Sterling Alternator to Battery charger, dead Domestic bank

[CatNewBee]

Well the science narrative sais:

change all batteries, all same type, size, age, manufacturer.
use short and thick connections.

If you parallel more than 2 batteries, use fuses on each positive when connecting. Reason is reverse current of the bank into the dead battery if one cell has a shortcut to prevent boiling and fire.

Connect loads diagonaly - minus pole on the first, plus pole on the last.

In larger banks you can even make a back connection minus last to minus first and plus last to plus first to equalize the voltage drop along the chain a little more and create a loop. Then chose the middle and place the connection there diagonaly. The inner batteries will be less stressed as the batteries connected by the loads, but also less charged by the chargers.

You can measure the voltage drop directly between the poles along the connections when under load, no need to measure resistance at all. With a amp clamp meter you also can measure the current along the interconnections under load or while charging.

Real world is different, even chosing exact same sizes and lengths can result in different voltage drops because of more or less tightened bolts and nuts, crimping issues, surface contact areas (corrosion) etc. that all can lead to imbalances in the pack.

[CatNewBee]

A parallel connection translates into a mesh of resistances with RL as the resistance / voltage drop of the wiring and RI as the inner resistance of the battery packs (which changes during charging / discharging). You can imagine how easy it is in such a mash to have imbalances if one of the components is faulty.

[Bob666]

Thanks. Right now I have to decide what type of the four AGM batteries to buy. I think I can narrow it down from starter, dual purpose or deep cycle to dual purpose or deep cycle.

As I am connecting 4 x 75 Ah = 300 Ah I think deep cycle is the way to go?

Check:
https://www.sailnet.com/forums/pacif...e-2.html?amp=1

I will keep the only good of the Gel batteries as a reserve for cranking.

Regarding parallel setup, it seems You recommend method 2 which I currently got? Later You recommend an improvement that doesn’t seem exactly like method 4? Somewhat confusing, could others tune in please?

I am considering keeping variable cable lengths but boosting the long cable runs.

Fusing between batteries is new to me. Is it common practice? It does introduce a voltage drop, doesn’t it? The fuse must be narrower, or it won’t break as expected.

[CatNewBee]

https://www.12voltplanet.co.uk/batte...s-50-300a.html

There are battery terminal fuses (cube fuses) with special terminal clamps for this purpose.
On my Lagoon they were installed already from the manufacturer.

Regarding variable lengths. It is not a good idea, but it will work. We all make compromises to a certain extent, but it is not ideal. Parallel installations have always some issues, that are minor when new, but shorten life on the long run or if one component fails.

General speaking, the outer batteries suffer from plate corrosion due to higher amps and deeper cycles or from drying out electrolytes, while the inner batteries usualy die from sulphation due to shallower absorption

Regarding the ring structure. With 4 batteries probably not relevant, but doable, aternatively 2 pairs of parallel batteries. with 6 or more batteries it would have more advantages. Anyway, it is complex and you can easily see what happens to the voltages and currents on each battery if you chose different cable lengths (RL) along the current paths.

[Bob666]

Originally Posted by CatNewBee

https://www.12voltplanet.co.uk/batte...s-50-300a.html

There are battery terminal fuses (cube fuses) with special terminal clamps for this purpose.
On my Lagoon they were installed already from the manufacturer.

Regarding variable lengths. It is not a good idea, but it will work. We all make compromises to a certain extent, but it is not ideal. Parallel installations have always some issues, that are minor when new, but shorten life on the long run or if one component fails.

General speaking, the outer batteries suffer from plate corrosion due to higher amps and deeper cycles or from drying out electrolytes, while the inner batteries usualy die from sulphation due to shallower absorption

Regarding the ring structure. With 4 batteries probably not relevant, but doable, aternatively 2 pairs of parallel batteries. with 6 or more batteries it would have more advantages. Anyway, it is complex and you can easily see what happens to the voltages and currents on each battery if you chose different cable lengths (RL) along the current paths.

Is the ring structure present in method 4 or in Your schematic above, please?

Thanks for the cube fuse tip. Do You think it’ll work on my battery clamps:
https://drive.google.com/open?id=118...fOkCMMACVgpRbH

Or should I go for:
https://www.amazon.com/Blue-Systems-.../dp/B071H9NL9G

How many Amps would you recommend please? The cranking engine uses about 100 A.

