32 Volt Starting Battery Bank

[Briankinley2004]

I have a battery bank that is about to go. Voltage drops rapidly and stays at 24 volts or more for a good half hour after cranking. They charge back up but the cranking load will bring them down to the point even the parallel switch won't re-start immediately. I have a bank that only starts the starboard engine. Nothing else is connected to this bank. Rolls is 6-8 week lead-time for their 8 volts. The place I buy my lead acid from has one 8V-21 in stock and is having trouble getting them. Is there any reason why I couldn't buy two 12 volt 8D batteries and put in series with the one 8volt 8V-21 battery to get a 32 volt bank?

All this bank will do is crank the starboard engine and run the shut down solenoid. The generator cranks off a 12 volt battery and is no longer on this starting bank.

[SKYCHENEY]

They won't charge evenly in that setup. One battery will likely boil while the others try to come up to full charge. All cells within the bank need to be of the same size. Even if the AH rating per cell is the same, the makeup has to be the same. Same number of plates and thickness, etc.

[Briankinley2004]

Would this also apply to using two different types of 8 volt batteries in separate banks. For instance I have a Charles C charger that charges both banks. It only has one indicator needle so I am assuming it charges both banks together. If I were to put the heavier Rolls on one bank and keep the lighter 8V-21's on the other would using the Rolls cause the same scenario being the lead is not as thick?

I don't think I can wait on the rolls as I am temporary staying on the boat and plan to run her as well before 8 weeks.

[kelpy]

Do it correctly the first time. Listen to those that know.

[madhatter1]

Brian, If you need batteries try Electro in St Pete on 22nd Ave N right off 275. Great prices on (at least for me) long lasting batteries. Everything is usually in stock. I am picking up an 8D AGM tomorrow.

And if you go check out Mazzaros market for some excellent cuts of steak, tuna, etc. Also have pans of magical (at least for FL) pasta dishes you can pop into the oven.

[Briankinley2004]

mad hatter thanks for the tip. I will give them a call. There was a place in Clearwater that has them but they want $400 each for lead acid. I can get them in Louisiana for $260 each so I think they are wanting too much. Worse case I will send the wife to LA to pick up 4 and save a few hundred

[SKYCHENEY]

A modern 2-bank charger will charge the banks separately. I don't know about the Charles.

[scottinsydney]

Analytics Systems made me a beaut 32 volt charger a couple of years ago.

[racclarkson@gmail.com]

mad hatter thanks for the tip. I will give them a call. There was a place in Clearwater that has them but they want $400 each for lead acid. I can get them in Louisiana for $260 each so I think they are wanting too much. Worse case I will send the wife to LA to pick up 4 and save a few hundred

Uh... Any outlet malls along that route?

[miboatnutz]

Analytics Systems made me a beaut 32 volt charger a couple of years ago.

+1. We're on Year 2 on our Analytic Systems charger and no complaints whatsoever. It's a two bank smart charging system.