Why is this battery not charging on the alternator?

[Ruffles]

I have two batteries of 110 Ah each connected via a 1-2-both switch in the time honoured fashion. Battery one is a delphi 'normal' starting battery. Battery two is a Delphi Freedom 2000 bought in 2000 oddly enough.

Now for at least the last 3 years battery 2 has not shown much in the way of voltage. I assumed therefore that it was knackered and put it on the list for replacement. So a couple of weeks back I extracted said battery, staggered with it down the ladder and brought it home.

Being of a mean disposition, before I took it to the tip, I dug out my hi-tech, switch mode, 3 stage battery charger (illustrated) and plugged it in. After a couple of days it was showing 15 volts plus.

Now I know just holding voltage doesn't mean it's not knackered. So I then put a 1amp load on it. That was on Sunday. It's still showing 12.5 volts.

Also the little charge indicator thingy is showing green for go!

Now the battery runs domestic loads fine which suggests the connections from switch to battery are ok doesn't it? The alternator charges battery one fine which suggests the alternator can see the battery switch ok. Also, I'm sure that I have run the engine many times with the switch on '2' so it can't be that the first battery is drawing all the charge current. Any ideas?

BTW are Delphi still around? Can't find them on the net.

 

[William_H]

Well last point first if the battery will run a light bulb for several days it is ,depending on the wattage of the light bulb, capable of doing the job you want of it. ie run domestic loads.

As for your charging system...... You don't say how you felt it had no voltage for 3 years. If the boat has a built in voltmeter switchable to the 2 batteries then perhaps the votmeter has failed on one battery side.
If on the other hand you have used a multimeter directly on to the terminals then that suggests battery was indeed flat.

It is unlikely that the engine battery is sucking all the amps and not leaving any for the domestic battery. The engine voltage will be forced to be the same as the domestic battery by the copper connection of the switch and current will end to flow to the most discharged.
So you have to look at that 1,2,both switch. I dislike the intensely and would rather see 2 seperate switches of high current or better still 2 high current switches, one from the engine battery to the engine circuits one from the engine circuits to the domestic battery (for charging and emergency start and a last smaller switch from domestic battery to the domestic circuits.

Anyway if you want to stick to 1,2,both then you will from what you say have to go back to the boat and check out the wiring once again.
It may not be wired as you expect. ie domestics load not via the 1,2,both switch.

You could take your trusty battery charger (I presume you are joking about it being 3 stage switch mode) (I actually like the old style.) to the boat and substitute it for the alternator. ie take off the fat wire from the alternator body and connect the charger to that wire. Then recheck with a multimeter where the higher charging voltage gets to. ie to the engine battery the switch and you want it to get to the domestic battery in both position. see if you can nut it out from there.
good luck olewill

 

[halcyon]

Back in the old days with Delco Freedom batteries, they had a number of odd habits.

They needed a high charge voltage, mains charger reaching 15 + volts is what is needed, posible the alternater is running at a low voltage.
Secondly if they were left part charged, they assumed that capacity, leaving a 110 amph battery 50% discharged would result in a battery of only 55 amph. This could be the result of being left over winter. or being charged by alternater for short perriods, resulting in a slow fall in capacity, due to stratification ( electrolyte not being stired ). I used to tell owners to get batteries bench charged at the end of the season before lay up.
Your bench charge may have bought it back to life, but it may not have a full 110 amph capacity.

Brian

 

[Ruffles]

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Well last point first if the battery will run a light bulb for several days

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Should last more than the rated 110 Ah suggests 'cos that is probably quoted at 10amps or more.

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As for your charging system...... You don't say how you felt it had no voltage for 3 years.

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There's a single 0-15v analogue meter with a 1/2 momentary switch. These things are chronically inaccurate. But battery 1 reads 13+ on a good day. Battery 2 is often 11.5 /forums/images/graemlins/frown.gif

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It is unlikely that the engine battery is sucking all the amps and not leaving any for the domestic battery. The engine voltage will be forced to be the same as the domestic battery by the copper connection of the switch and current will end to flow to the most discharged.

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Totally agree with you there.

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So you have to look at that 1,2,both switch. I dislike these intensely

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Yes they're not ideal. Actually the starter is also taken from the same switch. So you can start from battery 2 if you have a mind to. Also means the voltage drop resets the GPS when you start the engine!

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Anyway if you want to stick to 1,2,both then you will from what you say have to go back to the boat and check out the wiring once again.
It may not be wired as you expect. ie domestics load not via the 1,2,both switch.

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Actually I'm fairly sure of the wiring. It's completely symmetrical.

