Will's recommended OverkillSolar BMS is Out of Stock. Any recommendations?

[USMC_Winger]

Will's video recommends the OverkillSolar 100A 8S BMS (overkillsolar.com/product/bms-100a-8s-lifepo4-12/) for the Signature Solar EG4 8-Cell Pack Lithium Cells 25.6V 100AH pre-assembled battery, but it's out of stock. Searching the forum, I found a link to a search on Alibaba for some JBD BMSs (dgjbd.en.alibaba.com/collection_product/lifepo4/1.html?spm=a2700.shop_plser.41413.dlhlist.31303135VwHEjG&filterSimilar=true&filter=null&isGallery=N). I think it would be better to get a 120A or 150A 8S BMS, but I'm a newbie and need good advice on which BMS to pick.

Relevant info:

I'm building a 24 volt solar system for my RV trailer using Will's 2 KW 24V blueprint (www.mobile-solarpower.com/2000-watt-24v-solar-system.html). I already have:

EPEVER Tracer 4215BN 40A, 150V MPPT Solar Charge Controller with MT-50
Four HQST 100 Watt 12 Volt Polycrystalline Solar Panels with MC-4 connectors:
- Maximum Power at STC: 100W
- Maximum System Voltage: 600V DC (UL)
- Optimum Operating Voltage (Vmp): 18.1V
- Optimum Operating Current (Imp): 5.53A
- Open-Circuit Voltage (Voc): 21.6V
- Short-Circuit Current (Isc): 5.94A
30 feet 10 AWG UV-resistant solar power wire (no connectors)
Solar Connector Y-Branch 1 to 4 Adapter Cable Wire
Multimeter
10-22 AWG wire crimper
10 AWG wire stripper
Smoke alarm
Class ABC fire extinguisher

I plan to buy eight more 100w, 12V polycrystalline solar panels, two EG4 8-Cell Pack Lithium Cells 25.6V 100AH pre-assembled batteries, two 8S BMSs, one GIANDEL 24V 2000 watt Pure Sine Wave Power Inverter DC 24V to AC 120V, and the rest of the items on Will's plan, although not all at once. I'm a disabled veteran on a budget, and these items will be purchased within the next 6 months.

Next on my list of purchases is one battery and BMS and two 100W solar panels, but I should get both BMSs if they're being shipped from China, due to the long shipping time.

In the beginning, I just need to power a 24V RV refrigerator and a 12V fan (so I can get by without the inverter for a while).

Fridge: 45W * 24 hrs = 1,080W, but the motor only runs about 1/3 of the time, so about 360W
Fan: 7W up to 24 hrs = 167W
Therefore, enough power for 1,247W or 527W per day

So, any recommendations on the two BMSs for the Signature Solar EG4 8-Cell Pack Lithium Cells 25.6V 100AH pre-assembled batteries?

Thanks.

 

[PeSCaLo]

overkill solar bms is a rebrand of JBD

25.55US $ 29% OFF|Jbd 3s 4s 7s 8s 14s 16s 17s 20s 21s 24s 28s Bms Board 48v 36v 24v 12v Lifepo4 Battery Balance Bms 60a 80a 100a 120a Electric Car - Battery Accessories & Charger Accessories - AliExpress

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

 

[USMC_Winger]

Thanks, nbtesh! Any recommendations for a 150A BMS?

 

[HRTKD]

Are you sure you want to wire those panels in parallel? The solar charge controller can go up to 150 volts, so you could wire the panels 4s instead of 4p.

You don't need the 150 amp BMS. The 100 amp BMS from Overkill Solar should do the job, especially since you'll have two batteries in parallel. I don't know if Overkill Solar has a waiting list, but if they do it's worth buying from them in my opinion. That's where I bought my two BMS from.

Current Connected is another U.S.-based vendor of the JBD BMS.

 

[DerpsyDoodler]

seplos BMS seems to be a new hot DIY item in the community and I've noticed SOK now also sells a DIY BMS. I haven't used either. Just options to research and consider.

 

[Horsefly]

You can also get the same JBD BMS's from Currrent Connected, although I'm not sure what models Dexter is stocking right now.

EDIT: Ooops. I didn't notice that @HRTKD already mentioned Current Connected. Note to self: Drink coffee before posting.

 

[USMC_Winger]

Are you sure you want to wire those panels in parallel? The solar charge controller can go up to 150 volts, so you could wire the panels 4s instead of 4p.

