Wiring 8 batteries in parallel

[MHS]

More capacity means longer periods between charging. So we may have the same power usage, but I only need to charge once a week where you may need to do once a day. Not a big issue for leisure users, but for liveaboards it's handy.

That's our main aim. If we cruise for a full day, and then moor for a day, we won't need to run the engine, or for a shorter time when moored. Long term that will save on diesel.

[Robbo]

True same number of links but as you say, significantly more cable required. Also having 4 cables going onto 1 terminal can create problems of the physical space and bolt length needed to do that.

It's 3 cables max at one terminal, and only at the feeds. And it isn't that much cable

 

 

Edit, my bad it's 4 at the feeds. Was thinking my setup a I have 8 batteries but at 6 volt.

Edited August 2, 2014 by Robbo

[Justme]

If you need the capacity of 8 batteries why not go the extra mile & use fewer larger capacity ones?

 

Or better yet 6 x 2v cells of the right capacity.

[nicknorman]

If you need the capacity of 8 batteries why not go the extra mile & use fewer larger capacity ones?

Weight for manual handling!

[NigelMoore]

For what my input is worth, I support the idea of simplicity and quality. I don't remember all the fine details now, but I have linked up 8 pairs of 220 amp hour batteries for a 24V system feeding in and out from the one end pair. 300 amp generator for charging, 100 amp mains top-up, 5-10KW Invertor. No problems for all the years I was acquainted with the boat.

[Justme]

Weight for manual handling!

 

 

Total weight per capacity would be very similar so splitting it into 6 x 2v cells instead of 8 bats would not make a huge difference. Dropping down to 4 x 220ah bats would about double the individual weight but even they are not that heavy (about the size of a lorry or tractor bat) & you wont be moving them around much.

[Pete of Ebor]

I'm no electrician but would it make any sense to wire them up as two seperate banks of four with a set up such that you could use either bank singly or both banks together... I said I was no electrician, but is would seem to me that if say one battery failed, you could isolate that bank and still have power - not as much maybe, but some...

Edited August 3, 2014 by Pete of Ebor

[MHS]

I will be ordering the cables to connect up the extra batteries in the next few days. Have sorted the original issues with the battery bank as per my thread "Bright spark reqd"

 

Thanks for the help.

[smileypete]

Couple more variations:

 

In the end s'pose it depends on circumstances, how many ring terminals can fit on a batt/common point, what cable size works out best/cheapest and so on...

 

8 batts is a fair number of batts though, discharging a lesser number of leisure batts down to 20% on the odd occasion shouldn't hurt them.

 

cheers, Pete.

~smpt~

[PhilR]

That suggests that gas fridges are making a comeback.

 

Mine never went out of fashion, although it is getting a bit rusty at the edges. (reminder to self: I must get around to touching up the rusty bits).

[mango]

 

Mine never went out of fashion, although it is getting a bit rusty at the edges. (reminder to self: I must get around to touching up the rusty bits).

Being absorption fridges the gas/electric ones were too power hungry on 12V and a bit heavy on gas consumption.

 

I wonder if it would be possible to produce a fridge gas/12V Peltier cooling, taking advantage of solar power when available and switching over to gas when there is no sunlight. That would conserve gas and avoid the need for large domestic battery banks on boats without heavy electrical loads. Is anything like that available and is it BSS compliant?

[Robbo]

Being absorption fridges the gas/electric ones were too power hungry on 12V and a bit heavy on gas consumption.

 

I wonder if it would be possible to produce a fridge gas/12V Peltier cooling, taking advantage of solar power when available and switching over to gas when there is no sunlight. That would conserve gas and avoid the need for large domestic battery banks on boats without heavy electrical loads. Is anything like that available and is it BSS compliant?

Some marine fridges do cool a cooling plate when the batteries are been charged, and use that first so reduce the amount of overnight electric consumption.

[PhilR]

Being absorption fridges the gas/electric ones were too power hungry on 12V and a bit heavy on gas consumption.

