Battery Drain

[RickK]

There is actually a procedure to bring one back, especially with the right charger.  CB can explain.

[Capt. Bob]

The key is, as it is with any type battery, not to allow it to fully discharge. Proper maintenance will always extend the life of any flooded, gel or AGM, internal malfunction aside. So... with the correct charger, you can do this very easily. The hitch is the discipline to hook it up and plug it in on a regular basis. If you can do that, you will be surprised at how long a battery will last.

Although Yamaha does not recommend any type but flooded, both the gel and AGM have worked (for a long time) in my boat. While the gel type is said to be sensitive to overcharging, the AGMs are more like the flooded in that they tolerate the varying voltages found in older outboard systems so I think your older system will be fine for that purpose.

The old trick was to hook a fully charged battery to a "dead" AGM and then place the charger on that battery. The thought being to "fool" the charger. Forget that. While I can't speak for your charger, I can for mine. I spoke with the manufacturer before purchasing to confirm that the charging algorithms would work with a deeply discharged battery and the answer was yes so I paid a fair amount for it. It's portable (not wired into the boat) and I have used it for all my vehicles, boat, car, truck, lawnmower and motorcycle. Point being, a good all round device for my charging needs.

As to having the battery switch in the "both" position for charging, I guess there is some benefit to that but....
I like to isolate the batteries so there is a reduced chance that a defect in one could bring down the other. You would be better off served by adding this device to your system.

https://www.bluesea.com/products/7610/SI-ACR_Automatic_Charging_Relay_-_12_24V_DC_120A

This gives you the ability to isolate the starting voltage spike from your electronics, allow the charging of both (without the need to switch) and still allows (when used with the switch shown at the bottom of the link) the use of both batteries for emergency starting. I've considered it numerous times but I'm too cheap. Since you're upgrading your system's power, you may wish to consider this option as well. Several members have this and seem very pleased with the results.

Good luck.

[RickK]

I think I've read somewhere (maybe the Optima instructions?) that if you connect a good battery in parallel with the dead one the charger will charge both and once the "dead" battery reaches 11.5 or so volts to pull the paralleled battery off and let the charger continue to charge the "dead" one.
Doesn't work?

[Capt. Bob]

I think I've read somewhere (maybe the Optima instructions?) that if you connect a good battery in parallel with the dead one the charger will charge both and once the "dead" battery reaches 11.5 or so volts to pull the paralleled battery off and let the charger continue to charge the "dead" one.
Doesn't work?

I'm sure it does but for me ....I just ended up with two dead batteries so.... I bought the Optima charger.
It brought back both. Watch the handle. Mine finally broke off. Resting the hood of my truck on it while charging probably accelerated this failure.

[daniel123]

I'll look into that isolator. It is added in addition to the battery selector, not a replacement for a traditional selector switch, correct?  My on-board MK 330 digital charger has three banks and two banks are directly wired to each of the two batteries for post-trip re-charging, and hopefully I won't have to worry about parallel wiring/fooling that charger. My question is while underway will my outboard's charging system automatically charge both batteries when the battery selector switch is switched to BOTH or ALL. BTW: as usual, the info you guys are sharing is really helpful.

[wingtime]

I have the ACR on my boat and I love.  No more battery management to worry about.  Just turn it on and go.  I accidentally left my battery switch on for a while.  My stereo drained the house battery down flat.  But my starting battery was fully charged and unaffected. So that was a good test for the system if I ran things flat while out fishing or something I'd still have juice to start the motor.

[daniel123]

Doesn't the battery selector switch do that selecting for you, in terms of which battery(s) are isolated and which are 'connected' and therefore susceptible to accidental discharging? Wouldn't the same thing have happened (with or without an ACR) if you had the selector switched to only that battery powering the stereo, and it ran down? That would still have left you with the fully charged battery on the other bank to switch to, which is the purpose of a selector switch?  Just as the stereo would have depleted them all in the event you had left the selector switch on ALL or BOTH.

I'm still seeking an answer to my related question about whether or not the engine's charging system will charge both/all batteries when the battery selector switch is in the ALL or BOTH position. I assume it will only charge Battery 1 or Battery 2 when the selector is left in one of those positions. Can anyone chime in on that?

[Capt. Bob]

Doesn't the battery selector switch do that selecting for you, in terms of which battery(s) are isolated and which are 'connected' and therefore susceptible to accidental discharging?

Yes

Wouldn't the same thing have happened (with or without an ACR) if you had the selector switched to only that battery powering the stereo, and it ran down?

Yes

That would still have left you with the fully charged battery on the other bank to switch to, which is the purpose of a selector switch?

Yes

Just as the stereo would have depleted them all in the event you had left the selector switch on ALL or BOTH.

Yes

I'm still seeking an answer to my related question about whether or not the engine's charging system will charge both/all batteries when the battery selector switch is in the ALL or BOTH position. I assume it will only charge Battery 1 or Battery 2 when the selector is left in one of those positions. Can anyone chime in on that?

Yes to charging "1" and "2".

Possibly yes and possibly no to the "Both" position.

PY: If both batteries are relatively equal in their discharged state, they may share the charge equally though without a good rate of charge monitoring system, how would you know?

