Can I add a fourth battery?

[Shrew]

Originally Posted by S/V Illusion

I’d like to see an 800 amp 12v battery.

It appears to be:

Capacity: 95 Ah
CCA: 800a

So it looks like we're talking about adding a 95Ah battery to a bank of 3 x 100 Ah batteries.

Having the actual make and model of the batteries in question would be helpful. Varta has a wide line of batteries.

[Pete7]

Barry, yes you can try it.

However, the bad news is they are car starting batteries by the look of it. They certainly won't support a live aboard yacht and I suspect you will be replacing the lot in 12 months time. Bottle of wines says I am right

Now the good news, there is about 15 years of really good advice on here, shouldn't take long to read through that lot, if you don't loose the will to live first

What is the largest size of battery you can fit in the boxes? Better still will these fit? bearing in mind you will need 4 of the 6v batteries. It's the height that is the killer, European yachts seem to have battery boxes that only take shorter batteries. We have the same problem btw.

https://www.alpha-batteries.co.uk/t-...cycle-battery/

If they will fit then plan on fitting 4 next year.

If they don't fit then come back to us and we will find an alternative. Bottom line is:

12v car battery has 200 cycles.

12v Flooded Lead Acid (FLA) which you can top up has 700 cycles.

6v FLA has 1700 cycles (Those Torjan T105s)

Some deep cycle AGM and Gel have the potential to go 2000 cycles.

So on a live aboard yacht a house bank you need deep cycle batteries with lots of cycles. There is no definition for a cycle so you are at the mercy of the manufacturers telling the truth. I quite like the Alpha Batteries website because they at least have a go at listing the batteries by cycles and give each a number in the tech info tab. Worth having a search to see the differences.

https://www.alpha-batteries.co.uk/marine-batteries/

What ever you do don't mention Lithium, ever, under any circumstances, They are not suitable for your needs unless you are prepared to invest a shedload of time and energy climbing a steep learning curve before even lifting a screwdriver.

How is the auto pilot?

Pete

[Mike Banks]

I simply used heavy duty tractor batteries and changed the whole lot every two or three years. As soon as one is down, I replaced the entire bank and used any good ones as remote batteries in the fore and aft cabins heads, and the forward windlass supplementary supply. Had I retained the old electric deck winches I may have needed the extra battery--but the weight of them is considerable and that weight has to be borne by the hull and in bad weather people forget just how much inertia heavy batteries have. That is one of the hardly ever mentioned good things about nickel cadmium and lithium ion batteries--the HUGE saving in weight, as well as in the case of alkaline batteries, the superior performance for less money than lithium ion, but greater cost than wet or gel lead acid..

Three two hundred ampere-hour wet cell lead/acid batteries connected in in parallel is a hell of a lot of amps--so I reduced it to two main batteries because I fitted solar and wind and that took most of the daytime and wind often all of the night time loads--the batteries only supplied lighting, refrigerator and freezer, autopilot , radios, television/videos and radar and heads at night. All cooking was LP gas--as was all on-demand instant (almost) hot water supply.

I could have used the excess power to heat hot water, but storing twenty gallons of near boiling water separate from the rest of the water supply tanks seemed to me to be too much extra space taken up for the laudable aims of limiting fossil fuel usage..

How come no one ever mentions alkaline batteries in these discussions? It is always lead in one form or another and lithium ion. Alkaline batteries do not sulphate--the lifetime of them is many years if they are properly looked after--and yes, they do cost more and take up more space aboard than does lead--and they are only 1.4 volts each cell so you need bigger batteries to get the 13 or 14 volts--but that extra space is a preferable concession to the extra weight and longer life as I see it.

http://www.machineryspaces.com/batteries.html

[john61ct]

Nickel cadmium and alkaline are not suited to a marine House bank duty cycle.

And only LFP out of the many dozen lithium chemistries.

[StuM]

Originally Posted by S/V Illusion

I’d like to see an 800 amp 12v battery.

Would that be CCA or CA?


How about a Odyssey Extreme 65-PC1750 with 950 Amps?

[ramblinrod]

Originally Posted by AJ-SeaChange

Here's the story.



June 2018 - 3 x 95ah 800a Varta 12v batteries were installed.


Noticed a problem in October 2019. Checked batteries, two of them were toast at 10.2v each even after a full day of charge from 600 watts of solar. One of them still shows 12.6v of charge.



Bought 3 x 100ah 800a Varta 12v batteries and replaced all three original batteries. All working fine now.



