Battery Charger Cables Getting Hot

[btrayfors]

Chris,

Very glad you solved the immediate problem of hot battery cables. Cables should NEVER be hot; if they are, there's a problem.

All this amateur detective work trying to detect the problem could be made much easier if you had, and would use, a very important tool which IMHO should be aboard all boats: a clamp-on AC/DC ammeter. Some can be had for less than $50, but an extremely capable one like the Mastech MS2108 costs about $100 online. It is the best investment you can make.

Such a device can, inter alia, measure the AC or DC amperage in any active circuit. It can tell you HOW MUCH amperage is being passed from the batteries, the alternator, the battery charger, solar panels, wind generators, etc. That measurement is often critical to making a good determination of normal and abnormal functioning.

If you want to go all out, buy a Fluke 337...top of the line. But, the Mastech MS-2108 will more than suffice for most boaters. It is an extremely capable measurement instrument for not too many $$$.

I have both, but usually carry the MS-2108 on all jobs.

Bill

[tuberider]

chris whenever i install say a 2500w inverter, i always take the dc power straight from the batteries. i use 4/0 cable, so if i went to a buss bar on board i doubt that the buss would be fed with 4/0 . abyc says a fuse has to be within 7" from its source but if it is covered with say split loom then it can be within 40".

[capn_billl]

Originally Posted by bloodhunter

Would concur that most probable reason is at the connectors as this has to be a new problem.
What ever the reason, you now have two lines connected where one was before and an overheating problem that is likley to get worse. Would suggest you get or make new cables (2/0 wire should be more than enough to handle your current load) and a new switch and fuse holder before you end up with a fire which can ruin anyone's day.
I'd also suggest a label or sign with big letters near your AC switch reminding to turn on the generator. I have a numberf of those 'disaster avoidance labels on my boat.

Even better I split my AC wiring between INverter, and no inverter.

The no inverter, (A/C's stove, water heater, etc...), come directly from AC buss fuse bank, the buss is split with the only connection being a circuit breaker that feeds inverter, inverter output is then connected to the other side of the buss. With the inverter loads (outlets, fridge, lights), on that portion of the fuse bank.

Inverter has a bypass that essentially takes it out of the circuit and leaves all AC devices powered by shore power or generator. In case of power failure the loads on the first part of the buss simply lose power, and the inverter keeps the second buss powered.

No need to run around in a panic switching off high power devices in case someone trips over shore power cord, or worse blowing inverter leaving you with NO power.

Inverter is sized to power full load on second buss, so no worries.

I try to "idiot" proof my boat as much as possible, as the idiot may be me at three am, while fumbling in the dark to turn something on.

[David M]

Clamp ammeters measure current. Amperes are the units.