 

I wonder if it would be possible to produce a fridge gas/12V Peltier cooling, taking advantage of solar power when available and switching over to gas when there is no sunlight. That would conserve gas and avoid the need for large domestic battery banks on boats without heavy electrical loads. Is anything like that available and is it BSS compliant?

 

I know what you mean, and your suggestion sounds a great idea. But the old Electrolux fridge consumes less gas than the pilot light on my Morco water heater, which is why I don't keep that pilot light running 24/7.

The old Electrolux fridges were designed mainly for caravan use. 12v when towing and powered by the car battery/alternator. Gas when parked up and 240v when mains hook-up was available, although that must have been a rarity in the days when the fridge was first manufactured.

 

For my *cruising* needs the gas fridge does save a lot of expense on fancy electrics and large battery banks.

[peterboat]

EIGHT batteries????

 

I manage fine with two!

 

 

(Hope that helps )

 

MtB

And I manage with 12 2 volt cells full traction of course. Horses for courses

 

Peter

[peterboat]

Also may I suggest solar panels it will help your batteries stay alive longer

 

Peter

[Gypsey_Kings]

My way of showing the connections....ie: which ones need to be the same length for balanced charging... Cables don't need to be these colours, the colours are just to show which ones should have the same length. (also helps to see how the balanced charging works)

[smileypete]

One other thing, make sure the ends of the batt cables are well sealed with glue lined heatshrink, protect the crimp conections from moisture or spilt batt acid.

 

cheers, Pete.

~smpt~

[solorone]

Couple more variations:

 

In the end s'pose it depends on circumstances, how many ring terminals can fit on a batt/common point, what cable size works out best/cheapest and so on...

 

8 batts is a fair number of batts though, discharging a lesser number of leisure batts down to 20% on the odd occasion shouldn't hurt them.

 

cheers, Pete.

~smpt~

 

[solorone]

Smileypete's battery layout has been posted about the solar forums. Seems years ago I had a similar layout but for series and parallel. The diagrams here seems to be mostly parallel I wondering if y'all could suggest a best balanced diagram for series and parallel of a 24 Volt system using 8 -- 12 V. batteries.

Cheers, and

Thanks.

[MHS]

Sorry never reported on the final fitting.

 

Ended up fitting 50sqmm interconnecting cables and took negative and positive feeds off battery numbers 3 and 6.

 

All working beautifully.

 

If you cruise for a day, then moor for a day, you don't need to run the engine on the rest day. Should save diesel in the long run. Time will tell once the long nights really draw in.

[mango]

Fine, but phenomenally complicated, and unnecessary so IMO.

Agreed. What matters is heavy gauge interconnecting cables and secure connections. There might be a small voltage drop across the interconnects during the peak charging rate but that will disappear as the current decreases.

[Gypsey_Kings]

Smileypete's battery layout has been posted about the solar forums. Seems years ago I had a similar layout but for series and parallel. The diagrams here seems to be mostly parallel I wondering if y'all could suggest a best balanced diagram for series and parallel of a 24 Volt system using 8 -- 12 V. batteries. Cheers, and Thanks.

 

For balanced charging of 8 x 12v batteries in a 24V system ... Cables don't need to be these colours, the colours are just to show which ones should have the same length. (also helps to see how the balanced charging works)

 

[solorone]

Thanks for the diagram, that is about as I suspected, my problem will be that the + and - are on the same end of the batteries, will make wiring and testing a bit hard. My last battery setup was 14 years ago and I did not pay much attention when I ripped them out for salvage. Y'all talk about 70 MM wire, that is huge. I did use a 20 foot run of 600 MCM, about 28/30 MM , when I was at 12 V, but have been on 4/0, 212 MCM for last 20+ years. My current battery setup is about 10' further away so may add to the 212 MCM, as we are hitting a lot of 3+ KW loads with the new setup but rarely get over 150A at 24 V.

I have been off grid for 32 years, if I can be of any help here with the solar end, just let me know. I looked for a message setup but have not located it here.

Cheers.

Edited November 2, 2014 by solorone