One important point I forgot to make. Once the engine is running, when I switch from 1 to both the engine slows slightly. So there's power going somewhere - it can only be going into the battery or there'd be smoke coming from somewhere... It certainly seems that battery 2 draws far more current than battery 1. As you would expect if it is practically flat.

When I charged it at home I was only putting a maximum of 1 amp into it (for a few days). Could a battery cell have a fault where applying a current above a certain value causes the voltage to actually fall? I guess I could test this with a proper charger. Or by connecting it across my cars battery with the engine running.

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You could take your trusty battery charger

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Belonged to my grandfather. I may pass it on to my son. If he doesn't behave.

 

[oldharry]

I would strongly suspect the changeover switch and metering arrangement. Blow a fiver on a cheap digital meter (useful anyway for electrics, and find out what the voltages actually are at each battery terminal before you start ripping everything to pieces. I have a similar arrangement, and whenever I start to get odd readings (which is fairly often) it always proves to be the metering circuit thats faulty, not the actual power circuits!

 

[William_H]

High Ruffles again depending on the current from the lamp presummablu about 1/2 to 1 amp I still think if you can get 50% of rated amp hours out of the battery you should consider it still OK. It certainly is not new at 7 years old but possibly worth keeping for a while longer. olewill

 

[ms1]

I made some battery & charging decisions based on some tests and assumptions around the use of an old trickle charger that I have had for years. Wrong. after wrecking 2 domestic batteries I bought a Sterling marine battery charger, fitted new cables and connections and my troubles were resolved immediately. I think you need to get that battery FULLY charged and I doubt you can do that with your old charger. These big batteries can kid you they are oozing with power but actually, on test, they are far from able to do the biz.

 

[pampas]

Have come across this problem on many occasions, the owners have cleaned and checked the installation, looking beautiful. On checking by disconneting all cables and testing the resistance of said cables have found the high resistance caused the problem in one crimp terminal. to test place one end of your meter on the crimp and the other on the cable about 1/4" up the conductor,. Do this to every crimp and your fault will probally be found.Takes time but a point that many do not think of.Good hunting. /forums/images/graemlins/wink.gif

 

[Ruffles]

[ QUOTE ]
High Ruffles again depending on the current from the lamp presummablu about 1/2 to 1 amp I still think if you can get 50% of rated amp hours out of the battery you should consider it still OK. It certainly is not new at 7 years old but possibly worth keeping for a while longer. olewill

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Still I think I'll try to borrow a higher current charger and see how the battery handles that before I lug the thing back to the boat. The alternator definitely loads up when the battery is connected.

What worries me is that I've just fitted a fridge!

I checked it again and it is down to 12v on a 1amp load. Off load its back up after a while to 12.5. So is that discharged? Don't want to take it flat completely.

Also I'll try applying a large load. Say 20amps? I have a reel of resistance wire somewhere. Always useful for these things.

 

[Ruffles]

[ QUOTE ]
I think you need to get that battery FULLY charged and I doubt you can do that with your old charger. These big batteries can kid you they are oozing with power but actually, on test, they are far from able to do the biz.

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That old charger took the battery up to over 15volts after 2 days. I could hear it fizzing. That's as charged as it gets! Surely smarter charges are better at controlling charge - high voltage initially followed by float voltage to take it to 100%

Now my alternator is another matter. I doubt that goes much above 14v with a following wind.

 

[Ruffles]

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I would strongly suspect the changeover switch and metering arrangement. Blow a fiver on a cheap digital meter

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Got a rebadged fluke at home and an old digital on the boat.

What I don't have is a current shunt. Might invest in one today.

 

[Ruffles]

[ QUOTE ]
Back in the old days with Delco Freedom batteries, they had a number of odd habits.

They needed a high charge voltage, mains charger reaching 15 + volts is what is needed, posible the alternater is running at a low voltage.
Secondly if they were left part charged, they assumed that capacity, leaving a 110 amph battery 50% discharged would result in a battery of only 55 amph. This could be the result of being left over winter. or being charged by alternater for short perriods, resulting in a slow fall in capacity, due to stratification ( electrolyte not being stired ). I used to tell owners to get batteries bench charged at the end of the season before lay up.
Your bench charge may have bought it back to life, but it may not have a full 110 amph capacity.

Brian

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Halcyon,

Sorry missed your post for some reason.
I got the bill from the yard for this seasons mooring today. And the starter failed on my car yesterday. So I'm not minded to replace the battery! So your post is good news. Sort of.

