Need battery help and advice

[mrdeepseafisher]

Well it never fails, anytime we are planning on the boat fro longer than a weekend something pops up. Our heads are not working and we noticed that when the water pump turns on the 32 volt lights will dim. I checked the charger and it is fine, Knowing that all our 32 volt circuits are off our port battery bank I asked my wife to flush the head while I held the parallel battery switch. Heads flush fine when we do this.

So I check the port battery bank and I have 32 volts, but have no real way to load test the bank. Tried to start port engine and will not turn over without using parallel switch. At this point I am thinking I have a bad battery or two. We seem to have 32 volts but not amps to do anything other than run lights.

I have traced wires looking for loose connections and what not but we don't seem to have any.

So here's my question.

1. Do I most likely have a bad battery or a whole bank?
2. Should I replace a battery or the whole bank?
3. Is there any way to load test each battery while sitting in the boat (With each battery disconnected from each other)
4. What have I over looked and will regret when we are out on the hook all next week?

Batteries are as follows:
port bank- (installed in 2008) 4-discover AGM 8 volt

starboard bank- (installed in 2010) 4 full river AGM 8 volt

Thanks for the help.

[Canuck Dennis]

Firstly, you should have 36.5 volts at the bank, not much point doing a load test without proper voltage, check water levels, SG in ea. batt and charger output before anything else, if your charger is low output, start em up and use the alternator to give them a boost, start from there.

[jim rosenthal]

You at least have one bad cell (which means that battery is bad) or more than one. I can't think of any way to test them other than to free up all the connections and climb in there with a load tester and test each battery. I suppose if only one was bad and the rest were all fine, you could replace just that battery. They are five years old, so they are out of any warranty with which I am familiar; I think that's as long as they go. I think I would replace any battery that seems marginal with the load tester.

If you don't have a load tester (and most folks don't) I would see if the local supplier of AGMs is willing to come to the boat and test them with you, with the understanding that they will be selling you whatever replacement AGMs you need to get that disabled bank up and cranking.

Good luck, and let us know what you find out.

[Boatsb]

What type of batteries are they. Starting or deep cycle? Just delivered some full river batteries to a customer. Deep cycle for his electronics and a pair of 31 starting batteries for his genny. I bet he gets more than 5 years on them.

[jusbumn]

I just recently had to replace all four batteries in the bank. 1972 58' YF. The local "marine" supplier wanted $428 for each battery. I did some research and found that the Penn battery builder in Pa builds the same battery for a lot of companies that put their own label on them. I was able to purchase them for $228 from a nationwide auto parts store locally. Carquest is the national chain.

[Boatsb]

I just recently had to replace all four batteries in the bank. 1972 58' YF. The local "marine" supplier wanted $428 for each battery. I did some research and found that the Penn battery builder in Pa builds the same battery for a lot of companies that put their own label on them. I was able to purchase them for $228 from a nationwide auto parts store locally. Carquest is the national chain.

Not true. Each customer has the batteries built to their specs. Johnson controls makes batteries for interstate and walfart. No similarities except sizes. I just took out some group 31 batteries that failed. They were noticeably lighter than the replacements

[jim rosenthal]

What Scott said is right on the money. There are probably only a few battery factories in the country (East Penn, Johnson, a few others) but the company with the name on the case gets to pick the specs. You generally get what you pay for. Cheaper batteries have thinner plates, less reserve room for acid in the bottom, etc.

You should look at Trojan batteries, if there is a source near you. They make their own batteries, I think, and I have had very good service from them over the years. Odysseys are good, too, but I don't think they make eight-volt batteries.

[Boatsb]

Even the good companies are having cheaper versions made to sell to the cheapskates.

[Pascal]

1. Do I most likely have a bad battery or a whole bank?
2. Should I replace a battery or the whole bank?
3. Is there any way to load test each battery while sitting in the boat (With each battery disconnected from each other)
4. What have I over looked and will regret when we are out on the hook all next week?

It maybe just one bad battery but at 5 years old it doesn't matter...

You should alway S replace the whole bank, unless it s fairly recent like a year old or so

32 volts is too low for a 32v bank. Check the voltage with the charger off then on to make sure charger is working. Check starboard voltage too. It is possible that the charger is out and the port bank is the first on the below,since its your house bank

Personally i think an excellent upgrade is to install easy to read digital volt/amp meters in a spot where you always see them like in the helm overhead or by the stairs. This way you can spot trouble right away

[mrdeepseafisher]

Today's update, after going to the hardware store this morning and buying a real digital meter (left good one at home) I rechecked both banks.

I turned off charger and both battery switches in engine rooms to isolate banks. Starboard bank is reading 40.1 volts and port bank is reading 32.9 volts.

I turned on the battery switch to use 32 volt lights and watched the voltage fluctuate on port bank from 32.9 - 29.2 volts.

I turned on charger and checked we have 18 amps and good voltage going to both banks. I felt each bank and all batteries are warm to touch so I grabbed my infrared gun and shot each battery. It looks like the further most battery in the back of the port bank is shot? It is cold to touch and 15+ degrees below others in temperature.

I have spent the last 2 hours calling around Wilmington NC for a 8V AGM battery. No luck. Many places are trying to get me to buy wet lead acid but I have explained the need to keep all the same due to charger settings.

One vendor has offered to sell me all 8 (both banks) wet cell lead acid for the price of the 4 AGMs. I have had good service and no maintenance for the AGMs. Am I crazy to go back to wet cell?

Anyone know where to get AGMs within a few days? Already tried Sams Marine.

Thanks.