JBD 300a smart bms
- Thread starter Jgb3
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FilterGuy
Solar Engineering Consultant - EG4 and Consumers
Keep us posted on what you learn. It looks like it has replaced the FETs with a big relay.
I have seen this BMS on AliX and the two things that worry me are:
1) It appears to only have one relay. Does that mean it cuts both charge and discharge on any event? If so either an undercharge or overcharge will probably require manual intervention to correct. (However, If the system is working well and the loads & chargers shut off before the BMS, this should not be a common occurance...... Furthermore, some folks would argue that if the system gets to the point where the BMS needs to activate safeties, manual intervention is appropriate)
2) What is the power loss of the coil of the relay?
Yeah something would have to be wrong if the bms had to trip so I would want to intervene. Also as far as I can tell they don’t list the power consumption so I will have to try to figure that out once I get it. Really I don’t know what my Daly bms uses either since my shunt is after them.
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
Measure the voltage drop across the BMS and multiply that by current and that will give you the power loss in Watts. The interesting thing is that with a FET based BMS, the power loss go up as the current goes up. With a relay, the power loss will be pretty much flat. On most solar systems, the current will be low most of the time, so there is a good chance the relay will end up using more power.
I am very much interested in this BMS as I am planning on some very high amp loads.
And this is the model you are getting?
www.aliexpress.com
And this is the model you are getting?
150.09US $ |Jbd Smart Bms Continuous Current 300a Automatic Identifica 7-20s With Built-in Bluetooth Free Ntc Lifepo4 Bms Board Peak 1000a - Battery Accessories & Charger Accessories - AliExpress
Smarter Shopping, Better Living! Aliexpress.com
www.aliexpress.com
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
It occurs to me that if they used a latching relay, they could take the coil energy down to near zero. However: this is in their ad.... so it does not sound like they are using a latching relay.
Yeah that’s the one and I just chose LIFEPO4 16s 300a in the specificationsI am very much interested in this BMS as I am planning on some very high amp loads.
And this is the model you are getting?
150.09US $ |Jbd Smart Bms Continuous Current 300a Automatic Identifica 7-20s With Built-in Bluetooth Free Ntc Lifepo4 Bms Board Peak 1000a - Battery Accessories & Charger Accessories - AliExpress
Smarter Shopping, Better Living! Aliexpress.com
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
Interesting..... he had an issue with the relay failure and that is one of the two big downsides of a relay based system... but the problem is usually the contacts welding and that is not the issue his had. However, they changed out the relay model so hopefully the new one is more reliable. (The other big issue is the coil current.)
Interesting #2: It has a built in pre-charge system. That is nice.
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