Battery for Genset

[cordale]

I currently have 4 batteries...2 house batteries in parallel, one battery starts one engine, and then another for starting the other engine and generator. The issue I have is that if my generator is running and I go to start the engine that is sharing the same battery, the generator shuts off.

How hard is to break out the wiring and wire the genset on it's own battery OR should I just get a larger battery that can handle the generator running and the inrush of the engine starting??

I really don't want five batteries, so I would probably drop down to one house battery.

[ImRich]

I'd load test the battery that has both the engine and the generator on it. It sounds like it's getting tired. Also check all connections to be sure they are clean and tight.

I'm guessing that when you are staring the engine, there is too much of a voltage drop, this is probably why the generator is shutting down.

[Chris_in_Texas]

I would tend to agree with ImRich. Which genny do you have? How old are the batteries? I never had any issues with either of the boats once the genny was running I would always start the mains without any problems. They just had a single G27 for each of the engine batteries.

The other option to try is parallel the batteries and then try to start the main engine and see if the genny dies.

[Rpontual]

This could also be another issue unrelated to battery voltage. When the generator is running it might not even need the battery...

One experiment could be to turn off the battery charger breaker, to make sure the generator is not charging the battery, and then start the engine.

My guess is that there is a grounding issue which may be causing the generator to detect under voltage (on the 110V side). A design that causes the generator to shutoff when the battery is discharged is not likely.

[cordale]

24M-XHD Interstate
1000 cranking amps
135 reserve capacity

Brand new Battery this season.

Westerbeke - Model - 4.5BCGTC-614

[gofast24]

You indicate you have 4 batteries, 2 in parallel , the two in parallel start both propulsion engines and the gen set? what do the other 2 batteries of the 4 you indicate you have do? Cant understand why the gen would shut down , once running it shouldn't need a starting battery anymore! Only thing is that if the gen set has its own built in battery charging circuit (which all that I know of do) it might get fooled into seeing there isnt a battery (or dead battery) to charge and the alternator DC field might collapse and stop producing 120 VAC output but not shut down?? Agree with rpontual that might be a DC grounding problem but only for the starting circuit?

[cordale]

The two batteries in parallel are for the house. They are Deep Cycles. The other two are for starting the engines and apparently generator. They are Cranking Batteries.

What if I took one of the house batteries and ran it in parallel with the Cranking battery that starts the engine and generator?

Would that solve the problem?

[Chris_in_Texas]

Push the battery parallel switch on the dash. (If you don't have that just take a pair of jumper cables and jumper between the two main engine batteries. Just like jumping a car. That should tie the two start batteries together. Just DON'T ever shut off the battery switch with the genny engine running. It has a 17A alternator to charge the 12V battery and most likely would fry the diodes and it won't be able to charge. That being said the genny is carb based so its not EFI like the Kohlers, so in theory it would run without power, until the carb ran empty because the electric fuel pump stopped working. But that being said if the alternator is "broken" then (can check with DMM again make sure all AC power is off) and you start the main engine the pull down might be two low for the controller or the excitation of the generator field in which case the genny may stop because of a fault condition. Its strange that WB used such a small motor on that. That motor is only 7.54HP on a 4.5KW genny. Kohler used a 16HP engine on my older 5ECD 5KW genny. That is really cutting it close from a power perspective for sure. If its under full load that engine is really at the top of the power curve there. A 7.45HP engine is 5.6KW worth of power so its driving about 80% of full HP load at full genny rating with 100% efficiency.

If it use to work fine, and now it doesn't and no wiring changes have been done. Have you checked all the fuses on the genny and circuit breakers in all the panels on the boat? Just making sure something isn't tripped.

Check to see the voltage on the batteries before starting any engine, so lift the engine hatch and disconnect any shore power (just to get rid of any of that). Then wait a few mins and check voltage on each battery bank. Start the genny and wait a min or two (make sure all AC breakers are off in the cabin), recheck the voltages on the batteries, the one with the genny should have a slighly higher voltage and depending on how the battery isolator has been wired in the others might as well but will be from 0.3 to 0.7 volts lower. That should tell you what battery is doing what. ideally then you would to use a set of jumper cables and tie both start batteries together. Then try starting the main engine that normally kills the genny. If it does again then there could be some other issue maybe and not a battery issue, unless both batteries are low. Like I mentioned above never had the genny quit when starting the main, and the Kohlers are EFI based and need voltage to power the injectors. I know during start cycle the voltage drips in the 10V range while cranking.

[cordale]

Thanks for the info Chris...I'll check it out.

