Time for new batts, should i go 12v or 6v?

rwidman said:

A manual swith or a relay with a manual control would be much better.

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Maybe, but it seems to be a case of "if it ain't broke, don't fix it." In the one case we experienced (this was back when the boat had two 8Ds) the problem was exactly as you describe-- a shorted cell. The relay did its job and both engines turned over on their starters as though there was no battery problem at all. That is to say they spun fast and fired almost instantly just like they always do.

That's the only result we're interested in. There are probably a hundred ways our boat could be set up electrically. The way GB chose to do it in 1973 has demonstrated decisively to work as advertised so we see no case to be made for changing it. If we were starting from scratch there are undoubtedly new technologies that would be good to incorporate. But we aren't starting from scratch.

Per said:

it sounds as if there are different types of isolators and combiners and also combinations of both, i think as long as we know how these switches work then we are all the better off.

so i speak to my mechanic, he has I should consider one of two options:
1. switching all batteries over to regular lead acid (not agm)
2. install external regulators on my alts.. reason for this he says you cannot set up regular alt's with internal regulator to charge AGM batts properly.

your thoughts?
my alts are self exciting internal adjustable regulator leece neville marine alts.
yes, i would get better charging with an external regulator, but is it correct that these alts are not suited for AGM batts?

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No, it is not correct. People switch from flooded cell to AGM batteries all the time, in their vehicles as well as their boats with no problems.

AGM batteries use the same chemistry as flooded cell, just in a different physical form. My charger has a switch position for flooded/AGM and another for Gel batteries.

Gel batteries are indeed different and have different charging requirements, but we're not talking about them here (yet).

From OPTIMA battery corp...

Both the OPTIMA® Chargers Digital 400 & Digital 1200 12V Performance Battery Charger and Maintainer enhance the performance of OPTIMA and other AGM batteries, recover deeply discharged batteries and extend battery life. However, under normal vehicle starting applications, most regular automatic lead-acid battery chargers will properly charge an OPTIMA battery. However, since OPTIMA batteries are frequently used in high-performance applications or nonstandard vehicle starting applications, there are certain instances that must be given special considerations.

An OPTIMA battery is an AGM battery, not a gel battery or regular flooded battery. A deeply discharged OPTIMA battery (less than 10.5 volts) will not test or recharge properly if treated as a gel battery or regular flooded battery. A handheld electronic battery tester will most likely provide inaccurate test results.

An OPTIMA battery has the benefit of very low internal resistance, which allows high-amperage output as well as efficient charge acceptance. This benefit also allows an OPTIMA battery to run longer than its specified ratings and run to a lower voltage than typical flooded batteries. All of this can lead to confusion when it comes to recharging a deeply discharged OPTIMA. Most basic battery chargers have a built-in function to prevent charging a battery with less than 10.5 volts. If your OPTIMA battery is discharged below that, the battery charger may not start up.

Most high-quality, modern battery chargers now have built-in features to charge AGM batteries like OPTIMA batteries. Some have specific AGM settings which should be used to charge an OPTIMA battery. Do not use gel or gel/AGM settings, as they will not fully charge an OPTIMA battery and could damage it over time. However, even some AGM-compatible chargers will not recharge deeply discharged (less than 10.5 volts) OPTIMA batteries. It may be necessary to follow the instructions provided in Section #3.

For regular charging we recommend a maximum of 10-amps, 13.8-15.0 volts. For float charging, we recommend 1 amp maximum, 13.2-13.8 volts.

Under normal (engine-starting) conditions, an OPTIMA battery should never experience “at-rest” voltages below 10.5 volts. In these applications, most 12 volt chargers (old or new) or alternators will sufficiently recharge an OPTIMA battery with at least 10.5 volts. Typically, we only see issues with charging when it relates to stand-alone deep-cycling applications or severely discharged OPTIMA batteries.
http://www.optimabatteries.com/us/en/support/faqs/#

Marin said:

Maybe, but it seems to be a case of "if it ain't broke, don't fix it." In the one case we experienced (this was back when the boat had two 8Ds) the problem was exactly as you describe-- a shorted cell. The relay did its job and both engines turned over on their starters as though there was no battery problem at all. That is to say they spun fast and fired almost instantly just like they always do.

That's the only result we're interested in. There are probably a hundred ways our boat could be set up electrically. The way GB chose to do it in 1973 has demonstrated decisively to work as advertised so we see no case to be made for changing it. If we were starting from scratch there are undoubtedly new technologies that would be good to incorporate. But we aren't starting from scratch.

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You tried...and I concur.

I am rewiring my batts and putting in brand new ac/dc panels and switching.... I plan to keep it neanderthal with either a simple switch or relay. I go into the engine room 2x a day and within arms reach is the ability to mix and match as the condition of the batteries dictate.

Per said:

my alts are self exciting internal adjustable regulator leece neville marine alts.
yes, i would get better charging with an external regulator, but is it correct that these alts are not suited for AGM batts?

Click to expand...

I don't think its so much that they are unsuited for AGM batteries as that any internally regulated alternator is a poor choice for charging deep cycle batteries. There used to be a site called Phrannie.org which did an excellent job of explaining all the various factors that influence the choice of charging systems and battery types. It doesn't seem to exist anymore. I briefly scanned this one and it appears to cover a lot of the basics. In a nutshell the problem with internally regulated alternators is that they tend to charge too slowly to ever fully recharge a deep cycle bank. Its more complex than that but you should do the reading because I'm by no means an authority on the subject either.

