Alternatives to battery box for venting???

openplanetopenplanet Registered Users Posts: 34 ✭✭
I'd like to know if it's possible to effectively vent batteries by drilling a hole in each cap (on a drill press!), inserting and sealing a small diameter (.25") flexible tube into each, and running all tubes up and out of the structure. It seems to me that this could work, but I might well be mistaken. If effective, this would greatly simplify venting by eliminating the need for a battery box, intake and outflow tubes, and a relay-operated fan connected to either the charge controller or an H2 sensor.

Another question: has anyone had experience with the catalytic battery caps that are supposed to drastically reduce both watering requirements and off gassing of hydrogen?



  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: Alternatives to battery box for venting???

    For motorcycles and some aircraft batteries--They do have a single vent for a plastic tube.

    Should work OK, but seems a bit of a pain when you have to check electrolyte level (tubes and caps getting in the way ~once per month).

    Catalytic battery caps do work--Basically, that is also what is used in AGM type batteries.

    The Catalyst does have a life--Basically some number of AH's of charging (and converting Hydrogen + Oxygen back into water).
    The life expectancy of a Hydrocap Vent is more than 5 years with overcharge rtes below 3 amperes for 2 hours each day. Other rates can be calculated from the minimum expected life of 10,000 Ampere-Hours of over charge current.

    So--If you have a tendency to pump a lot of current into your battery bank (during final charging/equalization) with the cells gassing quite a bit--You can overheat and destroy the caps (the recombination back to water is generating heat).

    Hydrocaps are not cheap these days (one vendor on the web is quoting $18 each--don't know if this is high or low price). Back 25 years ago, they were probably less than $6 each. They contain platinum--And we know what is happening to the price of noble metals.

    NAWS used to carry them, but, if I recall correctly, they were having problems having their orders filled on a timely basis.
    We no longer stock Hydrocaps due to lead times of several months

    You might try Water Miser Battery Caps ... They are cheaper and don't "wear out". Some folks here have purchased the taller version of the caps--They have a more surface area internally to capture electrolyte mist and save a bit more water (I have an on-grid system--Just information from what I have read here).

    If you are thinking of going with Hydrocaps--You may want to look at good quality AGM batteries... Overall, similar life to hydrocaps and a nicer (and more expensive) lead acid battery.

    If you are going for cost and long life, a good quality flooded cell battery + Water Miser caps (if you wish) may be more cost effective.

    And if this is your first off grid power system... Trying a less expensive set of batteries for your first or second bank is probably a better use of money too... Most of us have killed our first set of storage batteries (over charging, under watering, under charging, over discharging, etc.).

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • PhotowhitPhotowhit Solar Expert Posts: 5,653 ✭✭✭✭✭
    Re: Alternatives to battery box for venting???

    Another option is to just not worry about the hydrogen, If your in a large enough room it will dissipate pretty quickly and pass through pretty much anything. So unless you have a lot of push pull or equalize daily, or a tiny room. If it's in your garage, I personally wouldn't worry at all/zero! Perhaps in an RV I might worry a bit.

    I've had hydrocaps 17 years ago(dang I'm getting old) and they do work pretty well, I thought the catalyst was palladium, but same cost rise. I added some watermiser caps to my lift battery trying to cut down on watering and it's helped a bit.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former, 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: Alternatives to battery box for venting???

    You may be right about the palladium... I could not find the catalyst on their website.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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