PN: Your switch and an outboard charging system are not highly sophisticated devices that recognize the difference and funnel the proper charging voltage to each battery so with your charging system just dumping voltage to one "large" battery, as mentioned above, you really can't tell. I would be especially nervous if one battery were fully charged and the other so discharged as not to have energy to crank the motor.

If you're going old school then my advice is stay old school.
Combo batteries (good build quality/high capacity).
Start on #1 and stay there all day with the second in reserve.
Next time out, switch to #2 and repeat.
Maintain batteries properly while on shore.

I would make no attempt at charging both underway by using the "Both" position (though I have no doubt some do). I would only use that position for emergency starting only.

Look, it all boils down to how you use your boat. This method above works great for me. I have no reason to change but everyone has different needs. Knowing this, you can then wire your system to properly accommodate that usage. Lastly, no matter what make or model year engine you have, count only on the charging system to keep a battery that is in excellent condition/state of charge that way, while underway. Don't rely on it to bring back the dead.
That only appears to have worked for The Almighty and Dr. Frankenstein and not real well for the latter.

Good luck.

[daniel123]

That sounds like good, sensible advice, Bob, and I thank you for offering it. Based on that I'm going to purchase two new identical size 31 dual purpose AGM batteries and via my battery switch will rotate their power use between starting and trolling motor duties as described.

That said, I'll have to select and wire one to power the lights, VHF, livewell, etc. and always switch to that one when I need those accessories, right? Any advice on that front?

What might the advantages be to installing an ACR with such a rotating battery set-up that is already rigged to a selector switch?

[daniel123]

I didn't get any responses to my last posted question, but now there's another twist: I'm replacing my 12-volt 55 lb thrust Riptide bow-mount on the 200 Osprey with a 24-volt Ulterra Riptide with 80 lbs of thrust. That means I'll need two batteries for the motor alone, and a starting battery. Space is tight under that Osprey steering console; can I get by with a 24 size AGM for the starting battery and two 27 or 31 AGMs for the bow-mount?

That also will mean I have to pay more attention to the two battery banks, since one is actually 24 volts and the other 12, when operating the boat and the idea of starting and running out on one and starting and running back on the other to allow the engine to offer a re-charge, as suggested when I was going to have two identical 31 AGMs aboard and rotating their duties with the Battery Selector switch. Any advice or suggestions?   

[RickK]

I didn't get any responses to my last posted question, but now there's another twist: I'm replacing my 12-volt 55 lb thrust Riptide bow-mount on the 200 Osprey with a 24-volt Ulterra Riptide with 80 lbs of thrust. That means I'll need two batteries for the motor alone, and a starting battery. Space is tight under that Osprey steering console; can I get by with a 24 size AGM for the starting battery and two 27 or 31 AGMs for the bow-mount?

That's what I am going to do - 24 starting and 2-27 or 31 for the TM.

That also will mean I have to pay more attention to the two battery banks, since one is actually 24 volts and the other 12, when operating the boat and the idea of starting and running out on one and starting and running back on the other to allow the engine to offer a re-charge, as suggested when I was going to have two identical 31 AGMs aboard and rotating their duties with the Battery Selector switch. Any advice or suggestions?   

An ACR is great for 2 batteries and keeps them isolated from each other even while charging - it doesn't allow one low battery from draining a charged battery.
For my setup I will leave the starting battery on the engine.  I will not worry about the TM batteries until I get home.  Then I'll get either connect a 3 bank charger or a single and a dual to charge them up, haven't decided yet.

[daniel123]

Thanks for chiming in, Rick. I've got a three-bank charger in the helm console already, and will also count on it to do most of the charging for the trolling battery bank. Whether I go with a pair of 27 or 31 AGMs for that 24-volt bank is a matter of space under that Osprey helm, which is tight. I have thought about putting those two batteries up under the bow somewhere, but that would extend the charger wiring and eliminates them as a back-up for starting? What's the advantage of an ACR in our instance (assuming you also have a battery selector switch)? I'm already pushing my envelope keeping up with the wiring/switching as it is! 

[RickK]

I planned space for 3x31s under my console seat.  I bought a 24 for the starting bank but can always step up to the larger size.  Haven't bought the TM or the TM bank yet.
I don't think an ACR will work well with two different banks of different voltages.  In a general sense, an ACR works by sensing the difference in voltage between two banks while there is a voltage present, i.e. the engine running.  If you have a house and a starting bank and start the engine, the charging starts on the starting bank, the ACR compares the voltage on both banks and if the house is lower than the starting bank, the ACR allows charging current to get through to the house bank.

Check out Blue Seas' site and see what they offer for what you're trying to do.

I had a 12v TM for years before the rebuild and agree that a 12v TM just doesn't cut it, at least on my 170. It's only good when no breeze or current.

[daniel123]

That's a good point and advice. I'll check with Blue Seas. Does it make sense to have an ACR for just the starting battery?

Are dual purpose AGM's ok for both starting and deep cycle use? I've got a buddy who says not...

[wingtime]

Check the cranking AMPS.  I think you will find the AGMS generally have a lower cranking amps.. Also they will not recover as quickly from a sudden high amp draw like a starting battery will.