[CatNewBee]

Originally Posted by Bob666

Is the ring structure present in method 4 or in Your schematic above, please?

Thanks for the cube fuse tip. Do You think it’ll work on my battery clamps:
https://drive.google.com/open?id=118...fOkCMMACVgpRbH

Or should I go for:
https://www.amazon.com/Blue-Systems-.../dp/B071H9NL9G

How many Amps would you recommend please? The cranking engine uses about 100 A.

it depends on your highest expected current while charging and discharging.

Lets say you expect not more than 200A in total (cranking engine while running other systems), maximum charging 100A, so 200A is the maximum expected. Then you have 4 batteries usually sharing the load, so each would contribute 50A for the 200A max.

Now one battery fails, so the remaining 3 will share the load, each 66A. 2 failing batteries will result the remainig 2 to provide 100A each. That would be the fuse I would chose. If three out of four fail, you still can crank the engine by shutting down all other loads.

The ring structure is not in the drawing as I said. The terminals are special regarding bolt length / size M8 with isolation washer etc. (CF8 is the standard)

https://www.12voltplanet.co.uk/batte...ube-fuses.html

[john61ct]

Deep cycle for sure.

TPPL AGM better for cranking than FLA at such a small bank size. Odyssey calls theirs dual use but no deep cycling compromise there.

If you can get to higher AH capacity quality FLA will be fine cranking and give longer service, just need to water.

[Bob666]

The ship Yard couldn’t help me. I am referred to this place:
https://www.lxbattery.pt/pt/barcos-e...rvicos-agm-gel

Are “Zenith” ok, please?
4 x 80 Ah would fit, maybe.

Thanks

[CatNewBee]

I guess, they will do, but I have no idea about the brand and how long they probably will last.

But anyhow, they will be good very likely for your passage and maybe 2-3 years of sailing at least.

That is what those sort of AGM batteries of this size (80..95Ah) tend to survive in RV's - where they are commonly used as house batteries.

[john61ct]

Can you find Full River?

Not as good as Lifeline or Odyssey, but. . .

Maybe a new thread in a Med-specific forum, titled

"Best deep cycle AGM brands in Europe?"

might get more responses?

Ask around the yards, docks and yacht clubs?

[Bob666]

Originally Posted by john61ct

Can you find Full River?

Not as good as Lifeline or Odyssey, but. . .

Maybe a new thread in a Med-specific forum, titled

"Best deep cycle AGM brands in Europe?"

might get more responses?

Ask around the yards, docks and yacht clubs?

Hi!

Portugal seems the way to go. Will try in Cascais. Don’t know about med forum as we’re on the Atlantic side?

Would be interesting though to get to know the best brands in Europe, true.

In Spain, with my limited language skill, it is very frustrating, they don’t speak much English. Portugal is different. Like my country, Sweden, they have realised they can make more money if they speak English properly.

[CatNewBee]

A well known brand are the Optima Yellow Top Spiral Cell AGM batteries, but they are expensive.
There are also Optima BLUETOP® Deep-Cycle-Batteries especially for boaters.

https://www.optimabatteries.se/sv-se/products/bluetop

Other common brands are Bosch, Varta, BSA, Winner, Winner Cyclop Spiral Cell (OEM Optima)...

There are many OEM re-branded batteries from various large supplier with fantasy names, but there are only few real manufacturers / sources left.

There are also Online stores for batteries of various brands, they ship EU-wide. So if you struggle to find a local store, maybe online ordering and shipping to your marina can be an option.

[CatNewBee]

more brands:

Exide, Banner, Moll... Exide are usually famous for their equipment GEL batteries, Banner produces all technologies (AGM, GEL, FLA, Ca-Ca..)

[john61ct]

Originally Posted by CatNewBee

A well known brand are the Optima Yellow Top Spiral Cell AGM batteries, but they are expensive.
There are also Optima BLUETOP[emoji2400] Deep-Cycle-Batteries especially for boaters.

https://www.optimabatteries.se/sv-se/products/bluetop

By US standards, Optima has not been a true deep cycling brand since JCI acquired it from Enersys.

I suppose it may be manufactured by a different OEM in Europe rather than simply imported?

Is there a minimum DoD vs cycle-lifetime for use of the deep cycle term in Europe? I know most countries are more advanced than the US in consumer protection regs.

[john61ct]

Exide is also not regarded as a true deep cycling maker in the NA market, I believe another JCI brand.

But as I stated above they may be better made over there.