charging a boat battery

[matt167]

My boat came with a 2 year old Everstart marine battery. The biggest one they make. I had very little faith that it was any good, but I stuck it on the bench and charged it until it lit up green and it actually did not take long. Since then it spun the motor over multiple times including at the lake. Now being that a 1966 Johnson RD-28 has no charging system, I stuck it back on the charger in preperation for Sunday when I'm taking it out next.. It sat on the charger showing 50% charge forever. surface voltage showed it was correct. I hooked it up to my Harbor Freight battery tender ( picture of a boat on the package ) and it stayed red for a day. I'm 90% sure I'm not going to trust the battery. and Walmart is on the way to the lake so I'm probably just going to replace it in the launch parking lot or Walmart parking lot... BUT could my standard charger have fried the battery? I've used this charger for years, but I think this is the first marine deep cycle I've hooked up to it

 

[GA_Boater]

On the way to the lake stop at an auto parts store and have it load tested.

Battery tenders aren't meant to charge, rather to maintain a charge. This Spring I hooked up my tender to my marine battery that sat since last fall and it took 3 days to get a green light. It lost no charge over winter.

 

[dingbat]

I ran a pair of Everstart grp. 27 deep cycles for 10 years before needing replaced.

Was going replace with same but found out they are no longer deep cycle. Couldn’t tell it by the marketing but the specifications give it away as a “marine” starting battery that is deceptively over rated.

Batteries, starting batteries in particular, left to sit partially discharged are prime candidates for sulfation. If you want any kind of battery life, the charger has to go on a battery at the end of the day.

True deep cycle batteries are less affected which is why I run deep cycles instead of starting batteries.

Need a 10+ amp charger to keep deep cycles happy. Maintainers will not cut it.

 

[Mcfltfyter]

I do not trust the testers the parts stores use now. I have had cranking batteries sit at 4 volts for several months, yet they don't hold a charge long and the tester says they are "good." Then again, I wouldn't trust a single inexpensive battery on the water. I've had Walmart batteries last a ridiculously long time, but I've had some that developed a dead cell after a few months.

 

[matt167]

My regular charger will do 1A/3A float, 10A automatic or 55A boost start.. The maintainer actually belongs on my spare lawn mower as I had to rig the wiring and it no longer charges

I remember Walmart batteries being decent when they were all made by Johnson Controls ( Interstate ), now they are made by Deka/ East Penn which manufactures most part stores batteries. This is the grp 27 marine starting battery, and is a Deka build based on the serial number.

fwiw, Walmart battery serial numbers starting with JCH are Johnson Controls and are now limited to midwestern states iirc, serials starting with EP are East Penn MFG