Forum Discussion

Snowman9000's avatar
Snowman9000
Explorer
Dec 29, 2015

Cloudy electrolyte

Typical group 27 "deep cycle" batteries, in my Class C. Almost exactly two years old. Most of the time the MH is sitting in storage. The first year when in storage, the battery switch was OFF and a Battery Tender was connected.

This year, the MH has not been used for 9 months in a row, and has been in storage again. I had replaced the stock converter with a PD converter which should be fine for storage, and so the battery switch was left ON and the converter was used for the storage needs.

Today in preparation for leaving for AZ in two weeks, I took off the caps of the batteries. Without even drawing any out, I could easily see the electrolyte was cloudy. Some cells white, some darker. I could not even see the tops of the plates even while using a flashlight into the hole.

We are going to be doing quite a bit of dry camping. Time for new batteries, I suppose. That stinks. I realize those batteries are likely cheaply made. I don't know whether to blame them or the converter. Well really, I guess we can blame the long period of inactivity. Ultimately this is user error, but is the equipment partly to blame?

3 Replies

  • Mex, it looks like you are right. Yesterday when I left the unit, I bumped up the PD to the full charge cycle where it goes to 14.4v for 4 hours or whatever. Today the electrolyte looks much better. I used the hydrometer, the electrolyte is clear. I got high readings from it just being off the charger, which had been running at 13.6v. I'm leaving them off for 24 hours and will get readings tomorrow. But all looks good, I think.
  • I'll find my hydrometer and check the SG. We moved this year, and everything is hiding from me.

    Also, I suspect the PD is under-floating during the cold weather. It does not compensate for temperature. Whereas the Battery Tender does.
  • Electrolysis is not a uniform process. Heavy charging can evolve single bubbles, while light charging can bring forth micro bubbles. So numerous and fine, that the electrolyte starts to look like watered-down milk.

    What IS important is the specific gravity. Make sure your maintenance charger has maintained the battery at absolute top level density.

    What you do NOT want to see is reddish or dusky gray electrolyte in the barrel of a hydrometer.

    If it's all correct...

    Electrolyte not reddish or dusky

    Density of all cells at maximum, and no excess drop in electrolyte level

    You are ready to go camping :)

About Technical Issues

Having RV issues? Connect with others who have been in your shoes.24,257 PostsLatest Activity: May 25, 2025