Electric outboard motor batteries

franticfisherman

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For those of you who use electric outboards I'll bet you are as sick as me humping the huge and heavy leisure batteries around. If you are lucky they might last a day, if not you are rowing back to the jetty!

When I get home and put an almost new 70Ah flattened battery on charge, I find it draws a 2-3 amp charging current and is fully charged after only 12 hours charging! That means I have only used about 30Ah during my days fishing so where is the rest of that quoted capacity?

I thought a car jump-starter battery would be handy as a 'get you home' device. It is small and light, and has capacities of 6Ah all the way up to over 80Ah (if you believe the claims from our Chinese friends selling on eBay.)

Then I thought why not put several of these powers packs in parallel, 5 of the 20Ah units would give enough capacity to last all day, It would only weigh about 3 Kg and cost about the same as a large capacity leisure battery! It would probably have a longer life as well. Has anyone tried it? I'm sure it would work if packaged properly and care was taken with charging.

It is an attractive proposition if you compare the price with a good sized Lithium Ion battery of the sort used in racing cars or the price of a spare battery for the 'Torqueedo' electric outboard.

Any comments anyone???:confused:
 

fredaevans

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For your intended use get a battery(s) designed for marine use. Internals are quite different as they are designed to a draw down to close to 'zero' and take a proper re-charge.

Auto bat's are not!
fae
 

Cap'n Fishy

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For your intended use get a battery(s) designed for marine use. Internals are quite different as they are designed to a draw down to close to 'zero' and take a proper re-charge.

Auto bat's are not!
fae

Fred - the OP is talking about leisure batteries, not auto batteries.

Col
 

Cap'n Fishy

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For those of you who use electric outboards...

I find there is a huge difference in battery brands. I can get a whole day's hard use out of a Halfords 70 AH, where I would have killed a cheap 110 AH battery such as a "UK Giant" with the same amount of use. I've never flattened a Halfords 110/115 AH in the course of a day, even on a good-sized water like Gladhouse (440 acres) in a stiff breeze, and they last a good 5 or 6 seasons. (I only get about 2 seasons out a Halfords 70 AH though.)

The downside is that the difference is shown when you pick them up - A Halfords 110/115 AH weighs about twice the UK Giant!

You are right though - we need something lighter. I hope lithium ion is the way forward and that prices will come down. Scobo on here has put himself together a cracking set-up using a set of lithium ion packs designed for drones and such like. All the details are in this thread on the same kind of subject.

Don't think anyone here has mentioned the starter pack idea, though I have noticed them and wondered about it.

Col
 

fredaevans

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Fred - the OP is talking about leisure batteries, not auto batteries.

Col

Hear you Col; here they're called 'Marine Batteries.' Another example of a 'Common People seperated by the same language,' or sum such.

fae

Got that Col; Marine vs. Auto Batt's are a very different design/build. Marine are designed to go through heavy draw downs (to almost zero) and that would distroy a auto battery.

fae
 

Cap'n Fishy

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Hear you Col; here they're called 'Marine Batteries.' Another example of a 'Common People seperated by the same language,' or sum such.

Indeed. Here, they are also used in caravans, so not restricted to marine use - hence the term 'leisure'. Same deep-cycle batteries though. :)

Col
 

franticfisherman

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Thanks all, especially the link from Cap'n Fishy, Lipos are interesting but are prone to damage from over-discharging (hence the voltmeter and alarm system.) They also need a balancing system. I think the jump packs are a possibility, the only problem is the price. I just came across a review of them in Auto Express magazine and the quality ones are all over £100! (Draper, Sealy, Energiser etc.) They don't quote the capacity either. I am wary of cheap Chinese copies and their outrageous capacity claims but there's only one way to find out....

Watch this space and I might report success...:thumbs:... or failure...:eek:

Cheers

frantic
 

franticfisherman

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Further to this, has anyone built a battery with the Li-ion 18650 cells? They have a capacity of around 3Ah. A group of 3 in series = 11.1 volts, 10 groups in parallel = a 30 Ah battery, simple! At a quid each only £30 plus 10 holders at about £1.50 each = £45. Weight would be about 5 lb. The only tricky bit I can see is charging them - how could you do it without dismantling the whole thing? Could you use a balance board with 10 inputs? Is there such a thing?
I am thinking out loud here because I weighed my Halfords 70Ah leisure battery yesterday and it weighs 39lb (18kg) !!!:eek: No wonder I am getting aches and pains :mad:
Cheers
frantic
 

stylie

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Chinese specials ?
I have bought at least 50 18650s over the last few yrs for torches and little projects etc. Different type but all offering 3Ah 5Ah etc..

