12v positive and 24v negative possible?

[fairbank56]

Originally Posted by goboatingnow

The term " ground " is frequently used in DC circuits to mean negative return ( hence the symbol)

Yes, and incorrectly so, hence the confusion

Eric

[pbiJim]

If the question is - can a 12 vdc system & a fully independent 24vdc system, with separate charging systems, share the same negative wire (sometimes called ground)? The answer is yes, if everything is sized correctly.

If the question is - can you assume that these two systems, as wired by someone else, will necessarily share the same negative connection? The answer is no.

If the question is - can I take 12vdc off of one of the two series-wired batteries in my 24vdc system & use it to run a 12vdc device? The answer is only for a short period of time in an emergency situation, as this will cause imbalanced discharge of the two batteries in series & a typical 24 volt charging system will not correct it.

[smac999]

asumming the old wire is big enough for the new pumps. I would find the other end of it. then move it from the 24v neg bar to the 12v neg bar. extend if need be. yes they probably interconnect somewhere. but the path might be really long. and 30a is quite a bit you want the shortest path you can.

if it's an easy and short run I would just run a new one though. but if long and hard I would reuse the old cable but move it.