Wrong battery or Alternator?

Post by **Greg-SiR** » Wed Mar 30, 2016 1:19 pm

So was out in the Bb4 for its longest spin possibly last night since ownership @1hr 15mins straight driving and 20 minutes from home the radio starts resetting gauges get dim headlights start to fade car starts spluttering unless gunning it and i've been here before with the alternator on an old civic same thing so anyway i made it close enough to home but had to pull in as it died when i came off revs and wouldn't start back up.

Made it off the motorway just!

Well i had changed the bigger battery down to one halve it's size just over a week ago and the one i'm using was put in the 1999 Crv new by RACQ roadside but i stole it before the Crv just got sold.

So i got the kind Mrs to drive down to me with the bigger battery i had set aside for the Bb2 and hooked it up started and drove home no issues.

Yet to get back out in it since but was glad not to leave the car on backroads or have to fork out for a towtruck.

I have been told by my wise old father that it could be an amp difference and the newer battery may not suit although working spot on for close to 2 weeks maybe its not paired with the alternators need.

I would have thought they would be the same spec more or less same sort of car make/engine size....

Is there a way of checking the alternator out through its running pace to see if thats the problem,i have read to start the car and take the negative battery cable off whilst running and if it hesitates or fails the alternator is gone?

I have one on the Bb2 if needed but yeah i have yet to get back out in it with it's old Heavy lump of a battery back in.

Something similar to the time i changed plugs on it and the dizzy died a few days later,maybe the car just hates a change

Post by **Gayno** » Wed Mar 30, 2016 1:27 pm

Size of battery won't make much difference. Certainly sounds like the alternator.

To test, put a multimeter across the battery terminals with the engine running, and it should read between 13-15V. Anything less and the alternator isn't charging.

Post by **vanzep** » Wed Mar 30, 2016 2:43 pm

Prelude battery is 70ah which is more than most car batteries
reading at battery terminals with car started should be 14.2 to 14.7 irrc

Post by **bluejackhustler** » Wed Mar 30, 2016 6:24 pm

Sounds like battery terminals/earth straps to me?

Post by **Greg-SiR** » Thu Mar 31, 2016 12:08 am

Thanks guys,My mutlimeter is shot,the screen is damaged i can't get anything off it.

Started both Preludes same battery took off Neg battery whilst running and Bb4 died instantly whilst Bb2 stayed on,so yep alternator swapping now i guess.

Post by **Merlin** » Thu Mar 31, 2016 9:03 am

Greg-SiR wrote:gauges get dim headlights start to fade car starts spluttering unless gunning

Alternator! I had this when I tried to drive home with an knackered alternator. No battery or CAT temp warning light?

Post by **Vtecmec** » Thu Mar 31, 2016 11:44 am

Just for info, the alternator can usually be repaired by fitting a new voltage regulator and/or rectifier, I did this to mine and the cost was less than £30.

Post by **vanzep** » Thu Mar 31, 2016 2:40 pm

bluejackhustler wrote:Sounds like battery terminals/earth straps to me?

even if the fault is traced to the alternator its not a bad idea to clean up the battery earth strap - this was the issue with non starting on merlins track lude last weekend. Im going to clean them up on my ludes

Vtecmec wrote:Just for info, the alternator can usually be repaired by fitting a new voltage regulator and/or rectifier, I did this to mine and the cost was less than £30.

good info - do you have a link to where you got these parts from? I take it you changed both parts...

Post by **Vtecmec** » Thu Mar 31, 2016 2:59 pm

I did swap both (though you can test them firstly) I just got them off ebay.

Post by **Greg-SiR** » Fri Apr 01, 2016 2:19 pm

Merlin wrote:
Greg-SiR wrote:gauges get dim headlights start to fade car starts spluttering unless gunning
Alternator! I had this when I tried to drive home with an knackered alternator. No battery or CAT temp warning light?

Was it a night time drive? So much more fun at night

Second time this has happened to me in 20 yrs of car driving and both happened in the dark.

I had a hunch when i got in the car for the return part of the trip the drivers window was slow going up so i thought ok motors on its way out,10 mins down the road the radio starts switching on and off so again i thought been here too bad earth acting up,then another 10 mins after the speed/rev needles go crazy and stop operating altogether i assumed the Vss was at it again too.

Scariest part was driving with no dash at all complete darkness and near no headlight or tail lights just waiting for it it die but it kept going till i got to a safe enough area.

Probably should have pulled in before all this but i was a man on a mission.

Also noted the crazy up and down idle revs were there when i pulled up at lights just before all this happened which since replacing alternators has gone too,was also an earlier addressed problem also.

Funny nearly every problem i have had to this car was there in that 30 or so minute cycle!

But it's back to health running it's donor alternator,Merlin no idea the CEL is always on in my car albeit i have tried pulling the code but no avail,i just live with it and it runs fine,i will get at it again though,hoping it's just an Ecu blip.

Swap and found out the P/S pump doesn't need to be taken off too late which would have saved me some time as the bolt holes were a PITA to line up again.

Going to get the bad one reconed next week as it's still needed for the donor.

Just glad to have it all running sweet again and before Saturday which means i have some time off for gardening instead of car work