Wet batteries for domestic bank, AGM battery for starter - any possible problems?

Aeolus

Aeolus

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Looking to add a separate starter battery to my boat - currently I have a single bank of 2 x 105 Elecsol batteries that function as starter and domestic. I have to replace the current battery charger anyhow as it seems to have died and plan to add a VSR to manage the charging.

Does anyone know of any problems I might encounter - particularly having a wet lead acid domestic battery bank and an AGM starter battery.

Any other thoughts or recommendations would be welcome.
 
I have 2no 110 sealed lead acid batteries as domestics and an AGM Red Flash as my starter.Worked fine for the last 7 years.I have my mains charger and alternator management system set to charge at 14.4 volts.
However my Victron VSR will not work.The supplier thinks that it is due to the difference in battery bank sizes.The Red Flash is 27a/h.It keeps switching from one to the other known as chattering.I have disconnected it and am using the 1/2/both switch as normal.
 
I have also run wet cell domestics (3x80Ah) in combination with a Red Flash starter battery (circa 40Ah) and had no problems for the last 9 years.

ditchcrawler said:
However my Victron VSR will not work.The supplier thinks that it is due to the difference in battery bank sizes.The Red Flash is 27a/h.It keeps switching from one to the other known as chattering.I have disconnected it and am using the 1/2/both switch as normal.
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As an alternative to a VSR, consider an ordinary, heavy duty relay activated by alternator D+ (the warning light circuit). This will avoid any chattering problems and also other potential issues with VSRs.

Also be aware that feeding the domestic battery bank directly from the alternator – and the starter battery only via the relay – works just fine in large parts of the world, although many advise against it here.
One advantage of this approach is that the current through the relay or VSR will normally be much smaller. It is also easy to disconnect the starter battery during very long engine runs, if you are worried that a small AGM might suffer.
 
Thanks to all for that information.

Why AGM - because they seem to be better starter batteries. They apparently deliver higher CCA and recharge faster.
 
pmagowan said:
Why do you want to use an AGM, won't that be more expensive? Why not just get another LA battery for starting?
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Advantage of an AGM is that it is significantly smaller than a LA and can be mounted in any orientation. The key is high CCA, not capacity so a Red Flash of 30-40 ah will do the same job as a conventional battery of twice the capacity. Which you choose depends on your priorities - if you have the space go conventional, if not using an AGM allows you to allocate more space to house capacity.
 
pmagowan said:
Why do you want to use an AGM, won't that be more expensive? Why not just get another LA battery for starting?
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Because it can be positioned in a small space where no other would fit.
April036.jpg

By doing this I was able to use the three moulded battery boxes in the boat for my domestic bank instead of one starter and two domestics. In the end this battery, a Red Flash 900, proved a little too small, not helped by problems with my solar panel dual bank controller, so it has now been replaced with a Red Flash 1100.
 
I currently have 3 wet batteries (110aH each), one for engine, two in parallel for house. Have separate switches with VSR arrangement, with alternator connected to engine battery so it is charged first. Also have smart regulator controller on alternator.

Considering making all 3 wet batteries for house circuits, and buy a Red Flash battery for the engine. But I have been told that I could damage the likes of a Red Flash battery over time with this arrangement - is this the case?
 
West Coast said:
I currently have 3 wet batteries (110aH each), one for engine, two in parallel for house. Have separate switches with VSR arrangement, with alternator connected to engine battery so it is charged first. Also have smart regulator controller on alternator.

Considering making all 3 wet batteries for house circuits, and buy a Red Flash battery for the engine. But I have been told that I could damage the likes of a Red Flash battery over time with this arrangement - is this the case?
Click to expand...

I run a setup similar to what you are planning, as per previous post.

I believe that if your smart alternator regulator raises the charging voltage much above 14,4 V (Sterling?) there could be a problem, especially on long engine runs.
You could overcome this by manually disconnecting the starter battery in such situations, but that might not be compatible with VSR and the "charging the starter battery first – philosophy".
 
Storyline said:
That engine looks brand new or do you keep it in such nice condition ?
Looks great
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2000 hours, ten years old. You can see that the engine mounting is rusty, I thought the manifold was leaking and bought a replacement against the time that it gave up. I then found that the leak was just the hose attachment, the manifold is perfect. Nothing seems to stop the Aquadrive from rusting, it is coated with grease which seems to do nothing for it.
 
BabaYaga said:
I run a setup similar to what you are planning, as per previous post.

I believe that if your smart alternator regulator raises the charging voltage much above 14,4 V (Sterling?) there could be a problem, especially on long engine runs.
You could overcome this by manually disconnecting the starter battery in such situations, but that might not be compatible with VSR and the "charging the starter battery first – philosophy".
Click to expand...

Good argument for a 1-2-both switch. I charge the starter battery for half an hour on engine, then switch to the domestic bank if motoring for a while. The solar panels then charge the starter battery while the alternator charges the domestics.
 
vyv_cox said:
2000 hours, ten years old. You can see that the engine mounting is rusty, I thought the manifold was leaking and bought a replacement against the time that it gave up. I then found that the leak was just the hose attachment, the manifold is perfect. Nothing seems to stop the Aquadrive from rusting, it is coated with grease which seems to do nothing for it.
Click to expand...
There is something satisfying about having a nice clean engine, especially if you are like me and unable to do anything more than basic jobs and servicing on it.
The reason we bought Storyline was because of the gleaming nearly new Nanni engine which looked huge to me. Now it gets regular cleaning - somehow it feels as though I am taking care of it ! Stupid really but satisfying.
 
Different types of batts require different charging profiles so the charger would need not only to be able to charge two banks, but have the ability to be set for the right type of battery in each bank.

Lead acid batts will need venting, AGM won't.
 
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