a question for the battery geeks

Nah mate thats tommorrow night. LOL

i did but i broke it. Is it common for a battery with a dead cell to read 11.3v, and go straight to a float charge. If so do i need another battery.
Cheers mate

Yes it is a wet cell batterry. AMPTECH is the brand

yep might head down to battery world tommorow before heading off camping. Sounds like i may be up for new batterry though, cant have the beer going warm on me.

Grungle, I'm about to link 2 70amp/hr AGMs together, one will receive the charge and be parallelled to the other - what are these strict control measures you are talking about? The wire connecting positives will be fused each end.

D-Jack

Hi D-Jack,

You can't do an equalisation charge on any sealed type of battery. This type of charge is for wet cell batteries only where you can take the caps off. You need to remove the batteries from the system and have them in a well ventilated area with the caps off - idealy in a place with access to water as when you do the charge the batteries will gas furiously and you will get some acid spillage from the top.

An equalisation charge is when you charge at boost + 1V (say around 15.5V) for approximately 2 hours and then let sit for around 24 hours. This is a common practice in battery shops and home systems is an option on some smart chargers. It is a process that is designed to shock the batteries and bring all the cells back to the same voltage as you do get some variences between the cells due to fluid differences, age, sulphation etc. It is commonly recommended that this take place every couple of months however literature varies with regards to frequency.

If anyone is to do this type of thing, either get your local battery shop to do it or if confident yourself, read up on this process first and make sure you understand what you are doing - remember acid burns so take the appropriate measures and please do not do this whilst your batteries are still installed in the van.

Regards
David

>You can't do an equalisation charge on any sealed type of battery.

Sure can:

http://www.cdtechno.com/custserv/faq.html#charging

Mike Harding

Well there you go Mike, so you can do it. I stand corrected.

Most of the literature that I have read (including the spec sheet for my Dynasty AGM's) says you can't as the batteries cannot recombine the gasses fast enough hence the batteries swell and deform the cases.

To cover myself then I should say to read the spec sheet for the batteries and see if they recommend that an equalisation charge can be done.

Regards
David

>including the spec sheet for my Dynasty AGM's

Interesting. The spec sheet for my Dynasty (UPS12-310, wonder if we bought them from the same guy? :) gives an eq. voltage?

Mike Harding

PS. iirc wet cell batteries like an eq. voltage of around 16V whereas AGMs seem to prefer (require?) about 14V5.

Quote from http://www.cdtechno.com/custserv/faq.html#charging

"When is the DYNASTY VRLA battery to be equalized?
When a system is initially installed it is recommended that it be equalized at a voltage of 2.4 volts per cell average for 12 to 24 hours. "

That's 14.4 volts - the SAME voltage that every Alternator puts out !

Describing 14.4 volts as an Equalising voltage is truly strange.