Battery Capacity

[nigel1]

Hi Bill,
Not really sure myself, just read the Rolls Battery Manual, see it quotes a range of 1.255 to 1.275 at 80F.
I'll take it as read that the liquid level is correct. Is the bulb in the hydrometer really clean?, not sure how a dirty bulb would affect the readings.
Hopefully one of the real battery guru's will be along soon
Happy new year

[S/V Alchemy]

Could be "operator error" if you are unfamiliar with the old chemistry lab concept of the meniscus:

Meniscus - Wikipedia, the free encyclopedia

Hydrometers, being float tubes within sight tubes, have a particularly pronounced meniscus in my experience.

[Bill Balme]

OK - so finally downloaded the entire Prosine manual - instead of the short version I was given - and have managed to re-program the unit to suit my Rolls Surrette batteris and finally an equalization was carried out properly at 15.5V - don't those babies bubble!
So this is the first proper equalization since I've owned the boat (2 years)...
All cells but one are maxing out the batter tester at SG of about 1.310. The last is making it to 1.28. I'm thinking I'll do another equalization in about a month or so - see if I can bring that last cell up to the rest.
Managed to learn a lot about both batteries and my inverter/charger through this process - thanks to all...

[S/V Alchemy]

Make sure that area is vented. The bubbling is hydrogen gassing out the caps, and it's flammable, but burns with an invisible flame. That makes extinguishing it...or oneself...problematic.

[Rustic Charm]

Hello everyone, can someone tell me where you fill the battery water level too? I'm asking because I wasn't quite sure, so I asked my local battery world guy, who surprise surprise said he didn't know.. Of course I queried why he was working in a battery shop and he angrily said, "I only sell em not maintain them".. wow! So I asked a friend and he said you fill them up to where the plastic lip inside touches the water. That's about a cm (1/2 inch) over the plates. I've just come back from a weeks sail and at that level a lot of the water came out into the battery box... Another person this week said you just put about 2mm over the plates??? I know there are more knowledable people on here.. Your input please.

[Maine Sail]

Originally Posted by tedsherrin

Hello everyone, can someone tell me where you fill the battery water level too? I'm asking because I wasn't quite sure, so I asked my local battery world guy, who surprise surprise said he didn't know.. Of course I queried why he was working in a battery shop and he angrily said, "I only sell em not maintain them".. wow! So I asked a friend and he said you fill them up to where the plastic lip inside touches the water. That's about a cm (1/2 inch) over the plates. I've just come back from a weeks sail and at that level a lot of the water came out into the battery box... Another person this week said you just put about 2mm over the plates??? I know there are more knowledable people on here.. Your input please.

You want it about 1/8" below the plastic "well" but not touching it.. Batteries on sailboats also need to be installed in the correct orientation so electrolyte does not leak out when heeling.. The individual cells in the batteries should line up port to starboard...

Port / Starboard has much less chance of exposing the plates (read BAD) and spilling electrolyte...


A bow to stern cell alignment, as below, is a poor choice for flooded batteries. Sadly "proper installation" rarely gets talked about....

[S/V Alchemy]

Thanks, MS...you've touched on an aspect of installation I've never considered...although I bloody well will now! (goes to alter templates...)

[Maine Sail]

Originally Posted by S/V Alchemy

Thanks, MS...you've touched on an aspect of installation I've never considered...although I bloody well will now! (goes to alter templates...)

It's funny that I discovered this back in the late 80's. I was on a friends fathers boat that we had just put a "state of the art" charging system on due to chronic short battery life. We incorrectly assumed it was "overcharging" or what we through at the time was "overcharging"... Even after the new alternator and regulator he still had short battery life.

He went through the first bank in less than a season. One day while helping him work on it I noticed electrolyte spilled in the cases. The cases of the batts were black and so were the cases so it was tough to see.

I removed the batteries, cleaned it out, and we went for a sail with no charging. We put her up on ear and sure enough electrolyte began to drain out of the batteries.. The cases were not cracked or leaking but it was spilling out when heeled.

It then dawned on me that the orientation of batteries on sailboats mattered. I looked at the cell layout and simply rotated his batteries to port/stbd and he never again had a single drop of spilled electrolyte. That bank lasted 6 years after those first few days of spilling after multiple years of replacing batteries aalmost annually..

In all my years I've yet to see any of the "experts" address this. Seems like common sense to me.. I have been harping on this since I discovered it but it still seems to fall on deaf ears.

