Chartplotter goes dead when engine is cranked.

Status
Not open for further replies.
Euphoria2011

Euphoria2011

.
May 24, 2011
139
Oday 28 Windmill Harbor Hilton Head, SC
I guess the DC load for the starter is so much that the voltage drops down below the minimum for the Raymarine A57D chartplotter and it turns off.

The 2 batteries installed, and selected through the Perco 1/2/all switch, are new as of November and they are 2 interstate SRM-27B battery deep cycle batteries.

Anybody have an idea of how to somehow filter this load?
 
Maine Sail

Maine Sail

.
Feb 6, 1998
11,709
Canadian Sailcraft 36T Casco Bay, ME
Euphoria2011 said:
I guess the DC load for the starter is so much that the voltage drops down below the minimum for the Raymarine A57D chartplotter and it turns off.

The 2 batteries installed, and selected through the Perco 1/2/all switch, are new as of November and they are 2 interstate SRM-27B battery deep cycle batteries.

Anybody have an idea of how to somehow filter this load?
Click to expand

1- If using just one battery to start this will happen.


2- If using both it ideally should not.

With both at 32f you should have 1500 cranking amps available which means that at 70f you'll have close to 2000 cranking amps. If you're dropping voltage enough to drop your instruments it is likely caused by something else.

I would suspect you have some poor/old terminations and or small GA battery cable. You probably have a Universal M-18 or M-25 and that should not be exceeding much beyond a 200A in-rush and those batteries should easily stay well above the "drop out" for your plotter if your wiring, terminations (including grounds) and wire gauge are sufficient..

This is the "peak", as in less than 1/4 of a second in duration, in-rush current that is needed to start a Universal M-25..

Those two batteries should easily support starting that motor without voltage dip sufficient to drop out your plotter. If your negative and positive load cables are connected to ONE battery move the negative to the other battery and you'll better support the in-rush loads across the bank. Check all connections and CLEAN them including the engine ground connections...

In the interim simply power up your instruments AFTER starting the motor. You can add a simple on/off switch to your 1/2/BOTH to create a dedicated "starting" bank but with everything working as it should, you should not be having this problem.

This is a 44HP four cylinder with a five year old bank of three group 31 deep cycle wets... 11.7V as the bottom is well above the drop out for most electronics. This bank and system is wired with 1/0 wire and very short runs..

Again we need to know if you use both to start or just one battery..

Best bet if this is happening is to turn the plotter on after you start..
 
Euphoria2011

Euphoria2011

.
May 24, 2011
139
Oday 28 Windmill Harbor Hilton Head, SC
Oh, sorry, I forgot to mention that the engine is a 2008 Beta Marine Beta 20 3 cyl.

New battery connetors installed when replaced both batterys and the cable is 4 AWG I think
 
Euphoria2011

Euphoria2011

.
May 24, 2011
139
Oday 28 Windmill Harbor Hilton Head, SC
another thought

I was thinking about this theory since the batterys are bran new....
this sailboat came with a Westerbeke 2 cyl engine in 1983 and the previous owner removed it and installed a 3 cyl Beta Marine engine.

Maybe the existing cables cannot fully support the current draw to start this bigger engine. Althought the cable from both batterys are huge, I think they may be 1 AWG.

I enclosed the schematic that shows the wiring to the starter.
 

Attachments

heritage

heritage

.
Apr 22, 2011
943
Hunter 27 Pecan Grove, Oriental, NC
If your engine cranks at a descent speed, I would look at all the connections and wiring between the batteries and the chartplotter. Is the plotter hardwired into the "nav equipment circuit"? If so, and you don't have any problems with other devices on the nav circuit, then take extra time looking at the wiring from the nav circuit to the plotter.
 
Maine Sail

Maine Sail

.
Feb 6, 1998
11,709
Canadian Sailcraft 36T Casco Bay, ME
I would be surprised if the factory wiring were 1GA. Some of them were 4GA. I just did an O'day 30 this past fall that had 4 GA wire, she now has 1/0 wire. It looked factory but on a early 80's boat who knows...

With small battery wire you are adding the wires voltage drop ON TOP OF the normal voltage dip that occurs with starting the engine.

If everything was perfect and your batteries dipped to 11V you'd likely be fine. But if your batts dip to 10.8V AND you have a large voltage drop of say 0.6V your instruments are now seeing 10.2V which may be below the drop out. Many cut out at 10.5V..


For example if you had a battery circuit that was 14' in total length, not uncommon, and 4 GA wire and a 300A in-rush from your Beta for starting, you'd be dropping an additional 1.1V from just the wire. This is on-top of the normal dip a battery bank has when starting.

If you had 2/0 wire in the same circuit your dropping roughly 0.33V... Sometimes that 0.75V difference is what will keep a device on or let it drop out. If you have 1 GA wire then check all your connections. If you have 4GA or 2GA wire you may be better to start the motor with the instruments off...


We still need to know if you are trying to use just ONE battery to start or both. If just one that is just a fact of life the way it is currently wired. If two then we have things we may be able to do.

Still, as mentioned, the easiest fix is to turn the instruments on after you start the motor.
 
Euphoria2011

Euphoria2011

.
May 24, 2011
139
Oday 28 Windmill Harbor Hilton Head, SC
battery switch pics


I looked at the schematic and the picture attached closer and I see that both #1 and #2 batteries positive cables go to the Perko switch.

Which ever batt I select is the one that will provide cranking current for the engine as well as the rest of the devices on the DC bus, which is my issue here.

The pic shows the two battery cables secured to the switch coming from the batts, looks like pretty big cables to me, what do you think? 1 AWG?
(the 2 smaller red wires are from the Promariner Protechi 20 amp battery charger to provide charging )

The grounds cables connect across both Neg posts of the batts and go to ground at what I think is the engine mount.
 

Attachments

Maine Sail

Maine Sail

.
Feb 6, 1998
11,709
Canadian Sailcraft 36T Casco Bay, ME
Euphoria2011 said:
I looked at the schematic and the picture attached closer and I see that both #1 and #2 batteries positive cables go to the Perko switch.

Which ever batt I select is the one that will provide cranking current for the engine as well as the rest of the devices on the DC bus, which is my issue here.

The pic shows the two battery cables secured to the switch coming from the batts, looks like pretty big cables to me, what do you think? 1 AWG?
(the 2 smaller red wires are from the Promariner Protechi 20 amp battery charger to provide charging )

The grounds cables connect across both Neg posts of the batts and go to ground at what I think is the engine mount.
Click to expand
If you're trying to start off a single group 24 deep cycle voltage drop is just a fact of life. With two you should be able to do it, but, still easier to power up the instruments after starting or use a dedicated "start" battery.

A single group 24 as a house bank is SMALL!!!! If you ever overnight you'll have about 25 usable amp hours, which is not a lot. You might consider combining those batteries into one bank and finding a spot for a new starter battery..?
 
Maine Sail

Maine Sail

.
Feb 6, 1998
11,709
Canadian Sailcraft 36T Casco Bay, ME
Euphoria2011 said:
The batteries are new Group 27 size units
Click to expand
Sorry about that. Still does not change much from post#8 except for maybe 5-8Ah's more capacity. A single group 27 will likely still drop your electronics but two should do it.

As has been said simply start the motor then fire up the electronics, use BOTH or wire one battery as a dedicated starter....
 
Status
Not open for further replies.

Top Bottom