If it was me I would definitely change all the batteries at the same time but I wouldn't necessarily switch to flooded cells - that's a personal choice you should make based on whether you want to do the service on flooded cells or pay for the convenience of AGMs. Its actually a little more complicated than that because the AGMs will also accept a charge faster than the flooded cells will. And at the same time I would install some form of external 3-stage regulator like the Balmar 614.

Marin, I can't dispute your account of your battery problem, you were there, I wasn't. It does seem strange if the battery truly had a shorted, not open cell. A shorted cell would produce the results I experienced with my car when it's battery developed a shorted cell. Perhaps the fact that your boat's manufacturer changed the setup after your boat was wired is worth considering. But if you are satisfied with it, that's all that's important.

psneeld, Your reluctance to accept new technology is something that's quite common among the "old timers", those who have been in a particular field for a long time. It can be difficult to let go of the "that's the way we've always done it" mentality. I assume you have removed the thermostat in your engine so you have complete control of the operating temperature? That you have replaced your airconditioning/heating system's thermostat with a manual switch for the same reason?

I remember an old timer (an electrician) at work who attended the demonstration of a computerized climate control system for a building with me. When the presenter finished and asked if there were any questions, the old timer's question was "How do you bypass it?"

Just as with Marin though, if you're happy with the old ways of doing things and see no need for newer technollogy, that's fine. At least you'll understand it and be able to deal with any problems that may develop.

rwidman said:

erhaps the fact that your boat's manufacturer changed the setup after your boat was wired is worth considering.

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I don't recall when GB stopped using the battery combiner relay. Sometime in the 80s sticks in my mind. As it was explained to us it was dropped because the electrical demands on the boats were getting much greater and the original, very simple electrical setup they used earlier simply couldn't cope with the electrical demands of their market.

Some owners of older GBs have changed their electrical systems including the removal of the combiner relay. On the advice of the shop we use we have elected to retain ours.

Our vintage of GB also has a master on-off switch in the engine room for each battery (now bank in our case). These big rotary switches totally isolate the battery or bank they are connected to. To the point where the bilge pump won't even run. This is a separate deal from the battery selector switch on the DC panel in the helm console. In practice these switches are never turned off.

So if there was a problem with one battery/bank that was adversely affecting the other one the main switch for the bad battery or bank could be thrown and it would be out of the loop altogether, combiner relay or no combiner relay.

Marin said:

I don't recall when GB stopped using the battery combiner relay. Sometime in the 80s sticks in my mind. As it was explained to us it was dropped because the electrical demands on the boats were getting much greater and the original, very simple electrical setup they used earlier simply couldn't cope with the electrical demands of their market.

Some owners of older GBs have changed their electrical systems including the removal of the combiner relay. On the advice of the shop we use we have elected to retain ours.

Our vintage of GB also has a master on-off switch in the engine room for each battery (now bank in our case). These big rotary switches totally isolate the battery or bank they are connected to. To the point where the bilge pump won't even run. This is a separate deal from the battery selector switch on the DC panel in the helm console. In practice these switches are never turned off.

So if there was a problem with one battery/bank that was adversely affecting the other one the main switch for the bad battery or bank could be thrown and it would be out of the loop altogether, combiner relay or no combiner relay.

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That will work.

I have seen recommendations that the battery switches should not be in the engine room because in the event of an engine fire you could not enter to disconnect the batteries, but in most cases it's very difficult not to have them in the engine room because any other location would involve a long run of cable and the resulting voltage drop. I think the chances of a problem are pretty rare so if it was my boat I wouldn't worry about it.

rwidman said:

Marin, I can't dispute your account of your battery problem, you were there, I wasn't. It does seem strange if the battery truly had a shorted, not open cell. A shorted cell would produce the results I experienced with my car when it's battery developed a shorted cell. Perhaps the fact that your boat's manufacturer changed the setup after your boat was wired is worth considering. But if you are satisfied with it, that's all that's important.

psneeld, Your reluctance to accept new technology is something that's quite common among the "old timers", those who have been in a particular field for a long time. It can be difficult to let go of the "that's the way we've always done it" mentality. I assume you have removed the thermostat in your engine so you have complete control of the operating temperature? That you have replaced your airconditioning/heating system's thermostat with a manual switch for the same reason?

I remember an old timer (an electrician) at work who attended the demonstration of a computerized climate control system for a building with me. When the presenter finished and asked if there were any questions, the old timer's question was "How do you bypass it?"

Just as with Marin though, if you're happy with the old ways of doing things and see no need for newer technollogy, that's fine. At least you'll understand it and be able to deal with any problems that may develop.

Click to expand...

You don't know me or my acceptance of tech...

If I got as much wrong as you do on this forum I'd be real careful about speaking about "what others think or not".

I have seen hundreds of systems like Marin's that you scoffed at. Yet they seem to work for a lot of skippers.... Tsome even piped up on here about saving them. Then you decribed a issue that you had that couldn't possibly be solved with any solution but yours...but it did for Marin.

Wow...let's talk about copper apint and underwater metal... or should we let that one stay in it's own thread where more than one member pointed out the "real" facts????