Charging 4S-12 Volt Lifepo4 Batteries with Made Well NPB-360-48? Slow Charging is the Question.

[kenden]

I just purchased 4 HiMASSi 12V 100ah low temp charging batteries to replace the SLA batteries in my Ryobi Zero Turn mower. I think that I have decided on the Made Well NPB-360-48 charger to use with them as it provides a 2 or 3 stage charging profile where I can adjust the output voltage (42-60V) and current (3-6amps). I expect that I will use the mower 1-2 times per week. So a long charging time is not a concern.

I am planning to only charge to ~90% by limiting the voltage to some value less that 57V and only using the 2 stage charging. The spec sheet for the charger suggests charging batteries with an amp-hr capacity between 20-65ah but recommends checking with battery manufacturer...

As I have no experience with Lifepo4 batteries, will charging these 100ah batteries with only 5-6 amps a cause problems with them? reduce their life?

Google and I have not been able to find anything that suggests that it does but I thought I would ask here as there seems to be a lot of experience.

Also, the battery BMS uses a bluetooth app that allows for monitoring the SOC and cell balance.

 

[time2roll]

Slow charging is not a concern. 5 amps is plenty.

Battery to battery balance is a concern. Need to fully charge all at 12v parallel to make them balanced. Or need a battery to battery balancer. The BMS will balance the internal cells but generally not battery to battery.

The other concern is to verify the 12v batteries are compatible with having four in series. The BMS for each battery needs to be capable of controlling the full 48 volts.

The Meanwell NPB series chargers work great.

 

[D71]

Himassi has instructions on the side of their 12 volt 100ah 1280w smart bt batteries. Picture of 1 of mine included for instructions: "they basically state charge battery individually -12 volt charger, tie parallel for more then 12 hours, remove from parallel configuration, and then tie all 4 in series for 48volts. "

The parallel gives the cells - in batteries time to somewhat normalize as was explained to me from Himassi.

I went to tie mine together and found that Amazon had sent me the wrong lugs. ?? so they should be here tomorrow. I am building mine inside of a roll around metal cabinet. Had planned to install attached inverter all in one MPP Solar 3048 on inside of metal cabinet.... clearance issues per the manual for cooling made me halt on that. The 3048 will provide my battery charging.
I also have a backup 48volt charger ~13amps advertised.
Amazon Now back in stock.
https://www.amazon.com/gp/product/B0BF5K3WGC/ref=ppx_yo_dt_b_asin_title_o00_s01?ie=UTF8&psc=1
figure maybe given my battery info statement of 1280watts per battery means 1280w x4=5120 watts so
5120w/100a = 51.2 volts.
51.2volts x my charger 13a = 665w
5120w / 665w =~7.7 hours with my charger 0% to 100% SOC

I doubt my batteries will ever see a 0%SOC from normal use The time maybe somewhat longer as the bms will drop the amps closer to 100% soc it gets. When charging mine with 12 volt smart charger - bms throttles them back when close to 90% or so. These batteries are suppose to be rated max 50amp charge.

This is an interesting charge calculator - I found online. If you intend to use it a lot would charge to 100% and stop at 10% earlier on the bottom end.

Battery Charge Time Calculator - Footprint Hero

Calculate how long it will take your battery charger to charge your battery with our free battery charge time calculator.

footprinthero.com

Any reason why you want to limit top to 90% SOC and 2 stage charging ?

Let me know how they work in your 48v lawn mower. Again in pinch think you might be able wire it up to also use your batteries with a 48 volt inverter. Definitely let us know how that charger works out It will be slow recharging at 3 amps. Is it selectable for 6 Amps or does it self adjust?

 

[kenden]

Slow charging is not a concern. 5 amps is plenty.
The Meanwell NPB series chargers work great.

Thanks for the validation. I bought the Mean well because it allowed for some ajustability and was the only supply I could find with either UL or CSA safety testing.

Any reason why you want to limit top to 90% SOC and 2 stage charging ?

As I am replacing SLA batteries, I thought that charging to the Lifepo4 to 80-90% would be closer to the SLA voltages. As for the 2 stage charging, I did not think the float was necessary. Also, from what I have read that not fully charging and discharging to ~20% improves life expectancy.

I charged all of the batteries in parallel and then left that way for several days. The charge dropped from 100% to 99% as the individual cells continue to balance. After a few days, the max difference between any of the batteries was .01v and only .002v max between any of the cells of any battery. I felt that was beyond the measurement accuracy of the BMS....

