battery charging voltage question

davo

Hello again all!
so I have a battery charger its a clarke not too cheap,call it mid range designed for lead acid has two settings high 15amps and low 4-5 amps.
I am using it to top up my trojans on cloudy days,if I put the multimeter neg on battery pos and pos on the pos of charger it puts out between 15-18v! however my battery voltage on the digital display never gets above 14.8 - I think it might if I left it on for ages but I keep a close eye and when its been on 14.8 and starts to flick to 14.9 I switch down to lower setting on the charger and voltage on digi display drops to around 13.5 usually,13.8 if its daylight and the panels are on,so my question- is the charger puting in too high a voltage and possibly damaging the batteries?its approx 12amps on high 4-5 on low and 240ah of battery-I always feel the temp of the batteries and they arent getting remotely warm...seems ok but the high voltage is worrying me!.
trojan recommend daily charge at 14.8 fyi.
thanks in advance for your help!

davo

Re: battery charging voltage question

also another battery related question for you all,I am starting about 4pm with 12.8 and by 10pm I am on 12.4v(under load).my loads are 3.5-4 amps constant does this seem about right for my rate of discharge? 12v 240ah bank.

thanks!

Blackcherry04

Re: battery charging voltage question

davo wrote: »

also another battery related question for you all,I am starting about 4pm with 12.8 and by 10pm I am on 12.4v(under load).my loads are 3.5-4 amps constant does this seem about right for my rate of discharge? 12v 240ah bank.

thanks!

Your post below, 14.8-9 is a little high depending on the battery temperature, I'd rather see 14.5-14.6. Your not killing them though because your absorb is a little lower.

If you consider that you have 120 amp hrs to 50 % dod and your using 20% or 10 % of the total amp hrs, it's not to bad. Every set of batteries I have ever owned had a little bit different way that they discharge and voltage. It's the battery chemistry and alloy material, temperature, load amps. Some will drop off a little faster then stabilize and hang at some lower voltage longer. It's kind of like a gas gauge they are never 100% linear and neither are batteries. Then there is your measuring meter, they not always 100% and it depends where they are hooked up. Sounds like your doing fine.

niel

Re: battery charging voltage question

to put the meter wired in series between the charger and the batteries is for measuring current, not voltage. i hope that didn't hurt your meter. to measure battery voltage put the meter negative on the battery negative and the meter positive to the battery positive with the meter in the proper volts range.