Adding new Trojans

[Island Mike]

This past summer I purchased 4-Trojan 105s, however, I feel I want to add two more. Would this be a problem adding newer batteries with the older ones in my excisting bank even though there will be a years difference in the batteries.

Thanks

[btrayfors]

Mike,

Conventional wisdom, and the recommendation of some battery manufacturers and "experts", is that you should not mix batteries of different ages and types.

However, there is more than enough empirical and experiential evidence to suggest that this generally accepted advice need not be followed slavishly.

On my boat a few years back, I did the same as you are planning, i.e., increased my house battery bank from 4 T-105s to 6 T-105s with no ill effect. Then, when it became time to replace the house batteries last year, I replaced all six, plus the two I use up forward for the windlass.

I'd think that if you've been treating your four T-105s well (not too deeply discharging them, fully charging them, maybe equalizing them occasionally) then you'll have no problem with adding two new ones.

While you're at it, be sure all connections are clean and tight, and you are using adequate size cables.

Bill

[Island Mike]

Bill,

Thanks I appreciate the information; I really have not yet even got to the point were I have taxed the Trojan at all. I am still adding equipment, lights etc.

[Pblais]

I wouldn't wait to add them but I wouldn't add them unless you are really sure you do need them, I have 4 Trojan's and they make a lot of power, but you need to watch the consumption to figure it out. If you added 10 more batteries you would soon find you can't get them recharged all that easy. Failing to properly recharge is a problem too, so you never want more than you really need and you really don't want to draw them down more than 50%.

A battery monitor really is a great tool for keeping an eye on the batteries. It's like a fuel gage that tells you how full they are and how many amp hours were used, are currently being used and how much is left. when you measure what you use you quickly know what you need and can see problems well before the lights go out. without a monitor you need to try and keep a log of how long things run to estimate the amp hours.

[phorvati]

I did just that. I had 2 trojan SCS225 and added two more two years later. As long as you equalize the old ones first and make sure they are fully charged, you should have no problem adding two more of the same type batteries.
Petar