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Basic boat 12v electrics

Basic boat 12v electrics

I see so many people with battery issues thought I would do a basic post.

Battery state is a bit of witchcraft, you can get an idea of charge by using a volt meter after leaving the battery’s for more than 3 hours with out use.

State of Charge (v)
100% 12.7
90% 12.5
80% 12.42
70% 12.32
60% 12.20
50% 12.06
40% 11.9
30% 11.75
20% 11.58
10% 11.31
0 10.5

While the battery’s are on charge or after use you will not get a valid idea.

Try not to take your battery’s lower than 12.00v If your battery’s are low recharge them as soon as possible, the longer you leave them flat the more long term life you lose.

Solar panels will help for long term battery health, give the battery’s a rest for a day to come to full charge every few weeks to care for them.

How to use a volt meter

Every boater needs a volt meter to hand. You don’t need an expensive one though spending a bit more will likely get you more robustness. http://www.ebay.co.uk/bhp/digital-voltmeter

Read the instructions of your volt meter.

To use turn the dial to 20v DC then put the red probe (pin/stick) onto the plus and the black probe onto the negative terminals of the battery. You can scrape the terminals if they are dirty to get a good connection. This should give you a volt reading in the range of 10-15v see my last post for what this tells you.

*** Be careful of placing any metal objects that could connect the + and – on the battery or wires as this could course a fire and will spark alarmingly ***

To get to know your battery’s you should do this often at different times of day for a while, if you care for your battery’s they will care for you.

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