billyfish
Active member
I can charge mine straight off 12 volt or through a inverter but can't work out what's best
Torqeedo charging
- Thread starter billyfish
- Start date
gregcope
Well-known member
Define best? I would assume through inverter is faster, but not as efficient.
Never Grumble
Well-known member
I'm thinking of one of these new fangled electric outboards will they charge off solar?
Wandering Star
Well-known member
Me too, Torqueedo do sell a solar charging panel for a mere £550 or so, There must be a way to use a common garden £50 solar charger to do the same job surely?
Andrew_Trayfoot
Active member
A Victron pv regulator has a 12v load output on it
Boathook
Well-known member
My epropulsion does but it requires a 12 volt box of tricks to charge the battery.
billyfish
Active member
They both seem to pull about 4 amps. C a nt see how it would make any difference in the speed to full charge
William_H
Well-known member
It should be possible to charge the o/b through the 12v input connection with any solar panel. (without regulator unless it is a huge solar panel) assuming 4 amps max into 12v connection then any solar panel from 180 watts down will put a charge in. The smaller panel will self limit to 12v (or there abouts) as current is drained. ie it will poor current in from an 18v open circuit voltage until volts of the panel fall down to 12v and if it can't provide the 4 amps then panel volts will drop so limiting current. Obviously a small panel 10w will not put in much charge but would work well full charge over many days.
Ideally use a 40 v panel as used in domestic PV with an MPPT regulator to give 12v. But can you carry around a huge panel. ol'will
Ideally use a 40 v panel as used in domestic PV with an MPPT regulator to give 12v. But can you carry around a huge panel. ol'will
AngusMcDoon
Well-known member
With a 10W panel on a boat imperfectly aligned with occasional partial shadows & at UK's 50-60 degrees latitude you will only get 5W in sunshine. A Torqeedo battery may hold 1 kWh which will need 1.2 kWh of electricity to recharge. At 5W that will need 240 hours of sunshine. Even if the sun shines all day only for 8 hours is it sufficiently above the horizon to be useful. That's all day sunshine for a whole month. Given that in a UK summer the sun shines only a third of the time being cloudy the rest that's pretty much a whole summer to recharge it once.
Fully recharging a 1 kWh Torqeedo battery on a boat is only going to happen if you have a lot of solar & the sun shines all day, you are running your engine for 8 hours, or have shore power. Fully charging a 1kWh Torqeedo battery from lead acid domestic batteries will take two 80 Ah batteries from fully charged to 50% charged, effectively flat.
You need a big boat with space for lots of solar panels or frequent engine/shore power if you are using a Torqeedo regularly, or take the battery home with you to recharge after use.
Fully recharging a 1 kWh Torqeedo battery on a boat is only going to happen if you have a lot of solar & the sun shines all day, you are running your engine for 8 hours, or have shore power. Fully charging a 1kWh Torqeedo battery from lead acid domestic batteries will take two 80 Ah batteries from fully charged to 50% charged, effectively flat.
You need a big boat with space for lots of solar panels or frequent engine/shore power if you are using a Torqeedo regularly, or take the battery home with you to recharge after use.
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arcot
Member
200 Watt hr solar = 200/12= 16 Amps but say 50% efficient so 8 Amps x 10 hours = 80 Amp hr x12 volts = 960 Watts .....sufficient for topping up 1 Kw Torqeedo battery?
AngusMcDoon
Well-known member
Your units are all over the place.
You need a big solar installation to get the needed 1.2 kWh in a day on a boat in the UK over and above the energy needed for domestic uses and battery charging, even if the sun shines all day. If it's a grey day you have no hope.
Boathook
Well-known member
You might get 50% efficiency in the UK if you keep moving the panel to follow the sun but for the average fixed panel it is nearer 25% or possibly less.
