Another battery question - replace 3 lead acid flooded with single AGM?

[wonkywinch]

Looking at upgrading the wigglyamp storage capacity and spoken to a few people, inc Exide tech staff and Crystec UK (installed battery charger).

Exide were surprised that I had 3 lead acids in parallel and said they wouldn't recommend it. I explained almost all boats I've sailed did this as do many motorhomes. They suggested it might be common practise but not recommended in the event one cell within one battery fails with the other good batteries still in parallel.

Looking at replacements, Crystec recommend Rolls batteries. If I go full lithium, I will need to upgrade my inverter/electrics (currently Marinco 700W, good enough for laptop, ePropulsion charger etc). I'm considering a single Rolls AGM which will physically fit the location of the existing 3x 80A/Hr Exides but the thing weighs almost 80kg and I am concerned about physically getting into place in a compartment in the bottom of a cabin cupboard. It will go through the space and in, but I'm not sure manoeuvering it into place is going to be practical.

Three new AGM that will fit similar to the old work out a similar price.

Single or replace 3 and parallel them?

Rolls S12-290AGM Deep Cycle Series 12 Volt Battery

 

[GEM43]

I had a pair of 80kg Lifeline batteries, I always worried about getting them out - but I sold the boat so not my problem now! On my new boat I fitted seven 110ah AGMs in parallel, much more manageable with no problems experienced. I’d go for multiple smaller batteries again.

 

[srm]

15 years ago I fitted 4 x100amp/h Rolls AGM batteries in parallel for house supply. I choose 100amp/h as being the heaviest I could realistically handle. I sold the boat last February and they are still in use, though the new owner is aware they are getting near end of life. I never discharged them below 50% though the spec said that they could be discharged to 80%.

 

[Blue Seas]

Have you considered the Rolls 230 AGM? They are about 18kg lighter and I found them much easier to handle when I fitted 6 of them in parallel. Original fit was to 'drop' them about 18 inches into a 4-sided battery box which I did with strops - I later took one side of the box out and replaced it with a slab of 4x2 hardwood as a retainer so that I could slide rather than drop the batteries in and fit the retainer afterwards. I also pre-fitted some of the cables (between batteries for 24v) and also the tails up to the first fuse so that I didn't have to reach in (The Rolls terminals are great for this). Like SRM I never discharge below 50% and after almost 10 years they are almost indiscernible from new in both appearance and performance - highly recommended.

 

[wonkywinch]

Here is the space I have to work with. Beneteau have built the compartment to exact sizing so very difficult to rework. There is another space behind the engine where a new tray could be constructed, room for a 3kw inverter etc. That option is going to be a lot more expensive than a flooded > AGM swap.

From left, one engine start battery, three domestic batteries. All Exide ER350s.

Have you considered the Rolls 230 AGM? They are about 18kg lighter and I found them much easier to handle when I fitted 6 of them in parallel. Original fit was to 'drop' them about 18 inches into a 4-sided battery box which I did with strops - I later took one side of the box out and replaced it with a slab of 4x2 hardwood as a retainer so that I could slide rather than drop the batteries in and fit the retainer afterwards. I also pre-fitted some of the cables (between batteries for 24v) and also the tails up to the first fuse so that I didn't have to reach in (The Rolls terminals are great for this). Like SRM I never discharge below 50% and after almost 10 years they are almost indiscernible from new in both appearance and performance - highly recommended.

6 in parallel! Trying to maximise use of existing space, the 290 fits nicely into the space, the 230 might be tight as it's 10mm longer than the 290.

520L x 270W x 225H = Available space (+/- few mm)
521L x 269W x 224H = Rolls 290
530L x 209W x 218H = Rolls 230

I'll be shopping at the boat show. Might need a heavy duty trolley!

 

[Sandy]

Exide were surprised that I had 3 lead acids in parallel and said they wouldn't recommend it. I explained almost all boats I've sailed did this as do many motorhomes. They suggested it might be common practise but not recommended in the event one cell within one battery fails with the other good batteries still in parallel.

