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These are small gasoline engines similar to car, motorcycle, snomobile engines, so expect operating temperature to be about 180F or so which is typical range. Note the pilot water outlets on the side of the boat are not engine cooling lines, they are from the exhaust, rectifier and if equipped the intercooler so they're not hot, they're just warm. The thermostat bypass outlets are under the swim platform at the transom and they get very hot at 160F+ and need to dump into cold water immediately to prevent burns.
Don't know for sure but since it's a wide range due to conditions, probably in the typical range of 20-80psi depending on temp of oil and RPM. Hotter oil is less viscous and pressure is lower than cold oil. As the engine revs up pressure is ramped up to keep components bathed in oil.
Based on the rectifier it seems to be about 28amps at 3500+ RPM on the 1.8L engines, about 14amps when idling and ramps up to 28 as the RPM increases.
Perhaps on a single engine with only 16amps at idle it would be slow but should charge. With my twins after floating for a while, I can fire up the engines and while just idling along I can see the batteries are charging and increasing voltage. If my house is down to 75%, a 30min ride cruising back to the ramp charges it back up to 100% give or take based on visual feedback from the Connext screen. Of course twins means 28amps idle and 56amps above 3500 RPM. This is max of course and some is used for the electrical and pumps to run the fuel/ignition systems.
Even with that much juice, I put the batteries on charge when I'm done for the weekend to make sure they get topped up properly and stay that way during the week. If I had a short run back to the ramp I'd make sure they get topped up with the charger nightly as this will extend battery life.
@212s ....very interesting! With the oem Interstate HD Series 24 flooded if we used the stereo at a beach then left for out slip I could see the battery slowly charging (almost nothing until I was at 4000+RPM) and it would nor be fully charged by the time (about 15 minutes) it took to get back. On a 30 minute trip it could get closer to full charge but still not fully charged. I could see that its failure to accept charge fast enough was going to result in its eventual sulfation and failure so I went with a TPPL which accepts (on average) charging 400% faster than oem flooded cells and (so far) the problem has been solved - the battery charges right up. I have no experience with a twin stator set-up but your hypothesis that it changes the charging game makes sense. This is new to me as with my past I/O experience there was always lots of charging power available from alternators for starter and house batteries even on single engines. My Twins with 65/75 amp alternators could easily charge a bank of six Series 31 AGMs or TPPLs.
@212s ....very interesting! With the oem Interstate HD Series 24 flooded if we used the stereo at a beach then left for out slip I could see the battery slowly charging (almost nothing until I was at 4000+RPM) and it would nor be fully charged by the time (about 15 minutes) it took to get back. On a 30 minute trip it could get closer to full charge but still not fully charged. I could see that its failure to accept charge fast enough was going to result in its eventual sulfation and failure so I went with a TPPL which accepts (on average) charging 400% faster than oem flooded cells and (so far) the problem has been solved - the battery charges right up. I have no experience with a twin stator set-up but your hypothesis that it changes the charging game makes sense. This is new to me as with my past I/O experience there was always lots of charging power available from alternators for starter and house batteries even on single engines. My Twins with 65/75 amp alternators could easily charge a bank of six Series 31 AGMs or TPPLs.
Based on the rectifier it seems to be about 28amps at 3500+ RPM on the 1.8L engines, about 14amps when idling and ramps up to 28 as the RPM increases.
Perhaps on a single engine with only 16amps at idle it would be slow but should charge. With my twins after floating for a while, I can fire up the engines and while just idling along I can see the batteries are charging and increasing voltage. If my house is down to 75%, a 30min ride cruising back to the ramp charges it back up to 100% give or take based on visual feedback from the Connext screen. Of course twins means 28amps idle and 56amps above 3500 RPM. This is max of course and some is used for the electrical and pumps to run the fuel/ignition systems.
Even with that much juice, I put the batteries on charge when I'm done for the weekend to make sure they get topped up properly and stay that way during the week. If I had a short run back to the ramp I'd make sure they get topped up with the charger nightly as this will extend battery life.
Based on the rectifier it seems to be about 28amps at 3500+ RPM on the 1.8L engines, about 14amps when idling and ramps up to 28 as the RPM increases.
Perhaps on a single engine with only 16amps at idle it would be slow but should charge. With my twins after floating for a while, I can fire up the engines and while just idling along I can see the batteries are charging and increasing voltage. If my house is down to 75%, a 30min ride cruising back to the ramp charges it back up to 100% give or take based on visual feedback from the Connext screen. Of course twins means 28amps idle and 56amps above 3500 RPM. This is max of course and some is used for the electrical and pumps to run the fuel/ignition systems.
Even with that much juice, I put the batteries on charge when I'm done for the weekend to make sure they get topped up properly and stay that way during the week. If I had a short run back to the ramp I'd make sure they get topped up with the charger nightly as this will extend battery life.