You don't need the 150 amp BMS. The 100 amp BMS from Overkill Solar should do the job, especially since you'll have two batteries in parallel. I don't know if Overkill Solar has a waiting list, but if they do it's worth buying from them in my opinion. That's where I bought my two BMS from.

Current Connected is another U.S.-based vendor of the JBD BMS.

Thanks, HRTKD!

Good point. Originally, I planned to cover the roof of my trailer with solar panels, and some panels were likely to be shaded by trees periodically, so I felt that stringing some of them in parallel would likely get the most bang for my buck powerwise. However, the trailer needs to be in the shade as much as possible, because it just gets too hot inside during the day. I now plan to ground mount the panels away from the shaded trailer to take advantage of the most sunshine. Stringing the panels in series will allow me to get the higher voltage needed for a longer wire. Buying the 4-to-1 Y-Branch connecting cable early in my build was surely a goof, but as I acquire more solar panels, I'll eventually use it.

Thanks for the link to Current Connected. Unfortunately, they're out of stock on the 24V 8S BMSs.

 

[USMC_Winger]

seplos BMS seems to be a new hot DIY item in the community and I've noticed SOK now also sells a DIY BMS. I haven't used either. Just options to research and consider.

Thanks, DerpsyDoodler!

I'll check those BMSs out.

 

[USMC_Winger]

You can also get the same JBD BMS's from Currrent Connected, although I'm not sure what models Dexter is stocking right now.

EDIT: Ooops. I didn't notice that @HRTKD already mentioned Current Connected. Note to self: Drink coffee before posting.

Thanks, Horsefly!

 

[wiseacre]

Thanks for the link to Current Connected. Unfortunately, they're out of stock on the 24V 8S BMSs.

I checked this morning and Current Connected had 4 in stock.
I was thinking of ordering one but wanted to check with Dexter about some cells.
I'll contact him now and see if there's any on the way.

 

[USMC_Winger]

I checked this morning and Current Connected had 4 in stock.
I was thinking of ordering one but wanted to check with Dexter about some cells.
I'll contact him now and see if there's any on the way.

Thanks, Wiseacre!

 

[Horsefly]

Thanks, Wiseacre!

If you are interested, I have one of the 100A 8S JBD w/Bluetooth that I bought as a spare but I don't think I will ever need a spare. I hooked it up to a battery only long enough to calibrate the cell voltage readings, and it has been sitting in a box every since. I'm sure I don't want much for it. PM me if you are interested.

 

[USMC_Winger]

If you are interested, I have one of the 100A 8S JBD w/Bluetooth that I bought as a spare but I don't think I will ever need a spare. I hooked it up to a battery only long enough to calibrate the cell voltage readings, and it has been sitting in a box every since. I'm sure I don't want much for it. PM me if you are interested.

Thanks, Horsefly! I'm out the door to run some errands, but I'll PM you later tonight.

 

[JJJJ]

Overkill will often show out of stock but will often build to order. Drop them an email

 

[USMC_Winger]

Overkill will often show out of stock but will often build to order. Drop them an email

Good to know. Thanks, JJJJ!

 

[wiseacre]

About a month to restock, 100 of the 8s, 100a JBD bms are on the way to Current Connected.

 

[USMC_Winger]

About a month to restock, 100 of the 8s, 100a JBD bms are on the way to Current Connected.

Thanks for checking, Wiseacre!

 

[USMC_Winger]

overkill solar bms is a rebrand of JBD

25.55US $ 29% OFF|Jbd 3s 4s 7s 8s 14s 16s 17s 20s 21s 24s 28s Bms Board 48v 36v 24v 12v Lifepo4 Battery Balance Bms 60a 80a 100a 120a Electric Car - Battery Accessories & Charger Accessories - AliExpress

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

I ordered the 120A 8S 24V BMS. However, it looks like it's missing some wires and attachments that the Overkill BMS has. Unfortunately, China's International Labor holiday is from Apr. 30th to May 4th, so I can't ask JBD questions about the necessary items for this BMS for a few more days, and I'm limited to 40 characters in a note to them when they do become available again. Perhaps someone here can advise me.

Aliexpress JBD 8S 24V BMS (although not in this picture, the 8 cell wires are included):

Overkill Solar BMS:

The JDB circuit board looks like it's missing a comm port connection. Do I need to get a different BMS, like a JBD Smart BMS (which only goes up to 100A on Aliexpress), so that I can attach a Bluetooth module or a UART box to change settings?

Looks like I need four 8 AWG wires, but an 8 AWG wire only handles 40A to 55A, so a total 80A to 110A capacity, when my BMS is 120A. There are only four holes, not six, in the circuit board for the 8 AWG wires, but there are more holes for smaller wires. Do I solder additional, smaller gauge wires to the circuit board so that the total wire capacity will exceed the 120A capacity?

