Tinned is a good choice... but usually not "cheap".
Tinned is a good choice... but usually not "cheap".
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
Tinned 4awg is $1.72/ft with free delivery, $20.64 for 6' each red/black. Get my marine grade heat shrink same place.
_______
Phil
'09 Hewescraft ProV
'09 150 Optimax
And, what did you see Mr. Savage?Originally Posted by Savage
The OP's question was never really answered and I have the same question.
How many amps can the Merc 250 Pro XS starter pull when starting? Like the OP, I am not looking to discuss lead acid battery load rating requirements. 12V lead acid battery "ratings", while consistent, are all misleading (i.e. rated AH's are never accurate in real-world applications, CCA rating test allows for draining battery to 7.2V, etc)
Someone out there has to have this information... Savage if you tested this, would you share the results? Not sure why you would reply with a "yes" and not add anything more.
Because it was years ago and I don't recall the EXACT reading, but confirmed that Yes I have tested it, which answered the OP's question. The OP asked....."has anyone actually hooked up a clamp on amp meter at the starter wire coming from the battery, and saw how many amps the starter ACTUALLY pulls during engine start?"
The OP asked if anyone connected a meter and saw how many amps. He did not ask for what the reading was.
Amp load will be less on muffs than water. I did the test on a 250 efi a few years ago and think it was less than 200 amps but not positive. The CCA requirement never made a lot of sense to me when you consider a 455ci car engine will start with less and I guarantee it pulls more amps. But, the experts and Merc have their reasons so good enough for me. Also I use #4 welding cable as I believe it is superb
Last edited by rvaha; 07-13-2020 at 08:01 PM.
Thank you for the helpful comment rvaha. I did some digging on the net, and found similar information around "actual" amp draw. It seems it's under 200A @ 12V (likely closer to 150A-180A). Anything over 200A draw could indicate a bad starter.
I believe the reason Merc wants a 1000CCA rated lead acid battery is to help ensure there's no voltage drop when starting with other accessories running (graphs, pumps, etc). It will never pull anywhere close to 1000 amps, but it needs to be able to pull 200 amps without much voltage drop. A voltage drop can mess with the outboard's electronics and injectors. The only way to ensure this doesn't happen is by requiring a 1000CCA+ lead acid battery.
To me, this also means that a Lithium battery rated for 300+ continuous amps should be more than sufficient as there's little to no voltage drop, but Merc "doesn't go there" with battery requirements (yet).
Color coded responses:
About right but many variables effect this, to understand this you must also understand Counter-electromotive force
Could be a starter, excessive cranking resistance, lower unit, scuffed pistons, improper starter mounting even the lubricant's used in the motor and gearcase, inadequate battery as well as several other things
Good luck on finding one that can do that, most 125 AH lithium's are only rated for 150 continuous and 5 seconds at 250 amps
Due to the many variables it is not likely for a manufacture to print a starter current specification, I have not seen that done in many years
Last edited by lpugh; 07-14-2020 at 09:25 PM.
Thank You Leon Pugh
bassburch,
Mercury clearly publishes the starter motor amp draw in the service manual for my 150 Fourstroke.
In my case, it states:
No load amp draw 50-70 A
Normal amp draw 150-225A
I would surmise the same information for your engine is also published by Mercury.[/QUOTE]
Maybe since it is 16 years old, my newer mercury manuals have no specs for current draw and no automotive manufacture offers that spec any longer.
A spec that wide is of very little use due to the variables mentioned above, voltage drops are far more useful for diagnostic work
Last edited by EuropeanAM; 07-15-2020 at 11:07 AM.
Thank You Leon Pugh
(I would surmise the same information for your engine is also published by Mercury)
Thank You Leon Pugh
Careful... Verado engine models hit the market about this time 16 years ago.
Most recent engines have a listed "no load" and "loaded" Amperage Draw for the starter. Look in Section 1A of the Service Manual, under Starting System. In the case of this 3L it's 170 amps loaded (the spec shown). However- specifications such as this are taken in a controlled environment at 76 degrees F.
JMHO... this is just general information, though it is slightly more informative than a listing of "paint color= Phantom Black".
A cold engine or a hot engine may require considerably more current... and I would absolutely not replace a starter SOLELY because it pulled 200 amps. I've seen higher than that on a pretty regular basis in cold weather (50 degrees F or lower).
The importance of the CCA rating is due to the large number of "engine running critical" electronics that must remain LIVE and functioning WHILE the starter is spinning the engine (as well as the all-important relay contacts in the MPR or Main Power Relay which simply can't remain closed consistently below 9.5 VDC).
Interesting topic... but it's one that must be tested on a engine-by-engine basis for most purposes.
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
Good deal -- thank you all for the additional info :)
I'll confess -- the reason I am inquiring is because I am building my own LifePO4 starting battery with high power BMS and high-discharge cells. It's not going to be cheap, but it should be a reliable and long-term solution capable of 400 amps continuous draw (1200 amps instant) with no voltage drop at any fishable temp. I'm building it for myself and no one else.
The alternative is a 250A BMS with 600A peak, but I am concerned I may run up against total power requirements in poor conditions.
I predict that at some point, outboard manufacturers will start providing SLA and Lithium ratings separately. Many people have had problems with Lithium starting batteries due to too much amp draw or too much alternator charging current cutting off the BMS/power and I can't have that. So I am leaning toward the 1200A peak 400A continuous BMS.
I'll keep y'all posted if this works out :)
You are correct it is published, was not where I expected to find it
Thank You Leon Pugh
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