Charging additional battery/batteries

My vehicle is a 110 hard top Defender 2008 if this is of any relevance.

I am ordering an Electric Outboard motor, either 12 or 24 volt (not ordered yet) so will need to purchase 1 or 2 12v batteries and will need to charge them on an almost daily basis through the summer. The battery/ies will need to carries to and from my dinghy and charged in the vehicle while driving to and from home (25 miles round trip) OR charged at home but this will mean faffing about removing the batteries from the vehicle etc. I am hoping to be able charge my battery/ies while driving home and hope someone might be able to suggest a solution. Thanks Mike

After some deep cycle work in an elec outboard I doubt very much your alt will charge them back up fully in such a short trip.

Going to be a lot less faffing about at home than it is at the boat.

I guess you need to have a search of the site for "split charging" system.

Plenty of info about it I think, but I've not got there yet with my own project.

Get yourself over to the ybw forums and have a search. http://www.ybw.com/forums/forumdisplay.php?13-Practical-Boat-Owner-s-Reader-to-Reader

Thanks, I realise I did not include the most important information in my original post.

I have decided I will buy a 12v outboard. Lynall is probably correct, it would be unreasonable to expect my vehicle alternator to replenish my outboard motor battery in a short journey.

The outboard power consumption is 60 amp. I will never use the outboard for more than an hour, sometimes much less. Therefore we can safely assume I will diminish the battery by max 720 watts. We now have to decide how to replenish 720 watts.

Would I be correct in thinking a 72 watt solar panel (working at 72 watts) would take 10 hours to replace this lost power?. (allowing a bit more for loss of efficiency)

Has anyone fitted a Solar Panel to your Defender roof?

Look forward to replies.

Mike

Solar panel wouldn't be reliable enough IMO, all you need is a cloud to drop the output loads.

Why battery outboard? Why not a little petrol one?

Worth some research on solar panels as none are as good as they say they are.
I have solar hot water and the variations day to day are unreal, nice day poor result, cold as buggery but bright and 40 degc water. obviously when the weathers warmer its much more consistent.

If it has to be a battery powered outboard, then two batteries are the best answer IMHO.

So if you want to use standard lead acid batteries and you your going to consume 60 amps out of the battery in an hour.

So you'll need at least 120 amp hour battery so they don't drop below the 50% discharge limit.

You need to put back into the battery a third more than what you took out of it to get back to the same level so you took 60 amps out for an hour need to put back 90 amps back in for an hour.

I've got 2 x 80 watt solar panels on the shack and I've never seen them provide more than 6 amps and that was direct sunlight.

I can't think of anything apart from a 20 amp mains charger that could do the job.

Perhaps running 2 batteries would give you the capaciy to go for a home recharge every couple of days - or more if you're not running at full speed? Even so, this deep drain/charge cycle will limit the lifespan of many batteries.

I have an electric outboard for my lake boat but i use it in conjunction with an outboard. I get to where i want to be with the petrol outboard then use the electric one for quieter movements around the areas i want to fish. One deep cycle battery does me and then stick it on the trickle charger until the next time i need it. I dont think its any hassle at all.

mike56 said:

My vehicle is a 110 hard top Defender 2008 if this is of any relevance.

I am ordering an Electric Outboard motor, either 12 or 24 volt (not ordered yet) so will need to purchase 1 or 2 12v batteries and will need to charge them on an almost daily basis through the summer. The battery/ies will need to carries to and from my dinghy and charged in the vehicle while driving to and from home (25 miles round trip) OR charged at home but this will mean faffing about removing the batteries from the vehicle etc. I am hoping to be able charge my battery/ies while driving home and hope someone might be able to suggest a solution. Thanks Mike

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just charge them at home. They'll need charging overnight, a 25 mile trip won't provide enough time to get them recharged.

My dads' golf trolley runs around on a 12v battery. He has two...one on charge at home in the garage, one in the trolley. Even at 81 he manages to keep his trolley working when he needs it......