Dead Chassis Batteries

[DunesView]

HI all,

I'm sure this has been covered over and over, but I have searched the recent posts and haven't been able to find exactly what I need. Our batteries are completely dead, all six of them, 4 house and 2 engine. Our power cord apparently had a bad connection and failed. So what I need to know is how to go about charging them? We have a new charger, but don't want to hook it up to the wrong battery, etc. From what I've read, it sounds like we can hook up the red clamp to one of the engine battery posts and the black one to a steel part of the frame to start charging and with the way they are all connected, they all charge. Anyone know for sure?

Thanks for any help you could suggest!

[nothermark]

Chassis and engine batteries will probably not charge together as the electrical parts that make that work are not powered up. You may also have a problem with your charger not working with a totally flat battery. What I would do is put an old headlamp or similar high current load in series with the battery and charger positive (red) post and the other terminal to ground (chassis). Let it cook for a couple of hours then measure the battery voltage. If it is back up around 12 VDC you lucked out and the plates did not buckle when the electrolyte froze. If they are still lower give them another couple of hours for the chemistry to re establish. If that does not do it they are toast. If they come up to 12 then switch to the other battery set and do the light bulb trick again. The house will take longer because the battery capacity is higher. If you get both banks up to 12 VDC or higher then plug in the converter charger and it should handle the load. I'd be tempted to put the charger you started with on the engine battery overnight to make sure it topped off while the converter charged the chassis. Check the water levels after charging.

The idea of the lamp is to limit the current while the chemistry in the battery is set up then the charger can take over. If you try the charger alone it will probably go into overload and shut down. A headlight is around 20 - 40 W depending on what it is. That will set the maximum current to around 2-4 Amps. That is enough without blowing out internal connections from very high currents like jump starting will give you.

[YC1]

That is fine. As suggested it may not charge both banks. Yours may not even be designed to do that when things are up to speed. Someone will answer that issue.

Be very careful and do as you say, connect the positive lead and then the negative lead safely away from the battery if possible.