I am considering using a Electrodacus BMS. Or should I use a solid state BMS like JDB. I am so confused. I've read the heard stories about fets burning out with solid state. I know you can also use a relay with some solid state BMS and use it shut down the inverter or close a circuit. Does Electrodacus have a high voltage cutoff? I believe Will Prowse said it didn't. Does Electrodacus have a low and/or high cell temp shuttoff. What if any protections to the battery does a JDB/Overkill BMS provide that the Electrodacus does not? Electrodacus is a "solar BMS" is it a whole battery system BMS? I am using 16 Frey/Fortune cells to make a 24V 2p8S battery. I will be charging them with a Victron smart ti 12-24 V charger and later I'll probably add one or more solar panels. I saw in a video how Will used a relay to shut off a inverter. Is it possible to use a relay and solenoids to shut off the alternator charging and the pv charging? I know the Victron has a relay to shut it off but not sure if it overrides the engine being on. I was reading all the different ways to wire the Victron sensor. So confusing. Could the solenoid foor the pv be above the mmpt or pwm. I also read that Electrodacus only works with certain shunts. Which ones? Would you also need a battery monitor with this setup? Thanks
Electrodacus vs Overkill/JBD BMS
- Thread starter Jet
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John Frum
Tell me your problems
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There are things that can be done to minimize that risk.
That can be done.
Using a solid state relay to control the inverter allows the inverter which is usually the vast majority of the discharge current to bypass the bms.
Yes but the realy can't usually be controlled directly by a fet based bms.
Usually though its not necessary to do this.
The charge current is most systems 20-33% of the discharge current and a decent BMS can certainly handle that.
Take the overkill 8s bms for example.
It is realistically rated at 100 amps current for charge and discharge.
Pushing 33 amps of charge current through it is not going to make it sweat.
Also a properly top balanced battery charged by a properly configured charge profile is unlikely to trip and even more unlikely to trip with significant current flow.
Not understanding this.
If the discharge current bypasses the bms as it does in the scenario above yes.
The topology would look like this.
Code:
dc_core {
pos {
|<->fuse<->battery.pos
|<-fuse->charger.pos
|->fuse->inverter.pos
|->fuse->shunt.pos
}
neg {
|<->bms<->shunt.p<-inverter.neg
|->charger.neg
}
}
shunt {
pos
neg {
p
b<->battery.neg
}
}Doesn't overkill prevent power from going into the battery (charging) in the even of low/high temp and high cell voltage? What I was saying is there would need to be a way of preventing the battery from charging when using the electrodacus. What's the best way to shut off charging with a electrodacus system without damaging the mmpt or the dc/dc charger. Could you use one replay to shut down the dc-dc charger, mmpt, inverter and the dc fuse block all at once? What shunts work and/or are commonly used with electrodacus?
I wasn't asking you to. Thanks for your help. I was just wondering how everyone set up their shunts, relays, solenoids with Electrodacus. Has anyone used the an Electrodacus BMS in your build. Do you have a diagram. I can't seem to find a beginner video of how they integrate the BMS into there system other then the inverter shut off video will did. There are alot of videos of hooking the lead wires to the batteries and configuring the settings. The wires in the ribbon cable they use are very small. That is also a concern of mine. Thanks in advance to everyone for their contributions.
Zwy
Solar Wizard
JDB dosn't make a 24v BMS larger then 100 amp. I've also read you don't want to use more then about 60% of the max amp regularly or they will have a short service life. If your mmpt fails it could fry the fets. I don't want to use to 2 BMS. I'm trying to figure out if it provides all the same battery protection features as a solid state BMS. I read the how to set it up manual but it doesn't answer my questions. I like how the Electrodacus can be used with any size battery making it more future proof and that it also works as a solar controller.
John Frum
Tell me your problems
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Using the method I described the discharge current going through the bms would be absolutely trivial for a typical system.
I'm using the setup I described in my own system and the discharge current going through my bms is milli amps.
The limiting factor would be the charge current, which in your case would be 60 amps or .33c.
Is that sufficient?
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If I had 16 cells and wanted 24v and was worried about the amp output, I would be building two 8s batteries, each with it's own BMS. Double the amp output/input. Double the redundancy. And the bonus is that you get a finer granularity of cell management.
I decided to stick with 12v since my RV trailer is 12v. I build two 4s batteries, each with a BMS. It's working great.
I decided to stick with 12v since my RV trailer is 12v. I build two 4s batteries, each with a BMS. It's working great.
I am using an SBMS0 on my truck.
I charge through a multiplus and an orion 12-12. The SBMS0 turns the multiplus inverter on or off based on battery voltage. It will turn the multiplus charger on/off (bulk/off) but you can also program them to go into float instead of off. The orion is not controlled by the BMS but instead charging from the orion is prevented by a BP65 that is controlled by the bms (The reasons for this is beyond this discussion) but the bms could control the orion as well. The SBMS0 will shut every thing down based on low and high temp but it is all or nothing. If battery is cold and you dont want it to charge, the inverter will be off as well.
The SBMS0 turns off the 12v circuit with 2 parallel BP220s
The shunts are not "special" you just need to get what is recommended. I am using one of these: https://riedon.com/resistors/view/dc-current-shunt-rs
The SBMS0 can only tolerate 50ma through the circuit that is used to control devices so you need to be aware of that before you start stacking multiple devices for it to control or picking relays that might require more than 50ma for it to control.
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Zwy
Solar Wizard
That's 2400 watts compared to a 12v JBD of 120a which is 1440 watts.
Instead of 2P8S for your battery, you would be better served with two 24v batteries in parallel. That comes to 4800 watts for the pair, and 200 amps.
Not on a JBD or Overkill, those will handle it. Daly or others on the other hand, yes, you would want to derate.
And your reasoning is?
In other words, you're trying to use the Electrodacus as a solar charge controller so you don't have to buy one? There are some limitations when going that route.
Need more information about the application. Voltage/current requirements, solar, etc.
Despite the horror stories, most of them are just stories. FETs are very reliable and used in almost every electronic device made. I have not looked at the Electrodacus circuit diagram, but it absolutely uses a transistor to control the relays, and possibly a FET.
FETs fail when you abuse them with too much current. If I recall correctly, the JBD is capable of over 800A, but rated and setup to shut down at 120A. The owner of Overkill Solar has tested them via a direct short, with no fuse, and after several attempts was able to kill one. But even with that abuse, it took several attempts. A relay would fail that abuse as well.
What I am saying is that trying to analyze by reliability probably isn't the best way for you to determine what to choose. Look at the features and your needs. Then design and build the system as a whole properly to achieve reliability.
Despite the horror stories, most of them are just stories. FETs are very reliable and used in almost every electronic device made. I have not looked at the Electrodacus circuit diagram, but it absolutely uses a transistor to control the relays, and possibly a FET.
FETs fail when you abuse them with too much current. If I recall correctly, the JBD is capable of over 800A, but rated and setup to shut down at 120A. The owner of Overkill Solar has tested them via a direct short, with no fuse, and after several attempts was able to kill one. But even with that abuse, it took several attempts. A relay would fail that abuse as well.
What I am saying is that trying to analyze by reliability probably isn't the best way for you to determine what to choose. Look at the features and your needs. Then design and build the system as a whole properly to achieve reliability.
grizzzman
Photon Vampire
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In the resources (in the blue banner above) there is a beginners guide and a resource guide on the ElectroDacus. I would also suggest that you download the manual for the SBMS0 and the DSSR20. It won't be real long before the DSSR50 will be out and that may discontinue the DSSR20. He also has a forum on this devices that is a great resource. He answers questions very quickly.
