteristics of a fuse and a BMS are different. But I stepped out a little bit (with the additional thought in mind that no one else has reported the problems I've been concerned about). So yesterday I went ahead and ordered the 140 AH LiTime with low temperature protection and a 150 amp BMS and Bluetooth. It should arrive sometime in the middle of next week, and after I get it installed, I will report back.

 

[JimM2109S]

Rich, please do check back and report your results after adding the new battery to your system, whether problem solved or still existing. Just as you were seeking others with the same problem, it can potentially help someone in the future.

 

[richp-FRF]

Will do. I took delivery of the battery today, and I'm waiting on the lithium compatible converter to arrive before I set things up.

 

[Aussieguy]

if you wanted to... connect the battery up now and get to know it and the app
see how to use it and test to see how much is actually charging..... AS IT IS (base charge)

while you waiting you can look for the cable connections and make sure they all good
especially the negative to frames

good negatives are vital for quick charging... otherwise you wasted good $$$ on a converter upgrade


do a second charge and see how much improvement you got from all your hard work and $$$

 

[richp-FRF]

I loaded the app, and just sitting on the bench, it's showing 52% SOC.

I'm reluctant to connect it to a non-lithium charger out of an abundance of caution, because the instructions say to charge it fully before using it. I suppose I could disconnect the current charger and just let my solar system pump it up tomorrow, after I changed the settings in the solar controller. Waiting a day or two more won't hurt anything, but I'll give that some thought

 

[tomkatb]

It is advisable to own a Victron battery charger or an equil.

If you were to completely discharge the battery most converters or battery chargers will not wake them up. Sometimes a jump start will. Sometimes not.

You should charge the battery before installation.

These new chargers also restore old wet cells. Buys you a year more use. Replaces those old relics in the garage.

Can be used in parallel with any converter. But, most old converters work fairly well.

 

[richp-FRF]

I have a Progressive Dynamics lithium capable charger on order, and I've been using a programmable Bogart Trimetic solar controller for years, which can easily be changed to lithium settings.

I'm living in the trailer right now and don't want to put a 12 volt load on the battery until I get it fully charged. That's why my current plan is to wait until I take delivery of the charger. Then I will kill the line and solar feed, install the new charger, change the settings on the solar controller, pull the Trojans, install the lithium battery, fully charge it off of 120, then reconnect the solar panels.

I maybe overthinking this, but it seems like waiting a few more days for all the pieces to be in place will be worth it.

 

[Aussieguy]

Lifepo4 don't have a memory like the laptop batteries did
if you used it at 60% no drama won't hurt it
BUT it will take longer to charge once you get your charger
60% will have plenty of good voltage output.. 13.1 to 13.2 more than enough to play with the landing gear

Just remember .... when boondocking overnight your battery just might be at 60% when you need to hook up the truck.... now is probably a real good time to test it!
don't get caught manually cranking the landing gear first time out camping

=============================================================
they send it to you half(ish) charged due to over caution for shipping... less charge = less chance of hurting something if cells were damaged in transport

me... use it NOW and see how it charges and lifts the landing gear
then add the newer charger later
always nice to confirm the newer charger performs well

or install the battery get it working... play with the app
but don't charge it until new charger arrives

one reason to go lifepo is the extended flat power curve
Inverters shut off at around 11v ,
motors slow down as volts decreases
amps go UP trying to keep the motors running ..... as the volts go down

 

[tomkatb]

Yes you are overthinking.

When you get the battery hook it up to a lithium charger for 24-48 hours. Then install.

You can monitor its progress and verify it is good to go.

Are we confusing the word charger and converter? They are not the same.

Battery people recommend using a charger not a converter for the first charge. A lot of bad batteries are shipped.

My battery guys recommended charging the battery with a charger and then discharging. Then recharging. Gets the battery monitor right also.

 

[TitanMike]

Yes you are overthinking.

When you get the battery hook it up to a lithium charger for 24-48 hours. Then install.

You can monitor its progress and verify it is good to go.

Are we confusing the word charger and converter? They are not the same.

Battery people recommend using a charger not a converter for the first charge. A lot of bad batteries are shipped.

My battery guys recommended charging the battery with a charger and then discharging. Then recharging. Gets the battery monitor right also.

Don't know who "your battery guy" is but the advice he gave you is contrary to what Battleborn and several others recommend. For the record modern Converters installed in RV's are both converter AND charger with battery specific charge profiles. Lead Acid profiles with earlier models and LiFePo4 profiles for those produced in the last couple of years either auto-detected or manual select.

