Bulk and float on 6v golf cart batteries

wu9b

I have just connected four 50 watt panels (approximately 18V - 3 Amp) to a Xantrex C40 Charge Controller and in turn to two 6V 220AH golf cart batteries in series (Interstate batteries made by Johnson Controls). The batteries gave me 12.6V when I brought them home from the store and after being on the charge controller all day they are at 12.6V still which sounds OK to this newbie. I have had little opportunity to put any kind of a load on the batteries yet as they are brand new.

My question however is about the proper Bulk and Float voltage settings on the charge controller. The manual suggests 14.6V Bulk and 13.4V Float for Deep-Cycle - Liquid Electrolyte Lead batteries.

The charge controller manual states that the LED will stay on without blinking if the batteries are fully charged and the LED blink slowly indicating that the batteries are not fully charged. I am guessing that behavior is based on my Bulk and Float settings as suggested. Ny charge controller suggests to me that the batteries are not fully charged yet they are sitting at 12.6V.

I am looking for a reality check. Are my settings correct? Don't want to damage my new batteries and hopefully I can have them for a several years of service.

We newbies appreciate the advice of those in the know and thanks in advance for any feedback.

Cariboocoot

Re: Bulk and float on 6v golf cart batteries

Well my advice is to buy a hydrometer and check the specific gravity of each cell. It ought to be 1.265 and 12.7 Volts but remember that temperature and individual testing equipment will make a difference.

A "good read", the battery FAQs: http://www.windsun.com/Batteries/Battery_FAQ.htm

Flooded cells can take a fairly wide range of Voltage set points, with Absorb (which I guess Xantrex calls "Bulk") being 14.4 to 14.8 and Float being anywhere up to 13.8. The best source for this info is the battery manufacturer, as different companies have different recommendations as per their particular product.

niel

Re: Bulk and float on 6v golf cart batteries

you should verify that it went through its bulk and absorb charge to know if that 12.6v means it was charged or not. in other words, did the batteries get to 14.6v or not?

as to the proper voltage settings, that is something the manufacturer of the battery should state as it does often vary from one manufacturer to another.

wu9b

Re: Bulk and float on 6v golf cart batteries

Hey guys,

Thanks for the comments and the battery FAQ link.

stephendv

Re: Bulk and float on 6v golf cart batteries

A problem with the C40 is that the absorb time is fixed at 1 hour- and you can't change it. So you may have to set the absorb voltage a bit higher than normal in order to fully charge in absorb. E.g. if your battery manufacturer recommends a 2 hour absorb at 14.4V, then you might need to experiment with 1 hour at 14.8V. The hydrometer will tell you when they're properly charged.