starting battery, just battery, not batteries, just one single battery

Topic: starting battery, just battery, not batteries, just one single battery (Read 2827 times) previous topic - next topic

Re: starting battery, just battery, not batteries, just one single battery

Reply #50 – February 14, 2011, 08:38:24 am

Quote from: Jon Twork – February 13, 2011, 11:39:12 pm

Stop at an Auto Zone or Checker and get it load tested and you will know for sure if it is the battery or not. All of the items you mentioned WILL make a difference. Some will make it a BIG difference.

Regards,
Jon Twork

I didn't mean to indicate that I disagree with this - I know it to be true. I just doubt that the factors would in such a predictable way on a timetable. (insert smiley face thing here)

oldMattB

Re: starting battery, just battery, not batteries, just one single battery

Reply #51 – February 15, 2011, 11:11:41 am

Matt, my moneynis on a bad battery.

Re: starting battery, just battery, not batteries, just one single battery

Reply #52 – February 15, 2011, 11:18:31 am

Kent,
Let me hold your money until the answer is discovered. I am impartial and can make sure the right person gets your money. Hey! What else are friends for?

Re: starting battery, just battery, not batteries, just one single battery

Reply #53 – February 15, 2011, 12:05:58 pm

Matt,

Just got an e-mail back from my friend with a 1994 U240. Here is what he said:

My coach came with two MK AGM 8D for the house. I have two Optima red top batteries for the engine. The house batteries are just behind the driver side rear tires. The engine batteries are in the engine room between the engine and the rear bumper.

Re: starting battery, just battery, not batteries, just one single battery

Reply #54 – February 15, 2011, 01:27:48 pm

Quote from: George Stoltz – February 15, 2011, 11:18:31 am

Kent,
Let me hold your money until the answer is discovered. I am impartial and can make sure the right person gets your money. Hey! What else are friends for?

I don't know George, can I really trust you with my two quarters? And if you held them, what would I have to rub together!!!

Re: starting battery, just battery, not batteries, just one single battery

Reply #55 – February 27, 2011, 01:46:57 pm

I thought this thread of mine needed a capstone.
Short description of problem: A single starting battery with clean connections that tested good under load routinely failed to start the coach. I did not want to convert one of my two house batteries to a starting battery (possibly the original configuration.)

Solution: I replaced the battery with two marine AGM batteries wired in parallel. Each has 800 CCA, and has screw terminals to match the cables present. I was able to take advantage of the battery type and mount them on their sides, which handily fit into the existing battery tray in the engine bay. The positive terminals are higher than the metal structure, so shorting risk is minimized. I chose to orient the negative terminal up for ease of wiring and quick disconnection for other service needs. I used the original mounting bracket and screws, after I installed bolt rings into the existing holes to extent the threaded rods an inch or two, to accommodate the additional height (actually width, but turned sideways!) The threaded screws are angled, to keep pressure on the battery against the mounting tray, and away from the cables.

With the batteries direct from the store shelf, the coach started eagerly.

I have attached photos - they should be self-explanatory.

Paying our great forum back... I hope this helps someone.

Matt B

Re: starting battery, just battery, not batteries, just one single battery

Reply #56 – February 28, 2011, 09:13:23 am

Batteries ; --- I was A boat dealer for 27 years , sold A few batteries . In A good year we would sell 800 plus , in A bad year maybe only500 . The reason that I mention all this is --name brands-- the most trouble name was INTERSTATE . They have A warrenty all right , but being honest ,or stright up ,was next to nothing . I saw that company stick it to my customers time and time again . I ate many , many batteries just to keep my customers . The company had more reasons to not be honerable about warrenty . Then the pro rated thing . Example ; If you bought A battery ,paid say $120.00 , with A 2 year warrenty . Ok you had it for 22 months , it has A bad cell . Now 2 months left what would you expect to pay

how about $149.00 . Well INTERSTATE always had this thing like " that battery has A retail price of $180.00 " Net results you can't win . Are INTERSTATE batteries bad ? ,no not at all ,most are good ,but you will have some nail bitting in A warrenty issue . I would recomend buying batteries at a place that you know will take care of you . Dont be name brand blind .