Chiara’s slave
Well-known member
True. But who charges from empty to full? We have a dedicated 100w panel to connect to our E propulsion charger. It’s connected when the motor is not in use. We have not so far lacked the battery power to do whatever we’ve asked of it.
ylop
Well-known member
Regularity is irrelevant. Even frequency is not the whole picture. It depends how much you drain it. If you normally use it only to go ashore and return one each time you anchor or to get too or from your mooring and then it has an opportunity to recharge if won’t have anything like an empty battery to fill.
If I’ve understood the claims of those who use them - a return trip ashore, for the sort of distance people typically go from an anchorage might be 10% of the battery pessimistically. Home Mooring are often further but not a return trip so let’s assume the same number. Following your logic a 10W panel would need 24h of sun to recharge 90-100%. I didn’t quite understand why it would take 8 hrs on engine - but by proxy that would be 48 minutes. Given most people will run the engine to check all is ok before leaving a mooring/anchorage and often whilst slipping lines and getting sails up and then when setting anchor you probably aren’t far off that even on a good sailing day? Certainly it seems that between the minimum engine use already likely and a small solar panel you should be able to keep up with typical light use of the smaller e-outboards. A larger panel (100W is quite common now) would cope on its own. Realistic actual cruising use of the engine would probably cope on its own too. If that was your daily use many people would be returning home or to shore power at least once every few weeks so even if you only managed to put back half what you drew each day you would never get to zero.
Clearly if you are making multiple trips because you have a small dinghy and large crew, dogs requiring walked ashore regularly, you live aboard etc then you probably need to think more carefully about charging. But most people won’t go 100-0 in one day so only need charging capacity that replaces what is used at the rate it’s used. For weekend warriors with a two week holiday in the summer its probably fine.
AngusMcDoon
Well-known member
It's because if using the 12V charger the cigarette lighter type plug can only pass 10 Amps. At 12 Volts that's 120 Watts. To put in a 1 kWh takes 8 to 10 hours. The push in connector will still get hot and likely eventually melt its housing as is their wont at that sort of current.
For the people whose usage pattern is as you describe, then great, crack on. Free yourself from petrol on board forever. However, there is a widespread lack of understanding of electricity, power, consumption and their units in this forum. My post on full recharge of a Torqeedo battery was just to point out the impracticability of using a 10 Watt solar panel to charge a 1 kWh battery. Even if only 10% of the charge has been used that will still be about 3 days of full sunshine with that panel in practice.
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AngusMcDoon
Well-known member
Spot on. A rare realist!
ylop
Well-known member
Ah OK - I hadn't reaslised they were using stupid cigarette lighter sockets. Its amazing that nobody had developed a better standard - ideally waterproof! So billyfish's original question - whilst there are losses of going via the inverter he might actually get a better experience - not overheating the socket, not wiggling loose etc.
Your assumption is probably reasonable for completely charging via "the engine". But to put, say, 10% back in - that could come from the boat batteries over a 3/4hr ish period and then be recharged by the engine in 20 minutes - depending on your alternator?
Fair enough thats not unique to this forum and sadly even infects manufacturers or panels etc!
Ah yeah I'm completely with you. A 10W solar panel is about the size of a piece of A4 paper though so not huge. 50W is probably the size of most "small" boat installations without an arch etc?
Supertramp
Well-known member
Your are right and I charge my Torqeedo like you say - it takes a long time but it will fully recharge on an 8+ hour motor. Or a top up takes an hour or two direct off batteries. My solar panel is 130W and over the past weeks in Scotland (without aligning to the sun) has given between 160 Wh and 480 Wh per day. That keeps the domestic battery more or less full without the engine but has no surplus except on a sunny day.
I have two batteries so I can choose to wait until I'm motoring to recharge and use surplus alternator output.
Electrical systems need some way to buffer between when you want to use and when you can generate unless you fit enormous generating capacity - for me its either got to be boat batteries or a spare Torqeedo battery.
migs
Active member
Chiara’s slave
Well-known member
Personally I wouldn’t bother trying if I had only 10w. A hiding to nothing. But on a bright day we can be doing 50-75w, which is starting to get useful. Under way, or lounging about at anchor, or wherever. We just plug it in whenever it’s on the mothership.
