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BobbyT if your 90 nissan takes a fully charged 1000cca to turn over in the morning something is very wrong with it,my cummins diesel 5.9 with 18-1 compression will turnover cold on a 750cca battery no problem. also all two or four strokes have only a very slight difference in compression, usually about 7 to 1 possibly a half a point difference on either side so there is no great difference in cranking power needed unless your running a highly modified piston and cylinder head combination in which case you would be correct then.

Whatever system works best for the individual , is what they should go with.
My system has served me well , for many years on 4 different boats . It has also enabled me to get long life out of my batteries. I have been able to enjoy luxuries in the cabin , such as running fans all night , inverters , crock pots , etc . AND knock on driftwood , I have never been stranded due to a dead battery .

No matter which system of use you decide ,
there are some cardinal rules to be followed , otherwise your new batteries will be scrap in a year .

1 // Never parrallel , different type or size batteries , for long periods of time . One will undercharge and the other will overcharge . To crank a motor , or to put a quick charge in a dead battery is okay , but not permanently .

2// Never let a battery discharge all the way down. 50% discharge in a perfect situation should be the limit.

3// A discharged battery should be recharged as soon as possible . A battery that sits up , discharged , will damage itself .


4// A battery reading less than 12vdc is dead . A battery reading over 12vdc is charged.
A perfect battery should read about 13 vdc 100% charged, but this isn't always true , so over 12 is good enough.

Just another opinion and you know what they say about those...

.....See one Thirty and you've seen them all???

Catigale wrote:

Just another opinion and you know what they say about those...

.....See one Thirty and you've seen them all???

I will have to remember that one.

Gypsy,

5. The batts can be connected for starting emergencies via some combiners and/or a manual switch of your choice. I’m going to re-use the 1 – 2 – Both – Off switch that came with the X to provide multiple failure recovery options.

If you plan on using the Yandina combiner, according to the selling points on the page - "Remote "ON" can be used for assisted engine starting" - which seems to address your concern. I have an older combiner and love it. I never have to do anything about the charging, it is all automatic. My combiner does not have a similar remote on function, but my solution to the "combine for starting" issue is to keep jumper cables aboard. I have never had to use them.

Jim, I have the Yandina combiner. It allows me to charge my twin group 30 deep cycle batteries and also the 24 group starter battery. This is great if you forget to turn selector switch to house batteries and once the engine turns off it's auto matic to keep the seperation in house and starter seperate.
Next time I need to get batteries I will have all 3 batteries the same deep cycle and let the Yandina keep the starter battery seperate so I don't discharge it. There will be many times I will use all 3 batteries on a 4-5 day cruise so I don't discharge 2 and keep the 3 running for 2-3 days before I go to just house batteries.(if voltage drops below 12.3 volts than the starter battery is disconnected from the House battery and selector switch goes to #2 house batteries)
This will allow me to dampin the discharge of House batteries.
Dave

Jim Bunnell wrote:Gypsy,

5. The batts can be connected for starting emergencies via some combiners and/or a manual switch of your choice. I’m going to re-use the 1 – 2 – Both – Off switch that came with the X to provide multiple failure recovery options.

If you plan on using the Yandina combiner, according to the selling points on the page - "Remote "ON" can be used for assisted engine starting" - which seems to address your concern. I have an older combiner and love it. I never have to do anything about the charging, it is all automatic. My combiner does not have a similar remote on function, but my solution to the "combine for starting" issue is to keep jumper cables aboard. I have never had to use them.

raycarlson wrote:BobbyT if your 90 nissan takes a fully charged 1000cca to turn over in the morning something is very wrong with it,my cummins diesel 5.9 with 18-1 compression will turnover cold on a 750cca battery no problem. also all two or four strokes have only a very slight difference in compression, usually about 7 to 1 possibly a half a point difference on either side so there is no great difference in cranking power needed unless your running a highly modified piston and cylinder head combination in which case you would be correct then.

well, i can only tell you that when i re-powered the cables were 20' long (from battery to outboard), and they were a very small diameter (IIRC No. 4 AWG or .35" wire thickness). the battery was 650CCA. it started my 50 Suzuki 4-stroke w/out problems.

when i re-powered to a 90 Tohatsu 2-stroke, it barely turned over and the cables were very, very hot.

so, it was decided that i go w/ a new West Marine 1000CCA battery. that helped the turn over, but the cables still remained hot.
finally, I changed out the cables to a 2/0AWG size (.57" wire thickness).
that fixed the problem.

however, on very cold mornings w/ a new and fully charged battery i notice that the initial turns to start are very slow. once started, the next turn over is quick, w/out delay.

two different tohatsu techs/mechanics said there's nothing unusual. very common with two-strokes vs 4-strokes. said it's a higher compression.

what can i say...the motor runs great and is bullet-proof.
i just notice that on cold mornings it lugs a bit during initial turn-over.