Re: starting battery, just battery, not batteries, just one single battery

Reply #57 – February 28, 2011, 02:06:12 pm

Matt,

What size cables did you use? They look a lot lighter than the originals. That might give you problems down the road as the batteries age.

Re: starting battery, just battery, not batteries, just one single battery

Reply #58 – February 28, 2011, 02:48:55 pm

I used 4 gauge cables, the largest I could find with factory-installed ring terminals. I figure they will handle half the load of the other cables, and for a short distance, so hopefully they will be fine. They are actually starter cables.

Re: starting battery, just battery, not batteries, just one single battery

Reply #59 – February 28, 2011, 03:06:28 pm

These are great... Select your length.
Battery interconnect cable #2/0 AWG x 18" Red

Re: starting battery, just battery, not batteries, just one single battery

Reply #60 – February 28, 2011, 10:21:47 pm

I am thinking that you will be replacing your starter sometime in the near future. I believe that your coach was probably set up with 4/0 starter cables. By using 2 gauge cable you have reduced your ampacity from 378 amps to a measly 178 amps.
That I would believe, will make it very hard on the starter but, again maybe you don't move around that often.

Regards,
Jon Twork

Re: starting battery, just battery, not batteries, just one single battery

Reply #61 – February 28, 2011, 11:13:48 pm

I see that I misread the data.
You are using 4 gauge cable so the difference is 378 v/s 136 amps. Worse yet.... What was I thinking.....

Regards,
Jon Twork
I firmly believe that tomorrow holds the possiblity for new technologies, astounding discoveries, and a reprieve from my remaining obligations. www. WERV2.com (UnderConstruction)

Re: starting battery, just battery, not batteries, just one single battery

Reply #62 – March 01, 2011, 06:54:56 am

I am Jon on this one, using the 2 gauge wire, (can not call it cable), is begging for a expensive problem including the starter failure, solenoid burning and hot wire. not to mention lousey starts.

Using the boost switch is needed.
Give it some time, have good investments, it will all work out,
Use the correct cable and your investments do not need to be so great.

Cheers

Re: starting battery, just battery, not batteries, just one single battery

Reply #63 – March 01, 2011, 09:22:12 am

I'm confused...isn't 2 gauge larger and able to carry larger currents than 4 gauge?

Re: starting battery, just battery, not batteries, just one single battery

Reply #64 – March 01, 2011, 10:24:07 am

Quote from: Peter & Beth – March 01, 2011, 09:22:12 am

I'm confused...isn't 2 gauge larger and able to carry larger currents than 4 gauge?

The short answer is yes. Perhaps there is confusion among 2 gauge, 2/0 gauge (00), and 4/0 (0000) gauge.

According to information at http://en.wikipedia.org/wiki/American_wire_gauge, current capacity is:

4 gauge 95 amps
2 gauge 130 amps
00 (2/0) gauge 195 amps
0000 (4/0) gauge 260 amps

Those appear to be values for sustained current. Values for brief usage, such as starting, would be higher. Good practice would be to consider OEM installations as minimum standards. Fatter, shorter wires are better for starting systems.

Re: starting battery, just battery, not batteries, just one single battery

Reply #65 – March 01, 2011, 03:16:49 pm

Okay, I will change the wires.

Yeah, I'm confused. I get that a thicker wire is better than a thin wire. It does not seem like two 8Ds at maybe around 1600 CA each would drop to 260 amperes total through a three-foot-long 4/0 as thick as my thumb. How long is a sustained current? The three seconds it takes to start my engine? Not being fussy, it just seems there should be a lot more to the story.

@Dave Remember only one battery is going through the 2-gauge wire, and the new setup has eliminated the need for the boost switch when starting. The engine starts in 2-3 seconds. God knows how much abuse the solenoid and starter experienced before the setup was changed. I hope the battery was stronger at another time, or the previous owner always used the boost switch. With a full charge, and testing good, the old battery would not turn the engine over.

Re: starting battery, just battery, not batteries, just one single battery

Reply #66 – March 01, 2011, 03:56:22 pm

Quote from: oldmattb – March 01, 2011, 03:16:49 pm

It does not seem like two 8Ds at maybe around 1600 CA each would drop to 260 amperes total through a three-foot-long 4/0 as thick as my thumb. How long is a sustained current?

