[WillieG]

I have merged them while plugged in. Our last trip I forgot to merge them.On out drive home about an hour I noticed volt gauge was showing like 11.5V Although I had only driven the coach about 4 times at that point I wasn’t really sure where the Gage had been previously. But when we stop for fuel, I definitely knew the batteries were low. It turned over extremely slow. I feel like somewhere along that last trip that isolator went bad somehow.

[WillieG]

I did change the alternator as it was noisy the rotor or something is cracked and was a clank sound to it.But possibly it had been charging yet. I’m going to take the old one in and see about getting it rebuilt and keeping that as a spare

[Jack Houpe]

You should have an echo charger which uses power from the house batteries to keep the engine batteries charged as a house batteries are charged from the inverter when plugged into shore power. Merging batteries all the time has left some people with difficulties.

[Richard]

I have an isolator that you can have for the shipping.

Email me [email protected] if interested.

[WillieG]

I emailed you about the isolator. Is an echo charger like a mounted trickle charger?

[Highlander4744]

Willie. We recently had the same issue with the delco remy alternator. 
The jumper wire on the isolator is the easiest fix. There is actually a post from 2020 on the same issue. Dario Perini says the jumper wire has worked for him since that time, without problems.

[WillieG]

I’m going to replace the isolator. Doesn’t to much current go through that size of wire the way that’s jumped

[Highlander4744]

The jumper wire has worked. No problems so far.
I didn’t want to replace a perfectly good isolator unless I had to.
If you decide to replace the isolator look at the Victron FETs models.
They are more efficient than the diode based older ones & they have a separate limited energize input that connects to the B+ terminal of the alternator, thus no need for the jumper. Good luck.

[Richard]

First, I apologize, I cannot find the isolator. Corrupted memory chips, for I know I removed it, and I see it in my mind in the spare parts storage area. But no luck on finding it.

But there are two ready solutions.

The first is to install the jumper wire as already discussed. If you are concerned about the gauge of the wire, go to the auto parts store and buy a heavier battery cable. It will fix the isolator problem, but I am not sure if the engine alternator will charge the house batteries with the jumper.

Second, and I am about to get on a soapbox, so the following is my OPINION based upon my own data with same setup that you have. There is a design mismatch between the alternator setup with the V belts and the huge 6 8D battery bank. If you try to charge a depleted bank that size with the V belt setup, the belts overheat, start slipping, and eventually fail. I tried a lot of things to get around that and nothing really helped. The problem is geometry. There simply is not enough wrap of the belt on the alternator pulley to keep it from slipping when under a heavy load. Some, such as Bestgenman, have overcome this problem by installing a larger diameter alternator pulley. If you have a serpentine belt setup, or the monstrous 50DN alternator setup this does not apply to you.

So Newell did what all other manufacturers did, which was to install the isolator to allow the alternator to charge the house batteries while going down the road. Great idea, but the belt setup combined with huge load of charging the extremely large battery bank creates this problem.

If you need to charge the battery bank after a night of boondocking, run the generator and let the inverter charge the bank.

Now, in your case, I make some suggestions.

First, install the jumper as noted, even if you don’t plan on using is that way. Installing the jumper will allow you to confirm that the isolator is the problem.

Second, and this is my opinion. Remove the alternator lead from the isolator and attach it to the chassis lead on the isolator. This essentially removes the isolator from the system. The coach will not charge the house batteries going down the road UNLESS you merge the batteries. That way you are in control, and you can monitor the alternator ammeter to see how big of a load you are putting on it.

[WillieG]

Richard, Right now I have the alternator cable mounted on the chassis post of the isolator. So you say it can be left this way and will only charge the house batteries if I merge them.you mentioned monitoring the volt and ameter.What would I be looking for on those or watching for?