So I got this fairly new battery in my SC400. I should actually describe it as "low mileage" because when my Dad put it in 4 years ago, he got sick and never drove it. funny thing about this car is the CD changer is ALWAYS on..whenever you pop the trunk the little light is on the eject button. Anyway, the dang thing's capacity is weak as hell. Itll kick it right over some days but leave it for 2 weeks and it wont even turn it over. Even after a 40 minute drive to a soccer game, it was scary slow cranking over to get home. So I look at the fluid levels and they are a tad low, with the tip tops of the plates exposed so I fill it with Distilled water. No change. So today I bought 24oz of battery acid and a hygrometer. I start pulling samples out of each cell and 1-4 are great, right in middle of green on meter. Cell 5 is terrible, it barely floated the test tube, all the way to the top of the red! Cell 6 was in middle of fair. So I start draining cell 5 with a turkey baster but I cant get past the plates so I keep pulling what I can and pouring in the 37% acid so as to replenish the acid to decent levels. After doing this for about 15 minutes, I get cell 5 and 6 in the middle of fair and Im left with about a quart of weak acid. So I think to myself..." I bet I could boil off the water to make a stronger acid so I could just add it and bring the levels up next time." Well, I google it and sure enough you can get it to like 98% by boiling off the water but you have to do it in a Pyrex or Borex flask on a hot plate...OUTSIDE. Well, why couldnt I do it in my (wifes) Pyrex measuring bowl on my BBQ? Hmm, it looks like it could take the heat if I put a pan under it...Sooo....Ill let you know how it goes once I get a day off and the wife takes the kids to school. BTW, the acid they sell is ~37% and is perfect for a battery fill, but not perfect for a battery booster shot. It needs to be stronger like 50% or so. I understand the dry battery still has the powdered sulfuric acid in the cells just waiting for the distilled water to rehydrate it, but I think this battery needed the good stuff. Ill check it tomorrow to see if it got any stronger or if the charger boiled any off. I liked my old farm charger, that thing would boil a battery dry if you let it. These new PWM ones trickle charge at best and are too smart to overcharge the battery. Heck its a chore just to get it to start charging a dead ass batter, you need to wire up a battery in series behind it to allow it to sense the proper polarity and a voltage so it will even start charging.