What do think the significance of the alternator being heavily loaded when charging might be? Is this something you've come across?

My alternator is less smart than I am. Standard Valeo/Paris-Rhone rebadged by Volvo jobby. I might invest in a replacement standard regulator for it. I believe more modern regulators have a slightly higher voltage setting. Worth twenty quid.

If I do have to replace the battery, my local farm supplies place is selling Numax batteries. Anyone know if they're any good?

 

[halcyon]

Sounds like what we had in the old days with Westerlys when they fitted freedom batteries. If they were allowed to go flat, then charged for a short time, then discharged, after time you had a short recharge, then the voltage to put charge into the battery shot up, alternator regulated and you got no more charge. It's like surface charging, sounds like thats what your getting.
We found that with freedom batteries dicharge a little, then recharge worked ok, never letting them drop below 60% capacity, then a annual bench charge before lay-up.
Remember Barclay's bank sailing club had a Merlin down Hamble Point, always flat batteries or little capacity, they always allowed the batteries to go flat before recharge. Another chap I knew with the same model boat, always charged batteries when the panel display went to yellow, never had a problem all year. This boat had no smart alternator regulater or charger, just what Volvo fitted.
So a little oftan does work.

Back to question, get the battery to LSUK or similar, and get the battery load tested, may be ok , or it may be down on capacity, or dead, only a test will tell.

Brian

 

[William_H]

High Martin Old style battery chargers have some attributes which make them actually better at charging than the modern stepped chargers. What they are not is automatic and you must monitor the charge rate and know when to turn them off.
The output from a crude charger ie transformer rectifier is a series of pulses of DC as produced by the sine wave AC. So DC voltage rises from zero fairly rapidly rising to round off in a peak and fall again.( at 50 or 100 times per second) At some point up the rise the voltage exceeds the battery voltage and current starts to flow. The higher the battery voltage the shorter the time when current flows in. The crude amp meter avarages the current by its mechanical inertia beautifully.
So we have a high voltage to enable the battery to be fully charged but we don't have the high average current associated with the high voltage. In fact the current tends to fall only a little as battery becomes more charged.
It is an ideal arrangement except that for a higher current charger ie the peak current is higher, the battery can be boiled and cooked if it is not turned off. So you have to monitor the current and time to know when to turn off.

Your expensive modern 3 stage chargers are in fact barely as good at fully charging a battery but what they can do is reduce the current automatically before the battery gets over charged and damaged.

Just by comparison your standard regulator on your alternator presents a smooth 14 volts to the battery. A voltage chosen so it will not overcharge the battery however it will provide a healthy charge rate initially to a flat battery but the current tapers off as the battery voltage rises so the last part of the charge is very slow and in fact it can never fully charge the battery. (near enough but not quite full).

So don't throw away your crude charger they do a good job you just have to remember to turn it off.......... olewill

 

[Anonymous]

The quickest thing to do is to check that it isn't the battery. Can you swap the batteries over and see if the problem is reversed, or whether the Freedom battery continues to behave oddly? You probably don't want to run the engine for ages to do this, so instead try a proper discharge test to 50% nominal capacity - from your posts you clearly know how to do this - I would suggest a C/20 rate, i.e. around 5A. Do you have some spare bulbs you can use as a dummy load though don't solder to them!! If not, treat yourself to a 12V inspection lamp (aka 'jack lamp') if you haven't got one. You will wonder how you ever managed without one so it won't be a waste of money.

If that proves the batter(ies) are serviceable, re-measure your system voltages using a DVM, put some kind of ammeter in circuit - doesn't really matter how accurate - all you want is a ball-park reading of current for this job. I wouldn't bother with the current shunt for the DVM but fit an automotive +/_ ammeter in circuit with the output of the alternator. You will forever be glad that you fitted one - it diagnoses and shows up charging problems you'd not otherwise have seen. Also fit a decent voltmeter across the output of the 1/2/Both switch - an automotive battery condition meter is fine - they have suppressed zero and are not bad but digital is best.

As someone else suggested, it seems very possible that there is a resistance in the circuit maybe in the connections, or the switch. He explained how to check the connections and if they are ok, check (with a DVM) the volts across the switch. The volts should be low - certainly less than 0.5V and hopefully much lower - across the switch contacts that are closed.

 

[Ruffles]

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Old style battery chargers have some attributes which make them actually better at charging than the modern stepped chargers.

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The problem with these old chargers is that of you short the output leads it blows the fuse. My grandfather resolved this by replacing the fuse with a nail. I presume the nail has the correct current rating. He did the same on his house wiring. Alas his expertise has died with him.