"Pulsing" Battery Charger

[hutch]

\"Pulsing\" Battery Charger

I have a 10+ years old battery charger - Tecsup 24V 40A - installed. But alas no manuals, specifications etc. It appears to be a multi stage charger. When charging from the mains, everything is fine until it tries to switch to the lowest stage which I assume is a trickle charge. The charger then "pulses" (approx. 2x a second) as it tries to switch down - the last red indicator flashes on and off. This does not happen when charging from the generator. The only difference between the generator and the mains is that the generator is not earthed into the boat's common ground.

Before I spend lots of money on a replacement charger - simpler than trying to repair an out of date old fashioned charger, any ideas on what the problem might be?

 

[VMALLOWS]

Re: \"Pulsing\" Battery Charger

I assume the charger is 'new-to-you', and not that its behaviour has suddenly changed.

The pulsing may be the deliberate way in which it reduces the charge (mobile phone chargers work that way once the battery is fully charged). Have you measured the voltage across the battery when the charger is in pulsing mode? If it has reduced to a lower figure (around 14v) then it is probably working as intended.

I cannot explain the difference when on the generator......can only guess the AC input to the charger is lower (and not pure sine-wave) and the charger is never reaching its switch-over point.

 

[hutch]

Re: \"Pulsing\" Battery Charger

The battery charger is the original one fitted at new - 1992. I bought the boat some 4 years ago. The problem did occurr once or twice only some time back and I thought nothing of it. However, after the boat was out of the water for a couple of months six months ago, it became a persistent feature immediately on return to the water. Had had some work done on the gearbox and prop shaft but do not think that this is inter-related in any way. Previously, I have rewired the batteries, installed a new distribution board, installed a dedicated DC/DC converter to run all 12V equipment, upgraded the alternator and fitted an ADVERC controller, replaced the instruments and autopilot, overhauled the windlass and main in-mast furler, etc. No problems!

I am currently off the boat and thus cannot remember exact voltages. I have tried recharging at different battery voltages down to as low as 23.6V. After charging at 27.6 volts, the house bank voltage rapidly reduces to 25.6 where it stays before then reducing further. Although "apparently fully charged", the voltage falls quite quickly with a fairly light load. The engine bank is fine and holds its voltage well. The house batteries are 2 plus years old whereas the engine bank is at least 5! When charged from the alternator (with the Adverc controller) the batteries appear to hold a much higher charge and do not need to be recharged for some while longer. The Adverc charges at 28.4 volts - I think it has been set for GEL batteries whereas mine are sealed maintenance free. Any idea how to reset the ADVERC?

I have looked for a "leak" but have been unable to detect one. The ammeter shows no current draw. Mind you it only reads to 1 decimal point! It is shunted on the negative between the bus (all DC equipment have separate negatives) and the common ground with the AC circuits. I have also measured for current draw at various different points on both positives and negatives from the batteries and elsewhere with a digital clamp meter but have found nothing!

I don't know whether this throws more light on the matter or just confuses.

Grateful for your input and assistance.

Regards

 

[VMALLOWS]

Re: \"Pulsing\" Battery Charger

If the charging voltages you quote are correct, they're all far too low and your batteries are probably never being adequately charged. How long are you charging for??

27.6v is the float voltage to maintain a battery indefinately that has already been fully charged. At 23.6v you would be maintaining the battery in a near-discharged state. Even 28.4v from the Adverc is really only a 'maintain' level (equivalent to the charge voltage on a car). It would takes days to get the battery anywhere near charged. All these voltages must be measured at the battery terminals.......not the charger output.

Are the batteries open-vented?......can you check the SG with a hydrometer?

Unfortunately I suspect your domestic (house) batteries have 'had-it'. The starter battery(s) get very little use and probably manage to just-about recharge themselves.

 

[hutch]

Re: \"Pulsing\" Battery Charger

Normally only takes ½ to ¾ of an hour for the charger to get down to the float charge! Under engine can be charging for ¾ of an hour upto 4 or 5 hours. Never any problem there!

The voltmeter reads from the panel for the house bank and from the battery terminals for the engine bank.

Batteries are sealed low maintenance lead acid! Can’t get at ‘em to measure the SG.

I will only be back aboard in mid October. If it is the batteries that are the problem – although this doesn’t explain why the “pulsing” doesn’t occur using the generator – I will run some more checks as well as recording voltages - at the batteries - and if agreeable to you will get back to you directly. It may be that I have two problems, one relating to the charger and the other spent batteries.

Many thanks –again - for advice and guidance. If you have any other thoughts, ideas or suggestions on additional checks, these would be greatly appreciated.