[gofast24]

Agree, old rule of thumb is 2 BHP/kWe for small (<10 kWe gensets) . In your case a 4.5kWe rated gen typically should have about a 9 BHP engine running it (actually should be 10% more to handle starting AC loads like Air Con units) . The efficiency of these smaller gen sets normally isnt over about 82/85% max. Go thru the steps that Chris mentioned and my thoughts are that the battery your gen is connected to is on its way out, whether new or old. Your gen set should be able to start fine with a small (200 CCA) battery vs. the problems you are having with a 1000 MCA battery that you indicate is the starting battery for the gen set. After reading many posts on these new 3600 RPM Kohler sets they are really fussy about any small fault that the ECU (if it has one) throws.

[cordale]

All in all, if my worst problem with my boat is that I have to restart my genset after my engine is running, then that's a successful day on the water!!

[Chris_in_Texas]

That for sure if its the worst thing.

One thing to note that is only a small group 24 battery with 800 CCA or 1000 MCA, most everything will reference CCA. I saw the G24 and had to look it up on the website, as it raised my curiosity on how they do 1000 CCA in a G24 lead acid. That would have been impressive, and some mighty thin plates. If you can jumper the the two starting together that might be the quickest test have the genny running and then start the ending with them together. If it stays running then you know it is sensitive to voltage drop, otherwise you could have a bad battery also. I have seen new ones go bad pretty quickly. In a boat in the heat of the engine room and the bouncing around can break things inside. Also make sure to check the fluid levels that they are topped off with distilled water. If you keep the charger on it can boil them off pretty quick with the heat, as many chargers aren't compensated for the high heat. The voltage has to be lowered during times with high heat. Some of the newer multi bank chargers will have heat probes that connect to the battery to compensate the charge during the hot conditions and as they cool will allow more charge in increasing the float voltage.

Starting a sideline discussion here...

I see that the battery only has a 1 year warranty, so that tells me that Interstate seems to have a pretty high failure rate if they won't stand behind it. That is the reason that I purchase the cheap automotive MAXX batteries at Walmart as they have a non-prorated 3 year plus two more prorated. In the Texas heat I would never get three years out of them. Don't fall for the "marine" labels on the batteries. There are people that say only use a marine battery over a an auto battery, however most compare a auto start battery to a marine deep cycle battery. The deep cycle batteries have much thicker plates to stand the higher depth of discharge without any problems. The starting batteries are thinner plates to supply higher CCA ratings. That is why VP states specifically in their manual not to use deep cycle batteries for starting there engines, and use only starting.

I would really like to see two batteries cut in half to compare two starting only batteries between a marine and automotive in the same group size. For example the Interstate MTP-24 against the 24M-XHD, that would be interesting to say the least. They are 0.2lbs different and 50 CCA different. They still aren't quite apples to apples as the marine is a Group 24MS (marine starting) which is 3/4" higher than the auto version. That would explain the weight and CCA difference. The interesting part is the auto version has a 30 month non-prorated warranty with up to 72 months coverage. They cost within about $10 of each other.

Sorry to get off in a rant, but none the less a bit interesting. Cordale nothing wrong with your selection of battery, just running into left field here.

[gofast24]

Try starting the one propulsion engine first that it's battery also starts the gen set and then after running start the gen set, what happens in this case. In theory, the propulsion engines alternator should be in it's starting battery charging mode and the gen set should have enough starting current/voltage to start the gen set?

[cordale]

While the starboard engine was running I was able to start the Genset, just can't do this in the opposite order.

[gofast24]

Starting to sound like a defective new(?) battery causing the problem. You indicate gen set will start after the propulsion engine is running (the propulsion engines alternator is working and providing 14+ VDC charge to the battery that also starts the gen set so the gen set is getting a little boost from the engines alternator?) As Chris indicated parallel both of the starting batteries either by a paralleling switch at the helm or jump both with battery starter cables and let us know what that does regarding your problem. Sounds like something is causing a unusually high starting load from the propulsion engine while the gen is running and then having to re start the gen set due to excessive voltage drop?
Regarding the comments about what size (HP) engine is powering what size gen set it really is a function of whether the gen set is a 1800 RPM (4 pole gen) or 3600 RPM (2 pole gen set). Still really glad we have a 1800 RPM 7 kWe internally balanced 3 cyl. Westerbeke other than the price of service parts for this set that are ridiculously high! With 869 hours on it still runs like a sewing machine and no noise attenuation covers over it. Wish they still made this set even though we dont need a replacement !

[cordale]

I've never used the parallel button before...So just push and hold while I'm starting my starboard engine? Guess another thing I could try would be to swap the starboard and port batteries to see if the issue goes away.

Once running, I've never had an issue with power output...A/C, microwave, Shopvac would be my higher users.

