Combiner question

[pegasus1457]

I am about to reorganize the batteries on my Pearson 32. There are 2 85 Amp-hr wet cells that were connected to a 1-2-both-off battery switch.
I would like to connect them to the alternator using a combiner.

I have found a combiner whose price is attractive: a Yandina C100.

Does anyone have experience with this product? How does it compare with a Blue Sea Systems 7610 or 7600 or a Charles Marine BATTCOM-93 or ...?

How reliable are these devices? Do I have to install a parallel switch for safety (as in Don Casey's Sailboat Electrics Simplified, p. 120) or is this overkill?

I also have a dual-output AC charger (old, old model). If I have a battery combiner in the system, do I connect the AC charger to both batteries using the dual outputs, or do I let the battery combiner do this?

Any advice would be appreciated.

[btrayfors]

Need a bit more info.

First, why do you want a combiner? If you want to combine the batteries, you could just use the "BOTH" switch position, which would in any case be a good thing to do in order to have one large battery bank rather than two smaller ones.

Do you have a separate start battery or do you use one or both of the 85AH batteries to start the engine?

I assume the alternator output (big red wire) is attached to the common pole on the battery switch. Right?

FYI, the recommended way to do things these days is to have ONE large house bank and one starting battery. All onboard charging sources -- alternator, solar panels, AC battery charger, wind generator, etc. -- are then connected directly to the house battery bank. An EchoCharge or DuoCharge device (not a battery combiner) is then used to keep the starting battery topped off. This system is simple and nearly foolproof. Doesn't require any throwing of switches, special monitoring, etc., and it maximizes the energy output and replenishment from your house batteries.

Bill

[pegasus1457]

Originally Posted by btrayfors

Need a bit more info.

First, why do you want a combiner? If you want to combine the batteries, you could just use the "BOTH" switch position, which would in any case be a good thing to do in order to have one large battery bank rather than two smaller ones.

Do you have a separate start battery or do you use one or both of the 85AH batteries to start the engine?

I assume the alternator output (big red wire) is attached to the common pole on the battery switch. Right?

FYI, the recommended way to do things these days is to have ONE large house bank and one starting battery. All onboard charging sources -- alternator, solar panels, AC battery charger, wind generator, etc. -- are then connected directly to the house battery bank. An EchoCharge or DuoCharge device (not a battery combiner) is then used to keep the starting battery topped off. This system is simple and nearly foolproof. Doesn't require any throwing of switches, special monitoring, etc., and it maximizes the energy output and replenishment from your house batteries.

Bill

I have 2 banks, each with one battery. Right now both charging and discharging is controlled by the battery switch. There are 2 problems with this: first, if someone makes a mistake and moves the switch past "off" while the engine is running, I risk an alternator repair. Second, if I forget to move the switch to "house" when the engine is off, I run the risk of not having enough charge in the starter battery to crank the engine.

The combiner solves both of these problems.

I am not sure what a duocharge or echo charger is, and how they differ from the battery combiner.

I am willing to be educated ...

[negrini]

Pegasus, I'm not sure wich-is-wich, but mostly have an internal mechanical relay to combine banks. I'm positive the BluSea system has a solid-state VMOS connection, so much more reliable in my opinion. There is also an additional feature of limiting the amps it puts when charging, what might be useful on your small batt size. I installed on a boat 4 yars ago, and still enduring. With a dual foot charger, you have a redundant selection, I'd connect them directly to the battery terminals, so you can disconnect the system entirely, including the combiner, and still charge your batts.

[wind_magic]

Seems like what you would want is to have your big house bank connected to your charge sources full time, that includes alternator, solar, wind, and the rest, so that it is always charging. Then separately, wouldn't it be nice if there was a device you could hook to the house bank that had built in charge pumps so that even if your house bank was nearly discharged this device could still suck every last ounce of juice out of it to insure that your starting battery kept a charge ? I'd like something like that, something that constantly floats the starting battery no matter what the voltage is on the house bank, using the house bank as the charge source.

Edit - maybe that is what btrayfor's EchoCharge and DuoCharger are doing.

[sailingdog]

The main difference between a battery combiner and the DuoCharge or EchoCharger devices is that they only allow current to flow one way, from the house side to the start side, not the other way around.

[btrayfors]

Pegasus1457,

If you're worried about someone moving the battery switch while the engine is running, you've got more than battery problems aboard :-)

That's one...of many...reasons why an EchoCharge or DuoCharge device makes sense: THERE'S NOTHING TO SWITCH....EVER.