Here's the question.


Would it be OK to add the June 2018 - 95ah 800a Varta 12v battery into the chain with the 3 new batteries? Does the 5ah difference cause issues?


Thanks in advance. Baz

I would not add the older 95 Ahr battery. Having a different capacity it most likely has a different internal impedance to begin with. If it was hurt, but to a lesser extent than the other two, it may have diminished capacity still. So the other batteries will always be working to make up for its losses.

If you truly want to increase capacity, I recommend adding a new 100 Ahr to the 3 known good 100 Ahr batteries.

I think the suggestions you have received to change out the entire bank, or change to a single series string of batteries are misguided.

Assuming the prior issues that hurt the old batteries was corrected, the new batteries should provide excellent service, and adding one more (assuming you have the space) will be even better yet, for lowest cost, representing best value for money.

[john61ct]

Originally Posted by S/V Illusion

I’d like to see an 800 amp 12v battery.

CALB 180 could do it easy I reckon.

Originally Posted by AJ-SeaChange

Nobody mentioned 800amp batteries.
Original post says - 95ah 800a Varta 12v batteries.

Originally Posted by Shrew

It appears to be:


Capacity: 95 Ah

CCA: 800a

Yes if that's the case and these are Starter type batteries being used for deep cycling House usage.

Just replace the lot with a proper bank designed for deep cycling, known strong reputation.

I mean you can wait for this bank to wear out first, but likely won't be long anyway.

That Odyssey PCM is a fantastic battery, for AGM and 12V, but only 74Ah, really don't want 5-6 in parallel.

The smaller voltage, bigger Ah capacity units I discussed above would last much longer, especially the likes of Rolls Surrette.

Trojan would be fine too.

Just dunno what else of quality is sold in Europe.

[Dsanduril]

Not mixing old with new batteries is "common knowledge" based on series installations. As (LA) batteries age their internal resistance increases, and thus their current carrying capacity decreases. If you put a new battery in series with an old the new battery can deliver more current, the increased resistance in the old battery restricts the current and turns to heat....

On the other hand, with batteries of the same chemistry, parallel installation of batteries of various ages is not a huge issue. In the OP's case maybe the battery only adds 80Ah of capacity to the system rather than the label rated 95Ah, but since they are the same chemistry the charging profiles are the same. So what if batteries 1-3 supply 80% of any load and the last one supplies 20%? You may get slightly more DoD on the newer batteries, but overall you will get less DoD since your bank is larger.

Since the OP already owns the fourth battery, since it will be in parallel, and since it is the same chemistry (even the same model) there is no real reason not to add the older battery to the bank.

[john61ct]

+1 to that last

if the new 95Ah is indeed already purchased not returnable, might as well.

But the setup as a whole won't last long if not proper deep cycling units un the first place.

At least the whole-bank replacement can be scheduled in advance at an advantageous time and place rather than having to take whatever you can get in a primitive location.

[Pete7]

Originally Posted by ramblinrod

I think the suggestions you have received to change out the entire bank, or change to a single series string of batteries are misguided.

Assuming the prior issues that hurt the old batteries was corrected, the new batteries should provide excellent service, and adding one more (assuming you have the space) will be even better yet, for lowest cost, representing best value for money.

Rod, you are of course entitled to your opinion. However, I don't think you will have any CF members agreeing with you that ordinary car starter batteries "should provide excellent service" You do understand that they live on board in the med 24/7, and that they have destroyed one set of car batteries in a year already despite lots of solar.

If the new batteries fitted this summer are similar then they will be end of life (EOL) in short order and there is not much they can do about it. If there is a slightly older 95Ah battery not being used they may as well connect it in with the new bank, use it for the winter / spring, especially if they are in a marina or harbour with shore power. Then late spring when they head out again and they do like travelling, fit something more suitable for a live aboard yacht.

Perhaps you should post an amendment to your post saying that deep cycle batteries would be more suitable for a house bank than their current car starting batteries on a live aboard yacht.

Pete

[ramblinrod]

Originally Posted by Pete7

Rod, you are of course entitled to your opinion. However, I don't think you will have any CF members agreeing with you that ordinary car starter batteries "should provide excellent service" You do understand that they live on board in the med 24/7, and that they have destroyed one set of car batteries in a year already despite lots of solar.

If the new batteries fitted this summer are similar then they will be end of life (EOL) in short order and there is not much they can do about it. If there is a slightly older 95Ah battery not being used they may as well connect it in with the new bank, use it for the winter / spring, especially if they are in a marina or harbour with shore power. Then late spring when they head out again and they do like travelling, fit something more suitable for a live aboard yacht.

