Hey guys. So I have finally purchased a battery for my boat. It's the Costco deep cycle and it is an awesome battery. It has 140 RC minutes and was only $70. I went to charge it last night and I realized the meter on the charger is broken. I have no way to tell how much I discharged from the battery. It is an old charger but still works. Is there any reasonably cheap way to test the charge on a deep cycle battery? Thanks in advance. I put it on for 6 hours with a slow charge. I just put it at 50% discharged because I only ran it on and off for a couple hours.

One of these if you can take the caps off. http://www.otctools.com/products/professional-battery-hydrometer.

I prefer this style with the thermometer for moe accurate readings. The one like it without the thermometer is ok also. Don't waste your money on those that havethe colored balls or pointer. You can find the one with and without thermometer at many parts stores, eBay and Amazon for $5-10.

Depending on the electrolyte used, a fully charged battery will read 1.260-1.280 after resting 24 hours.

Granted, the ideal way to check it while charging is with a current meter. As the battery charges the current drops as it reaches full charge. Once it reaches full charge the current will level off as some very low rate. This low charge rate should be maintained for approximately 20 minutes for the battery to reach a proper full charge. This 20 minutes or so over charge is called an equalization charge, which ensures all cells are fully charged, and is very important for long battery life. This phase of the charge your cheap hot box automatic chargers can't do, once the current drops drops to minimum, they quit charging.