What kind of Batteries (Was-HELP!!!Starter Woes)

[Sean]

Stan,

I have to bow to your greater experience with MCI's.  On my coach, I've never seen the relay connected to the R terminal drop out, no matter how much load I have on the system.  And I do have a shunt with a meter on this, so I can say unequivocally that I've had 200 amps of load on there, and it will still stay connected even at idle.  YMMV.

-Sean
http://ourodyssey.blogspot.com

[gus]

Sean,

My comment was unclear. What I meant was, what advantage is there in using Gp31 over other Gps with the same specs?

It appears that there is none and, as I said, I don't really remember the reason I bought them for starters. I think that I will replace them with another Gp when they wear out because WM does not carry them. The major advantage in using WM batteries is the large number of stores around the country for warranty service.

My 4104 battery needs are very simple. I use two each for starters and house and they are more than enough. I have used the house batts as boosters for low starters, but just one time when I was stuck in the middle of traffic at a traffic light!

My guess is that the Gp 65 is a lighter weight battery (Fewer plates). Otherwise, why have two groups unless there is a major difference in connections?

[Stan]

Sean: Probably something neither of us thought about is alternator speed. Obviously, there is a point where either my condition or your condition will be met. I have no idea if different ratios are used by different manufacturers or if it was simply that my low idle speed was set too low to keep the alternator charging.

I think all MCIs in commercial service are switched to high idle when stopped when the A/C is on and the 50DN certainly puts out at 1000 RPM engine speed.

[buswarrior]

Hello.

I've seen the No Gen light come on in fleet vehicles with high loads, low idle, and it goes out again when the thottle is advanced. The lights/fans go from dim to strong and back again. Usually attributable to an alternator that will shortly fail completely, the voltage having dropped sufficiently to trigger the dash indication. The big Delco's are unforgiving, they don't warn for long they are failing.

Perhaps it would be better to think in terms of the batteries being there to start the engine, and buffer the charging system? The big batteries are for starting the coach in commercial service, where there needs to be some extra capacity to compensate for all manner of operational realities in the hands of hired help, and are sold all over the continent to operate all over the continent.

Add in some widely held traditions as to battery spec'ing that might not stand up to modern scrutiny....

In our bus conversions, since we are more caring and attentive, we may quite reasonably skinny down the extra reserve according to our own conditions and willingness to take corrective action if we get too skinny.

Find the least expensive batteries, with the smallest capacity that you can get away with for your expected operating environment, with the best warrenty, that are readily available.
And then you will be....

happy coaching!
buswarrior