Bob T.
"DāBob"
'02X w/ '04 90-TLDI (14" x 11 pitch)
Dinghy Motor: '06 2.5-Suzuki

Well upgrading your cables helped,all thats left is to give all connections in your system a good cleaning and corrosion prevention coating, be sure to check the connections right on your starter motor,this is most often a neglected spot.just a little corrsion on any connection can almost double your amperage requirement . 20 feet is a long run for a starter motor even on a boat, the larger cable is the only remedy,other then shortening the run.but any small motorcylce or lawnmower battery will easily crank and start one of these small 2-3 cylinder o/b motors,if not then you should be checking your system to find where the problem is so you don't get stranded at a inconvienient time.Take a look sometime at the bat size in one of these japanese rice rocket motorcylces of about 1000 - 1200 cc's., they pump out over a hundered horsepower at a really high compression ratio on a battery not much bigger than a quart of oil.

raycarlson wrote:Well upgrading your cables helped,all thats left is to give all connections in your system a good cleaning and corrosion prevention coating, be sure to check the connections right on your starter motor,this is most often a neglected spot.just a little corrsion on any connection can almost double your amperage requirement . 20 feet is a long run for a starter motor even on a boat, the larger cable is the only remedy,other then shortening the run.but any small motorcylce or lawnmower battery will easily crank and start one of these small 2-3 cylinder o/b motors,if not then you should be checking your system to find where the problem is so you don't get stranded at a inconvienient time.Take a look sometime at the bat size in one of these japanese rice rocket motorcylces of about 1000 - 1200 cc's., they pump out over a hundered horsepower at a really high compression ratio on a battery not much bigger than a quart of oil.

20 feet is a long run for starter cables . I would suggest shortening the run and maybe running parrallel cables ( 2 positve cables , 2 negative cables )
Ray is right motorcycle engines twice the size of our outboards , start up on batteries a 1/4 our size.

Does anyone have any idea what the cranking amps would be of a 50hp 4 stroke outboard ?

I posted the number from my mercury manual in another thread...but im 3000 miles from the manual at the moment...

175 amps according to Jamesv in 2006 posting

Thats a lot of amps to pull from a deep cycle battery !
What about the socalled start/deepcycle marine batteries , used in fishing boats to both troll and crank ?
Anybody use these ?
To me , it has alwys sounded a bit like an oxymoron , since they are two different batteries , built completely different .

If you use AGM type deep cycle batteries, starting is no problem, due to the low internal resistance.

~Rich

Since no one has discussed this yet, I thought I'd mention that deep cycles have much thicker and fewer lead plates. This means less surface area and reduced instantaneous cranking amperage. However their thicker lead plates are more durable (less likely to flake and short) than standard cranking batteries. Most "deep cycle" batteries today are really hybrids between cranking and deep cycle; decent for cranking and duration. Based on this, I opted for BIG deep cycle batteries when I re-energized this year. Cranking my 70hp on one battery isn't a problem, but I wondering about cranking and running in the "both" position with my blue seas system switch (1-2-both-off). I plan to power the cabin overnight on battery 1 and switch to "both" in the morning to crank and run. Will the difference in charge level shorten either battery life?

Hey everybody! Points to consider…

When using a true deep cycle battery for starting purposes it’s recommended that you oversize it by around 20%. So going bigger was a good choice, csm.

Also csm, another difference is the plates in a deep cycle are made from solid lead, as opposed to sponge lead, which is porous and used in a starting battery.

If a so-called deep cycle battery has a “cranking amps” or “cold cranking amps” or “marine cranking amps” rating when you buy it, be suspicious that it is not a true deep cycle battery.

CCA is measured at zero Fahrenheit. CA is measured at zero Celsius, and I think MCA is too(?)

Therefore, if you are comparing two batteries and want an apples to apples comparison; if the number on a CA rated battery (a “marine” battery, which would likely be the rating that the outboard manufacturer would give) were equal to the number on a CCA rated (“car” or “starting”) battery, then it would stand to reason that the CCA rated battery will in reality have a higher current output for starting your outboard motor.

I’m just sayun…

- B.