A few years ago a buddy who does UPS installations had some polycarbonate case UPS batteries and I saw a great opportunity to photograph the "why" of sailboat battery orientation.......

This problem is only compounded in batteries that have "off set" fill caps meaning they are closer to the edge of the battery than the center. Orient those bow/stern and you'll have some real leakage issues on that particular tack....

Exposing the plates, especially under charge or discharge, can really shorten battery life..

[svmariane]

About the battery orientation...

Knowing nothing, I installed 4 batteries how they would fit in the battery box area: 3 fore/aft, and 1 port/stbd. The latter is the one that spilled fluid, took the most attention, and died first.

Now I've 3 Rolls/Surrettes T-12-250 installed in a custom-built battery box (that makes use of every millimeter of available space) and all 3 are mounted fore/aft. I suppose time will tell how that works out. I'll monitor for spillage - do that anyway.

Redoing the orientation is problematic: T'would mean tearing out the built-in companionway stairs.

As always, reading these threads brings new info to me -- some of it taken with a grain of salt...

[Maine Sail]

Originally Posted by svmariane

About the battery orientation...

Knowing nothing, I installed 4 batteries how they would fit in the battery box area: 3 fore/aft, and 1 port/stbd. The latter is the one that spilled fluid, took the most attention, and died first.

Now I've 3 Rolls/Surrettes T-12-250 installed in a custom-built battery box (that makes use of every millimeter of available space) and all 3 are mounted fore/aft. I suppose time will tell how that works out. I'll monitor for spillage - do that anyway.

Redoing the orientation is problematic: T'would mean tearing out the built-in companionway stairs.

As always, reading these threads brings new info to me -- some of it taken with a grain of salt...

It's not just the spilling that causes issues such as low electrolyte. The bigger issue is the exposing of the plates under load or charging when heeled....

Don't worry many builders over the years have built molded in battery boxes that force the batteries to orient in the wrong direction. In this situation GEL or AGM are the only real option... Builders ship boats even today with improperly installed batteries.

The mid 80's Pearson 34 is one that comes immediately to mind with molded trays that force an improper installation for flooded batteries.

[deckofficer]

A bit of a topic drift, but on off grid systems that I've done, I've kept hydrogen gas and the need of watering the cells to almost nil using hydrocaps. Used them on L16s and the large single cell flooded batteries.
Hydrocap | Information

[sabray]

Thanks Maine sail for your input. Never heard that before but makes so much sense.

[Rustic Charm]

Originally Posted by Maine Sail

You want it about 1/8" below the plastic "well" but not touching it.. Batteries on sailboats also need to be installed in the correct orientation so electrolyte does not leak out when heeling.. The individual cells in the batteries should line up port to starboard...

Port / Starboard has much less chance of exposing the plates (read BAD) and spilling electrolyte...

A bow to stern cell alignment, as below, is a poor choice for flooded batteries. Sadly "proper installation" rarely gets talked about....

Thank you again for your advice and Wisdom. I can't think which way the cells in my batteries are alined, but I'll be checking this the very next time I go down to my boat, later this week. I know the batteries themselves are port to starboard though and they would have quite a lean on them when healed as their battery box is 1.080 meters wide with the reserve battery sitting in the middle facing stern to bow.

[sailinglegend]

Originally Posted by svmariane

...3 fore/aft, and 1 port/stbd. The latter is the one that spilled fluid, took the most attention, and died first.

Could be other factors involved - maybe overfilling that battery because you couldn't get to it easily. I don't think this should detract from Main Sail's excellent suggestions.

Originally Posted by svmariane

....Redoing the orientation is problematic: T'would mean tearing out the built-in companionway stairs....

Too many times we see on here people who get advice and then say "They can't be bothered to make the changes because it is too much work....."
For serious cruisers with a big boat like yours you could probably find space away from the hot engine compartment to fit the batteries correctly, and perhaps to increase the bank capacity at the same time, instead of having to make use of "every millimeter of available space". Batteries need a bit of space around them to keep cool.

[Maine Sail]

Originally Posted by sailinglegend

For serious cruisers with a big boat like yours you could probably find space away from the hot engine compartment to fit the batteries correctly, and perhaps to increase the bank capacity at the same time, instead of having to make use of "every millimeter of available space". Batteries need a bit of space around them to keep cool.

This is very true and one reason why pre-made battery boxes are not a "tight fit". If your batts are in an engine space this becomes even more critical to help circulate air around the batteries and help to keep them cool. If you sail only in cool water, and the battery box is always sub 70F, not a real issue but if sailing in warmer climates it can become a problem over time.