Finally found a LiFePO4 BMS with Low-temp Charging Protection

[Sgt Raven]

Quick question from a newbie. I have decided to jump in and built a 200ah battery pack using everything from Will’s $555 video for use in our 5th wheel trailer Instead of buying the Battleborn batteries. I did upgrade to the 4S 120a BMS And seem to have gotten everything put together and working. I downloaded the Xiaoxiang BMS app for my iPad/ iPhone, paid the $6 upgrade, and it instantly connected and works perfectly. My question is about the app and the parameter settings I should use for these batteries. The app has clearly been updated to a newer version, which is why I’m a bit lost as it does not look like the one Will was adjusting. I did figure out how to change and save the ‘designated capacity’ to 200k mAh, but that’s about all I know. If somebody who knows these LiFEPO4 battery parameters could please help me adjust whatever other parameters need adjusting I’d really appreciate it. It should be as simple as changing the numbers, clicking ‘save configuratio’ button then clicking the ‘BMS write’ button. I hope !! I’ll include photos of what the updated app screens look like and it’s current default settings. Thank you much

I can't help you with the settings or the App, but in general, iOS Apps tend to look a little different than a Android App. Sometimes a lot different.
I happened to have that video cued up and stopped where Will has the App on his phone and I'm pretty sure it's an Android phone.

 

[Chaos DIY Solar]

View attachment 4546View attachment 4547View attachment 4548View attachment 4549View attachment 4550View attachment 4551

It also has "Battery State" view, "App Setting" and "About Xiaoxiang" views.

Thanks for the screenshots. Hopefully I can compare mine to yours and try to in brick my BMS. I'm not holding my breath though.

 

[Archie]

I have only used android for programming these units. I will try to find a apple version. Not sure if one exists. Many of these bms apps from china support mainly android. Sounds silly, but if you go on their main website, I do not see the apple version anywhere. I will try to ask tom to ask the supplier and see what they can do.

Hi Will,
You really ought to look at the Chargery BMS16T. I just got one. They are not cheap but will handle up to 500A and can use external relays. They claim to support low temp cutoff although mine is still in the box. The "T" on the end of the model name is very important. The regular BMS16 does not balance cells.

 

[emeraldcoastcamper]

Hi Will,
You really ought to look at the Chargery BMS16T. I just got one. They are not cheap but will handle up to 500A and can use external relays. They claim to support low temp cutoff although mine is still in the box. The "T" on the end of the model name is very important. The regular BMS16 does not balance cells.

Will one Chargery BMS16T support an (8) cell 12.8V 200 AH battery?

 

[grizzzman]

Yes but you may save money by buying a Chargery BMS8T version.

Will one Chargery BMS16T support an (8) cell 12.8V 200 AH battery?

 

[emeraldcoastcamper]

Hi Will,
You really ought to look at the Chargery BMS16T. I just got one. They are not cheap but will handle up to 500A and can use external relays. They claim to support low temp cutoff although mine is still in the box. The "T" on the end of the model name is very important. The regular BMS16 does not balance cells.
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[emeraldcoastcamper]

Has anyone here bought from Tech Direct? They have a nice 8S 130AH kit with all the componentsfor $150.00.

 

[Sgt Raven]

The solder they used is very high temp. I used a dremil tool to grind down the solder and remove the old wires, Then used a soldering heat gun and lower temp solder for my 8 guage wires x 3, then set the solder well with a small butane torch. Worked very well

After you ground it down to a certain point, did you solder the new wires on top of a layer of the old high temp solder?

 

[Old Jarhead]

Hi Will,
You really ought to look at the Chargery BMS16T. I just got one. They are not cheap but will handle up to 500A and can use external relays. They claim to support low temp cutoff although mine is still in the box. The "T" on the end of the model name is very important. The regular BMS16 does not balance cells.

Archie,
I've read that the Chargery BMS's need other items to work, things like Temp Sensor, relay wire, shunts, etc.. If this is true, can you tell me what else I'd need to buy? I've got 16 3.2v 152Ah cells for my 48v system arriving tomorrow and the BMS I ordered is not expected to ship from China until 29 April.
Thanks for your help!

