Converting to a bank of 3 batteries?

[Posset]

Hi All,

 

I have just ordered 3 150ah deep cycle batteries to replace my 2 old 110ah ones. Can someone tell me the best way to wire up a bank of 3 in parallel so they all charge up balanced?

 

I have read through this page http://www.smartgauge.co.uk/batt_con.html and method 3 would be ideal but not very practical with requiring extra external terminal posts. Method 4 looks simple on 4 batteries but I can't get my head around using it on 3 batteries lol.

Edited October 12, 2016 by Posset

[mross]

It does say in the text that method 4 can't be used on 3 batteries so you are not daft. The link you posted won't work until you delete the space and "and" at the end.

[WotEver]

You'll be fine with method 2. If you're using thick enough cable with well crimped ends and good clean connections the difference between 2 & 3 is unlikely to be measurable.

 

Tony

[ditchcrawler]

Hi All,

 

I have just ordered 3 150ah deep cycle batteries to replace my 2 old 110ah ones. Can someone tell me the best way to wire up a bank of 3 in parallel so they all charge up balanced?

 

I have read through this page http://www.smartgauge.co.uk/batt_con.html andmethod 3 would be ideal but not very practical with requiring extra external terminal posts. Method 4 looks simple on 4 batteries but I can't get my head around using it on 3 batteries lol.

 

http://www.smartgauge.co.uk/batt_con.html

Edited October 12, 2016 by ditchcrawler

[Posset]

It does say in the text that method 4 can't be used on 3 batteries so you are not daft. The link you posted won't work until you delete the space and "and" at the end.

 

Thanks, I must be going nuts as I have read it over and over and cannot see no mention of it not working on 3 batteries lol.

You'll be fine with method 2. If you're using thick enough cable with well crimped ends and good clean connections the difference between 2 & 3 is unlikely to be measurable.

 

Tony

Thanks, it looks like I will have to go the method 2 route. What thickness/amperage link cables do you think I should use? The most common sizes available ready made seem to be 100amp 16mm2 and 170amp 25mm2.

Edited October 12, 2016 by Posset

[Jess--]

I've got mine hooked up as per method 2 with 3 exide 115Ah batteries

 

with 140w of solar the batteries are still solid after over 12 months, even fairly heavy overnight use still shows the bank above 13v at dawn

[Jess--]

 

Thanks, I must be going nuts as I have read it over and over and cannot see no mention of it not working on 3 batteries lol.

Thanks, it looks like I will have to go the method 2 route. What thickness/amperage link cables do you think I should use? The most common sizes available ready made seem to be 100amp 16mm2 and 170amp 25mm2.

for links between the batteries (which will be short) I would use the thickest cable that will fit the connectors, I think (from memory) I have 25mm on mine.

[Posset]

I've got mine hooked up as per method 2 with 3 exide 115Ah batteries

 

with 140w of solar the batteries are still solid after over 12 months, even fairly heavy overnight use still shows the bank above 13v at dawn

 

Thats good to know. The current setup 2 x 110ah batteries and 200w of solar doesn't appear to be enough. We only have 12v fridge and 12v tv and by the morning they would be down to 12.4, if the solars control meter is anything to go by on a sunny day the batteries would be fully charge by the early afternoon. The current batteries have lasted 30mths and last weekend they were 11.2 by the morning.

for links between the batteries (which will be short) I would use the thickest cable that will fit the connectors, I think (from memory) I have 25mm on mine.

Thanks. I am not sure what size the current link cables are. Once I have made the battery box and have then sitting in situe I can work out what lengths I will need and order a full set

[WotEver]

As said, 25mm will be fine. 50mm would be truly belt & braces if you can get/afford/fit them.

[mickp]

Op mentions deep cycle so maybe not 12v .worth a check unless i missed it

[WotEver]

Op mentions deep cycle so maybe not 12v .worth a check unless i missed it

He also said three...

 

Tony

[Sea Dog]

I'd go with method 2 for 3 batteries too.

 

Iirc, 25mm is the minimum acceptable to BSS, but the bigger the better for reasons of lower resistance. For that reason, and for the minor extra expense as a one-off cost, I'd certainly look to be at least 50mm. As an example, my 12v supply and charging cables (175a alternator and 2500w/100a inverter/charger) are all 70mm.

[mickp]

He also said three...

Yes suppose that would be big oversight if 6v....zip

Tony

[Posset]

Yes 12V lol. They are supposedly 150ah deep cycle batteries, they arrived this afternoon but I am a little disappointed that they only had 12.55v in all of them. I have put them on charge for a day or three. My boat only has an 80amp alternator which has to charge the house batteries and engine battery so 25mm link cables will probably be fine but I will look for bigger ready made ones before ordering.

 

I hope they perform better and live longer than cheap 110ah ones...

Edited October 12, 2016 by Posset

[WotEver]

Note that the larger cable doesn't only cope better with high currents it also helps to balance the batteries at all times which is particularly relevant with method 2.

[bottle]

Yes 12V lol. They are supposedly 150ah deep cycle batteries, they arrived this afternoon but I am a little disappointed that they only had 12.55v in all of them. I have put them on charge for a day or three. My boat only has an 80amp alternator which has to charge the house batteries and engine battery so 25mm link cables will probably be fine but I will look for bigger ready made ones before ordering.

 

I hope they perform better and live longer than cheap 110ah ones...

 

It is not necessarily the amp capability of the cable (although important) it is the volt drop so the bigger (mm²) the better.

 

All mine are 50 mm² and that is on a 24v system.

The batteries will only perform better and last longer if you treat them right and fully charge them correctly.

 

Good ones can die just as fast as bad ones if treated incorrectly

[MtB]

Yes 12V lol. They are supposedly 150ah deep cycle batteries, they arrived this afternoon but I am a little disappointed that they only had 12.55v in all of them. I have put them on charge for a day or three. My boat only has an 80amp alternator which has to charge the house batteries and engine battery so 25mm link cables will probably be fine but I will look for bigger ready made ones before ordering.

 

I hope they perform better and live longer than cheap 110ah ones...

 

 

What make and model of batteries have you chosen please? I'm planning to buy some decent batteries too shortly...

[Posset]

 

 

What make and model of batteries have you chosen please? I'm planning to buy some decent batteries too shortly...

They are Yuasa DCB1275-12's

[Posset]

Thanks everyone. I have ordered 50mm cable, terminals and the proper crimp tool to fit them.

[lockedout]

I have 4 135s in my new bank, used method three with a large Blue Sea Powerbar bus bar and 25mm Cables made for me by Bardens so they were all exactly the same.

 

Works perfectly, as designed and talked through with the clever people at Merlin (very clever and very helpful).

 

Having the busbar really helps with connectivity allowing for all sorts of things to be connected - i.e. auto bilge pump connected directly.

[Posset]

I have 4 135s in my new bank, used method three with a large Blue Sea Powerbar bus bar and 25mm Cables made for me by Bardens so they were all exactly the same.

 

Works perfectly, as designed and talked through with the clever people at Merlin (very clever and very helpful).

 

Having the busbar really helps with connectivity allowing for all sorts of things to be connected - i.e. auto bilge pump connected directly.

Any chance of a picture of your install?