Marine Electronics Forum - house batteries wired in parallel

THE HULL TRUTH is the world's largest FREE network for the discussion of Boating & Fishing. Whether you're researching a new boat, or are a seasoned Captain, you'll find The Hull Truth Boating & Fishing Message Forum contains a wealth of information from Boaters and Sportfishermen around the world.




View Full Version : house batteries wired in parallel


ninetoes
03-27-2012, 06:55 PM
I upgraded to size 31 AGMs for each of my 200 HPDIs due to their high CCA and RC requirement. I was left with two small AGM 34s. I plan on wiring these together in parallel to increase reserve capacity. My question is as follows:

1. I have a 6kW radar, small JL amp, 1kW sounder, 2 large chart plotters, sonic hub, and two VHFs running off of one house battery. If I connect two in parallel can I connect half of the components to the + and - of ONE battery and the other half off of the + and - of the other battery and still have the same reserve capacity or do I have to have them connected to the + and - poles of OPPOSITE batteries to maintain twice the reserve capacity.

2. Do I connect my two bank charger to each battery individually or charge them together in parallel?

Thanks for any help.


Glen E
03-27-2012, 07:10 PM
you really don't need to worry about the yam reserve capacity at all, ask a good Yam guy tech here like SIM or Jethro...

ninetoes
03-27-2012, 07:25 PM
you really don't need to worry about the yam reserve capacity at all, ask a good Yam guy tech here like SIM or Jethro...

I would like to think so. However, ever since new, my Die Hard Platinum Marine AGM size 34s cant turn over my engines if they are not FULLY charged.


Glen E
03-27-2012, 07:27 PM
I would like to think so. However, ever since new, my Die Hard Platinum Marine AGM size 34s cant turn over my engines if they are not FULLY charged.

then something is wrong......

ninetoes
03-27-2012, 07:46 PM
point taken! thanks. any advice on the parallel wiring question?

Bayfly
03-28-2012, 08:32 AM
when you connect two 12 volt batteries of equal size, age, and condition in parallel you end up with one larger 12 volt battery, thus you can connect your charger to the positive of one battery and the negative of the other, and they will both charge together, as one battery, or you can connect the charger to the positive and negative of just one of the parallel connected batteries and they will both charge, as one battery. However, if one battery is weaker than the other, for some reason, the combined or larger battery will be compromised and not charge well.
In making connections to the battery or batteries connected in parallel connecting to one is in essence connecting to both of them. In other words an amp draw from one is an amp draw from both of them.
There are at least two good books on marine electronics and I would encourage your reading or at least referencing one of them. Good luck with your electrical system.:thumbsup:

yandina
03-28-2012, 08:44 AM
when you connect two 12 volt batteries of equal size, age, and condition in parallel you end up with one larger 12 volt battery, thus you can connect your charger to the positive of one battery and the negative of the other, and they will both charge together, as one battery, or you can connect the charger to the positive and negative of just one of the parallel connected batteries and they will both charge, as one battery. However, if one battery is weaker than the other, for some reason, the combined or larger battery will be compromised and not charge well.
In making connections to the battery or batteries connected in parallel connecting to one is in essence connecting to both of them. In other words an amp draw from one is an amp draw from both of them.
There are at least two good books on marine electronics and I would encourage your reading or at least referencing one of them. Good luck with your electrical system.:thumbsup:

What Bayfly said except that if the batteries are not matched, it doesn't "compromise" the better battery. It still contributes its share and the smaller battery contributes its share in proportion to capacity.

If wired in SERIES for a 24 volt system then matching the batteries becomes important but this does not apply to parallel connections.

The only downside of a newer or larger battery in parallel with a smaller or weaker battery is for the same weight and storage area you would have more total capacity with brand new batteries.

dreamin-on
03-28-2012, 02:24 PM
What Bayfly said except that if the batteries are not matched, it doesn't "compromise" the better battery. It still contributes its share and the smaller battery contributes its share in proportion to capacity.

If wired in SERIES for a 24 volt system then matching the batteries becomes important but this does not apply to parallel connections.

The only downside of a newer or larger battery in parallel with a smaller or weaker battery is for the same weight and storage area you would have more total capacity with brand new batteries.

You should only use a matched set. Meaning, same manufacturer, same battery, same age, size and same state of charge. Even if wired in parallel.

Sure you could take two batteries of the same voltage and wire them in parallel and it would work, but that's only if you dont plan on using its capacity like it was designed to. The smaller of the two batteries will limit the overall capacity.



Search Engine Friendly URLs by vBSEO 3.2.0