Partial shading - two panels - two controllers

[KristinKaye]

The fire issue is a non issue unless you do what some others do and extrapolate LiFePO4 to a more volatile Li chemistry like LiCoO2..

I had to check with my technical people on this. The answer to your previous question is yes, both the MidNite Classic and KID can be configured to charge lithium battery packs and turn off when charging is complete.

There's evidently some inherent problems with li-ion batteries, namely that voltages between cells can vary and cause some cells to get overly hot. And good li-ion battery packs come with a BMS to help prevent fires.

 

[Maine Sail]

I had to check with my technical people on this. The answer to your previous question is yes, both the MidNite Classic and KID can be configured to charge lithium battery packs and turn off when charging is complete.

There's evidently some inherent problems with li-ion batteries, namely that voltages between cells can vary and cause some cells to get overly hot. And good li-ion battery packs come with a BMS to help prevent fires.

I got your email and had already spoken with Chris. I am getting on the list for beta/pre-ordering the KID..

Yes, any good Li build will incorporate a BMS but more so to save your wallet than anything else... LiFePO4 can not be over charged or over discharged or they will be ruined in short order..

On my designs I don't use the BMS for balancing only for insurance for LVC (low voltage cut) and HVC (high voltage cut). My BMS does balance but there is not any need to push the cell voltage into the upper knee, which causes the need for balancing. The two extreme ends are where cells seem to go out of balance. For boats top balancing is preferred but EV guys bottom balance...

My 400Ah bank now has 207 cycles on it most of which are to 80% DOD and a few to 0% for capacity testing. The cells are still in balance out to 0.003V and have not been balanced for 207 cycles.. Even under a 150A load they are still balanced to 0.006V. 207 cycles is more cycles than most lead acid "marine" batteries even last in the real world.

Again this technology is NOT for everyone and I was glad to hear from Chris that the KID will incorporate a trigger feature from a BMS........

 

[KristinKaye]

#7 The MidNite KID is awfully bulky for the limited panel real estate we have on boats. Can the 150 remote be used with the KID? My wholesaler was shown a prototype that looks nothing like the KID they are now showing....?

Hi Maine Sail - I pulled my KID out of its box and took a photo of it with my hand by it to show the relative size. The keypad is the same as the Classic but it does not have a MNGP like the Classic, nor does it have provisions for a remote that I can see. It does, however, incorporate the features of the MidNite battery capacity meter that shows when the house batteries received the last full charge.

It also has a menu selection item to set up charge profile for lithium batteries. As soon as I get a chance to dig out some AWG10 and hook it up to a battery I can fire it up and look thru the menus to see how it's laid out. This controller will be going in our Legend 37.

 

[Maine Sail]

Thanks! Smaller than I thought...

 

[KristinKaye]

Hi Maine Sail - yes, it is reasonably sized I think. It is fairly heavy. The bracket would be handy to mount it on a navigation station or chart table with some other equipment like PC or GPS screen if you would want to keep track of the PV system and battery status there. It also wall mountable so it could mounted alongside the power distribution panel, etc. with the wall mount bracket.

It is really no bigger than a SSB radio.