SimpliPHI 3.8-48 Battery Switch Disconnect/reconnect

JRHill

I haven't had the batteries' BMS activate a breaker. Yet. But I have to ask the question and I hope its not to stupid....

- Will the battery breaker/switch reset automagically in any circumstance or is it strictly a visual and reconnect issue;
- If disconnected batteries in the SimpliPhi string are found what is the procedure? I don't think best practices would be to just flip 'em on with diverging voltages among the units since the disconnect.

I can't find any guidance. I just preparing for a potential event.

Best to y'all.

Edit: Of course a fault was troubleshot beforehand. But if all was ok and a protective fault....

BB.

Jr, can you give us a link to the manual for your exact battery setup?

I would suggest that tripping a battery bank cutoff is a serious event. And usually requires a manual reset (after debugging).

A battery back disconnect does run the risk of causing damage itself. The battery bank is what sets and controls the DC bus voltage. A trip can cause an inductive voltage spike or let other chargers spike the DC bus voltage (charge controllers regulate charging current and cannot hold 14.5000 volts exactly without the battery to buffet the bus voltage).

If I remember correctly, Dave A. was working with (at least one mfg) li ion bank that used a (for example) 200 amp fuse and would throw a dead short ("crowbar") on the DC battery bus (through an SSR, solid state relay or similar) and blow the fuse if the bank voltage was outside the "safe" Li Ion voltage range or exceeded charge/discharge current. And the 200 Amp fuse was not a simple pull and replace (required some system disassembly to reach).

The big thing is to ensure (to the best of your ability and system design) to stay within the operating specs of the battery bank. The use of "crowbars" (short the output) and similar bank disconnects are a last ditch effort for the BMS to protect the bank. This is not something you would want to see happen once or twice a year... (I could be wrong too--Just from my readings)

-Bill "in my humble opinion" B.

JRHill

No, I can't reference a manual. That's why I ask the question. We are REALLY light users of power. In and out. That's why we went to lithium cause they are much more tolerant of short charges and high/low limits vs FLAs.

I of course read the manual and it was available on line. No, I didn't print it out. So I arrived at my settings based upon other inputs (OB Forum). I don't charge to 56.4 and I don't go low. I split the difference of 55.4 to 52.0. It's really well within my range of demand and I rarely hit the lower voltages.

I really like these SimpliPHI units but the battery monitor is a mess as it was built for lead acid batteries. It is all over the place for SOC regardless of attempts to calibrate it but I mainly watch the shunts.

So I ask again, how do the SimpliPHI battery's breaker/switches work in a fault condition? I'M REFERING TO THE BATTERY SWITCH NOT THE SYSTEM BREAKER/DISCONNECT.

Dave Angelini

I do not use simpliphi because they can't be networked Bill. They have promised one and maybe they will have one someday....

There is an internal fuse that will blow in a fault. The BMS will log what happened for warranty. The disconnect is also an 80A circuit breaker. Since you do not know the model, it is hard to be accurate.

This design type of lithium is easily damaged from large inverters and large solar chargers. That is the reason they have a minimum number of batteries required. It is a sizing chart on their webpage for charge and discharge. You need about 3 or more for a large Radian or any XW.

Did you buy them from the store here? Here is a link that may help you ID your battery.
https://www.solar-electric.com/residential.html?manufacturer=541&nav_battery_type=537

JRHill

Thx Dave. They are sized correctly. Yes, I used the sizing app. Yes, I bought them from NAW&S.

I'm just curious about the switch.

TY, JRH