Trojan Boat Forum

I just bought this used 8 amp dual Bank Battery Charger on Ebay for $28 shipped



I bought it as-is off a parted out boat. I am assuming it works or I can get it to work. Either way I would like to add 2 more batteries to my boat. I am contemplating where to put them and how to use them...

One option is to mount them on the fly bridge under the cabinet where the stereo is and use it to drive my stereo and amps while on hook.
My question is, would this setup work for my stereo's to run on all day if the generator wasn't running or would I need to still start the Generator every once and a while to charge it back up?

Another option is to add two more batteries and wire them to the already 2 house batteries that already in series as well as add the new charger to it.
My question on this option is: How to wire them into the existing battery bank AND how to add the secondary charger into the battery bank since it's already charged by the on board charger?

Here is how the batteries are curerntly wired





Please let me know what you think I should do. I value your opinions...
Let me know what you would do...

I would make those 4 batteries stand alone... remove the cables joining each pair + and - terminals.
Then the new batteries I would put in series with the house battery (joining all the + and then all the - terminals.)
Charging the gen battery is done by the generator and not a stand alone charger.
I would then use a three bank charger to charge these three banks... port battery, starb battery, house battery bank.
You may have a Trojan crossover to join starb & port in the event one runs low and is unable to start it's engine. If you don't have one it is quite easy to do using a solenoid that is energised by a switch to join the batteries.
Doing things as I have suggested means that you are unable to discharge two banks at the same time... which your setup can do, both engines can go low and the house and genny can as they are connected in pairs.

what do have for battery switches?

kevin babineau wrote:what do have for battery switches?

Is that question for me? None... as my 4 banks are standalone.
I can't think of a reason to have a switch... my Trojan emergency start switch handles any need to parallel starting batteries in an emergency.

jwrape wrote:I just bought this used 8 amp dual Bank Battery

What comes to mind for me is why go back in technology for charging batteries which are a boats lifeblood?
The few hundred bucks for a charger like this is worth it in the extra security and longer lasting batteries due to the charger microprocessor design. Faster charging and longer lasting batteries is the key for me. (I got the 40 amp one for shorter charges)
http://www.xantrex.com/web/id/256/p/1/pt/7/product.asp

no i was asking jwrape

No No battery switches

if it was me i would put in two battery switches...if u run the boat enough i wouldnt charge the starting bank with the ac charger....thats just me...if ur interested in more info on how to setup the switches etc let me kno

kevin babineau wrote:if it was me i would put in two battery switches...if u run the boat enough i wouldnt charge the starting bank with the ac charger....thats just me...if ur interested in more info on how to setup the switches etc let me kno

That might be a consideration for old type chargers... but the new microprocessor chargers have no ill effects on batteries. In fact they are better for the battery than the engine Alternator!

the comment on the switches has nothing to do with the type of charging used...just on how i would set up the switches....no matter what type of charging used; generator, solar, ac, i have batt switches in the system...again that is just me

I have 4 batteries on my boat with selector switches. With those switches I can connect any battery to the engines or the generator. The switches give me the peace of mind knowing I will have the power to start either engine or the generator. I also have 2 duel bank AC chargers, so each battery is isolated when charging.

kevin babineau wrote:the comment on the switches has nothing to do with the type of charging used...just on how i would set up the switches....no matter what type of charging used; generator, solar, ac, i have batt switches in the system...again that is just me

So say more... what are the switches doing for you? What are their capabilities?
I'm interested to understand what I am missing as the theory I follow is one of minimal connections in the battery system. The more variety of connections one has the more chance for that error to happen that makes things worse.... e.g. a switch that can parallel both starting batteries is left on and both run low. An emergency start switch solves the problem of one being low that a switch can also do but does not have the potential to leave in the both position for a long time. Also both position may not be best for a charging situation... alternator or mains charger.
I guess I'm not a believer indoing something just because... I rather have it well designed to ensure trouble free use.

I do have an emergency switch that I have had to use on occation but I think that's all I really need.

well mike we've had our pissing contest before and im not about to get into it again...i have my way and u have urs.....i wont waste my time arguing why or weither i should or shouldnt have switches.....i like them and thats what i have...i also like to be able to control what is on and what is off especially when i leave the boat....another factor is that when u all batteries together the charger will not equally charge nor fully charge all batteries without isolators of some sort....the charger will charge until it gets a full reading which the charger can be tricked by one fully charged battery in a bank...im sure ull argue this....again this my opinion and what i have on my boat and what i recommend to others....peace out dawg

I'm not trying to get into any contest... was just interested in the reasons why you value them.
You can do whatever you wish to your boat and set it up to suit you.... as we all set our's up to suit ourselves too.
I was interested to see if there was a valid reason to have the switches so that we could modify our non switched setup.
From what you have said you just like it that way and like to interconnect batteries... which is OK for you, but maybe you should reconsider suggesting other's do it that way too.

It seems to be an extra cost with no real advantage when applied to the battery layout we have been discussing earlier (not multiple batteries per bank). The OP has an emergency start system so there is no need to gang the starter batteries with a switch nor as he showed them wired in the picture.