The Xantrex EchoCharge and the Balmar DuoCharge devices are intended to maintain a second battery by sensing whenever there is a charge on the main battery bank (the house bank). When the voltage rises above about 12.8VDC, these devices then bleed off a portion of the charging current and send it to the second (start) battery. The EchoCharge can handle a maximum of 15A. The DuoCharge is somewhat more sophisticated, programmable, and can handle up to 30A.

NOW, what most people fail to realize is that while starting your engine draws a lot of current, it does so for a VERY SHORT TIME, resulting in a VERY SMALL DRAW of amperage from your start battery. If you run your starter for 10 seconds (that's a lot...most diesels start much faster) and it draws 250amps while cranking, that's only less than ONE AMP HOUR total draw from the start battery. This is replaced in seconds by the alternator.

Please read the preceding paragraph again....for some reason, it's counter-intuitive and most folks think starting an engine draws down the start battery a lot. It doesn't. It's only a drop in the bucket. And, it's very easy and fast to replace that drop.

What's to choose between the EchoCharge and the DuoCharge? Some start circuits have other draws on them....exhaust fans, and any number of other things which are sometimes attached. If yours does, and you think the draw is going to be 10A or more while the engine is running, then go for the DuoCharge (or change your wiring). Otherwise, for the great majority of sailboats with small diesels -- like mine -- the EchoCharge is more than sufficient to maintain the start battery, and won't even be challenged. It'll just loaf along.

BTW, these are smart devices: they won't overcharge your batteries and they don't need any maintenance at all.

All the above is predicated on a situation where there is a start battery separate from the house bank. As I said in an earlier post, this is highly desirable because it allows you to combine all other batteries into a single large house bank, which has numerous benefits for exercising the batteries, recharging them quickly, and extending their usable life.

I'd certainly think about adding a small starting battery in the case of the original poster, maintained by an EchoCharge, and would combine the two 85AH batteries into a single large house bank.

Bill

[thekeip]

There is something about adding a relay to ANY circuit on a boat that just sends shivers up my spine. I have scads of experience with marine relays...enough to state that they are failures waiting to happen...no if's, no but's and no maybe's. Start solenoids come to mind, or I/O tilt mechanisms, etc. They are mechanical contrivances. You could make a case I suppose, that there are electronic switching devices that some call relays...maybe so, but I'm not inclined to experiment.
Pay attention to what btrayfors says and you'll be very happy.
Howard Keiper
berkeley

[pegasus1457]

Originally Posted by btrayfors

Pegasus1457,

BTW, these are smart devices: they won't overcharge your batteries and they don't need any maintenance at all.

All the above is predicated on a situation where there is a start battery separate from the house bank. As I said in an earlier post, this is highly desirable because it allows you to combine all other batteries into a single large house bank, which has numerous benefits for exercising the batteries, recharging them quickly, and extending their usable life.

I'd certainly think about adding a small starting battery in the case of the original poster, maintained by an EchoCharge, and would combine the two 85AH batteries into a single large house bank.

Bill

Bill -- thanks for the informative reply.

Since your first reply I have been learning from various sources on the web, mostly from manufacturers' literature.

I am getting the feeling that the EchoCharger, while still available from some retailers, is no longer being manufactured -- it does not appear in Xantrex's catalogs.

Xantrex's owner's manual for the Echo Charger

http://www.xantrex.com/web/id/421/docserve.aspx

says that the EchoCharger is only as smart as the charging device, since it is a voltage follower. So with a stupid alternator (like mine), the charging profile using the Echo Charger will still be stupid.

It still may be that the Echo Charger is the best solution to my needs.

Thanks again..

[btrayfors]

Yes, the EchoCharge is a follower, i.e., it will follow the charging profile of whatever is connected to the house batteries. Presumably, EVERY CHARGING SOURCE, including your alternator, has a smart, multi-stage regulator. If it doesn't, it should.

The EchoCharge is still shown on Xantrex's website: Xantrex Technology Inc. - Recreational Vehicles - echo~charge - Product Information

and it's still available from a number of sources.

I've had mine for five years next month, and it's been flawless in 24/7 operation. Ditto for those we've installed on customer's boats.

We've installed a bunch of DuoCharge's, too, and they've been very good as well. They cost about twice as much, but most people really don't need them. The EchoCharge is more than sufficient for most needs.

Bill