diy solar

diy solar

Finally found a LiFePO4 BMS with Low-temp Charging Protection

got my 4 new 200ah cells wired up to the BMS, it seems one of my cells is always charging a lot higher than the others and setting off the over voltage protection. When left overnight without charge and some discharge they seem to go back to equal voltage. Any idea what is going on please ?
Did you Parallel Top Balance the cells to 3.65V before building the battery?
 
No. I do not have a proper charger to do that, I thought they would balance out themselves. Do I need to do that now ?
 
No. I do not have a proper charger to do that, I thought they would balance out themselves. Do I need to do that now ?
It seems to help quite a bit. More often than not, most the people who have problems, skipped that step.
For the most part, it's a one time thing. Not something you need to do past that.
 
Ok will do that, hopefully not to late. Do you have a recommendation for a charger to do this please ?
 
Ok will do that, hopefully not to late. Do you have a recommendation for a charger to do this please ?
Just a regulated Constant Current/Constant Voltage Power Supply. Most common ones are 0-30V 5A or 10A models. It doesn't have to be a real expensive one. Once you get one, you can use it to top of the battery, too. Once I built my battery, I'm using a 30-40A 12V power supply or charger. Or a DC-DC/MPPT charger in my vehicle. Just because it would take days to charge a 280AH battery at 5-10A. But if I had a reason to finish charge the battery up full my bench PS would do the job.
 
You should be able to find one for $50-$75. Maybe check your local Craigslist, too. My frame of reference is in the USA.
I am in Australia and all of the power supplies in Wills videos and recommendations here are not available on our Amazon or eBay.
this is closest I could find on our Amazon, do you think this will be ok ?
 
I am in Australia and all of the power supplies in Wills videos and recommendations here are not available on our Amazon or eBay.
this is closest I could find on our Amazon, do you think this will be ok ?
Seems to have decent reviews. Just double check the output voltage with your DMM. The meters on my Mastech are off about 0.05V, so I set by my DMM. Someday I'll open it up and adjust the trimpot for the meter adjustment.
 
Hi guys. I’m new here. I recently bought this BMS from eBay:

It did not come with a Bluetooth module but I’d like to get one for it. Does anyone have a link to one that will work?

also, people keep talking about a paid version of the iPhone app but I do not see it in the AppStore. Can anyone send me a link to one?
Thanks!!
 
I am in Australia and all of the power supplies in Wills videos and recommendations here are not available on our Amazon or eBay.
this is closest I could find on our Amazon, do you think this will be ok ?

You need 2 decimal places for LiFePO4, there is an enormous dofference between 3.6V and 3.7V !
 
You need 2 decimal places for LiFePO4, there is an enormous difference between 3.6V and 3.7V !
The readout is not as important as long as you have a decent DMM to set the output by.
Setting it is easier if your PS has course and fine adjustment knobs.
Also, early in the charging cycle, you could set it a little high without real problems. IMO.
I'm talking about 0.5V higher, when the cells are at 3.3V..
Once they're at 3.4v-3.5V then you need to get it set right, because the cells will fill up a lot faster from there.
 
Anyone using the relay control output on this BMS?

I would be very curious to learn/see how others are using this. Seems like it adds a lot of flexibility
 

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Anyone using the relay control output on this BMS?

I would be very curious to learn/see how others are using this. Seems like it adds a lot of flexibility
That port is used for adding an external switch to turn the BMS on and off. I went through the manual after you posted. The manual is excellent and a good read even if not purchasing the BMS as it goes through parallel top balancing and some other useful information. The manual does an excellent job of covering everything related to the BMS. Kudos to whoever wrote it.
 
That port is used for adding an external switch to turn the BMS on and off. I went through the manual after you posted. The manual is excellent and a good read even if not purchasing the BMS as it goes through parallel top balancing and some other useful information. The manual does an excellent job of covering everything related to the BMS. Kudos to whoever wrote it.

Oh darn, I guess I misunderstood its purpose, that is too bad. But still probably useful for some people and use cases.
 
I am having trouble with my Bluetooth the light is on but will not connect to either my phone or my tablet. I'm not sure if it is safe to charge without seeing what is going on.
 
I am having trouble with my Bluetooth the light is on but will not connect to either my phone or my tablet. I'm not sure if it is safe to charge without seeing what is going on.
If it were mine, I would be suspicious that if the Bluetooth isn't working ..... other functions may not be working either.
 
I am having trouble with my Bluetooth the light is on but will not connect to either my phone or my tablet. I'm not sure if it is safe to charge without seeing what is going on.
Try unplugging the balance cable plug and plugging it back in. I think that causes the BMS to turn off and on. Also, restarting your phone/tablet might help. In the app, there's a refresh/reconnect button where you tell it to connect to that signal, too. I would not worry charging my battery without the app connected. I've turned on the charger and come back out with my tablet later many times. It doesn't need to be connected to the app to do it's job, once it has been set up..
 
Try unplugging the balance cable plug and plugging it back in. I think that causes the BMS to turn off and on. Also, restarting your phone/tablet might help. In the app, there's a refresh/reconnect button where you tell it to connect to that signal, too. I would not worry charging my battery without the app connected. I've turned on the charger and come back out with my tablet later many times. It doesn't need to be connected to the app to do it's job, once it has been set up..
Thank you for your comments, I have tried disconnecting everything nothing fixed, I have ordered a new one, have to see if that fixes it.
 
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