Split Charge Diode Installing

[sailinglegend]

One thing everyone seems to have overlooked is the effect of temperature and the charging voltage.

Batteries gas at about 14.4 volts when they are fully charged at a temp of 25 deg C. At a temp of 40 Deg C the gas at 13.98 volts.

It's not difficult to get batteries to this voltage when charging, or in hot climates, or if they are in the engine room. If they are open wet lead acid they they can be topped up. Sealed batteries especially do not like this treatment.

It is worth noting that Odyssey will not honour their warranty if a charger cannot drop the voltage down to float mode. A starter battery will "WANT" to drop down to FLOAT voltage long before the service battery is fully charged, even though it is only taking a very small charge current.

[Andina Marie]

Originally Posted by sailinglegend

One thing everyone seems to have overlooked is the effect of temperature and the charging voltage.
TRUE but ignored by the majority of shore power chargers and (nearly) all alternator regulators.
<SNIP>
A starter battery will "WANT" to drop down to FLOAT voltage long before the service battery is fully charged, even though it is only taking a very small charge current.

WRONG. The Combiner will keep transferring charge during the bulk stage and that will prevent the service battery getting up to the threshold for the charger to switch to float. Not until the destination battery gets to the threshhold too will the float mode be started. (Although this may be true for an Echo Charge since it has a voltage drop.)

[sailinglegend]

Originally Posted by Andina

A starter battery will "WANT" to drop down to FLOAT voltage long before the service battery is fully charged, even though it is only taking a very small charge current.
WRONG. The Combiner will keep transferring charge during the bulk stage and that will prevent the service battery getting up to the threshold for the charger to switch to float. Not until the destination battery gets to the threshhold too will the float mode be started. (Although this may be true for an Echo Charge since it has a voltage drop.)

That is exactly my point - the starter will be sitting far too long at the bulk voltage, its current will have been reduced to almost zero, and will be fully charged well before the service bank - and if the temperature is too high any make of battery combiner will cause the starter battery to gas.

I am not talking about "overcharging" the starter battery but damaging the starter battery because it will gas when its has reached full charge. This WILL happen well before the service bank reaches the point that the charger drops to a float voltage.

I refer again to the Odyssey Warranty. Batteries need to be protected by dropping to a voltage that is below their gassing voltage when they are fully charged.

[capn_billl]

That is true, the battery will not overcharge if pushed to the correct voltage,....BUT if it is run at full charging voltage, you will need to top it off, as it will use water.

As long as you keep it topped off it will not destroy the battery, but why waste the effort. If the charger correctly drops to float charge you will have less maintenence on the battery.

To combine house, and start batteries, I use a starter solenoid between the banks, with a push button next to the start button. If the starter battery doesn't start the engine, I simply press, and hold this button while starting the engine to use both banks.

I like to connect the starting battery directly to the engine as I like THAT battery to be charged first. I use a diode to the house bank. Through the diode, it doesn't charge all the way, but other charging sources, (solar), can top it off.

A device to drop the alternator from the start battery when charged is another good way.

But on my car the start battery is directly connected to the alternator, and is run several hours per day after 10 secs of starting, and lasts 5 years....in Texas heat....adding water once per year....no regulator, or charge controller.....so.

[Stu Jackson]

Originally Posted by sailinglegend

That is exactly my point - the starter will be sitting far too long at the bulk voltage, its current will have been reduced to almost zero, and will be fully charged well before the service bank - and if the temperature is too high any make of battery combiner will cause the starter battery to gas.

I am not talking about "overcharging" the starter battery but damaging the starter battery because it will gas when its has reached full charge. This WILL happen well before the service bank reaches the point that the charger drops to a float voltage.

I refer again to the Odyssey Warranty. Batteries need to be protected by dropping to a voltage that is below their gassing voltage when they are fully charged.

1. When it is hot out, either use battery temperature monitoring on your charger or alternator regulator or simply lower your voltage.

2. RTFM - The combiner literature allows and even suggests that you put an I/O switch in the ground leg. This turns off the combiner. Simple.

I repeat, you are making a simple management issue into an unnecessary big deal. You should also re-read the post where I quoted Maine Sail about this very subject.

[sailinglegend]

Originally Posted by Stu Jackson

1. When it is hot out, either use battery temperature monitoring on your charger or alternator regulator or simply lower your voltage.

So gassing is a problem - thank you. Temperature sensors on solar and wind regulators are not always available on all models. My Victron temp sensor has been disconnected (Victron's advice) with my Lifeline batteries because it raised the charging voltage when they were cool and during equalizing.

