Can 3 different size deep cycle batteries work together??

[Bloodyaussie]

Through the conversion process I was left with 3 different deep cycle batteries and wanted to know if I can use them in my trailer build together.

I have been told you need to match your batteries?

I have one 105ah and 1 80ah and 1 60ah... all are Supercharge deep cycle.

[the evil twin]

They will work fine Cobber... absolutely no issue at all.

[Bloodyaussie]

They will work fine Cobber... absolutely no issue at all.

I like you.....

[the evil twin]

I like you.....

... awesome !!!

For quite a few years I thought I was the only one.

[Bloodyaussie]

... awesome !!!

For quite a few years I thought I was the only one.

Ha ha ha..... also can i put all 3 batteries on charge together instead of playing the juggling game when need to top them up.

[AB]

Are you sure ET?

I thought it was a bad idea to use different ah batteries together?

How would the larger capacity charge when the lower one is full, won't the smaller one overcharge or larger one not fully charge?

What happens when the smallest one is discharged too much, won't the larger capacity start trying to charge smaller one reversing the voltage?

[the evil twin]

Yep

Nope, well, depends to be more accurate I spose
If the biggest isn't more than twice the size of the smallest and they are otherwise the same then no dramas at all

No difference to running two or three the same capacity and no difference to running a cranker and an aux in a vehicle (DC/DC chargers aside).

If they are paralled together they will discharge equally together and charge equally together
If they are discharged unequally and then paralleled for charging two things will happen
Until the Charger is connected, the highest SOC battery no matter what it's capacity current will flow to the lowest SOC (same as hooking up two cars for a jump start and waiting a few minutes)
When the Charger is connected the charging current will begin to charge the lowest SOC first regardless of the capacity due to it having the better charge acceptance rate of the three.
Charge Acceptance is directly related to SOC

Mixing capacity within reason doesn't matter esp if they are identical in all other respects
Mixing deep cycle with crankers matters IF the deep cycle specs don't allow for high current charging otherwise that is OK as well
Mixing flooded and sealed AGM etc isn't the best but often works Ok
Mixing technologies IE flooded with Ca/Ca or whatever is a terrible idea

[blocko05]

Hi BA. You could call Brett Bear. He has his own battery business and he advertises on Facebbok. Here is one of his advertisements that I have attached. He can answer any questions you may have and then some. 61464

[Bloodyaussie]

Cheers mate but we have some very smart people here on the forum when it comes to batteries and solar and so on so prefer to draw on their talents... thanks.

Plus i keep getting in trouble if i use Facebook...lol

[the evil twin]

Ha ha ha..... also can i put all 3 batteries on charge together instead of playing the juggling game when need to top them up.

Depends but not a real biggee IF the batteries are within the capacity range quoted.

I would either run them as a bank or run them switched seperately for both supply and recharging.

It won't matter which battery is low in the 'split' scenario and it won't matter on a good charging source but if you are using low current charging IE Solar or a low (say 10 amp) mains charger where the lowest battery is waaay down in relation to the others it can be less than ideal.

Again, not a bigee but if the load can pull the charging source voltage below one of the other batteries then that battery will 'assist' the charging source for a while.
Any current flow out of a battery isn't 100% efficient IE there are losses due to heat, resistances etc.
That means the say 10% lost out of the high battery doesn't translate into 10% added to the low one.

To keep it in perspective we are talking minimal to no effect pretty much most of the time.

If I was starting from scratch I would buy similar batteries but I sure wouldn't spend a couple of hunjee to have say two 105's instead of a 105 and an 80 + 60 making 140

Now... there is one other thing to consider IF you want to run all three as a single bank and that is that you should diagonally connect the bank
Here is a random link with a pretty good (IE simple) explanation why
http://www.smartgauge.co.uk/batt_con.html

[BigRAWesty]

Hi BA. You could call Brett Bear. He has his own battery business and he advertises on Facebbok. Here is one of his advertisements that I have attached. He can answer any questions you may have and then some. 61464
I'm sorry but that guys is a complete twat.. lol..
Some good info there et. Cheers

[the evil twin]

... I should have added that all 3 batteries do need to be in good condition.

Obviously a battery in poor nick will affect the other/s but that is irregardless of capacity matched or otherwise

[the evil twin]

... I probably should also add that I bet parts of this thread gets taken out of context and starts an 'animated technical discussion' :1062:

[Bloodyaussie]

That link you posted is brilliant thanks heaps et....