FWIW I just finished FULLY charging my lifepo4 battery bank using my
"Converter/Charger " (Phoenix IP-43 12/50) which brought battery bank to 14.6v, held it there for prescribed Absorption Time, and now switched to 13.5v which is Float. At this voltage the "Charger" behaves just like an old fashioned Converter, maintaining a set voltage that now provides power to the 12v system so the batteries are maintained at near full charge. New converter chargers are multistage rather than just single voltage units of the 90's

 

[tomkatb]

I think it is the old kiss principal mostly.

90% of batteries are ok when shipped. It is wise to make sure they are ok before installation. These batteries are not user serviceable. So they have to go back. Save the box.

Converters are missing a portion of the ability of the fancy lithium chargers. Many will not wake them up. Usually requiring very low voltage and amperage for several hours gradually increasing. Your converter likely does not have that profile.

I doubt there will be any issues. This recommendation came from SOK and Advance auto who sells a lot of batteries.

Follow whatever instructions are in the box.

 

[TitanMike]

Converters are missing a portion of the ability of the fancy lithium chargers. Many will not wake them up. Usually requiring very low voltage and amperage for several hours gradually increasing. Your converter likely does not have that profile.

Where are you getting this information?

On the contrary many "Chargers' can't wake up LiFePo4 batteries as they require sufficient voltage from the battery to wake THEM up before they start to charge. Simple test, see if the CHARGER will light up a light bulb with no battery connected.

Even WFCO states their lifepo4 capable converter/chargers will wake a sleeping lifepo4 battery.

 

[richp-FRF]

I may have created part of the problem here by using the term charger instead of converter. The model I've ordered has specific lithium settings.

 

[TitanMike]

I may have created part of the problem here by using the term charger instead of converter. The model I've ordered has specific lithium settings.

Progressive Dynamic's Converters are also Chargers.

A converter first charges any battery connected to the 12v system. When battery reaches 100% charge ( by measuring voltage and tail current) it switches to a maintenance charge at a Float Voltage, providing power as long as needed.

A separate charger can do the same although if a Converter is part of the system it's redundant and unless properly configured, potentially damaging.

 

[Aussieguy]

any 12v source can charge up a battery... jumper cables between cars leave them on long enough and the dead battery takes on some charge

connect two batteries in parallel .... they will eventually reach the same voltage one charges the other

basic alternators are pretty dumb...
no real charge profile that's why they set the voltage lower so it won't hurt the battery
Smart alternators ... can increase the voltage for faster charging (never tested or used a smart alternator)
Voltage is the battery killer high volts will boil lead acid
Or swell lithium cells... that's why there is a BMS, if it detects high volts it will shut off charging

Converters are chargers in that they reduce the voltage to a float level when it detects battery if full
never had to see if my battery wakes up by converter... but I see no reason why it should NOT... converter will just see a flat battery as another load..
just like the lights and water pump are LOADS to the converter

once the converter see the amps on the battery "load" go down ....
there must be some sort of logic programed in there...
"hey I think this is a battery better use float voltage" ........ because other 12v stuff , don't behave this way...
voltage stays high and amps go down.

Good thing about Lifepo4 .. the BMS makes it harder for us goofus's to hurt them

Please no comments on non technical use of battery / converter wordings

 

[tomkatb]

We had serious issues with our lithium batteries.

I worked with a senior tech in China at SOK.

Their documents are on line. Not second hand opinions from non professionals with perceived information. They used the term most converters.

I have read many specifications for a living. Reading between the lines is an art.

My batteries could not be awakened by two converters and a battery charger or jumper cables. A power supply did not work.

We carry a Victron charger. We have a non lithium converter.

Works well. I will use the Charger once or twice a year. Not apparently necessary.

 

[richp-FRF]

Okay, time for what I hope is the wrap up report.

I installed a LiTime 140 ah, 150 amp BMS, Bluetooth battery this morning after fully charging it overnight. It came with a 52% state of charge, and didn't require any particular procedure to start topping it off. The LiTime Bluetooth app immediately started giving data, as it sat there charging. After I got the battery in, I installed a Progressive Dynamics lithium compatible converter, and reprogrammed my solar controller for lithium.

The original question was whether the jacks would work, and they do.

All of the other systems seem to work fine, with one odd exception. The LED lights in the trailer flicker when on battery alone. I went out and retightened all of the connections, and we'll just wait to see what happens on that.

Thanks to everyone who contributed to this discussion and to helping me work through this.

 

[Aussieguy]

test it without the shore power and less than 100% charge
make sure they got the oomph
(simulating a night's discharge while boondocking)