Log in
Article search:

Q & A


Hi I have my boat on a marina but due to ill health we cant get to the boat at the moment I'm worried about the battieres they are being charged by solar panels are they safe to leave for long periods I have heard about there can be a build up of gases is this ture many thanks

Asked by: Sheila  | 6.59pm, Friday 19 July

WW says:

All batteries produce gas- hydrogen- when charging. In open cell batteries (the type you can check the level of electrolyte in the cell and top up with distilled water if required) the hydrogen vents off.
In sealed batteries, the gas can vent off, but only with high voltages or current, generally. In gel or AGM batteries, the hydrogen should be reabsorbed into the electrolyte.
If the solar panel is fitted with a regulator, then gassing should be minimised, as the voltage, once the battery bank if full, should reduce the current applied to the battery. A general rule of thumb also suggests that, if a solar panel is connect that is equivalent of 10W per 100Ah of battery capacity, then they can usually be safely left connected, even without a regulator.
If hydrogen is produced, being lighter than air, it will vent off from the battery and dissipate into the atmosphere. Only if you have a very large solar panel bank and a cheap regulator, may there be excessive hydrogen build up. At the very worst, you might have to top up the electrolyte in the batteries next time you visit the boat.
It must be said that maintaining the batteries with solar panels is far better than leaving them to self-discharge. Any damage done to the battery, if at all, would generally be far less than letting the batteries stand without charging.

Mark Langley  | 11.27PM, Friday 19 July

You must log in to post an answer.