12v charger use with motorhome leisure batteries - Newbie query 3

We will also have a 12v charger with our bikes so I can charge batteries off our 12v 2 x 110Ah leisure batteries (latter are kept charged by 80w solar panel)

 

Anybody done this? How much Ah will a single full charge take out of the leisure batteries, ignoring any contribution by the solar panel? I believe 2-4hrs will bring bike battery to 80% full and 4-6hrs will bring battery to 100%

 

Bike batteries are 16Ah 36v

 

Arthur

There are two issues, amount of charge and rate of charge.

 

Really the amount of energy is small, but needed at a greater rate than your solar will provide - but you have loads of capacity waiting to be drained in those leisure batteries.

 

Check the current (amps) required by your charger - it should be equivalent to a couple of 60w table lamps (someone will correct me...)

 

You will use more than the 16AH in charging fully, because of inefficiencies. But charging for just half your requirement will make better use of your solar. Charging takes longer and longer the more you attempt to fill a lithium battery, so go for 80% rather than 100% (you will have to use time to judge this).

 

You're going to have a great time using up those charges... Congratulations!

My rough calculation says that you'll use about 80 aH at 12v to charge one battery. Don't forget that you shouldn't take your 12v batteries past half way. Your 80w panel will take about 3 days to replenish your 12v batteries. Much better to get a small portable generator, but then you get the noise.