Engine Start Protection

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sona

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I only have a single battery on my boat and would like to ensure the battery does not reach a level of discharge that it will not start the engine.
I have seen the "Prioritystart" automatic battery isolation unit that I think will solve the problem. Has anyone any experience of these or any other units.

Thanks in advance.
 
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about £86.80 incl.vat

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WOW !!

Go to local caravan shop and speak to them - I'm sure they can come up with something more kind to the wallet. It's not unusual to have caravans wired via a second socket to the car to feed fridges and so on - so relays are fitted to prevent drain of car battery when engine not running etc.
 
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Considering the cost of the device would fitting a second battery be better, for little more you can have much more security.

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In fact for less you could have second battery.
 
Exactly, even two batteries in parallel would be an improvement, meaning they could provide more discharge without voltage dropping so much. However most yachties have a separate house and starter battery, easy to charge with a voltage switch relay. A sudden onshore wind in an anchorage combined with a flat battery can put your boat ashore.
 
I am looking at all options, the general factors are:-
24ft Sun Odyssey with very little space to fit second battery.
Yanmar 1GM10 engine with 35A alternator and Sterling advanced alternator. 70AH single battery.
Power usage for tillerpilot,Garmin GPSMAP555,VHF and basic instruments. Day sailing singlehanded with the engine run for 30 to 60 minutes per day. Boat kept on swinging mooring.

I could possibly fit a sealed engine battery on its side. Should I be looking at second battery with VSR and additional charging capability since I do not think the engine will charge very quickly, or use jump start battery as backup. Recommendations appreciated with limited funds available.
 
Silly question perhaps, but can that engine be hand-started, or at least de-compressed to provide an easier swing?(low current draw)
If so, I suggest a bit of practice, and soon you won't be worried if the battery gets a bit low.
 
What about a compact battery that is easier to take on / off boat if battery locker space is limited ? You could then charge at home inbetween stints.
Or carry a starter pack - halfords etc. do them for 30 odd quid.

Trouble is your engine run time is not enough with or without booster system. Plus your alternator is not going to exceed its designed. In fact I suggest that upping alternator won't make much difference anyway as normally your battery will be reasonably charged at start, so alternator will not be punching in very much. End of day when you go to start battery of course has run gear and will be down.

IMHO - your lack of engine run time is going to be the harder nut to crack. VSR / Booster / whatever you fit will be having hard time keeping up with battery. Going bigger battery will be even worse ! You will get longer discharge time before voltage falls away - but you'll never make it up again.

I think it's one or combination of any of the following :

More compact but high A/Hr capacity battery - to be easier to take ashore for charging.

Emergency Starter pack battery as back-up - in case battery does go too low.

Solar panel to charge up battery while moored.

??
 
I have a starting handle and a jump start booster pack, but have not tried them yet, but will try the handle when the boat is launched and see how things go.
Thanks for all the helpful replys
 
I have always been a fan of decompressors. If the battery is low, one can spin the (decompressed) motor on the low volts then flip the lever to start. A Halfords pack would easily cope with that. As you say there is a starting handle, I assume a decompressor is fitted? Be a pig (impossible?)to hand start without.
A
 
Where can you get a Prioritystart thingy from? It would solve my worries. I was thinking of a 2nd battery but it's not cheap with all the VSR etc.
 
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Where can you get a Prioritystart thingy from? It would solve my worries. I was thinking of a 2nd battery but it's not cheap with all the VSR etc.

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Cheapest way - local breakers yard for battery, they will test before you buy. That's maybe a tenner.
1-both-2-off switch and some welder cable to fit.

That's two battery system and a lot less money than anything above. Once fitted and working - later worry about VSR's etc.
 
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Where can you get a Prioritystart thingy from? It would solve my worries. I was thinking of a 2nd battery but it's not cheap with all the VSR etc.

[/ QUOTE ]If a VSR is too dear, you can use a £6 headlamp relay from Maplin. It's second best, but will allow automatic separation of start and domestic batteries. I reckon you could get set up completely - starter battery, relay and switches for less than the cost of the Pstart. PM me with an email if you'd like s circuit diagram.
 
Fully understand your concerns re: batteries running low. I'd end up scowling every time crew switched on a light.

For what it's worth, my last boat had the yanmar 1GM and I could start it by hand quite easily (and with my pipecleaner arms that must mean its easy).

My current favourite toy is a cheap generator that lives in the locker. I can now bask in bright lights, heater running and music playing safe in the knowledge that I can recharge the batteries if necessary in the morning... never needed to yet though.

I really do recommend one of these just for the peace of mind they bring and actually allow me to enjoy all the more expensive gadgets with doing amp hour calculations in the back of my mind.
 
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I have seen the "Prioritystart" automatic battery isolation unit that I think will solve the problem.

[/ QUOTE ]OK, here's the scenario. You're sailing along quite happily when, without warning, your battery drops below 11.9v. The Prioritystart disconnects it. All of a sudden, you have no instruments, your Garmin plotter dies, the VHF won't work. Is that a sensible solution? Get another battery!
 
Yes, but that could happen with a 2nd battery anyway. At least the PS thing will stop the battery going so low it's knackered. I am short on space as well, this seems an easy to instal option.
Thanks sona for the link.
 
I am showing my ignorance now but would a 20Ah drain from a fully charged 120AH battery require the same time to recharge from the engine as a 20AH drain from the 70AH fully charged battery.
 
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