what batteries to get and where

[Hollywood]

Can anyone say TO MUCH INFORMATION ! LOL But yes if you have a switch with 1, 2 or both you can switch to both and crank if you kill one.........
I think we have exhausted this thread......

NO! If you kill one battery do not combine it with the other, that will just drain the good battery trying to even out the charge between the two.

If you kill one battery simply switch it to the other one, start the boat, THEN switch it to combine. A much better solution is to have a professional install a combiner/isolater since we are not grasping this here.......

[jaybird]

Hollywood, NO? PLEASE!
Leave the nit picking to the Mastercraft fans, not welcome here. Combining for a start or switching to the 2nd battery both work fine, in the time you switch they will not even out unless you do it many hours before starting and that’s not what is being addressed. Compared to the starter motor amp load the amp draw of a dead battery will not amount to a grain of sand, lets be realistic here. As for the charging relay, I have stated over and over a charging relay as they are more commonly known (combiner/isolator) should be used if you will read back in this post. If you can install a battery you can install your own charging relay, it’s not something you need a professional for. A charging relay simply is a high amps relay that closes to connect the positive poles of battery A to B when a charging source is present and disconnects them when no charge is present thus if stopped with the engine off battery’s are isolated from each other and the battery being used by the accessories will not drain the other battery. Not rocket science. Compared to installing an audio amps it child’s play and most of the guys here are savvy with there boats.

[Mikeski]

My solution:

http://www.skingcompany.com/Power_In...150A-P135.aspx

[Miljack]

Since we've arrived here, and there are two EE's present;

Is there a difference between the Yandina "combiner/charge relays" and the ACR units from Blue Seas? Is a Perko or battery switch the ideal setup with one of these, or is that an option for the really anal?

Also, anyone care to comment on Jaybird's assesment of the effect of a dead battery on a charged battery? I've "heard" that when combined a dead battery will "instantly" pull down a charged battery.

thanks

[waterskifanaticGAJ]

My boat is a 1994, and I am on my second interstate MEGA TRON battery. The original lasted 12 years. The key in long battery life is to store them in a warm place and put them on the charger every 30-45 days during the off season. Interstate batteries have served us well. If you look on the lid for the battery box in the floor, there is a decal that contains the battery specs. Our current one is an Interstate MEGA TRON 75 month. So far so good.

[8122pbrainard]

The key in long battery life is to store them in a warm place.

Do you bring your car battery inside on cold winter nights too?

[jaybird]

Miljack,
IN response to your question:

Also, anyone care to comment on Jaybird's assesment of the effect of a dead battery on a charged battery? I've "heard" that when combined a dead battery will "instantly" pull down a charged battery.

I was just irritated by the proof reading and nit picking. It’s a forum to help people, not an English class. Have you ever had a battery in your boat that would take an instant charge, not likely! What I though we were discussing is switching to start when you have weakened your battery from running the accessories with the engine off. When you jump off your car do you remove the dead battery so it doesn’t instantly kill the other car you are jumping from, I think not. Technically it would be better yes, but from a practical stand point it is like explaining to someone to be sure they drain there ballast tanks before loading onto a trailer and then a proof reader saying “You didn’t remind them to remove those half empty beer cans in the cup holders” it simply has no measurable effect.

To answer your question about the charging relays, I see very little difference in the relays you asked about, one may handle a few more amps but only a few technical differences. They are both simple high amps relays that combine when a charge is available based on voltage, for example if say it senses 13.3 volts (approximate) it will combine A with B. Now please you proof readers, the 13.3V will vary depending on the charging relay. Anything over 12.6 volts (6 cells @ 2.1V each) would be considered a charging condition. The Blue Seas has what is called “starter isolation” that if used will isolate the accessories battery while starting to prevent any voltage spikes that could damage sensitive electronic equipment.

Frankly if you have two batteries a charging relay is just a good idea. The thing I like is the long term storage issue, if you forget to disconnect your battery’s and over time for whatever reason one has a bad cell or a minor drain it will not affect both battery’s and the main reason for battery failure is prolong periods of time at low voltage.

Hope this helps... And please excuse the bad grammer and mis spells...LOL

[jaybird]

And before the proof readers say: "When you jump off your car the other car has an alternator supplying the power" The typical alternator is 40 to 80 amps, the starter will require approximately 250 amps, it comes from the battery or batteries.

[Hollywood]

jaybird, I haven't studied the data to know exactly how long it would take to kill a good battery when combined with a dead one, but since we don't know the quality or condition of each members' batteries I suggest it is not a recommended practice to do so.

Over the past 5 years I have gained a good feel for what is welcomed. I am glad this thread is very active, it looks like we are all gaining some useful electrical knowledge!

[JUST-IN-TIME]

Since we've arrived here, and there are two EE's present;

Is there a difference between the Yandina "combiner/charge relays" and the ACR units from Blue Seas? Is a Perko or battery switch the ideal setup with one of these, or is that an option for the really anal?

Also, anyone care to comment on Jaybird's assesment of the effect of a dead battery on a charged battery? I've "heard" that when combined a dead battery will "instantly" pull down a charged battery.

thanks

same thing
but anything with a west marine name is over priced crap

go with blue seas

[gride300]

how come cc doesnt put in isolators with two battery setups?

[jpduster]

after reading some of the things that have been said and to stir the pot a bit, talking short term does it really matter combining (in parallel of course) a fully charged battery with a drained (not faulty) one, wouldn't the same amount of charge be present just spread between the two?

[JUST-IN-TIME]

how come cc doesnt put in isolators with two battery setups?

cuz time = $$$$$$

[8122pbrainard]

after reading some of the things that have been said and to stir the pot a bit, talking short term does it really matter combining (in parallel of course) a fully charged battery with a drained (not faulty) one, wouldn't the same amount of charge be present just spread between the two?

No, the internal resistance is different. The fully charged battery will actually get more of the charge! Bad! This is why if you have a multi battery set up in parallel (without a combining system) it's very important to get batteries exacty the same and even look for same date code of manufacturing. This way, the resistance is as close as possible between the batteries. Your are actually better off using two 6 volts in series. Both batteries then get the same charge.

[jaybird]

pbrainard is exactly correct, I briefly mentioned this early in this forum.

It is best to have a matched set (type, size & age) so they keep a balanced charge.

If a system stays combined with no charging relay it is very important that batteries are the same AGE, TYPE and SIZE. Basically a duel system is a battery with double the amps hours. The drawback is you have twice as many cells (12) and a short in one cell could damage both.

The manual battery switch (Off- A - B - Both) is fine as long as you remember when not in use they do not remain combined, but when operating they must be combined if you expect to gain a charge from your alternator.

I would guess CC does not install an ACR since it cost $$ and does not add show room value. Most people see single battery or duel battery and the ACR is just not a selling factor.