Offshoreonly.com

Offshoreonly.com (https://www.offshoreonly.com/forums/)
-   General Boating Discussion (https://www.offshoreonly.com/forums/general-boating-discussion-51/)
-   -   HELP with twin engine battery bank charging system!! (https://www.offshoreonly.com/forums/general-boating-discussion/310950-help-twin-engine-battery-bank-charging-system.html)

US1 Fountain 04-17-2014 10:39 AM

Whoa, didn't catch the series comment.

pstorti 04-17-2014 11:16 AM

if they were in series he would have had a fire already or some other major problem, they have to be parallel.

pstorti 04-17-2014 11:19 AM


Originally Posted by Wobble (Post 4108012)
House batteries are in parallel I hope. You would be better putting both house batteries on one engine or through isolator as shown above. you can not tie both charging systems together through the house batteries except for emergency start as mentioned above.

Since you need the full house battery capacity you do want them tied together but only tied to one alternator.

I would suggest that the house batteries are on the engine that does not have your power steering.

that works also but then you have one alternator charging 3 batteries and one alternator doing almost nothing. I have 6 batteries in my boat and have 2 house batteries on each motor so I can take advantage of both alternators output, they only combine if I flip the switch. I have the stereo on one house bank and everything else on the other. Each engine has its own starting battery.

ALL_IN! 04-17-2014 12:44 PM

As previously mentioned, you need to move house batteries to one motor - or - put one house battery on each motor, but not connected together. Your alternators are fighting each other.

If you've already looked in to this situation - what did you find? Is the issue resolved?


Originally Posted by 290enticer (Post 4106195)
I have a 90 powerquest 290 enticer...I added two house batteries to run inverter and fridge about two yrs ago and I am having problems ever since....I know this can be done. I am using blue sea acr's to dump charge over from each cranking battery to house batteries, these batteries are linked together via b+ cable in series then to battery switch and on to inverter. I keep the boat plugged into shore power at home and onboard charger keeps it all topped off. After several hours on the water...it seems like the Alts can't/won't keep up and they start getting HOT...so hot that you can smell them and the "charge" indicators start going lower and lower. I dont ever have dead batteries on the water even when overnighting...but my set up dont seem to work well. I have replaced both Alts with the 65amp Mando's from DB electrical. They test good on the bench but dont know it they are really putting out when they have a load on them and get hot. I know there are alot of boats like mine that have two house batteries added to run house loads....I dont know if the alts are fighting each other or what?? I dont know how to post pics on here but have a complete diagram drawn up of the system. I have had a marine electrician
look over the drawings but couldn't really come up with any better ideas???? Please help or give input. I can email you the diagram if need be...it is much simplier if you can look at the diagram...Thanks for any help fellas!!


US1 Fountain 04-17-2014 01:15 PM

Having the house batteries seperate defeat the purpose of having them to run his inverter. I'd put the 2 house batteries on one motor isolated from that motors start battery by the ACR, but upgrade that alt and wiring to handle the larger load when charging. Run the charge wire from that alt to the house side and keeping the wire from starter to the battery. This will give the house bank priority charging at the ACR. And keep the other motor/ start battery totally separate.

US1 Fountain 04-17-2014 01:21 PM


Originally Posted by pstorti (Post 4108046)
if they were in series he would have had a fire already or some other major problem, they have to be parallel.

Had thought the same, but not quite sure with the 2 ACRs in the mix if still applied. hopefully just wrong terminology used and it is indeed the alt fighting each other. But you read all the time how people with twin engines just run their boats with the battery switch in the both position. Same thing, right.

290enticer 04-17-2014 09:39 PM

I have thought the same thing..I discussed my issue with an alt repair person and he said if they are tied together, one will take primary and
the other will take secondary...and it would be ok to do. I didnt think they should be combined myseld...That being said...we went out last weekend for the day and overnited, i only had one house battery hooked up to test this idea. So the starboard engine only had its cranking battery which is tied into all helm controls, port engine had its cranking battery as well as one house...they werent tied together because the other house battery wasnt even in the boat..Did great during the day...at night running all factory lights, alts got hot and showed almost no charge 12v on guage. Its like the alts dont/cant keep up when more load is applied. Discussed these issues with Db electrical tech team and they advised me that it sounds like they are breaking down and told me they have a 110amp mando..that has bigger rotor, tighter windings and bigger regulator..I could put both cranking batts on starboard engine and both house on port engine (which does not run power steering) and see how it does. I will have to change the whole original layout of the way its wired from the factory....I told the guy that I wasnt trying to run a small town with these things...just wanting to run normal loads on a boat?????

Wobble 04-17-2014 09:50 PM

The problem with marine alternators is that they use remote sensing. Which is a good thing mostly, means that the dash will see a full 13 volts when charging, but could also mean that the alternator is putting out its maximum due to the load on the dash distribution and voltage drop in the distance between.

If you are still having problems, I would pull both alternators and have the diodes checked and also the function of the voltage regulator.

On the other hand you could disconnect one at a time and see which one carries the load

290enticer 04-17-2014 09:58 PM

US1...You see what i am trying to achieve...Im sorry for the terminology...the house bank is wiring in parallel...NOT SERIES. I need to combine both house banks, I have a 3000w Xantrax inverter that i use to to run fridge, tv/dvd and every once and a while i will run my 7k btu
cruise air hatch ac unit for short periods of time right before we go to sleep to cool the cabin down. Before I added all this, and before I changed alts, I always ran my switch on combine and didnt have any problems, then added a perco switch on/off/combine that supposted to isolate alts from each other, as you can see in the diagram, the house bank is combining the alts when acrs are closed..I didnt have any problems like this until i changed alts, one of the original mandos went out and i replaced them both with these New aftermarkets from DB electrical. I just want to look down at my guages and see a good charge level...Keep in mind I don't ever have dead batteries...they just get hot and DO NOT want to have a fire!!!

Wobble 04-17-2014 10:03 PM


Originally Posted by 290enticer (Post 4108389)
US1...You see what i am trying to achieve...Im sorry for the terminology...the house bank is wiring in parallel...NOT SERIES. I need to combine both house banks, I have a 3000w Xantrax inverter that i use to to run fridge, tv/dvd and every once and a while i will run my 7k btu
cruise air hatch ac unit for short periods of time right before we go to sleep to cool the cabin down. Before I added all this, and before I changed alts, I always ran my switch on combine and didnt have any problems, then added a perco switch on/off/combine that supposted to isolate alts from each other, as you can see in the diagram, the house bank is combining the alts when acrs are closed..I didnt have any problems like this until i changed alts, one of the original mandos went out and i replaced them both with these New aftermarkets from DB electrical. I just want to look down at my guages and see a good charge level...Keep in mind I don't ever have dead batteries...they just get hot and DO NOT want to have a fire!!!

Which ones did you get? http://www.dbelectrical.com/c-7773-mando.aspx


All times are GMT -5. The time now is 07:00 AM.


Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.