Charge Rate

Did a check today and found I was getting 13.25 volts across the battery with the headlights and heater blower on. I thought this seemed a little low. With lights and heater blower off I got 13.8 volts
Engine was running at approx 2000rpm for both tests.
Its a 1996 Duetto. What does the group think?
Brad

Sounds okay to me.

Blossom wrote:13.25 volts across the battery with the headlights and heater blower on. I thought this seemed a little low. With lights and heater blower off I got 13.8 volts

Sounds pritty well spot on to me. You could get the alternator ouput checked if you're worried, but with figures like that I wouldn't bother.

Brod

I am reassured by that. Thanks gents

Brad

Sounds about ok.
You should be getting 14.3 to 14.8 while the engine is running without any load on the system.

Yes Celticbiker thats what I was thinking, but I'm only getting about 13.7. which I thought was a bit borderline

Brad

Sorry, I misread your original post.
There are a couple of things you can do though.
I am assuming you have 2 batteries under the bonnet?
Before starting check the voltage of each battery with the engine off.
If not sealed batteries, check fluid levels.
1, Check all terminals are tight
2, Remove-clean-replace-grease one set of terminals at a time.
If you have a Ford fitted stereo make sure you have the code before disconnecting batteries.
Lettuce know the results.

I think you'll find that the condition (voltage) of the battery/s has an influence on the alternator charge-rate, as its on-board regulator senses the battey

voltage & adjusts the output accordinly, i.e, low battery, results in a high alt output until the battery is 'brought-up', a well charged battery should

result in the regulator sensing this & therefore chucking out a lower voltage.

We used to switch on headlights, heaters, HRW etc. for around 5 mins ( engine OFF ) & only THEN start up & do a voltage check, this way the battery is

given a 'hammering' & thus the full output can be expected from the alternator & measured.

Regards

Thanks Celticbiker and Modelman. Terminals all good (and nonstandard stereo. Been caught with that one before) This all came about because the other morning Doris wouldn't start.
I noticed that the "leisure" battery was rated 570amps whereas the engine battery was rated 540amps.
I swapped them around and she started straight away. I believe the original engine battery is beginning to fail.
I have contacted the dealer where I bought the van and he will fit a new one. Both batterys are Halfords sealed type so unable to check individual cells.
I will try your suggestion tomorrow Modelman and report back afterwards.
Thanks again.

Brad

Assuming the second battery is fitted properly - isolated by a relay so you only use the leisure batt when parked. I would suggest you isolate the system by taking a wire off the relay.

Now when you do your checks - you are checking the vehicle battery - before when the engine was running both batteries were in parallel and the better battery would be "dragged down" by the worse one.

Really the second battery - the habitation battery should be a leisure battery - you do not need the cranking characteristics but it does need to go through being relatively unused at times etc.

Jon

Hi all
I’ve looked at all the comments, had a re-think and decided that I still agree with myself!

My Haynes manual quotes the regulating voltage as 13.7V to 14.6V at 4000RPM (engine speed) and with a load of <7A. So 13.8V is “in spec” as far as the regulator goes. Ok it’s at the lower end of the spec but that’s not necessarily a bad thing.

The engine speed is only 2000RPM and the alternator is still achieving 13.8V off load. Actually it’s not off load is it because it’s still charging two batteries at an unknown rate. On load it’s supplying what? 10 to 15A (not sure what the fan motor takes) and still achieving 13.25V again at only 2000 RPM. Maybe run it up to 3000 RPM for a while and if the voltage goes up to 13.5V the charging system is almost certainly ok.

I think the question is – are there any other symptoms to suggest a problem? If not I wouldn’t worry.
Brod.

Good morning folks.
I found a dirty connection at the alternator, I think a cover over the terminals is missing.
With a clean terminal I am now getting 14 volts with no load (except the second battery) and 13.9 with the headlights on. I think this seems reasonable.
Many thanks to you all for your input.

Brad

Blossom wrote:Good morning folks.
I found a dirty connection at the alternator, I think a cover over the terminals is missing.
With a clean terminal I am now getting 14 volts with no load (except the second battery) and 13.9 with the headlights on. I think this seems reasonable.
Many thanks to you all for your input.

Brad

Clean contacts always help - A good tip is to smear the connectors and your battery posts with Coppaslip, or any other copper based grease.
The grease helps prevent corrosion - The Copper base helps make an electrically improved contact.
A win win situation

Yes, copper grease is good, but if you can find a small quantity at a reasonable, price Nyogel 760 is the real deal!

[You must be registered and logged in to see this link.]

If you have some you'll find loads of uses for it!

Bartfarst

Thanks for the tip Bartfast I will look out for some of that
Brad

Blossom wrote:Thanks for the tip Bartfast I will look out for some of that
Brad

That makes 2 of us - thanks for the tip I will give some a try.

Jon