charging batteries while driving?

[mbratz]

I'm just curious, if i used a car inverter and ran an extension cord from the inverter in the truck to my 3 bank on-board charger on my boat could I charge my batteries while driving down the road, and at what cost to the truck battery?

 

[bruceb58]

Wouldn't hurt it at all. Your alternator would be the one supplying the current while driving. You wouldn't want *** connected when the engine wasn't running.

 

[Silvertip]

Ensure your inverter can handle the anticipated load.

 

[Bondo]

Ayuh,.... Or just skip the inverter, 'n wire all three batteries in parallel to the truck's system,....

 

[alldodge]

Ayuh,.... Or just skip the inverter, 'n wire all three batteries in parallel to the truck's system,....

Agree with Bondo simplest solution, your going to need some large cables (maybe 6 AWG) going from the ALT to the inverter, so just run them to straight to the batteries with an ACR. Don't forget the same size ground cable going back, and a fuse between the truck and boat (maybe 90amp). Start battery (truck) House battery (3 parallel)



But on the other side why not just plug it in when you get back home?

 

[bruceb58]

It's a trade off. 6AWG wire will be around $1.30/ft and you have to run 2 wires and you need to fuse it. It's basically a question of what way is cheaper given what is already installed on the boat. If the boat already has ACR's I would likely run DC. Since he already has a 3 bank charger, if he doesn't have ACRs, the inverter way is probably best.

My parents used to do something like this when they towed their boat back from Canada to California with their Norcold full of fish.

If we are talking anything less than 10 hours of driving or nothing is on in the boat like a fridge, it's not worth doing anything.

 

[gm280]

If I were going to wire a charging system like proposed, I would absolutely install the fuse/breaker for obvious reasons but also some huge "steering diodes" as well! I certainly wouldn't want anything in the boat causing any problems in the charging and/or battery system of the drive vehicle. When installing everything paralleled together offers such possibilities. So directional or steering diodes would stop anything like that. But ha, that is just me! While steering or directional diodes would deduct from the available voltage at the boat (by less then a volt), it would be worth it to protect the alternator and battery of the drive vehicle. JMHO!

 

[bruceb58]

How would diodes protect the alternator of the drive vehicle? You are just adding a battery. This is done with RV/trailers all the time. The tow vehicle typically have a relay that only energizes the the tow vehicle engine is on...just like an ACR but cheaper.

 

[H20Rat]

Do you REALLY need to charge them? Alternators don't like being used as battery chargers, and will eventually fail if you are asking them to output 100% duty cycle constantly.