Can't thank you guys enough for the info 14 to 28 amps per engine really puts my mind at ease. I just installed a Battery Tinder 12v 1.25amp charger/Maintainer on board and plugged her in one the approx 2 week old AGM she charged for around 1:40 min the gave the green light charged and cycled into auto float mode so all the trips in the last 2 weeks the charge system has kept the new batt up nicely.
Thanks Again to all for helping my learning curve.
I am with canuck, tppl is the way to go. Have a pair of gp27 northstar pros myself. Thats all they use at the boat mfg i do work for. Usually banks of 6-8 gp31’s. Every boat that comes off the line. With all the electronics in our boats anymore, having good stady voltage is important. Things can get a little wonky if the batteries arent in too shape
@212s ....very interesting! With the oem Interstate HD Series 24 flooded if we used the stereo at a beach then left for out slip I could see the battery slowly charging (almost nothing until I was at 4000+RPM) and it would nor be fully charged by the time (about 15 minutes) it took to get back. On a 30 minute trip it could get closer to full charge but still not fully charged.
That sounds about right...the charging system is not as strong, but you have to remember these are little 1.8L engines, not 350mag engines, so the torque/power loss to run an alternator can really kill power output. As you probably know, a car alternator is not just a generator, it has an energized rotor inside the stator that greatly increases the rotor magnetic field generating a lot more current than just a standard rotor and stator. That's why alternators can produce so much current output, but it's at the expense of torque/power from the gasoline engine. A big car engine can still turn an energized alternator, but try to turn one by hand and you wouldn't be able to move it at all. The car engine has torque to spare and still move the car, but a small jetboat engine can't afford to expend a good portion of it's energy to spin an alternator.
For the most part, typical usage with the stock stereos shouldn't really be an issue for the charging systems - except in the case where it's 15mins back to the slip/ramp so they can't get a good charge. Unless you can go boating every day, everyone should have a battery charger on their boat anyway to keep the batteries topped up.
Yes...if you have a charger in the boat (just to clarify).
Without a charger, putting in larger/more batteries will just cause them to sulfate faster as they might never fully recharge from the engines without long drives back to the docks.
Yes that's right, but if your boat isn't charging what you have now, you need to add an A/C battery charger to top them up or you'll just end up killing them with sulfation.
That sounds about right...the charging system is not as strong, but you have to remember these are little 1.8L engines, not 350mag engines, so the torque/power loss to run an alternator can really kill power output. As you probably know, a car alternator is not just a generator, it has an energized rotor inside the stator that greatly increases the rotor magnetic field generating a lot more current than just a standard rotor and stator. That's why alternators can produce so much current output, but it's at the expense of torque/power from the gasoline engine. A big car engine can still turn an energized alternator, but try to turn one by hand and you wouldn't be able to move it at all. The car engine has torque to spare and still move the car, but a small jetboat engine can't afford to expend a good portion of it's energy to spin an alternator.
For the most part, typical usage with the stock stereos shouldn't really be an issue for the charging systems - except in the case where it's 15mins back to the slip/ramp so they can't get a good charge. Unless you can go boating every day, everyone should have a battery charger on their boat anyway to keep the batteries topped up.
Exactly.
And it means two things: 1. the 1.8 is very easy to crank so any group 24 deep cycle battery has sufficient reserve; 2. shore powered charger is a must if larger batteries are installed.
Yes...if you have a charger in the boat (just to clarify).
Without a charger, putting in larger/more batteries will just cause them to sulfate faster as they might never fully recharge from the engines without long drives back to the docks.
@212s agreed with comments -well put. My answer to not wet slipping and having no ability to charge from May to September was to purchase a "specialized" battery: both in the size and chemistry that my stator could charge - hence the Series 24 TPPL - last season the stator managed to charge that battery on even short runs (15 minutes) back to the slip. Fingers crossed for a similar result this season.
@Pullen724 ......it depends. If you can charge your boat at your dock or at home you can install pretty much any battery size and chemistry you want although I'd use AGMs as a minimum - HOWEVER - if you wet slip the boat and can not charge the battery(s) then too big a battery will usually not be charged sufficiently and its charge acceptance will decline as it sulfates into oblivion - therefore if you wet slip your boat and it came with series/group 24(s) I'd replace them with series 24 TPPL(s) as they accept a charge 400% (on average) faster allowing your stator(s) to charge them.
No it doesnt work that way. Typically in marine you will see group 24 which are the tiny ones then geoup 27 then 31. 27 and 31 are somewhat close in power ratings. 27 just under the 31. Dimensions are different though. For those 3 yes higher # is bigger but there are many others in there with all different #’s and different sizes
No it doesnt work that way. Typically in marine you will see group 24 which are the tiny ones then geoup 27 then 31. 27 and 31 are somewhat close in power ratings. 27 just under the 31. Dimensions are different though. For those 3 yes higher # is bigger but there are many others in there with all different #’s and different sizes
Gp31 is a good heavy duty size battery for a boat. You can do a google search for battery group sizes and there are charts with all of them and their measurements