I connected the batteries in series and installed them in the mower. Once I tried to turned the key to power mower, the c-mos and d-mos kicked in on all 4 of the batteries. It clears as soon as I disconnect the battery bank. The mower key powers a 48v relay that charges all of the motor controllers. I assume the inrush current is more than the BMS can handle so it shuts shuts the batteries off. After a bit of research, I found several pre-charge circuit concepts that seem to be what I need to limit the current so that the controllers capacitors charge a bit slower.
The key switch on the mower has two settings,run and accessory. I plan to use the accessory connectors to switch in a 48V relay that connects a PTC and 33ohm resistor across the main power relay. That way I can turn the key left to accessory then right to power the mower up....That the plan anyway.

 

[D71]

Thanks for the validation. I bought the Mean well because it allowed for some ajustability and was the only supply I could find with either UL or CSA safety testing.


As I am replacing SLA batteries, I thought that charging to the Lifepo4 to 80-90% would be closer to the SLA voltages. As for the 2 stage charging, I did not think the float was necessary. Also, from what I have read that not fully charging and discharging to ~20% improves life expectancy.

I charged all of the batteries in parallel and then left that way for several days. The charge dropped from 100% to 99% as the individual cells continue to balance. After a few days, the max difference between any of the batteries was .01v and only .002v max between any of the cells of any battery. I felt that was beyond the measurement accuracy of the BMS....

I connected the batteries in series and installed them in the mower. Once I tried to turned the key to power mower, the c-mos and d-mos kicked in on all 4 of the batteries. It clears as soon as I disconnect the battery bank. The mower key powers a 48v relay that charges all of the motor controllers. I assume the inrush current is more than the BMS can handle so it shuts shuts the batteries off. After a bit of research, I found several pre-charge circuit concepts that seem to be what I need to limit the current so that the controllers capacitors charge a bit slower.
The key switch on the mower has two settings,run and accessory. I plan to use the accessory connectors to switch in a 48V relay that connects a PTC and 33ohm resistor across the main power relay. That way I can turn the key left to accessory then right to power the mower up....That the plan anyway.

I was worried when you stated were going to use them in a lawn mower…. You have a lot of amp requirements with a mower…. Not only pulling it’s weight, your weight, but mowing too. The 4 bms can be seen as 4 safety devices or as 4 problems. I wanted a 48volt battery with just 1 bms but they were a lot more money. A 48v rack type was around twice the cost with shipping fees. These lifepo batteries are incredible but the amp output being limited by the bms may make it unusable for you.

Are you 100% sure of your connections? Or have you figured it out yet? Is it working for your purpose. Is this your mower?

edit added did read where a guy used these batteries in a golf cart.

 

[D71]

If this is your lawnmower see 2 motors 2 drive controllers, 2 deck motors 2 deck motor controllers, a charge controller, and a 12 volt dc converter

 

[kenden]

Are you 100% sure of your connections? Or have you figured it out yet? Is it working for your purpose. Is this your mower?

Yes that is the mower I have. I have really enjoyed using it. The blades are a bit thin and have bent them on two occasions. I am looking forward to losing more than a 160 pounds by replacing the batteries. Mowing uses ~40-60 amps.

I am sure of my connections? Yes. The LIFEPO4's are exact same size as the SLA, so connections are easy. I have verified that I can power everything except the drive controllers. With them in the circuit it shuts the BMS down as soon as I turn the Key on. The Key energizes a relay that powers the drive controllers, a 48-12v converter, and the useless power meter. It sure would be nice to have a true schematic of the wiring. I have been using the part drawing like you have attached and and a VOM to trace out the circuits and it is a pain.

I am waiting for the resistors to arrive. I should know early next week if the issue is solved. I hope they solve the problem.

I am not fond of the EE-BMS app. I was hope to use it as my only battery monitor. Not sure why a password is needed to see the cell voltages or fault codes.

 

[D71]

Yes that is the mower I have. I have really enjoyed using it. The blades are a bit thin and have bent them on two occasions. I am looking forward to losing more than a 160 pounds by replacing the batteries. Mowing uses ~40-60 amps.

I am sure of my connections? Yes. The LIFEPO4's are exact same size as the SLA, so connections are easy. I have verified that I can power everything except the drive controllers. With them in the circuit it shuts the BMS down as soon as I turn the Key on. The Key energizes a relay that powers the drive controllers, a 48-12v converter, and the useless power meter. It sure would be nice to have a true schematic of the wiring. I have been using the part drawing like you have attached and and a VOM to trace out the circuits and it is a pain.

I am waiting for the resistors to arrive. I should know early next week if the issue is solved. I hope they solve the problem.

I am not fond of the EE-BMS app. I was hope to use it as my only battery monitor. Not sure why a password is needed to see the cell voltages or fault codes.

