MIXING BATTERIES ?

larglo · Post by **larglo** » Wed Feb 16, 2011 11:18 am

This will be copied,,,,printed,,,,,and framed.

Larry

Paul · Post by **Paul** » Wed Feb 16, 2011 11:24 am

Hi Larry,

I'm assuming that this house bank is for running house loads only and is in no way tied in with your cranking battery. Is this correct?

larglo · Post by **larglo** » Wed Feb 16, 2011 11:48 am

Absolutely.

Larry

g36 · Post by **g36** » Wed Feb 16, 2011 12:17 pm

its good to have a diagram this is parallel setup yes. the whole issue is the batteries be charged or overcharged when one is weaker. thats where you will find a problem with this setup. when you have a weak cell or completely dead cell or more in a battery then your charger will continue to charge it and it will over charge the battery that doesnt need it. you may not see this right away but believe me you will. batteries will perform at different rates and being hooked up parallel all of the time they will draw power from each other . meaning the weaker will suck power from the healthy one to equalize the bank. a means of charging them seperately is still the best way and i am meaning like all week long sitting at the dock . best thing is do what you think, go with or without a means of independant charging, your decision. i'm telling you from experience my profession is electronics for the past 30 years.

Paul · Post by **Paul** » Wed Feb 16, 2011 12:29 pm

This is why it's important to start with 2 new batteries from the same lot.

g36 · Post by **g36** » Wed Feb 16, 2011 12:32 pm

he's not

larglo · Post by **larglo** » Wed Feb 16, 2011 1:27 pm

I will start by buying one Maxx 29 from WalMart end of this month, and use it only, I will try and buy another Maxx 29 battery later this summer and connect it in parallel to the first, that's the best I can do!

Larry

wowzer52 · Post by **wowzer52** » Wed Feb 16, 2011 10:58 pm

Larry, what we're trying to say is If you are going to have two house batteries in parallel buy them at the same time, together and you can use one charger because they will be an equally matched pair. If you are going to use two different dated batteries or different types, or different sizes you will get the best results and longer life by charging them seperately.

larglo · Post by **larglo** » Thu Feb 17, 2011 2:52 am

When you explain it in simple terms as you just have, I understand it, and I thank you. If I can charge 2 batteries hooked as you say, then I won't have to buy the second charger as I had planned. That way I hope to be able to buy 2 Maxx 29 batteries the first of the month, so they should match, when the ol' SS check arrives.

I wonder why they have up to 4 bank battery chargers? That's why I thought I would need a charger for each battery.

Thanks very much.

Larry

alexander38 · Post by **alexander38** » Thu Feb 17, 2011 4:39 am

A 4 bank charger that easy 1, gen set 2, and 3, start battery for port and stbd engines, 4, to 4d's for house bank

larglo · Post by **larglo** » Thu Feb 17, 2011 10:07 am

Cool.

Larry

wowzer52 · Post by **wowzer52** » Thu Feb 17, 2011 11:16 am

I installed a three bank battery charger/maintainer that doesn't over charge the batteries and cook them dead, which, by not knowing the difference, I have done, more than I care to admit. I have found that only the "automatic" battery chargers will stop charging when the battery is fully charged. If it is not "automatic" you will have to watch it and manually turn it off when the battery is charged. Though it will reduce the amount of charge going in, it will not completely stop charging. I have destroyed many batteries by leaving a "non-automatic" charger on too long and cooking them to death. With my three bank charger I have one for port engine starting battery, one for the stbd engine starting battery and one for the "house bank" which consists of a matched pair of two group 27 deep cycle RV/Marine batteries. I designed an elaborate isolation system using two continuous duty solenoids plus battery switches as back-up. A "battery isolater" will do the same thing, keeping your house batteries seperate from your starting battery when the ignition is off so you don't run the engine starting battery down while at anchor. As the engine is running, all batteries are being charged. I found this system to work very well a year after I got the boat. The previous owner said he put new batteries in before I bought the boat but he had bought the batteries at different times and not as a pair. On the hook, I woke up one morning and the furness fan was barely running, the fridge was not working and when I turned on the cabin lights they were just barely visible. After shutting everything off so these wouldn't get a power surge when I started the engine, I started one of the engines and then turned everything back on and went about my business. This happened twice before I realized (by testing) the batteries were damaged from not being a match pair and being charged with one charger causing one to be continually overcharged and one to be continually under charged. Though the three bank charger is a great tool, it could not bring back damaged batteries. Having a battery isolator and/or a battery switch is a must. Life can be miserable waking up in the morning with all dead batteries and no one around with jumper cables. That said, I am good for three days on the hook with my 12vDC/110vAC fridge, LED cabin lights and a small 400 watt inverter for charging cell phones and laptops. If I need my furness to run at night (on low) I will run one engine for a while during the day to recharge/top off the batteries. I also recharge my batteries by engine during the day while moving to a new anchorage. However, my navigation laptop "Nobeltec" runs off the inverter continually while running. I charge my 2 laptops while running so I don't use my battery too heavily while on the hook. I have found (the hard way) that an inverter, if used for a microwave, can suck a pair of batteries dry in minutes. Being able to go out for an overnighter with confidence is priceless. Isn't boating fun?

alexander38 · Post by **alexander38** » Thu Feb 17, 2011 2:54 pm

Wowzer , no gen-set , but it sounds like you have it wire in.

wowzer52 · Post by **wowzer52** » Thu Feb 17, 2011 8:50 pm

No genny, I really like the quiet and I think others around me while anchored do too. My wife and I have coffee at 5:00am every day, even when on the boat. A friend of mine that has a F-32 likes my set-up so well he wants to get rid of his gen and go to just batteries also. Also, my boat sits six inches higher in the water than his.