 

[Sgt Raven]

Archie,
I've read that the Chargery BMS's need other items to work, things like Temp Sensor, relay wire, shunts, etc.. If this is true, can you tell me what else I'd need to buy? I've got 16 3.2v 152Ah cells for my 48v system arriving tomorrow and the BMS I ordered is not expected to ship from China until 29 April.
Thanks for your help!

Well, while you're waiting you can hook them up in parallel to balance them. Then build your battery pack/s, do a discharge test, and charge them up. There are things you can do without the BMS, as long as you pay close attention to the cells and their individual voltages.
Maybe put them in a 8S configuration and use one of these.

https://www.amazon.com/ISDT-Battery...P9M2T1FF&qid=1583311213&s=toys-and-games&th=1

 

[mndare]

After you ground it down to a certain point, did you solder the new wires on top of a layer of the old high temp solder?

I ground the area of solder down to the point I could pull the old wires out. Then I used new slightly lower temp solder for the three new wires per side. That solder was so hard to melt. You need a torch flame.

 

[Sgt Raven]

I ground the area of solder down to the point I could pull the old wires out. Then I used new slightly lower temp solder for the three new wires per side. That solder was so hard to melt. You need a torch flame.

60/40 rosin flux core? Did you use extra flux, too? What diameter solder? I would guess something little bigger than normal electronic repair, because of the wire size.

 

[emeraldcoastcamper]

Well, while you're waiting you can hook them up in parallel to balance them. Then build your battery pack/s, do a discharge test, and charge them up. There are things you can do without the BMS, as long as you pay close attention to the cells and their individual voltages.
Maybe put them in a 8S configuration and use one of these.

https://www.amazon.com/ISDT-Battery-Meter，LCD-Capacity-Balancer/dp/B07797N9BG/ref=sxbs_sxwds-stvp?cv_ct_cx=ISDT+battery+meter&keywords=ISDT+battery+meter&pd_rd_i=B07797N9BG&pd_rd_r=52a90e01-7c92-4ab6-b04f-3da836493e35&pd_rd_w=NNJ4J&pd_rd_wg=70y9V&pf_rd_p=a6d018ad-f20b-46c9-8920-433972c7d9b7&pf_rd_r=DY8M80VDRG8AP9M2T1FF&qid=1583311213&s=toys-and-games&th=1

This looks like a good step if one wants to not deal with a BMS. My battery bank will be easily accessible for removing every few months to balance. It's in my RV so useage will be limited. Ordering today. Thanks for the research.

 

[mndare]

60/40 rosin flux core? Did you use extra flux, too? What diameter solder? I would guess something little bigger than normal electronic repair, because of the wire size.

I will look and get back to you. It had flux, it has to...

 

[mndare]

This looks like a good step if one wants to not deal with a BMS. My battery bank will be easily accessible for removing every few months to balance. It's in my RV so useage will be limited. Ordering today. Thanks for the research.

Crazy not to have a BMS, hell they are a 85.00 item to protect a very expensive battery pack.

 

[mndare]

This looks like a good step if one wants to not deal with a BMS. My battery bank will be easily accessible for removing every few months to balance. It's in my RV so useage will be limited. Ordering today. Thanks for the research.

Really: USE a BMS

 

[emeraldcoastcamper]

Really: USE a BMS

I appreciate the input and advice. I contacted Jason at Chargery and he put together the following proposal. I am fairly certain my Magnum Inverter does not have a switch for the relay to control so this setup may not work for me.

I will appreciate any additional advice.

BMS8T-300, 90USD, including 300A current shunt. the maximal discharge and charge setting is 300A, over settings, BMS will cut off charge or discharge.

400A relay, unit price is 62 usd., 2pcs for charge and discharge.

shipping cost by DHL is 48usd.

the total is 262 usd,

 

[lmwilco1]

I appreciate the input and advice. I contacted Jason at Chargery and he put together the following proposal. I am fairly certain my Magnum Inverter does not have a switch for the relay to control so this setup may not work for me.

