1.28 vs 1.31 electrolyte density (for offgrid cycling)

liamg

Hello,

I found two similar (in terms of weight) 6V traction batteries. One of them has a nominal electrolyte density of 1.28kg/l and the other one has a nominal density of 1.31kg/l. 

Like I've just said, they both weight approximatively the same but the former has an increased capacity (obvious).

As far as I know, a higher electrolyte density level could lead to an increased plate corrosion effect, as long as the battery stays in full charge/floating state (telecom, ups).

I want to use the batteries with my offgrid (solar) setup hence they will be cycled on daily basis. That means they won't be staying in full charge/floating state for too long (few hours per day only).

Is there a problem if I'll go with the higher electrolyte density ones? They are both golf cart batteries hence they are made for high cycling anyway.   

Estragon

Do they have the same recommended charging regimes?

Vic

If you absolutely do not need the small extra bit of Capacity of the 1.31 SG batteries,  would avoid those batteries.

YES,   higher SG electrolyte does increase plate erosion,   increases self-discharge,   generally increases charge and EQ voltages,   and does shorten battery life,   all else being equal.

1.31  SG electrolyte is very high,  1.280  is high  but common for GC-2 batteries  (1.277 - `.280 SG).
Personally  I'd prefer 1.250 SG for my off-grid batteries  ...

FWIW,   just opinions,   Good Luck,   Vic

liamg

There's a common instruction manual for both models and the manufacturer do mention the EN 50272-3 standard for charging scheme (I could not find that document though).

liamg

@Vic:

Sorry, I've missed your post. Yep, your explanations are legitimate and I just can't explain why the manufacturer claims the same parameter (life cycles) for both models.