battery charger wiring

[gumpy]

Gumpy,

I am certain without doubt that you corrected the problem by resolving the symptom.  You are one of the greatest guys for creating your site and sharing your experience and joys with the board.  I have spent many an hour learning from you and to my distinct advantage as I didn't need the harsh teachings of failure and experience to gain the knowledge.  You did resolve your problem but I think you now have a system that isn't working as well as it could.  The up side of that is that you may be missing only a small fraction of a volt or a few amps. without consequence.  What is probable to have been the problem, after you verified that ALL the connections were perfect, is that there was a difference between the battery that boiled and the rest of the bats in the bank.  Maybe the others were from the same mfr run and the "odd" bat took the hit and that position continued to get trashed until you got a bat in that position that  had a match to the others.  For me, the up side here is that you solved the problem.  Lets see now, you had the "elephants" involved....hmmmmm .....They were confused and finger pointing... hummmmm..you finally resolved a problem that was destroying batteries that confused every mothers son involved?....HUMMMM.  How did you do that again?   Thanks Gumpy.  I would have fought your solution cause it flies in the face of what I know about simple "DC Circuit Analysis" and I taught that subject.

John

While I appreciate the comments regarding my site, I think you've confused me with Makemineatwostroke in this thread. I wasn't the one who had boiling batteries; I just agreed with Sojourner regarding his schematic.

I also agree with the DC circuit analysis indicating it should work, and in the perfect world, it will. But that's theory, and theory seldom takes into account the minor differences between two physical components.

[boogiethecat]

Sojourner is absolutely correct with his circuit and how all banks of parallel batteries should be wired. I take definite exception to anyone who says otherwise.

In practice, yes you can wire them anyway you like.  And yes, for charging it makes zero difference.

But the reality is, when you draw heavy currents from the system such as starting and/or inverters, if you wire it like Sojourner recommends, then each battery will equally share the load, because any resistance in the wiring balances out.
If you wire it as Len's diagram suggests, there will absolutely be differences in what each battery contributes to the load due to milliohm differences in the wiring, measurable in millivolts if you're lucky, or hundreds of millivolts or more if you're not so lucky, no matter what the wire size. And these differences ARE definitely measurable, easily. Sorry to disagree with you len, but this time I must.  The result of any differences in non-sojourner schemes is that out of the entire bank, one or more batteries will be consistently drawn upon more than the others in the bank, and will fail sooner because the bank, over time, becomes unbalanced.

Again,  just like on another current thread, Sojourner's method will work perfectly; other methods may work but you takes your chances. 

Luckily it takes exactly zero additional wire to do it one way over the other, so why not just do it the right way !!!!

More mud!!!

G

[johns4104s]

I have a MCI 9 the starter batteries are conected to give 24 volts. How do I connect these to the charger?

Thanks

John

[Sojourner]

JohnEd...I admire you for giving your honest opinions and expert suggestions in electrical wiring – system. You know how to explain to anyone on board much better I can. Thank you. I am trying to learn from you about how to get a point across about whatever I am experience in. My high school English (lady) teacher told in front of class "I should have my head dunk into milk pail" She knew I was a farm boy but she didn't under stand my binaural hearing loss. Wear one hearing aid but it always confusing to hear them. Later on, my mother found out from another class mate about it...mom went the principal and then the fire fly.
Gumpy...like wise as JohnEd said about your great efforts you put in your website.

Now back to the subject:

I attach a picture of both ways that will complete the batteries circuit connected for the high ampere starter motor and charger.  However, all batteries short cable links are to be design with same wire size & equal length but the cable to the starter can be longer than ground cable or vice-versa.
If for any reason one the cable has a weak joint into terminal end...mean higher resistant but will not affect the bank of batteries for unequal power and its life. It's just less power to starter or lower charging current to charge.

Cost for cables is the same for either ways of connecting.

1)   Diagonal.....Equal resistant connection is each one of the battery's polarity a (one) short cable link before remote cable to starter and/or charger. The sum of resistance of cable A link through battery No 1 are equal to the cable B link through battery No 2
2)   Straight....Unequal resistant connection is the furthest battery has two extra cable links before the closest battery to starter and/or charger that has no short cable link. The sum of resistance of battery No1 is less than battery No 2 through cable A and cable B.

BTW....all golf carts and high end coaches are connected for equal resistant load.

The bottom-line that all storage bank batteries with 2 or 10 batteries are to be equally resistant connected in order to maximize power and longest life at a favorable cool temperature range.

Normal life for a 6v or 12v wet cell battery is about 7 years. To get same life of single battery with the bank of batteries....you must follow the equal resistant connection to be like a one big giant battery unit. In other words, it like having a double or more amperages or voltages (if in series) into one larger battery unit.