Originally Posted by Stu Jackson

2. RTFM - The combiner literature allows and even suggests that you put an I/O switch in the ground leg. This turns off the combiner. Simple.

So they admit there are times when it doesn't work! Simple solution but not automatic. My BEP VSR - not used anymore except for emergency paralleling - has an off - auto - manual position.

Originally Posted by Stu Jackson

I repeat, you are making a simple management issue into an unnecessary big deal. You should also re-read the post where I quoted Maine Sail about this very subject.

Repeating yourself and being abusive means I shall not be adding to this post anymore. Maine dismisses overcharging but doesn't talk about gassing. This IS important for all those who have sealed batteries.

My simple management solution is not to have any split charging but a small solar panel just for the starter battery.

I'm not trying to make an issue out of this but Andina is aggresively trying to sell his product without talking about gassing. All VSRs have the same problem.

Why is nobody willing to talk about gassing being a big potential problem?

[Andina Marie]

Originally Posted by sailinglegend

That is exactly my point - the starter will be sitting far too long at the bulk voltage, its current will have been reduced to almost zero, and will be fully charged well before the service bank - and if the temperature is too high any make of battery combiner will cause the starter battery to gas.

I am not talking about "overcharging" the starter battery but damaging the starter battery because it will gas when its has reached full charge. This WILL happen well before the service bank reaches the point that the charger drops to a float voltage.

I refer again to the Odyssey Warranty. Batteries need to be protected by dropping to a voltage that is below their gassing voltage when they are fully charged.

I'm not trying to make an issue out of this but Andina is aggresively trying to sell his product without talking about gassing. All VSRs have the same problem.

Why is nobody willing to talk about gassing being a big potential problem

Batteries do not start gassing until they are above 14.2 BUT If the alternator on your engine is like 99.9% of engine alternators it has a regulator that will limit voltage to somewhere between 13.6 and 14.6. If you apply this to either the starting battery or connect directly to the house battery, then for the period of time you spend above 14.2 you will have some gassing and nothing you can do about it.

Gassing does no harm to lead-acide batteries (and in fact can be good for avoiding stratification of the electrolyte) but gassing in sealed batteries can cause problems.

At least with the 14.2 volt limit on a Combiner you can protect ONE of your batteries from gassing if it is not lead-acid.

You are correct that the starting battery will spend extended time in the bulk stage while the house battery acquires a charge but that is totally harmless because the voltage will be below 14.2 for most of that time and no current will be flowing into the fully charged starting battery.

IF your regulator is not smart and one of the batteries is going to be stressed at over 14.2 volts, then personally I wuold prefer it to be a single $150 starting battery than a $1000 house bank. By using a lead-acid starting battery and deep cycle house batteries protected by a Combiner you have the best of both worlds.

Yes I have made Combiners for 20 years and sold them under the West Marine brand name for over 10 years but I'm defending the reputation of ALL combiners without mentioning brand (I don't regard the Echo Charge as a Combiner). I invented Combiners in 1992, all the rest are copies and may not have all the featurs such as voltage limiting, current limiting, overload protection, under voltage protection, zero load when not Combining and unconditional warranty.

I believe debate like this is educational and welcome constructive response. Where are the other manufacturers?

Ann-Marie

[Stu Jackson]

Originally Posted by sailinglegend

So they admit there are times when it doesn't work! Simple solution but not automatic. My BEP VSR - not used anymore except for emergency paralleling - has an off - auto - manual position.



Repeating yourself and being abusive means I shall not be adding to this post anymore. Maine dismisses overcharging but doesn't talk about gassing. This IS important for all those who have sealed batteries.

My simple management solution is not to have any split charging but a small solar panel just for the starter battery.

That's a good idea.

I'm not trying to be abusive, and I'm sorry you took it that way. I simply disagree with you and pointed out where I had previously mentioned it in this very topic.

Many, many of us do NOT have sealed batteries. In reading this and many other websites, and many of them about electricity on boats, I have come to trust and believe Maine Sail, btrayfors, mitiempo and a few others. They know what they are talking about, and aren't quite as contrary as I am! For instance, their concerns and information about the "dangers inherent in AGMs" which require properly caring for them, which most folks don't understand, is very important. They have explained the use of the simple 1-2-B switch in remarkably clear and easy to understand language. That's why I trust them.

Your concern is overcharging a start bank, which has been explained to you: 14.2 V will not overcharge a full start bank at 70F. Adjust the voltage for higher temperatures. It is basic battery charging 101.

The battery combiner just became available when I designed and installed my setup in 1998. The echo charger hadn't been invented yet. I RTFM and found the cutoff switch. Maine Sail has since explained why it is not necessary.

Good luck.