8d batteries/charging

[Jackman]

Just replaced my 2 8ds because one was hot and only at 6v. The other I replaced because it was time...they were installed in 2006. What amps are considered trickle charge with an onboard charger? I want to make sure the charger isn't shot and cooking them. 2 new batteries installed and the charger was at 8amps...figured they'd be fully charged new.

[Boatsb]

You need to measure voltage and specific gravity to see how charged they are. Just because you just got the does not mean they are new or charged. They could have been on the shelf for months.

[Jackman]

Voltage across the battery posts with the charger on was 12.85 volts. Voltage was 13.5v at charger. Doubt the batteries were on the shelf long. They are a very high volume seller for della. Batteries and starters is all they do.

[bostonhatteras]

8 amps or rather 4 amps each, into an 8d battery is next to nothing. Consider the amperage that the battery is capable of in comparison. However, the 8 amps in relation to what state the battery is in at that time is your concern. A 50% discharged battery getting only 8amps and something is wrong, conversly a fully charged battery with 8 amps continueing to be pushed into it is a problem to. Bring your batteries to what you think is fully charged with your onboard charger, then disconnect them at the battery posts and let them sit and rest for 24 hours to let the electrolyte equalize. Now take a hydrometer and note the spcific gravity of each cell. This will let you know the state of charge of each cell and the battery as a whole. If the battery is fully charged, great the charger did bring it up to full charge. Now hook up the charger and if its a smart charger, it will go through its entire charge profile but then settle down to off or 1 or 2 amps. If not there is something wrong with the charger. Buy a hydrometer and a good one at that, you'll use it frequently. Btw flooded batteries self discharge at a pretty good clip in warm temperatures.

[Jackman]

Guess you were right and I was just a bit more concerned than I needed to be. Checked the batteries 24 hrs later and found the charger in trickle mode at 1-2 amps total. I just thought the batteries were ully charged at purchase. Must not have been and the guy at the shop also said that the last 10% charge on the matteries is typically the hardest part of the charge to obtain.

Thanks again guys!

Jack