Can I connect diferent batteries?

[McIntoshUSA]

I have a trolling motor (marine battery) for a dinghy that I was thinking of connecting to my boats engine battery to keep it charged with the engine and/or charger. My thinking is that this way I can have 2 engine batteries (which i do not need) and keep the trolling motor charged till I need it for the dinghy.

My house batteries are 3 batteries connected together and the charger and alternator appears to keep them charged good. I have 2 chargers one for house and one for the engine battery. The are just alike (guest) see photo.

The 3 house batteries are exactly alike. I read that connected batteries in one bank have to be alike. So my question is, do they really need to be alike or is it preferred. Will it hurt anything If I connect 2 different brand deep cell batteries together both 12V?

Also I would have to store the additional engine battery about 10 ft away from the original battery. Therefore' I would have to run 10ft of wire. Will this hurt the charging. I know the longer the wire the more voltage drop. I have some 6 gauge wire I can use.

Thanks Mike

 

[Ken Cross]

What technology does each battery use? If you connect identical technology (read that made from identical materials and design but differing in size) the parallel circuit may be fine up to a point. I

However, if you discharge one battery then re-connect it to others with a greater charge, there will be a current surge (depending on internal battery resistance) which may cause damage.

Paralleled batteries which use different technology (therefore different fully charged voltage) will be a problem always. That's because one battery won't ever get a full charge and the other one possibly overcharged.

Bottom line: I wouldn't do it.

Ken

 

[centerline]

as the first poster said in his first paragraph, if the batteries are of the same technology, it will be fine.
I am assuming you are using conventional flooded wet cell batteries. not that it matters as long as all the batteries are the same type... the size doesnt matter, but the type does.

the only thing is, because of it being a "remote" battery/bank and not wired directly into the charge circuit, it will not uptake the charge quite as fast as the bank that is directly connected to the charging source...

think of it as being no different than pulling a travel trailer down the road behind your pickup, and having the house battery charge from your alternator as you drive... it will charge but there is resistance in the run of wires and so the current will flow thru them slower... but it works perfectly fine when there is no other reasonable option.