 

[Guest]

Re: \"Pulsing\" Battery Charger

Many chargers in such as Radio Control Models etc. have a pulsing style .... basically being a 12v 0r higher and pulsing the charge to reduce it to the required levels even as low as the 1.5v required for Glow-plug igniters etc.

I have seen an old battery charger exhibit the same, but that was an old one my father had !! As another postee has said ... check the voltage as it si probably reached nera charged state and is now just keeping it topped up ....

 

[hutch]

Re: \"Pulsing\" Battery Charger

The "pulsing" is not a natural state for this charger - and it also affects other AC equipment. The AC lights also "pulse"! As mentioned before, I will investigate further on my return to the boat next month and will measure voltages at the terminals. I will also try and check the state of the batteries to see if they have had it!

Thanks again for input, All greatly appreciated

 

[ccscott49]

Re: \"Pulsing\" Battery Charger

This sounds more like a shorepower problem, than a boat one, especially as you mention the lights and the fact that it doesn't happen on genny. Could you get the marina to check there supply?

 

[VMALLOWS]

Re: \"Pulsing\" Battery Charger

OK Hutch. Look forward to your further input in October. This one is quite intriguing. As Colin comments, it is looking as if it may be partially related to the shore power (a very high resistance feed? .. a faulty protection device?).

 

[hutch]

Re: \"Pulsing\" Battery Charger

Thanks for all the input! Given me a lot to think about - and to follow up when I am back aboard next month. Hadn't considered the possibility of a shore power problem. Thanks for that thought, Colin. Marinas in Thailand are renowned for not having properly earthed supply!

Watch this space!

 

[VMALLOWS]

Re: \"Pulsing\" Battery Charger

And full marks for keeping the Thailand bit to the end.......otherwise it might have distracted us!. And to think I was about to say I'd be happy to pop round if you were nearby!!

 

[hutch]

It\'s a tough life!

Had to keep somehting back! But you are very welcome to drop in! It's a great area to sail - in comfort. The sun shines! It's always warm! Conditions are generally pretty benign. Lots of anchorages! Great food! Cheap booze - especially in Langkawi, a leisurely 140 miles away! Under 25p - yes, pence - for a can of beer! I could go on! Best of all, she who must be obeyed stops complaining - well, most of the time! Seems to think that the sails are to provide shade or not, as the mood takes her!

Will keep you posted about the batteries and look forward to your wisdom! Many thanks to all.

 

[halcyon]

Re: \"Pulsing\" Battery Charger

Sounds like a earth problem/fault.
Battery charger works with genny, not connected to earth.
Put boat back in water after work on shafts, what do you do, connect props and shafts to earth, ie water, these intern are connected to common neg in boat. The marina earth may well be a spike in the ground, thus giving a circuit thought the ground, water and props.
Possible there is a charger fault, sounds like the domestic batteries are linked into mains (via transformer?) under certain conditions, ie when tries to switches to float charge.

Brian

 

[hutch]

Re: \"Pulsing\" Battery Charger

Brian

Thanks for your input. Everyone's feedback has given me lots to think about - and given me some more areas to investigate. Once I am back aboard I will investigate further and will report back. Am hoping not to have to call in a "professional" who I know will suggest a new charger to be the solution. I do have access to a very good electronics guy who I will get to look at the circuit board to see if it is the charger that is the problem. Alas, he wasn't around when I left the boat two months ago.

Thanks again

 

[ccscott49]

Re: \"Pulsing\" Battery Charger

Hutch,
I still say check the shore supply first, I don't see how it can be your charger, when the supply to the boat pulses, as you've seen and the genny doesn't! Just putting a low wattage bulb across the shore supply will probably show the light pulsing, if it does, theres nothing wrong with your charger, think laterally.

 

[hutch]

Re: \"Pulsing\" Battery Charger

Colin

I will check the shore power. If anything, it is likely to be an earth problem - probably none and thus eveything is being earthed through the water. I do run a 240V circuit inside the boat - for TV, HiFi, fridge/freezer and lights - and all are fine when the charger is not on. I had previously ruled out possible problems with neighbouring boats. I was moored next to a rusting steel hulk but moved and am sandwhiched between two glossy plastic fantastics which I have assumed are properly wired. As I am learning from this exchange and from other subjects, never assume anything so will try and measure for any stray voltages around the boat! Thanks again.

 

[hutch]

Re: \"Pulsing\" Battery Charger

Referring back to my original post in September last year and to all the advice given, I have still not been able to solve the problem. However, the boat is now out of the water and I am now going over everything once again. I hope to have a positive result before too long and will post a report on what if anything I find!

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