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Problems with domestic power

I have a long story but please bear with me. My narrowboat has an Eberspacher 5 dwsc water heater with a mini timer control unit. Also a Sterling 1250 50amp battery charger and 3 Superbatt 110ah domestic batteries. Yesterday I pressed the button on the timer start the Eberspacher for 60mins of water heating. The unit would not fire up and the display on the timer was flashing, as it would when the battery isolater switch is turned off, and I had to reset the clock. I tried this several times with the same result. This has happened in the past but with a bit of fiddling (turn battery charger of and wait a while, then back on again) I have managed to get it to fire up. This time it did not work so I decided to switch the engine on and heat the heat up (I turned charger off). I ran the engine for 1 1/2 hours (I have 70amp alternators) switched the charger back on (forgot to mention I am connected via landline and keep charger on constantly) and took a shower. while in the shower I noticed Whale Gulper was running very slowly and seemed to be labouring but after a couple of minutes it sped up to normal operating speed!. After the shower I decided to try the Eberspacher again and it fired up straight away. I obviously suspect some kind of power problem but do not want to purchase expensive batteries (only 7months old), Charger etc. without knowing what the problem is. I would appreciate any advice on how to isolate the problem and thereby fix it. Thanks in anticipation Paul

Asked by: Paul Jones  | 12.19pm, Thursday 1 November


WW says:

It sounds like your batteries are either failing or there is a bad connection.
If you disconnect the batteries and check the voltage of each immediately and then after an hour; they should be the same.

Rupert Smedley  | 5.49PM, Thursday 1 November

Sorry my previous answer was rather brief!
The Superbatt 110 is a basic flooded lead acid battery; however they should not have failed in 7 months given that you keep them charged. Although they are a "Maintenance Free" sealed battery, it would be worth checking the electrolyte levels in each cell. Low levels would give the symptoms you describe. The acid should cover the plates and there is usually a simple plastic bar below the cap to indicate the normal level. If any are low top the level up with de-ionised or distilled water.
It is possible that with the extreme hot weather over the summer, the water might have evaporated. Another possibility is that the charger might be faulty, as overcharging will also cause water to be lost. Check the battery voltage when charging (preferably with little power drain); if it is over 15V you have a problem.
If you are lucky and top the cells up, the batteries will recover most of their capacity; otherwise they will need to be replaced.

Rupert Smedley  | 12.26PM, Sunday 4 November


Readers say:

Thanks for your advice. Will test the batteries and if there is a problem a dispute with the supplier is on the cards!

Paul Jones  | 4.36PM, Saturday 3 November

Thanks for the response. Will go through the various steps to check things out once I can find my hydrometer.

Paul Jones  | 3.41PM, Wednesday 7 November

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