Some time ago I visited the HQ of a major organisation who ran a very, very large mission critical IT system, no names no pack drill, on touring their power facilities I entered their battery backup room was confronted with a battery bank the size of a shipping container.

Where do these guys come up with such silly ideas?

 

[Tranona]

Have you considered using the space behind the engine to fit a high powered AGM start battery such as a Red Flash or an Odyssey then seeing whether you can get more domestic capacity in the existing space, either by 4 of the existing size or 2 larger ones. The photo shows my installation with 2*895ah Exides and an Odyssey. There is a custom mounting box available for the odyssey for when they are mounted on racing cars siting on top of the gearbox which will fit well on a vertical bulkhead

The Odyssey is this one demon-tweeks.com/uk/odyssey-extreme-power-motorsports-ods-agm-battery-7000367/

 

[B27]

Some time ago I visited the HQ of a major organisation, no names no pack drill, on entering their battery backup room was confronted with a battery bank the size of a shipping container. Where do these guys come up with such silly ideas?

Quite often charged in series sets of 4.

 

[Blue Seas]

Exide supply and fit submarine batteries in both parallel and series combination as required. The difference is that they are being monitored 24/7 and, as well as lots of different charging / discharging routines for optimum performance. The fluids can also be agitated to prevent stratification.

 

[Refueler]

Although a single large battery may make sense in terms of capacity vs dimensions etc - my thoughts are always to lifting in / out / replacing ...

With a bank pf smaller batterys making up the required capacity ... its easier to lift out offending battery .. replace ... especially if on a cruise ... cheaper too.

 

[Bouba]

I have the same problem in that the house battery is heavy.....although my installation under the companionway stairs looks easier than yours....my solution is to carefully study the move in all aspects....I told the delivery guy where to put it (right next to the boot of my car)....so only one lift into the car. And used a hand trolley to get to the boat...and a dolly on wheels on the pontoon and through the boat....this might seem off point but the logic is simple ....one lift is going to be hard...getting the big battery into a place it doesn’t want to go...so save all your energy for that task only.
Unless that cabinetry comes apart...the battery has to slide in at an unnatural angle....I don’t know if it will go. If you plan on using a plastic battery box that will be the approximate size of the battery....if you can get the battery box in you probably can get the battery in. Good luck

 

[B27]

You can get the 80Ah Exides for £90 each.
I'm in no rush to buy lithium, but no rush to spend £500 on an immovable lead battery either.

I suspect in 3 years time, lithium will be a fair bit cheaper?

I'd be wondering if a bit more solar or slight modification of habits might reduce the Ah needed?

 

[wonkywinch]

You can get the 80Ah Exides for £90 each.
I'm in no rush to buy lithium, but no rush to spend £500 on an immovable lead battery either.

I suspect in 3 years time, lithium will be a fair bit cheaper?

I'd be wondering if a bit more solar or slight modification of habits might reduce the Ah needed?

Actually a very good point highlighting cost vs benefit. Thank you. Bigger is not always better.

 

[srm]

Actually a very good point highlighting cost vs benefit. Thank you. Bigger is not always better.

Surely working life should also be part of the equation. My four 100Ah Rolls AGM are still working after 15years, though they may not have lasted so long if I had a smaller bank and used their deep discharge ability. I don't think I ever got more than3 or 4 years from wet acid house batts.

 

[B27]

Surely working life should also be part of the equation. My four 100Ah Rolls AGM are still working after 15years, though they may not have lasted so long if I had a smaller bank and used their deep discharge ability. I don't think I ever got more than3 or 4 years from wet acid house batts.

That's fair comment.
But it's possible for some people to get good life out of 'leisure batteries'.
And with the price of lithium batteries falling, along with the associated electronics, it's hard to plan 15 years ahead now.

Also, there's a lot of battery banks 'still working' but not 'working' at anything like their original capacity.

It seems that cruiser sailors almost divide into two camps, those who seem to need ever larger house banks, and those who can get away with smaller banks now because it's easier to have enough solar to keep up.