Cells on thier side

[Ohms_Cousin]

Can EVE 304 or 314 amp/hr cells be installed laying on thier side? If so, any particular orientation that one should use? Or is it not such a great idea to put these cells on thier sides ?

 

[wpns]

Doesn’t really matter, though if you care about compression the cells on the bottom of the stack may be more compressed than the ones above. The only orientation the manufacturers don’t seem to like is with the vents down.

 

[Ohms_Cousin]

Doesn’t really matter, though if you care about compression the cells on the bottom of the stack may be more compressed than the ones above. The only orientation the manufacturers don’t seem to like is with the vents down.

that's a good point - the weight of the cells on top of the cells below them. They are 5.5Kg each so it adds up.

 

[S Davis]

I have seen posted that certain orientations are not recommended because the electrolyte is not dispersed correctly in the cell, it would be best to check with the manufacturer.

 

[wpns]

I have seen posted that certain orientations are not recommended because the electrolyte is not dispersed correctly in the cell, it would be best to check with the manufacturer.

Aren’t LFP cells more like AGM batteries? There’s no actual electrolytes slashing around in there like there is with FLA for instance

 

[PVGeezer]

The EVE MB31 compression spec is 3000-7000 N. Put another way that's 5000+-2000 N or 5000 N +-40%. The mass of one cell is 5.6 kg which implies a force of 55 N at 1 gravity.

If you stack them the typical 8 high then the bottom cell will have 7x55= 385 N more compression force that the top one. So that's 8% of the nominal compression spec which allows for a range of +-40%.

Maybe if you mount them in an F16 Fighting Falcon and start pulling 8 or 9 g's stacking them might be a problem, otherwise I doubt it.

Any other reasons not to stack them?

 

[RCinFLA]

The plastic cell terminal posts grommets are not perfectly hermetic and will have some small amount of leakage over time. Standing vertical it will only leak a little gas.

During electrolyte filling there is some overflow that collects at bottom of cell. You may have heard some sloshing at bottom of cell when you handle cell.

Cell turned on the side, this excess electrolyte may come up to terminal grommets seals resulting in some electrolyte bleed around terminal posts. This dries out to white powdery crust around terminals. Not a catastrophe but a little messy.

 

[PVGeezer]

The EVE MB31 compression spec is 3000-7000 N. Put another way that's 5000+-2000 N or 5000 N +-40%. The mass of one cell is 5.6 kg which implies a force of 55 N at 1 gravity.

If you stack them the typical 8 high then the bottom cell will have 7x55= 385 N more compression force that the top one. So that's 8% of the nominal compression spec which allows for a range of +-40%.

Maybe if you mount them in an F16 Fighting Falcon and start pulling 8 or 9 g's stacking them might be a problem, otherwise I doubt it.

Any other reasons not to stack them

The plastic cell terminal posts grommets are not perfectly hermetic and will have some small amount of leakage over time. Standing vertical it will only leak a little gas.

During electrolyte filling there is some overflow that collects at bottom of cell. You may have heard some sloshing at bottom of cell when you handle cell.

Cell turned on the side, this excess electrolyte may come up to terminal grommets seals resulting in some electrolyte bleed around terminal posts. This dries out to white powdery crust around terminals. Not a catastrophe but a little messy.

Thank you, that helps clarify things. My take away is that it's preferable to orient the cells with posts up. But if the physical constraints of your project favor stacking the cells horizontally then that's OK to do.

In my case I'm getting some 15kwh battery box kits and planning on placing them in a truck box/job box. They battery boxes need to be face up to access terminals and displays when I open the job box, so the cells will need to be on their sides.

 

[pete75]

The EVE MB31 compression spec is 3000-7000 N. Put another way that's 5000+-2000 N or 5000 N +-40%. The mass of one cell is 5.6 kg which implies a force of 55 N at 1 gravity.

If you stack them the typical 8 high then the bottom cell will have 7x55= 385 N more compression force that the top one. So that's 8% of the nominal compression spec which allows for a range of +-40%.

Maybe if you mount them in an F16 Fighting Falcon and start pulling 8 or 9 g's stacking them might be a problem, otherwise I doubt it.

Any other reasons not to stack them

Thank you, that helps clarify things. My take away is that it's preferable to orient the cells with posts up. But if the physical constraints of your project favor stacking the cells horizontally then that's OK to do.

In my case I'm getting some 15kwh battery box kits and planning on placing them in a truck box/job box. They battery boxes need to be face up to access terminals and displays when I open the job box, so the cells will need to be on their sides.

 

[pete75]

does they work on their sides? What have you find out about this case?

 

[PVGeezer]

does they work on their sides? What have you find out about this case?

Good question.

I just finished building my battery kits. Havent installed them yet. After building them I decided that I want to be able to access the cells and electronics after installation without having to hoist them out of the enclosure. IMO there's just too much stuff in there to expect the batteries to not need maintenance access.

So Im now planning to build a larger enclosure and mount the battery boxes on shelves with enough clearance to be able to remove the covers and front panels.

If you were ok with not being able to access the cells and electronics then I dont see any reason not to orient them vertically.