I won't be down for another week or so, but I'll report back my findings.

[Chris_in_Texas]

Yep that is it, there should be the parallel button somewhere on the dash area. Its just a large relay, which you should hear click (if the engines are off) if its working correctly. My 2007 had a parallel switch on the dash, and my 35SC had one under the helm by the steering wheel. Its a momentary switch and hold it in when you start the engines. On my 3060 I did that to help from lowering the voltage enough it would mess with the chart plotter and radar if they were on and running.

[gofast24]

Agree with Chris, start the gen set then just push and hold in the parallel switch (button) at the helm (start both main propulsion engines the same) after starting the gen set and let us know the results. With 2X 1000 MCA main engine starting batteries in parallel (using the parallel switch) and the gen set still stops running this will become an interesting thread:)!

[cordale]

Update on the genset issue. I think I have a two fold problem here, maybe related, not sure.

Starting with the one I originally started this thread with.

With the genset running, I tried pushing and holding the parallel switch and then simply turned the starboard engine start key to the "ready" position and the genset dies. I also tried again having the starboard engine running and then starting the genset. I could get the genset starting and it would stay running until I put a load on it. See more info on next issue.

So even after all the work Marine Max did to "fix" my genset (see their info below) here is what's going on.

I've typically always started the genset with a load applied. Turn blower on, hold the "on" switch up for 5 seconds, then push the start switch up, release the start switch, then when fully running release the on switch.
Now in order to start it and keep it running with a load applied, I have to hold the on switch up for probably 5 minutes or it will die. I told Marine Max about this and they said to let the genset warm up for 5 minutes with no load and then apply load. So I tried that...It starts up and stays running instantly with no load. I let it warm up for ~5 minutes then applied load. It wanted to die so I held the on switch up to keep it running. I only had to hold it up for 30 seconds this time before it would stay running on its own with load applied.

I think I'm just going to try to wire the genset to its own battery and see if it solves either issue.

Marine Max Comments below.

REPLACE GENERATOR WATER PUMP IMPELLER
CHECK SEA STRAINER AND TURN OFF WATER SUPPLY
REMOVE IMPELLER COVER AND INSPECT COVER AND HOUSING FOR WEAR
REMOVE OLD IMPELLER AND INSTALL NEW WITH GASKETS
RESECURE PUMP COVER OPEN WATER SUPPLY INSPECT FOR LEAKS
RUN GENERATOR TO VERIFY PROPER WATER FLOW AND COOLING
CHECK COOLANT LEVEL IN GEN

COMPLAINT: WHEN GEN IS RUNNING AND YOU TRY TO START STB ENGINE GEN DIES DO NOT
SPEND A LOT OF TIME ON
CAUSE: HEN GEN IS RUNNING AND YOU TRY TO START STB ENGIN
Gen dies sometimes and wont shut off by cabin off switch
CORRECTION: gen battery cable is hooked to starb eng battery switch which is pulling power away from
gen when starting, gen could be moved to mastter power switch or seperate battery installed or a larger
starb battery.
Ran for some time and did not get unit to die but I finally saw unit not shut off by cabin off switch . Ran down
wiring schematic and tried a new overspeed board. New overspeed board let me shut down from inside but
would not stay running after the first time i tried it . I thought something toojk out the test board or it was just
bad so I ordered a new one. I also found an oversize fuse in place of the 8 amp one so I ordered a new
one. Installed new board and unit fired up and died again. I next checked all of the safety shut down
switches then just ran a jumper wire to overspeed board to power out on safety switch circuit bypassing the
whole system and gen still starts and dies. I next tried a test relay in place of K1 and K2 relays with the
same results. Each time I tried these test I would switch back to the overspeed board and gen would run so
this tells me the original board would have let the gen set run if a safety switch was trying to shut it down
plus it would not allow you to shut off unit untill oil temp was warm enough which is also a safety concern . I
next checked engine RPMs with a hand held tach and found the governer was a little out of adjustment
which was allowing the RPMs to go high enough to shut unit down as the overspeed board should do.
Adjust gov, put a load on gen set and seems to be working fine now. Please advise customer to on
occasion start then right away try to shut gen off to sort of check on board function . It had multiplle
problems but I have never seen an overspeed board act in this way.
1 Overspeed board
2 wrong size fuse
3 Governer out of adjustment

[ImRich]

It sounds like you have or had more than one problem.

I always allow the generator to warm up before placing an AC load on it. Sometimes this can be less than a minute or a couple of minutes, it depends on the temperature, the amount of the load, etc.

As always, without all the data, it's hard for online diagnosis and help. It seems like we didn't get all the details.

So how is it working now?