Also, according to the product description, I'll need external temperature sensors, a switch control interface -- is that the Bluetooth module? -- and a detection light board.

1.Production Descriptions
①3-28S BMS for 3.2V Lifepo4 / 3.7 Li-ion battery
②Maximum continuous discharge current 120A
③Multiple charge and discharge protection functions
④Very low quiescent current consumption
⑤No communication like BT
⑥Built-in temperature sensor, external temperature sensor can be added
⑦Can add switch control interface (control charge and discharge)
⑧Equipped with equalization function (to ensure a certain pressure difference), the detection light board needs to be purchased separately

According to this web page, the Bluetooth module is available, or do I need the UART box and LCD UART port for this particular BMS?

I found the JBD external temperature sensor (select 1st item in the "Color" section). I'll need to buy four of these for two BMSs for two 24V batteries.

Can someone recommend where to get the detection light board compatible with this BMS on a budget? I can't find one with Aliexpress or Alibaba search.

Thanks.

 

[HRTKD]

I ordered the 120A 8S 24V BMS. However, it looks like it's missing some wires and attachments that the Overkill BMS has. Unfortunately, China's International Labor holiday is from Apr. 30th to May 4th, so I can't ask JBD questions about the necessary items for this BMS for a few more days, and I'm limited to 40 characters in a note to them when they do become available again. Perhaps someone here can advise me.

Aliexpress JBD 8S 24V BMS (although not in this picture, the 8 cell wires are included):

Overkill Solar BMS:

The JDB circuit board looks like it's missing a comm port connection. Do I need to get a different BMS, like a JBD Smart BMS (which only goes up to 100A on Aliexpress), so that I can attach a Bluetooth module or a UART box to change settings?

Looks like I need four 8 AWG wires, but an 8 AWG wire only handles 40A to 55A, so a total 80A to 110A capacity, when my BMS is 120A. There are only four holes, not six, in the circuit board for the 8 AWG wires, but there are more holes for smaller wires. Do I solder additional, smaller gauge wires to the circuit board so that the total wire capacity will exceed the 120A capacity?

Also, according to the product description, I'll need external temperature sensors, a switch control interface -- is that the Bluetooth module? -- and a detection light board.

1.Production Descriptions
①3-28S BMS for 3.2V Lifepo4 / 3.7 Li-ion battery
②Maximum continuous discharge current 120A
③Multiple charge and discharge protection functions
④Very low quiescent current consumption
⑤No communication like BT
⑥Built-in temperature sensor, external temperature sensor can be added
⑦Can add switch control interface (control charge and discharge)
⑧Equipped with equalization function (to ensure a certain pressure difference), the detection light board needs to be purchased separately

According to this web page, the Bluetooth module is available, or do I need the UART box and LCD UART port for this particular BMS?

I found the JBD external temperature sensor (select 1st item in the "Color" section). I'll need to buy four of these for two BMSs for two 24V batteries.

Can someone recommend where to get the detection light board compatible with this BMS on a budget? I can't find one with Aliexpress or Alibaba search.

Thanks.

Your experience is why I threw up my hands and decided to order from the Overkill Solar website. I couldn't figure out all the mumbo jumbo on the Alibaba sites for picking the right BMS with the right options. The Overkill Solar site had the BMS and options clearly defined, at least clear enough for me to understand exactly what I was ordering.

It looks like you're going to have to solder on your own cables to the BMS.

My understanding is that the 24 volt model only comes in 100 amp, not 120 amp. Only the 12 volt 4s model is 120 amp. I think that's part of your problem right there.

 

[USMC_Winger]

Your experience is why I threw up my hands and decided to order from the Overkill Solar website. I couldn't figure out all the mumbo jumbo on the Alibaba sites for picking the right BMS with the right options. The Overkill Solar site had the BMS and options clearly defined, at least clear enough for me to understand exactly what I was ordering.

It looks like you're going to have to solder on your own cables to the BMS.

My understanding is that the 24 volt model only comes in 100 amp, not 120 amp. Only the 12 volt 4s model is 120 amp. I think that's part of your problem right there.

I don't mind soldering and crimping wires to save a good chunk of money, as long as it works. Unfortunately, I think I need to get a different BMS, because without a comm port, I can't change any factory settings to fit my battery and charger. As you mentioned, the 8S 24V JBD Smart BMSs (with Bluetooth) only go as high as 100A.