That’s part of reverse engineering for a name and it sucks. Sorry can’t help more. That lawn mower looks very interesting…. I have a cub cadet S zero turn … it is getting older now….. if it goes have considered an electric mower. Btw bent the blades on mine too. Bought some new ones. The blade spindles had a recall on mine too. They put steel parts in carburetor that rust and corroded due to alcohol… replacement carbs have same junky parts. It is the epa required electric solenoid shut down valve. Gasoline with alcohol causes a lot of problems.

your lawn mower looks interesting. I will do my best try to help you find a print … now that know it is what you have. Mtd use to make a lot of lawn mowers. …. Just different names labels.

I don’t like that app either. The 666666 code is a pita to enter every time. Be nice to see all 4 batteries at same time too

 

[D71]

Did you see this post?

Ryobi Zero-Turn Mower SLA to LiFePo4 Conversion - (Updated - Build Complete With Pics!)

Hi. I'm new to the forum. I have a 48V Ryobi Zero Turn that runs off of (4) 100AH AGM batteries. It's been about three years and now I can't get through a full cut. I would like to upgrade to LiFePo4 batteries. I'm thinking of using these ones...

diysolarforum.com

they may be able to tell-share their findings and resolutions

 

[kenden]

Did you see this post?

Ryobi Zero-Turn Mower SLA to LiFePo4 Conversion - (Updated - Build Complete With Pics!)

Hi. I'm new to the forum. I have a 48V Ryobi Zero Turn that runs off of (4) 100AH AGM batteries. It's been about three years and now I can't get through a full cut. I would like to upgrade to LiFePo4 batteries. I'm thinking of using these ones...

diysolarforum.com

they may be able to tell-share their findings and resolutions

Oh yes, I thought that I would be building my battery pack as demonstrated in that post. But these batteries are cheaper and I hope have a warranty should they fail within the next few years. I was able to wire a 33ohm resistor using the accessory part of the key switch and it works fine. It would be nice to put a time delay relay in line with the main switch so that one could start the mower without have the turn the key both ways...
I did my first mow where I scalp the yard and bag it taking all of the clippings to the compost at the back of the yard. Everything worked great and I used up ~70% of the battery. The charger did fine at 6 amps and charged overnight.
As soon as I plugged the charger in the cycle count on the battery BT app registered 1 cycle. I would like a better way to monitor SOC but not really interested in buying a new meter.

 

[D71]

Oh yes, I thought that I would be building my battery pack as demonstrated in that post. But these batteries are cheaper and I hope have a warranty should they fail within the next few years. I was able to wire a 33ohm resistor using the accessory part of the key switch and it works fine. It would be nice to put a time delay relay in line with the main switch so that one could start the mower without have the turn the key both ways...
I did my first mow where I scalp the yard and bag it taking all of the clippings to the compost at the back of the yard. Everything worked great and I used up ~70% of the battery. The charger did fine at 6 amps and charged overnight.
As soon as I plugged the charger in the cycle count on the battery BT app registered 1 cycle. I would like a better way to monitor SOC but not really interested in buying a new meter.

I think the amazon listing said 1 year for battery warranty. ? glad to read it is working as you needed. It ought to be several hundred pounds lighter with the lifepo vs lead acid.. Are you getting longer run time mowing with lifepo vs the lead acid? I’d think the lighter weight would extend run time Vs former lead acid?

I don’t like fast high amp charging …. makes me nervous…. My external stand alone 48v charger normally runs around 10 amps…. or so. My all in one mpp solar inverter battery charger can dump a reported 60 amps into the batteries. Problem is the batteries are only rated 50amp charge for a max. I have the all in one mpp solar inverter set to 20amps for my battery charging.

I think someone said if recharge batteries from 30%-40% SOC or below that the batteries would show an added cycle. I am at 2 cycles now. I had topped them off when at 70% or so…never cycled. Ran it down to 45% in 24 hour period testing …… when recharged - flipped to 2 for the cycle count according to my bt app. Might have been on the amazon website for triggering the SOC cycle count

Had used my 12v series to 48v battery system to run mpp solar 3048 inverter and refrigerator for 24 hours. Drained batteries to about the 45% SOC. About $3500+ into system Including solar panels. The shipping on solar panels is high right now. The inverter is hungry but it has lot going on for internal circuit draws..… powering internal battery charger - mppt solar charge system

I’d just use the bms bt app to monitor SOC if I were you and save the money. It is a shame can’t buy that mower with lifepo already in it. Maybe they will update that model in the future without going insanely expensive.

I never did find a print for it…. Use to be able find things like that online but not that mower. ?