installing different AH batteries in Parrallel

[nauticalnomad]

I want to install an extra 2 batteries in my battery bank.
I have 2 x 110 AH leisure batteries already installed and where i am they sell either 110AH batteries or there is a 220AH battery which works out a fraction cheaper than 2 of the 110AH ones and takes up less space.
Is it going to be problematic to have in the parrallel 110/110/220
Or should they all be the same 110AH?
Will the charging be affected if there is 1 x 220AH battery amongst the pair of 110AH.

[ranger58sb]

Originally Posted by nauticalnomad

I have 2 x 110 AH leisure batteries already installed and where i am they sell either 110AH batteries or there is a 220AH battery which works out a fraction cheaper than 2 of the 110AH ones and takes up less space.

That description could suggest the 220Ah battery might be 6V??

If so, no you can't add one 6V battery to a bank of 12V batteries. There's a way to use 6V batteries in a 12V system, but not one at a time.

-Chris

[Zanshin]

Is the battery chemistry identical - i.e. the same make and model of battery? If so, the charging system won't see a difference since a 12V battery is just a set of cells arranged in series. The general recommendation is to use batteries of a similar age (in addition to being of identical make), as internal resistance changes over time and a newer battery might get charged and depleted disproportionately more.
But what all pundits do stress is that you need to have the exact same chemistry for all batteries. Since each manufacturer has a different mix in their batteries, it means that you need to stick to the same brand.

[TurninTurtle]

Same chemistry (flooded lead acid is not the same as gel)
Same voltage
You can parallel.

Same capacity
Same chemistry
Same use history (this matters due to the older, more abused battery does not have the same capacity any more)
you can put them in series.

[newhaul]

There will be no significant issues as long as two things are adhered to.
First ). They must be the same volt type. Such as 12 volt or two 6 volt in series making 12 volt
Second). They must be the same type ie: all fla or all agm or all gel

[Zanshin]

Newhaul - not quite, for instance a flooded-lead-acid battery from Vetus should not be mixed with a flooded lead acid battery bank from Exide; as both use different additives in the plates and their internal resistances/charge curves differ. Similarly, an AGM from Lifeline doesn't play well in a bank of Trojan AGMs - same issues with resistances and voltages.
It isn't as bad as mixing chemistries, but it means that some of the batteries will see a lot more wear-and-tear and others won't; so the life expectancy overall will be diminished.

[nauticalnomad]

Thanks.They are all 12v lead acid.
The batteries are mixed brands as im now in France and their stock isnt the same as the UK and i want to leave next week to sail South.
So i can only use what is available.. Im not going to buy 2 new batteries to satisfy this new battery..

[newhaul]

Originally Posted by nauticalnomad

Thanks.They are all 12v lead acid.
The batteries are mixed brands as im now in France and their stock isnt the same as the UK and i want to leave next week to sail South.
So i can only use what is available.. Im not going to buy 2 new batteries to satisfy this new battery..

Sounds fine to my trained ears. Worst case you may just reduce the new battery life by a couple months . Or it most likely will have no effect. Are you planning on combining all into one bank or separate running two 220ah banks?

[nauticalnomad]

Originally Posted by newhaul

Sounds fine to my trained ears. Worst case you may just reduce the new battery life by a couple months . Or it most likely will have no effect. Are you planning on combining all into one bank or separate running two 220ah banks?

I have a battery splitter and
Bank 1 has
1 x 110 AH starter battery for engine..

Bank 2 will have this week
1 x 110 AH (existing)
1 x 110 AH (existing)
1 x 220 AH (new)

[newhaul]

Originally Posted by nauticalnomad

I have a battery splitter and
Bank 1 has
1 x 110 AH starter battery for engine..

Bank 2 will have this week
1 x 110 AH (existing)
1 x 110 AH (existing)
1 x 220 AH (new)

Sounds fine to me just remember to keep an eye on water levels and best idea would to keep a written record of watering to track any potential issues that may or may not arise. Fair winds.

[Terra Nova]

Ideally all batteries will be the same type, a/h, size, brand, age, lot. The farther you get from this ideal, the more compromised will be your battery bank.

[Tikka]

Yes, you can charge any sizes parallel, also discharging is no problem.
the only time become problem, when there is no charge or discharge for
extended period of time, the should be disconnected othervwise they
killing each other.