If I correctly understand the chart from Wikipedia to which I referred, the 0000 cable would carry 260 amps indefinitely and not heat to more than 90C. The cable will not limit the current to 260 amps, but that is a maximum safe current for continuous use if the insulation and environment can withstand heating to 90C. I referred to the chart primarily to direct attention to the relative difference between "2 gauge" cable and "00 (2/0) gauge cable."

For starting the engine, the duty cycle is short enough that heating is usually not an issue. The current to the starter is indeed way more than 260 amps, but the maximum recommended engagement time for a starter motor is likely to be about 25 seconds, with lots of time for cooling between cycles.

Re: starting battery, just battery, not batteries, just one single battery

Reply #67 – March 01, 2011, 05:03:29 pm

It would appear that with that reasoning, you could start the engine once a week using a 16 gauge wire, that would provide plenty time for the cool down

Re: starting battery, just battery, not batteries, just one single battery

Reply #68 – March 01, 2011, 07:02:10 pm

Quote from: Dave M – March 01, 2011, 05:03:29 pm

It would appear that with that reasoning, you could start the engine once a week using a 16 gauge wire, that would provide plenty time for the cool down

Hmm. But if your first attempt failed, you should wait another week to try again. While you are waiting, you might as well install some 4/0 cables. (And you could also use the time to clean up the residue from the first attempt.)

Re: starting battery, just battery, not batteries, just one single battery

Reply #69 – March 01, 2011, 07:07:03 pm

BINGO

I am just amazed how much traction this simple subject has gotten

Re: starting battery, just battery, not batteries, just one single battery

Reply #70 – March 01, 2011, 10:55:51 pm

I knew there was more to it. I have seen people jump-start a car with a coat hanger, and given the brittle metal used, probably has about the same ampacity as a 16-gauge stranded copper wire. Not recommended, but marginally effective.

Maybe we should call the 2/0 and 4/0 double-ought and quadruple-ought to avoid the cornfuzion.

I am proud to have started such a successful post!

Re: starting battery, just battery, not batteries, just one single battery

Reply #71 – March 01, 2011, 11:12:04 pm

Quote from: oldmattb – March 01, 2011, 10:55:51 pm

Maybe we should call the 2/0 and 4/0 double-ought and quadruple-ought to avoid the cornfuzion.

I like that! It certainly does help differentiate 4 gauge from 4/0, which many of us, ahem, present company included

, might not have recognized.

Michelle

Re: starting battery, just battery, not batteries, just one single battery

Reply #72 – March 02, 2011, 08:27:41 pm

What you really need to be looking at is the resistance in Ohms per foot. 0 gauge wire has approximately .001 Ohms in ten feet. If you figure that the instantaneous current is 500 amps then the voltage drop would be .5 volts, assuming every thing else is perfect and does not add to the overall resistance of the current path. Since 2 gauge wire has twice as much resistance then there would be a 1 volt drop from the battery to the starter. Bigger wire equals less voltage drop to the starter and the starter does not have to work as hard. You can also see why it is very important to keep all your wiring connections pristine to avoid additional voltage drops and greater harm to your starter. Most of us cannot shorten the wire but we can make the wire bigger.

Re: starting battery, just battery, not batteries, just one single battery

Reply #73 – March 02, 2011, 08:51:11 pm

John, with a starting motor (Inductive load) I would expect the "instantaneous" or "lock rotor" amp load to be much higher. See you have the 3208 Cat, that being a small engine that starts very quickly, you can get by with less battery than when using a larger engine.
As usual the text book info seldom takes into account all that affects the end result.
For the chaps that want to know the real voltage drop, simply use a good recording DC volt meter at the starting batteries, get the reading during a start cycle for max volt drop. Then put meter on the starter and get that volt reading. A very simple and relieable way of finding what is what with out all the guessing.

Re: starting battery, just battery, not batteries, just one single battery

Reply #74 – March 03, 2011, 07:59:23 am

Another very accurate way to measure voltage drop is to put the positive lead of the digital VOM on the battery positive post and the negative lead on the starter large lug.

Have someone engage the starter. No more speculation needed-- you will now have the facts. And, if you have two batteries on parallel with a smaller gauge wire connecting the two batteries, do this test from each battery positive. Let us know what you find.

Brett

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