Atlantic 75 Battery Problem

747sp · 14 September 2017, 21:28

Here is the battery tray from my EX Rescue Service Atlantic 75. As with everything else on this boat it was in beautiful condition when i got it (for a 20 year old boat), but it weighs a ton. As you can see great redundancy. Recently, the port engine (Suzuki 90) is either very slow or refuses to power down and certainly won't consider starting. I have three isolators on the system, one port, one starboard and a link between the two, so i can start etc. I pulled the battery tray out and conditioned / charged all four batteries independently - all read extremely close to each other afterwards (a range (i seem to remember) of 12.4 to 12.8 Volts) . Put it all back together lugged it back to the boat. same problem. After a run for a couple of hours the port engine will power up and down (faster, but not entirely enthusiastically) but it will not start on its own circuit.

The batteries are Enersys SBS - 30s probably installed because they are inversion proof. They are ridiculously expensive (around GBP300 each).

Here's my question - do replace the two on the port engine side, or do i simply get rid of the four and replace with two more normal marine batteries. I have checked the requirement in the Suzuki specs and can get two varta batteries from my local agent for an awful lot less.

One more thought - could it be that my larger four stroke engines need more grunt to turn them over than the old 2 stroke Yamaha 75's did?

All thoughts / opinions gratefully received...

Iron Dials · 14 September 2017, 21:39

Have you tried changing batteries from the left bank to the right bank? (eliminating the batteries from suspicion)
Are the cables, connections and isolators all in tip top condition?
What do you mean by power up and down?

747sp · 14 September 2017, 21:59

Sorry I mean the auto trim button on the throttles that lets you lift the engines clear of the water.

willk · 14 September 2017, 22:18

Could be a poor connection/bad copper?

Pikey Dave · 15 September 2017, 06:23

Quote:

Originally Posted by 747sp

Sorry I mean the auto trim button on the throttles that lets you lift the engines clear of the water.

Do the buttons on the engine cowls work ok?
Do the engines start ok?
If so, it isn't the batteries, much more Oomph required to start the engines than operate the trim. Most likely dodgy switch/connection/trim motor

747sp · 15 September 2017, 07:44

Quote:

Originally Posted by Pikey Dave

Do the buttons on the engine cowls work ok?

No the port engine doesn't drop or rise offeither the throttle switch or the switch on the engine cover.

After a good run (2/3 hours) it will drop and rise slowly, but I get nothing but a click when I try and start it.

I am going to try Mr. Dials suggestion of swapping the batteries around and see what happens

I wonder if I can just swap the plugs over where the batteries plug in under the helm?

Pikey Dave · 15 September 2017, 08:05

When you say "try & start it" are you talking about the trim & tilt (PTT) or actually starting the engine. You need to clarify whether you have one problem or 2.
Does the engine start ok?
Is the problem just with the PTT?

747sp · 15 September 2017, 08:11

Quote:

Originally Posted by Pikey Dave

When you say "try & start it" are you talking about the trim & tilt (PTT) or actually starting the engine. You need to clarify whether you have one problem or 2.
Does the engine start ok?
Is the problem just with the PTT?

If I leave to boat for more than a couple of days, the port engine will not drop on the power trim switches (Throttles and or Engine Cover)

Neither will it start

Until I combine the circuits then it does both.

When it has been running for a couple of hours on its independent circuit, it will drop and rise on the power trim switches slowly. It will still not start.

Phil M · 15 September 2017, 11:31

Sounds like a dud battery. Do you have a load tester? I got a cheap silverline battery tester off of amazon for about £18, which tests the battery under load rather than just the voltage under static conditions and it has helped me diagnose battery issues on several vehicles. One may help avoid costly replacement bills.

As for replacing the batteries, if it is cheaper to replace the lot, that's what I'd do, assuming you can fit the replacements in.

Phil M

747sp · 15 September 2017, 14:53

Thanks Phil. Will do. I wonder that given they are wired in two parallel pairs whether the meter will "spot" if it's one battery or whether it will read two together. Doesn't matter- it will tell me if I have a dud pair anyway...

Pikey Dave · 15 September 2017, 15:13

Quote:

Originally Posted by 747sp

If I leave to boat for more than a couple of days, the port engine will not drop on the power trim switches (Throttles and or Engine Cover)

Neither will it start

Until I combine the circuits then it does both.

When it has been running for a couple of hours on its independent circuit, it will drop and rise on the power trim switches slowly. It will still not start.

Right, we're getting somewhere [emoji106] as Phil says, could be a dud battery or a bad connection. First thing I'd do is swap over the batteries as previously mentioned & se if the fault follows the battery. I'd also split up the batteries from their parallel config, if you have one battery in the pair which is dud, it will drag down the other one. You also need to check the charging circuit of the faulty engine to ensure you're getting correct charging.

A1an · 16 September 2017, 14:59

And just because you are getting the correct voltage it doesn't guarantee your batteries are good.

I've got a battery here that reads 12.8v but doesn't have the guts to start a kids quad bike.

Phil M · 19 September 2017, 11:15

Quote:

Originally Posted by A1an

And just because you are getting the correct voltage it doesn't guarantee your batteries are good.

I've got a battery here that reads 12.8v but doesn't have the guts to start a kids quad bike.

That's where the load tester comes in. It will give you an Ah reading so you can compare against spec.

Phil M

Erin · 19 September 2017, 14:59

The batteries are definitely the first thing to 'load' test, however the condition of electrical switches, contacts and lugs is critical for high power drain items such as tilt/trim motors and starting circuits. It is quite possible the batteries are fine but there is a poor connection which is sufficiently overcome when the batteries are fully charged after a run or when paralleled, but not so when cold. As said, swap the batteries around first and see if the fault follows. If it doesn't then start checking each connection. A corroded earth or a failing switch could be enough.