Should I add a second Battery?

[RichH]

Hi

I have recently had problems with the battery being flat when I go to start the boat, apparently the boat is fitted with a Mercathode system which constantly runs down the battery. So I am wondering whether to fit an additional battery. If I did fit an additional one what should I run off each and what should go through the battery switch.

Any help or advice much appreciated

Richard

[ColinR]

I would say go with a second battery and put the starter circuit on one and everything else on the second. Start on one then switch to both when running. Switch to two only when at anchor etc.

[RichH]

Thanks, very helpful. I will look into where I can put another battery I think.

[BruceK]

Solar panel is another option and these days a good one will cost about the same as a second battery and good split charger. If you go the split charger route have a read on the different types re benefits / cons etc.

[mlines]

Rich

I have just remembered that you are a Regal 2250 owner as well.

Thanks to Mark, the previous owner of our boat, we have a full twin battery set-up. This consists of twin batteries, changeover-switch and VSR (Voltage Switching Relay).

The twin batteries are fitted inside the single battery compartment, side by side. The switch/VSR fits in the existing power panel (2007 model 2250). The VSR keeps the engine battery charged first and then switches to charge the house battery once the engine one is charged, all automatically with no manual intervention. The switch is used to force the two batteries to connect together for an emergency start.

He moved all the wiring around so that one battery is engine only and the second battery is every other electrical system. This means we can run the sound systems and underwater lighting and guarantee to start the engine afterwards.

I will sort out some pictures for you.

On the Mercathode, these should be quite economic on the battery unless it is having lots of work to do. Are your anodes ok? I know where you berth on the Avon at Christchurch the water is probably quite brackish rather than salt as the river will have a lot of influence on the water. Perhaps you have salt water anodes on and they are not working well? Googling suggests the Mercathode draws roughly 15mA when idling and up to 100mA when working hard. At 15mA it will last a long time on a boat battery although at 100mA it will start to have an impact.

[mlines]

[Little Gem]

I also recommend a solar panel. We recently installed a 50W panel on the cabin roof. The voltage controller will trickle charge a main battery until a maximum of 90% capacity is reached - and then switch to a second load, which can be another battery. The controller then alternates charging between the two. I agree that the newer battery should be kept purely for engine starting. I suppose the best option is a large leisure battery for all the boat systems - and a new car type battery for starting. Important not to connect the two batteries together.

[mlines]

solar panel on the roof of a new Regal 2250 :O

Sent from my Nexus 6P using Tapatalk

[Ianfs]

I've read this post with interest and don't have much more to offer the great advice already offered apart from trying to make sense of why your battery has started to go flat.

I would guess it's close to a 120 amp hour starting or leisure battery. Therefore at 100ma or .10 amp drain from the Mercathode the math calcs to 50 days until fully discharged. Having said that, if the battery is brand new a starting battery with lots of cca (cold cranking amps) might discharge naturally if not used nearly everyday but also may get close to its discharged point earlier. An older battery might just be knackered and the small draw from the mercathode finishes it off.

On anything above a day boat I like the idea of a ancillary battery and leave the starting battery alone. Love the idea of solar for top up too.

I'm now only a few minutes from your boat, I'm not an expert but I'll have a look and help with putting a meter on the battery under load.

[RichH]

Thanks for all the advice and suggestions, I think I will look at a second Battery as I will feel happier knowing it should always start.

Thanks for the photos Martin although my Battery looks bigger than your two, I will also check what anodes are fitted as it is definitely not salt water there.

Unfortunately I think it maybe the fact the boat is not used as often as I would like (which would be every day) but it was not as long as 50days since fully charged so I will keep an eye on it.

Not sure I want to fit a solar panel permanently but I suppose I could look at fitting one just when not in use.

Thanks again

Richard