AGM batteries for Johnson 88 SPL

[fishforsanity]

I bought four Johnson Controls AGM non-liquid batteries. I hooked them up to my outboard and got the best responce from my starter ever. 3 of the batteries are group 27 and one is a group 31. I recently had to replace a rectifier and a stator on my motor. I now have a 6 amp system. The stator that I took off had a different look and an OHM reading that started at 1.9 and dropped to .9. The guy at the shop told me that I could not use anything but a wet cell battery. I can not find anything in print to confirm this. The AGM batteries use a special charger that has a different setting for AGM, wet, or gel. I have the batteries paired up in two banks of 12 volts each. Is it safe to turn the key? I really don't want wet cells in my boat because it is constantly bouncing over the waves and the acid will eat through everything.<br /><br />Thanks in advance<br /><br />SkipperArch

 

[fishforsanity]

Re: AGM batteries for Johnson 88 SPL

These are computer batteries that have a L shaped tang on the top of them where a bolt is used to secure the positive and negative cables to the batteries. AGM batteries are all the same I am told as long as the voltage is correct. The shop that sold them to me told me that they are frequently used in vehicles of all types and many off roaders. I was also told that they were used in motorhome applications. By nature wet batteries have more reserve than AGM but AGM are supposed to charge faster. These charge a lot faster than the wet exide stowaway 31's that I bought this season for my camper. They both will run a power inverter and are concidered deep cycle. I wonder if they are too much for the charging system on this 88 SPL (1988)outboard motor that is pushing this 17-1/2' Proline boat.

 

[CATransplant]

Re: AGM batteries for Johnson 88 SPL

Interesting question. To answer it, you'd need to know the current for the proper charging system for these batteries. You have a 6amp charging system. A little research should tell you more.<br /><br />There's a good chance that these batteries require a tapering charge as they reach full charge. In that case, your charging system could conceivably damage them. I don't know, but I'd do a little more investigating.<br /><br />That's a lot of battery power you have in that boat. How are you using all these batteries?

 

[CATransplant]

Re: AGM batteries for Johnson 88 SPL

I went and looked a couple of sites on AGM batteries, and I can't see where their specs indicate that your 6 amp stator is going to cause any problems at all. You'll always be well within the limits for the batteries.<br /><br />Go here, and read up on it:<br /><br /> http://www.batterystuff.com/tutorial_battery.html#3

 

[CATransplant]

Re: AGM batteries for Johnson 88 SPL

I went and looked a couple of sites on AGM batteries, and I can't see where their specs indicate that your 6 amp stator is going to cause any problems at all. You'll always be well within the limits for the batteries.<br /><br />Go here, and read up on it:<br /><br /> http://www.batterystuff.com/tutorial_battery.html#3

 

[Salty Tricks]

Re: AGM batteries for Johnson 88 SPL

Hey Skipper<br /><br />Why don't you contact Optima Batteries (owned by Johnson Controls) and ask them. They were very helpful to me when I was changing my battery set-up.<br /><br /> http://www.optimabatteries.com

 

[fishforsanity]

Re: AGM batteries for Johnson 88 SPL

Thanks, I will go to these sites but I think that I have been there before. Optima is what I was using before and it was ok. There was no info on this particular stator-rectifier set up one way or another. I read about different sized batteries that could discharge from one to another through the rectifier in another thread but am not sure if that was a credible source. I am using a bait tank pump (360gpm) an eagle ultra fish finder an eagle gps (same family) a vhf and a stereo for about 6-8 hours. At night I will need running lights.

 

[fishforsanity]

Re: AGM batteries for Johnson 88 SPL

I called the factory and talked to a guy who was concidered the expert. I told im about the batteries that I had and what I was using them for. He told me that 12v=12v. He gave me the green light. I started the motor and paid close attention to the rectifier. At first it was fine but it began to heat up in about 2 minutes. In three it was hard to keep my hand on it. I shut down the motor and checked the stator and rectifier with an ohm meter. Maybe someone knows something as to why everything is checking out and the system still heats up. Is it supposed to do that? Are the batteries too thirsty for the 13v of power? Thanks for any help.<br /><br />Skipper Arch

 

[blacktip18]

Re: AGM batteries for Johnson 88 SPL

Sorry I don't know enough of the tech stuff. But I use a couple of those batteries on a trolling motor. I got them free from a computer back-up system. Asked an electrical engineer about boating applications and he said the same "12v=12v". I just recharge after use with a little 1.5 trickle charge in the garage. They rock, smaller and lighter.