I will appreciate any additional advice.

BMS8T-300, 90USD, including 300A current shunt. the maximal discharge and charge setting is 300A, over settings, BMS will cut off charge or discharge.

400A relay, unit price is 62 usd., 2pcs for charge and discharge.

shipping cost by DHL is 48usd.

the total is 262 usd,

I ordered via aliexpress from the IC GOGOGO Store, BMS8T-300, 400A relay for load, 100A relay for charging, relay delay board, and DHL shipping to Phoenix AZ for $206.73. It took about 10 days to arrive.

If you are going to power an inverter you probably want the relay delay board so you can precharge the caps.

 

[emeraldcoastcamper]

I want to give a SHOUT OUT to Battery Hookup. They let me return the (2) BMS units for a full refund and even sent me a prepaid UPS label. I realize they do advertize complete customer satisfaction but we all know there is sometimes a "disconnect" from what is advertised and what is delivered. Great service Battery Hookup.

 

[mndare]

Hello Everyone. Big update on my LLT Power 4S LiFEPO4 120 Amp BMS with Bluetooth (SAME as Will's but 120 Amp version)

I switched the input and output wires to silicone 8 gauge x 3 per side which is equivalent to 3 gauge effective size.

(https://www.aliexpress.com/item/4000425316662.html?spm=a2g0s.9042311.0.0.38e94c4dDlIoAU)

TEST TODAY

Set new high and low cutoffs to test for the final setup to stay off the most vertical part of the discharge/charge curve (the knees) where very little amp hours are gained at either end yet voltages are pushed low/high.

Set:

Cutoff high: 3.50V per cell
Cutoff low: 2.90V per cell

Testing the following on my new EVE 280 AH cells in a 2P4S configuration (560 AH bank) from Amy at Shenzhen Xuba Electronic Trading Co. The other bank being made is a 4P4S x 280AH. so a 1120 AH pack. All for our offshore sailboat.

1. Usable capacity test for these new high/low cutoffs at .20C (Approx 112-120 Amps): Klien 505AH, 483 AH with DROK Meter: Will use these parameters.
2. Over current test of BMS, with BMS protection in app set to 160 amps. Ran at 147 amps discharge for 10 minutes. BMS board temp was 45C (normally at 112 amps 39.5C) and 3 wires were 35C. BMS handled load with no issues. Did not want to push further. Worked Perfectly
3. Tested high current discharge cutoff, Worked Perfectly
4.Tested high and low voltage cell cutoffs, Worked Perfectly
5. Tested High Temp Cutoff, works. Put heat gun load pointed at temp sensor, 65C set and shut down system. Worked Perfectly
6. Tested low temp cutoff discharging, works (salt ice solution, -10C set in app). Worked Perfectly
7. Tested low temp cutoff charging, 0C, Worked Perfectly

Measured amps with Klien CL380 as DROK Digital DC Multimeter Hall sensor was off 5-10 amps under for most of test

Test started at 1528 BMS Temp Battery Pack Negative 3 wire 2 wire on battery

1528 147 Amps
1538 147 Amps 44.9C 24 35C -
1539 113.6 Amps
1602 113.6 Amps 39.4C 25C 36C 36C
1620 115 Amps 39.7C 26C 37C 35C
1700 117 Amps 40.8C 27.2C 39C 37C
1730 117.5Amps 41.7C 28C 40C 37C
1800 116.2Amps 41.4C 29.7C 45C 39C
1830 120.2Amps 42.8C 30.9C 45C 41C
1900 118Amps 44.3C 31.8C 51C 43C
1930 121Amps 45.5C 33.1C 51C 45C
1951 121Amps (TEST ENDED LOW VOLTAGE CUTOFF CELL 3, 2.90V)



Therefore with above cutoffs 90% of battery capacity available still with a bit more of a safety cushion


Here are some pics of the app and of my dinning room table workshop. 4 more cells to come from Amy and I will be able to make up the 1120 AH pack.