Community Forums

C.Martin · 07-18-2019, 04:50 PM

It's not a question of capacity. We are staying at 97 to 100% SOC the whole time. It's the current or RATE that is my focus.

Wbago97 · 07-18-2019, 04:57 PM

Quote:

Originally Posted by C.Martin

It's not a question of capacity. We are staying at 97 to 100% SOC the whole time. It's the current or RATE that is my focus.

If you are matching what you use then the battery is really not an issue then. Are you only worried about the cables, fuse protection?

10 fan · 07-18-2019, 07:06 PM

When I removed everything in the battery bay I also noticed there was no fuse on the bi directional relay line. I put 400a fuses on both inverters so I put the original inverter 350a fuse on the bi directional line along with a single pole 400a disconnect. I was surprised there was no protection on that line from the batteries.

NealC · 07-18-2019, 07:36 PM

Quote:

Originally Posted by 10 fan

When I removed everything in the battery bay I also noticed there was no fuse on the bi directional relay line. I put 400a fuses on both inverters so I put the original inverter 350a fuse on the bi directional line along with a single pole 400a disconnect. I was surprised there was no protection on that line from the batteries.

Your coach has a nuclear reactor in it, remember we don't have that

10 fan · 07-19-2019, 06:39 AM

Reactor aside, I can't believe Newmar (maybe many others) has 15' of cable connected directly to many batteries with no protection. Not a safe install.

twinboat · 07-19-2019, 06:49 AM

Battery starting cables are exempt from fuses because of the very high currents starters can draw in cold weather.

Alternator output cables aren't always fused because they should be wired with heavy enough wire to handle their maximum output. Of course if you upgrade the alternator, you need to also upgrade the output wires coming from it.

NealC · 07-19-2019, 06:51 AM

Quote:

Originally Posted by 10 fan

Reactor aside, I can't believe Newmar (maybe many others) has 15' of cable connected directly to many batteries with no protection. Not a safe install.

I agree. And no disconnects such as between battery and inverter which I added. I don’t think things like this will change for them until a catastrophe forces them to relook at their design. Wish there was a way to get through to them about these things. I think the suggestions for Newmar thread is a way and hopefully they read it.

10 fan · 07-19-2019, 07:07 AM

The wire being protected from the max output of the alternator is only one of two power sources. Many feet of cable connected to thousands of amps of short circuit current is my point. Especially with the high dollar protection of split loom.

10 fan · 07-19-2019, 07:25 AM

Quote:

Originally Posted by NealC

I agree. And no disconnects such as between battery and inverter which I added. I don’t think things like this will change for them until a catastrophe forces them to relook at their design. Wish there was a way to get through to them about these things. I think the suggestions for Newmar thread is a way and hopefully they read it.

400a disconnects aren't cheap so they probably see those as a convenience. I put both inverters and the house 12v on double pole disconnects so I wouldn't have to worry about disconnecting the positive first (I have always disconnected the negative first, hard to change). Also put the chassis ground on the negative side of the 12v house disconnect. That way if I disconnect positive battery leads and touch metal some where I won't get a surprise.

C.Martin · 07-19-2019, 07:55 AM

Yeah...I think I would like to add a T-Fuse’s...one at the chassis battery cable going toward the Bi-directional relay, and another at the house battery cable going to the bi-directional relay...that way a short, anywhere in between will cause the problem to isolate itself.

I’m actually a bit surprised that the current wiring meets the “code” for RV wiring. You can arc weld with fewer batteries than we have installed. Every other positive cable coming off the house bank is fuse protected. Why did they skip this one???

Nice job wiring your system 10 fan...

10 fan · 07-19-2019, 04:32 PM

Thanks for bringing the chassis side to my attention, I didn't even think of that side not being protected. Will have to give it a look tomorrow. A fuse is cheaper than my deductible.

joes2901 · 07-19-2019, 07:07 PM

The BIRD relay would determine the size fuse to put on the connection between the chassis and coach batteries. The gas coaches have a 100 amp relay and I have a 100 amp fuse installed. Diesel coaches have a 200 amp relay (double check that OK).

10 fan · 07-20-2019, 06:28 PM

I looked at my new BIM and installed it today. LI-225 is rated at 225a continuous and 1200a for 30 seconds. If the chassis batteries are dead and I use the dash switch to connect them I may even blow the 350a fuse I installed. Not sure what the starter draws and the dead batteries may add to the load also. When I noticed there was no fuse I wanted short circuit protection. I had the 350a fuse and holder so I used that one. Not a calculated amount just available and free. Leaving Nappanee Monday so will see how the new BIM works.

C.Martin · 07-21-2019, 10:41 AM

Quote:

Originally Posted by 10 fan

I looked at my new BIM and installed it today. LI-225 is rated at 225a continuous and 1200a for 30 seconds. If the chassis batteries are dead and I use the dash switch to connect them I may even blow the 350a fuse I installed. Not sure what the starter draws and the dead batteries may add to the load also. When I noticed there was no fuse I wanted short circuit protection. I had the 350a fuse and holder so I used that one. Not a calculated amount just available and free. Leaving Nappanee Monday so will see how the new BIM works.

If your chassis battery is dead??? With solar and the Li-BIM...it's not something I would worry to much about, until the Chassis Battery is dead. When the Li-BIM sees a charge source in the House (say solar)...it does a timed cycle relay contact. Those Lithiums have much greater potential than the chassis batteries and will more than likely charge the chassis very easily.

The flip side...alternator charging house is somewhat different. If you are let's say running the Air Conditioner...the Inverter pulls from the House Lithiums mainly. The time cycle on the Li-BIM isn't gonna keep up. So you will drain the House Bank while driving...how fast will depend more on your solar than the Alternator.

Hopefully the relay won't be closed when you hit the starter. I haven't measured the peak amps on the starter...but I've seen the feedback from the field collapsing. I think it spiked to -650A. But it is very momentary. I guess you'll have to carry spare fuses, or a copper bar...in case this causes a problem. But I really don't think the occurrence will be something that happens often or at all.