Perhaps you should post an amendment to your post saying that deep cycle batteries would be more suitable for a house bank than their current car starting batteries on a live aboard yacht.

Pete

Pete,

The OP declared that they had an “issue” that quickly destroyed the first set of batteries, that had now been fixed. The actual issue was not disclosed, but it is reasonable to assume that the issue prematurely killed the first set and now being fixed will not prematurely kill the second.

The OP has not declared the battery model, just voltage, capacity, and cranking amps. It is reasonable to assume that with the warranty issues, working with a battery supplier, that we are talking about some for of deep cycle lead acid.

So, if the problem has been fixed the 3x95 Ahr batteries should provide excellent
service to the limits of their design capability.

IMHO, there is absolutely no reason to remove and dispose those healthy batteries, that may provide excellent service for some time.

If the battery design is such that it does not provide long service life, then after they reach end of life, it may be wise to change to another battery model to increase this.

Either way, it is not necessary for the OP to discard healthy batteries today, or ever change battery voltage, series/parallel configuration (I would never recommend a single series string house bank to anyone) or any of the other recommendations.

If they are starting or dual purpose batteries, when due for replacement, I recommend changing them to deep cycle. At that time, the OP can consider all kinds of alternatives OR if the service life was acceptable, replace with same.

No amendment to my previous post necessary.

[ramblinrod]

Originally Posted by ramblinrod

Pete,

The OP declared that they had an “issue” that quickly destroyed the first set of batteries, that had now been fixed. The actual issue was not disclosed, but it is reasonable to assume that the issue prematurely killed the first set and now being fixed will not prematurely kill the second.

The OP has not declared the battery model, just voltage, capacity, and cranking amps. It is reasonable to assume that with the warranty issues, working with a battery supplier, that we are talking about some for of deep cycle lead acid.

So, if the problem has been fixed the 3x95 Ahr batteries should provide excellent
service to the limits of their design capability.

IMHO, there is absolutely no reason to remove and dispose those healthy batteries, that may provide excellent service for some time.

If the battery design is such that it does not provide long service life, then after they reach end of life, it may be wise to change to another battery model to increase this.

Either way, it is not necessary for the OP to discard healthy batteries today, or ever change battery voltage, series/parallel configuration (I would never recommend a single series string house bank to anyone) or any of the other recommendations.

If they are starting or dual purpose batteries, when due for replacement, I recommend changing them to deep cycle. At that time, the OP can consider all kinds of alternatives OR if the service life was acceptable, replace with same.

No amendment to my previous post necessary.

Correction, typo, 3rd paragraph.

Reads, "95 Ahr", meant "100 Ahr" (batteries installed after battery killing problem fixed).

Sorry for any confusion.

[Shrew]

Too much speculation without knowing the specific model of batteries. Varta makes a line of Deep Cycle batteries. In fact they have a wide variety of battery lines (Automotive, Heavy Commercial, Powersports, and leisure (which include Deep Cycle and Dual Purpose).

I am of the camp that believes all the batteries in the bank should be the same age. But then again, I don't replace just a single tire on my vehicles either.

[Dsanduril]

Originally Posted by Shrew

....I am of the camp that believes all the batteries in the bank should be the same age. But then again, I don't replace just a single tire on my vehicles either.

It's just not the same thing. You can't borrow tread from one tire to help out another. With batteries, if the OP adds one reasonably aged and undamaged (which could be questionable given the original circumstances) battery to the bank it will add capacity and reduce overall depth-of-discharge of the batteries (assuming loads remain the same with the battery addition) thereby extending life overall. Can't do that with tires.

The risk is that an older battery may die sooner, and when it dies it could take the others with it - if the death is a short in a cell it could draw down the newer batteries. You have to balance that risk with the decreased DoD that extends overall length of life.

Ideal world, yeah, all batteries same age. But the OP has an existing system and a spare used battery. Why not make the most of all of those until they die, then replace the whole system? Could be years.

[Pete7]

Originally Posted by ramblinrod

Pete,

The OP has not declared the battery model, just voltage, capacity, and cranking amps. It is reasonable to assume that with the warranty issues, working with a battery supplier, that we are talking about some for of deep cycle lead acid.

Barry posted an image of the 95Ah batteries with the part number. Likely the 100h are similar.

https://www.varta-automotive.com/en-...ic/595-402-080