Did you know that all of the multiple wet cells battery in it-self is internally equal resistant connection design?

I didn't make this rule but you can do the ohm law numbers that will show you the results. The results are very small numbers but after times after times of starting and charging will add up to determined how much life can you get from the batteries.It's the law of physics.

Ohm Calculator:
http://www.the12volt.com/ohm/page2.asp

Wire Chart:
http://www.powerstream.com/Wire_Size.htm

BTW..Welcome any suggestion to improve or better clarify this subject. Thank you.

FWIW

Sojourn for Christ, Gerald

[JackConrad]

I have a MCI 9 the starter batteries are conected to give 24 volts. How do I connect these to the charger?
Thanks John

Disconnect and charge separately with a 12 volt charger or get a 24 volt charger.  I found a 12/24 voolt charger at Sears years ago.  I do not if they still sell that model.  Jack

[JohnEd]

Jack,

I would add that he only needs to disconnect on cable to one bat to do the charging.  He can also charge both in parallel by using a single jumper to the isolated bat.  A diagram would be nice.....Sojourner?

John

[Sojourner]

Here a drawing with information about a 12v charger to a bank of 24v batteries without disconnecting cable.

FWIW

Sojourn for Christ, Gerald

[Paul]

Can you charge the batteries like this?

With a 40 amp Vanner battery equalizer on the bus.  Hook up a 12-volt battery charger under 40 amps to the 12 volt / 24 volt battery. Then the equalizer would charge the – GND / 12 volts Battery.


Paul

[Sojourner]

Hi Paul: Good point!
About Equalizer to charge the other battery. You need to call Vanner for proper answer. I didn't think about someone having Equalize in this single 12v charger to one of two 12v battery. Right off hand to be safe is to remove Equalizer's fuses until both is fully charged. I think Vanner will tell you that it is only for equally taking power from both batteries and can only 24v charge as a bank via alternator or 24v charger.

Let us know what the verdict is, if you will.

Sojourn for Christ, Gerald

[JohnEd]

Gerald,

Ref your 3:39 post:  I suggested that the bottom line connecting the + and - of the bats be lifted so that you could charge both at the same time by running jumpers from the charger.  I see no reason why that wouldn't work as it would be a 12 volt bank.  Your config is going to charge them one at a time.  Yours is what I would do if the unit was in use.  If I was leaving it in storage I would break the circuit and let them both be maintained to "trickle charge" level.

John

[Paul]

Answer to reply#22 & 23
Talked with Vanner today and the verdict is NO.

But it sounded good to me.

Looking at Vanners dwg. the grounded battery is called  battery "A"  The other is Battery "B".
The next time I will not remember this "A" ? "B" thing.

Having new battery's in our bus and not using the bus I decided to purchase a charger to keep them in A1 condition. Battery Plus recommend this charger.  (Battery Tender Power Tender Plus Waterproof 24V 2.5A Charger - DBT022-0158)  This is a high/low/off charger. We keep it on the bus at all times and has worked very well for over the last three years. Have checked the water in the two 8D regularly and once a year have add less than 1/2 gallon of distilled water to each battery.

       Paul

[Lee Bradley]

Here a drawing with information about a 12v charger to a bank of 24v batteries without disconnecting cable.

FWIW

Sojourn for Christ, Gerald

To bad the chart didn't say more about fooling the charger.  Regulators and regulated chargers don't charge to a voltage they charge to a conductance of 4 mhos (1/4 ohms resistance) in the case of a 12 volt battery. If the top of the battery is dirty and the dirt has some acid in it, there will be an electrical conductance through the dirt/acid and when it reaches 4 mhos the charging will drop off no matter the battery charge. Many batteries have been discarded for not taking a charge or not holding a charge because the top was dirty. The example above explains not taking a charge. The not holding a charge (not self discharge) happens when you charge the battery with an un-regulated charger (most aren't regulated) which will charge right through the 4 mhos. You then put the fully charged battery back into the vehicle where the charging system never quite completely fully charges the battery because of the dirt conductivity and after a while the battery is dead. It just will not hold a charge, no it is just not being recharged. No fault of the battery or the charging system just dirty top. You can check this with a good voltage meter; contact the negative lead to the negative post and drag the positive lead across the top of the battery toward the positive post as you move away from the negative post the meter will start reading voltage which will increase as you get closer to the positive post if you have conductivity across the top of the battery.

[JohnEd]

Lee,

I have certainly heard it said and read that you have to keep the battery clean.  To this date, I thought that was for asthetic or hygene reasons.  Maybe thats silly and maybe not but it is a pretty big chunk of data to miss.  Course, cars don't get filthy like a bus bank might.  Thank you for the information/explaination.

John