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If you have one bad battery, and you set to ALL< the bad one will drag down the good one.

I have 2 new deep cycle batteries, and I get a LOW BATTERY warning with my X-5 AP, but I have yet had time to figure out the problem. It may be that I have no ground on the main controller, only a positive and a negative connected.
After a 3 day sail, using the AP 30 minutes or so, plus GPS/depth sounder, water pump, and LED lights, with some motoring recharging the batteries, both batteries are still at 100%.

Phil M

I had the ground connected to the negative on the battery, but that did not seem to make any difference with the low voltage warning when cranking the engine. It happened in both cases. I wonder if I do have a bad battery. Both are barely a month old.

richter372001 wrote:Hm, that's kinda disturbing. The starter battery is 60 Ah, the deep cycle one is 66.
I jump started it today with the help from a service guy, and the voltage went up to over 13 V, which he said was the sign that the motor WAS charging the batteries. After running it for cca 15 min, it had enough juice to start the engine after I turned it off, so I guess I'm ok for tomorrow. However, the power from the batteries seems to be too low. Would the way the two batteries are connected influence how they are charged? I set the switch on ALL, which should do it.

90 mins of autopilot shouldn't kill your batts. My guess is you have a bad battery or two that need replacing.

I don't know how your switch is wired, but typically I would only have it on ALL if the engine is running and to A or B otherwise. This way you can preserve a battery for starting if you drain the other. I have a battery combiner that isolates the starting battery from the house battery unless they are being charged.

BTW...my Suzi DF70 came with a rope for manual starting. Theoretically you can wrap it around the crank and pull start the thing. I've never tried that and I'm not sure if I want to. Maybe I should just to know if it's possible.


--Russ

Well, it doesn't feel right to me, either. The rope solution did not work. Engine is way to heavy. Maybe I need to go to the gym first ; )

richter372001 wrote:I had the ground connected to the negative on the battery, but that did not seem to make any difference with the low voltage warning when cranking the engine. It happened in both cases. I wonder if I do have a bad battery. Both are barely a month old.

My LOW VOLTAGE comes on and stays on, unless I use a battery charger overnight on both batteries. Charging them by use of the motor does not seem to be enough, even though they measure 100% full charge. The constant beep is slight, but annoying. Maybe that helps to reduce the amount of time I actually use the autopilot.

I measured the voltage on my batteries with a digital voltmeter. One was 12.7 and the other was 13.2 volts. Neither should cause a warning on the AP. I will hook up a ground to the negative, and see if that makes a difference next time I'm out.

Phil M

From what I heard from a service dude, the voltage is likely to stay above 12V, but the power will drain out. I'll have someone knowledgeable check the wiring, since it was I who reconnected the batteries after the purchase. How do you check the power that is left in the battery? Is that even possible?

You can measure the density of the acid/water mix with a hydrometer - looks like a turkey baster with some ball bearings stuck in side.

Catigale wrote:You can measure the density of the acid/water mix with a hydrometer - looks like a turkey baster with some ball bearings stuck in side.

If you have a battery that is not up to snuff, not holding full charge, instead of topping off with distilled water and recharging, O'reillys Auto Parts now carries actual Battery Acid Electrolyte to use instead of the distilled water. It is part #32096 Line code SSB. It is 32fl. ounces for $7.49. What I do is, using a turkey baster, I draw equal amounts out of each cell to equal 32 ozs. or double if you buy 2 bottles. It will revive weak or old batteries and has worked great on my auto/tractor batteries. Battery must not have bulging sides or sulfated plates. Much cheaper than a new battery. I do use Optima starting and deep cycles in my which cannot be rejuvenated but for a wet cell battery it works well. Disclaimer- I am not responsible for any injuries or dead batteries if you decide to go this route. This message will self destruct in 5 4 3 2.... Rob PS: for your edification about batteries - http://www.jaycar.com.au/images_uploaded/battglos.pdf

Catigale wrote:You can measure the density of the acid/water mix with a hydrometer - looks like a turkey baster with some ball bearings stuck in side.

that is the best way to see if you have fully charged the battery.

Then disconnect the battery from all sources and check the voltage in a couple of days. Use this chart to determine if your battery is holding a charge. All batteries are a little different but if it drops to the low 12V range it is probably needing to be replaced. also look at the battery if the sides are bulged out it is an indication of sulfadation and should be replaced.

http://www.solarnavigator.net/battery_charging.htm

You can rope start a 50 HP Merc with no problem. FIrst time I tried it I almost fell over, antipating a lot more resistance. I dont think a 70HP should be hard - the Merc 70 and 50 share the same engine block IIRC.

I did find the 'stock' Merc rope too stretchy for this.

One note - my EFI engine needs about 7VDC to turn on the EFI control unit - if your batteries are below 7 VDC you wont be able to start. This would be a really dead battery though - even if you left your fridge on for a week, if you took the load off the battery for a few hours you would probably get 7 VDC back.

We have been all over this "add acid to the battery" routine before. Do not do it! You will mess up the battery chemistry. Even if the battery has been tipped over and lost 100% of the electrolyte, you will not know what state the plates are in and what concentration of electrolyte to add. Don't just take my word for it, do some research. Finis.

~Rich

Ive found adding acid battery not only makes them like new, it also protects you from lightning strikes

Seriously - this is a bad idea, for no other reason that you should be trained how to handle acids, disposal, etc.

A new battery isnt that much coin.

Just revisited some old posts of mine. I noticed that I never posted the resolution to this mystery. Maybe because of being ashamed of my stupidity. Yeah, that was probably it. At this point, I have no shame left , so I will inform the forum that the problem was as simple as a battery clamp that was not properly tightened. I guess since I installed the new batteries only a month prior to the events, it did not occur to me that there might be a problem with the connections. A local guy who works on a charter fleet came by, took a look and figured it out in 2mins. I guess he gets to see that more often. Come to think of it, I still owe him that cold one I promised him back then....Anyhoo, it's good to remember to check the most obvious things first. I will try to stick to that principle in the future.

Phil M wrote: My LOW VOLTAGE comes on and stays on, unless I use a battery charger overnight on both batteries. Charging them by use of the motor does not seem to be enough, even though they measure 100% full charge. The constant beep is slight, but annoying. Maybe that helps to reduce the amount of time I actually use the autopilot.

I measured the voltage on my batteries with a digital voltmeter. One was 12.7 and the other was 13.2 volts. Neither should cause a warning on the AP. I will hook up a ground to the negative, and see if that makes a difference next time I'm out.

Phil M

The problem seems to be an non-hooked up ground wire. I hooked up a separate ground wire to the negative terminal of the battery, and the low battery warning did not come on. It says to do that in the manual, so I guess I should read the manual. RTM, or, as I've heard before, RTFM.

Phil M