Advice needed...BMS for U27-12XP Valence batteries???

[ChasRob]

Hello,I bought a couple of used U27-12XP battery off ebay, at the time I thought they had a complete BMS built in, I later learned otherwise. I want to put these two batteries in parallel in my winnebago view . Just bought 4x 100 watt panel to permanent mount on roof, and have a 100 watt suitcase panel I will add to the system so it can be moved with the sun.Seems there are three options for a BMS for the Valence batteries. Thunderstruckmotors sells a Master BMS for the batteries for $250 but it does not have a temp control. The other would be Muller Industry BMS for the valences at $600 and they have been out of stock for months...so not really an opinion. However the Renogy DC-DC controller might be a solution. Has over voltage protection, overheat protection/battery temp. My question is, will this controller protect the Valence batteries or am I missing something? Any suggestions about using these batteries would be helpful.

 

[tictag]

I am assuming that you cannot get hold of, or don't wish to use, the official BMS for these batteries?

A BMS 'protects your investment' by protecting the battery from a variety of different risks:

1. Cell under/over voltage
2. Cell disparity
3. Too high charge current
4. Too high discharge current (aka short circuit protection)
5. Cell balancing
6. Temperature control (too hot, too cold)
7. Data analytics

I doubt very much you'd be able to get all these functions from an external device like a DC-DC converter.

You could use the batteries without a BMS, they will function just fine, probably for years, but they won't obviously be protected. A BMS is just insurance.

 

[Deleted member 1888]

I have 2 of them and they do have some lvl of BMS in them, they do have protections. The external BMS allows you to link them all together and control there voltages and cell levels manually. If you just use them for solar you will never need the external bms unless you plan to link more than 100 of them together.
One of the features the internal bms has is asleep mode if it site for more than a month with not used it will go to sleep. Once in sleep mode you can not wake it up without the external bms so be warned on that.

 

[Deleted member 1888]

I am assuming that you cannot get hold of, or don't wish to use, the official BMS for these batteries?

A BMS 'protects your investment' by protecting the battery from a variety of different risks:

1. Cell under/over voltage
2. Cell disparity
3. Too high charge current
4. Too high discharge current (aka short circuit protection)
5. Cell balancing
6. Temperature control (too hot, too cold)
7. Data analytics

I doubt very much you'd be able to get all these functions from an external device like a DC-DC converter.

You could use the batteries without a BMS, they will function just fine, probably for years, but they won't obviously be protected. A BMS is just insurance.

They have that on the internal BMS, the external one allows you to change all the parameters and monitor them with a PC in real time.

 

[ChasRob]

I am assuming that you cannot get hold of, or don't wish to use, the official BMS for these batteries?

A BMS 'protects your investment' by protecting the battery from a variety of different risks:

1. Cell under/over voltage
2. Cell disparity
3. Too high charge current
4. Too high discharge current (aka short circuit protection)
5. Cell balancing
6. Temperature control (too hot, too cold)
7. Data analytics

I doubt very much you'd be able to get all these functions from an external device like a DC-DC converter.

You could use the batteries without a BMS, they will function just fine, probably for years, but they won't obviously be protected. A BMS is just insurance.

Thanks for the reply, maybe could find a used factory U-BMS. So if a had the factory BMS if can be used to control only 2 batteries, I was told it would not work for only two batteries???. Let me know and I'll start look on ebay for a used BMS.

 

[ChasRob]

I have 2 of them and they do have some lvl of BMS in them, they do have protections. The external BMS allows you to link them all together and control there voltages and cell levels manually. If you just use them for solar you will never need the external bms unless you plan to link more than 100 of them together.
One of the features the internal bms has is asleep mode if it site for more than a month with not used it will go to sleep. Once in sleep mode you can not wake it up without the external bms so be warned on that.

Can you wake them with the computer/software hook up and not the u-BMS?

 

[Deleted member 1888]

Can you wake them with the computer/software hook up and not the u-BMS?

No the internal BMS is propitiatory and will only work with there own external BMS. As for if it will work with only 2 of them I do not know the answer to that. You may need to contact the makers of them.

 

[ChasRob]

No the internal BMS is propitiatory and will only work with there own external BMS. As for if it will work with only 2 of them I do not know the answer to that. You may need to contact the makers of them.

On ebay the BMS appears to be a high voltage one(100-450volts)several used for $300. and a low voltage one (10-150volts)Lv from china new $600.00.

 

[tictag]

Crikiebobs, that's an expensive BMS!

I'd be thinking of stripping out the cells and using my own BMS. A task not suited to the faint-hearted, though.

 

[floridianman27]

I am assuming that you cannot get hold of, or don't wish to use, the official BMS for these batteries?

A BMS 'protects your investment' by protecting the battery from a variety of different risks:

1. Cell under/over voltage
2. Cell disparity
3. Too high charge current
4. Too high discharge current (aka short circuit protection)
5. Cell balancing
6. Temperature control (too hot, too cold)
7. Data analytics

I doubt very much you'd be able to get all these functions from an external device like a DC-DC converter.

You could use the batteries without a BMS, they will function just fine, probably for years, but they won't obviously be protected. A BMS is just insurance.

I tried talking to lithium werks glto get a BMS. They will not sell me one. Kinda pissed off.