They are not the Ah they say they are. Fine for torches, but I had 6 powering a 12 volt apprx 5amp bilge pump at the end of some piping. It was a portable unit to empty water from boats, and it worked a charm pumping the water up 3 feet through the center of the pipe and out, for 2-3 mins.
When you have those batteries they are light as feathers. Not exactly a sign of high capacity.

Find out where golfers get their caddy cars serviced. Those batteries are 18Ah at a minimum. What happens is they lose power and cant do the full 18 or 36 depending on the battery type. Golfers will buy a new battery and leave the old one at the shop. The shops cant get rid of them, I picked up a dozen a few yrs ago from a local golf course and most are running fine, nearly getting a full season out of the 18Ah one in my boat powering a bilge pump. And a friend of mine put two into a little kids car thing, powering it away fine. So might be worth checking out.
 

franticfisherman

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Thanks for the info Stylie, after a lot of consideration, I have cecided to go the lipo route. I did buy a jump starter pack which was supposed to have 20Ah capacity but when I tested it, it only had 4Ah 😡
I will be sending it back today!
Had some good help off Scobo after looking at his set up pictures 👍
Will report back when I've built my 'Powerbox'
Cheers
frantic
 

scobo

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Further to this, has anyone built a battery with the Li-ion 18650 cells? They have a capacity of around 3Ah. A group of 3 in series = 11.1 volts, 10 groups in parallel = a 30 Ah battery, simple! At a quid each only £30 plus 10 holders at about £1.50 each = £45. Weight would be about 5 lb. The only tricky bit I can see is charging them - how could you do it without dismantling the whole thing? Could you use a balance board with 10 inputs? Is there such a thing?
I am thinking out loud here because I weighed my Halfords 70Ah leisure battery yesterday and it weighs 39lb (18kg) !!!:eek: No wonder I am getting aches and pains :mad:
Cheers
frantic
I looked at 18650 cells before going the Lipo route.
The trouble with the cheap ones is they have low amp rating and wouldn't cope with the power required for most outboards.
You can get them rated 20 amps but they're about £10 each and given you'd need about 30 of them as you say, it works out pretty expensive as well as a lot of work to wire them up.

Sent from my GT-I9505 using Tapatalk
 

beyond the blue

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I got a lot of advise of Scobo earlier in the year about a Lipo set up but after costing it up between £350-£400 (admitidly using top quality gear) I went for a Halfords 115ah. My knees are now totally knackered.
 

scobo

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I got a lot of advise of Scobo earlier in the year about a Lipo set up but after costing it up between £350-£400 (admitidly using top quality gear) I went for a Halfords 115ah. My knees are now totally knackered.

There are some crazy prices out there but you can definitely do it for a lot less than that.
I probably spent somewhere between £100 to £120 by the time I was finished.
The cheaper brand batteries are fine as long as you use a good charger and charge them properly.
 
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Cap'n Fishy

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My knees are now totally knackered.

It's my back I have to be careful with. :p Some guys I know have two 70 AH Halfords batteries to avoid health issues. I have a 70 AH Halfords as well, for using on dual, petrol plus leccy days, and have twice this year spent all day on the leccy without flattening the 70.

Col
 

Cap'n Fishy

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Aye, me too. That's what got me looking into lithium batteries.

I tweaked mine, bending forward to open my knicker drawer, the day before going off to Uist for the week - where we have to humph petrol outboards, leccies, batteries, boat seats, petrol tanks, and all the gear back and forth to the boats every day. :eek:mg: Then I tweaked it another twice up there - both times just bending forwards after getting out of bed. :( At the time I thought I was getting away with it not too bad, but I paid for it all after getting back home.

Col
 

beyond the blue

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Went to Cuba a few years ago for an holiday, on the second day I sneezed and did my back in, finished up curled on the bed for the next week. Only managed to get out of the hotel for 4 days and that was because I had to pay for expensive injections every other day.:mad:
 

franticfisherman

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I'll be a lot more than £120 by the time I'm finished :( Could've bought a bloody good fishing rod I reckon!

BUT... I'm trying to save weight not money, afterall, I don't want to end up like some of you guys!:whistle:

If anyone is still suffering - get well soon:)

frantic
 

scobo

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Just think how much faster your boat will be too with less weight.
Your bound to catch more fish. :D
 
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