i have a 93 ranger 2.3l 5 sp when driveing down the road the pointer on the batt gauge on the dash will move quite a bit i had the alt tested and the guy at advanced said it was good but when the in car test was running the truck almost stalled (when, i am assuming a load was placed on the batt) is this a sign that the battery is going i have no idea how old it is it came with the truck about 2 yrs ago, could there be a short somewhere in the elec. system? it just started a few weeks ago. o the alt. is new replaced this summer no problems untill now. what size battery does ford or you guys recommend for this truck in the cny winters it has been having a tough time starting too thats why i suspect the battery

 

Not sure about the stores where your located, but the parts store that I work at will test your battery for free if you bring it in. Maybe you could give that a try, if you do end up having to replace the battery I would replace it with the same strength (CCA) as what's in there now unless it's drastically different from what the parts store comes up with on their computer.

 

A bad battery will cause the gauge to float around as the rpm's change . Have the battery tested and check the battery and alternator connections. If the battery is bad I like to replace them with the highest cold cranking amp battery I can get the will fit the battery box.

 

I believe Ford specifies a BXT-59 size battery.

Motorcraft batteries, made to Fords specifications by Johnson Controls are a good value.

The best model has a 36 mo free replacement & 100 mo prorated warranty, that I've found to be price competitive, work real good & last a long time.

My 99 Ranger still has it's OEM Motorcraft battery & the 94 Taurus is still going on it's 2000 Motorcraft replacement battery, but I did upgrade it to the alternate larger CCA & RC size.

In general, use a battery with the highest Cold Cranking Amps (CCA) & Longest Reserve Capacity (RC) rating, that has the most plates & largest plate surface area, in the size specified for the vehicle.

Generaly these longer lasting batteries will be the heaviest in weight, because of more plates & will have more surface area for more current output, so look at the batteries weight too, as it'll help to kinda give us an idea of how much is inside on the business end!!!! lol

On the volt meter fluctuations, it could be a number of things, so imo it was a good idea to have the "in vehicle" electrical system testing done, but it sounds like maybe the guy that did it, may not have been sure how to fully use his equiptment.

It should have been able to spot a bad battery, like weak or shorted cells, faulty battery cables, or connections, or a acting out alternator.

So if you aren't equipped to do some home load testing, or aren't sure of the stores test results, maybe consider having another in vehicle electrical test done by someone else, or somewhere else.

Why was the alternator replaced this past summer???? There-in may lie a clue to what's going on now!!!!

I agree wih the guys, from your description of having recently replaced the alternator & now the voltmeter acting up & developing some starting problems, along with not knowing how old the battery is, kinda puts the battery up there on the suspect list imo.

Could be a battery cell shorting out, or maybe a battery cable or connection, issue.

Could also be a Alternator slip-ring brush issue, or voltage regulator, or leaky, shorting diode issue.
Just because the alternator is new, doesn't automtically give it a pass, so for now keep it on your suspect list & make it earn a pass test too.

Do a site search for Battery Tutorial & look over the site listed there, as it'll offer up loads of info on batteries, from who makes then, how to choose them, care for them, test them, charge them & which chargers to use & why.

Let us know what you find the problem to be.

 

the alt was replaced with serp. belt and tensioner the main alt shaft was bent the tensioner was worn and the belt was a "might as well while im in here" the battery has no numbers listed on it which annoys me its a interstate mega-tron again no clue to its age, cca or anything the alt has been working fine thus far just started acting up as the weather has gotten colder that is why i suspect the battery

thanks for all your input

 

I have had plenty of issues with Interstate batteries I have seen them do some really strange things. I won't intentionally own another one.