36 Volt In Place Of 32V?

[Brian Degulis]

Many years ago we did some work on a 70' steel comercial trawler this boat had only a 32V DC system with very few electrical acessories. The entire system was shot batteries charger etc all bad. What we did was replace the 8V batteries with three 12V 8D batteries and three 12V battery chargers one for each battery. So we created a 36V system to replace the 32V the chargers were always on so I'm not sure how it would work with alternator charging only it might not bring the batteries all the way up? All of the lights and motors seemed to tolerate the aditional voltage with no problem. One of the advantages I see to this is that you would no longer need a seperate 12V system for electronics etc. With the individual chargers you could tap the 12v off the grounded 12V battery. Also you no longer expensive and hard to find 8V batteries and a 32V charger. I did this about 20 years ago and can't speak for the longevity of it the boat left for Shrilanka shortly after we were done. My 61' MY is 32V and I'm facing some of the problems you guys are talking about and I would be real curious as to your thoughts on this aproach.

Brian

 

[MikeP]

I haven't found any of the 32V stuff to be particularly hard to find. I don't think it would be worth the trouble to try to convert. Hatts came oem with voltage reducers (32-12) for the electronics so there is no advantage to going to 36V for that purpose. The 32v charging system would not charge the 36v batts properly so you'd have to revise that. Also the 36v system would be too much voltage for any retained 32v items.

IMHO there is nothing to be gained by this and a LOT of money to be spent.

 

[SKYCHENEY]

IF you were going to convert a 32v system to another voltage, 36v would be the cheapest way to go, but it would still not be cheap. At least with 36v (vs 24v or 12v), you would not have to change wire sizes, but you would still have to get all new starters and alternators and chargers. Also, new bulbs and converters and volt gauges.

Why spend that kind of money when you can still buy all of the 32v stuff? It is not as readily available and you will pay a little more, but that price is substancially less than the cost to convert the whole system.

You cannot just throw 3-12v batts in there to replace the 4-8v ones. They will not get charged completely and they will not last. If you do charge them completely, you could have as much as 48v and that will not run a 32v blower for long without burning it up.

 

[Brian Degulis]

OK First I'm not sugesting the posability of doing this unless your looking at tired batteries and an old charger. To the best of my knowledge the 32V chargers available today are very expensive and even the new ones are out dated and the 8V batteries are more difcult to find and more expensive. I'm also not sugesting changing all the 32V loads I'm sugesting running them on 36V That's about 1.5 percent higher. The starters and larger motors will definetly handle that. Smaller motors and lights I think would but I'm not sure. And the alternators would proubably need to have the regulators turned up or replaced to get a higher output voltage. Like I said we did this to a simple boat and it apeared to work great.

 

[SKYCHENEY]

A fully charged 32v system is about 34-36volts. A fully charged 36volt system is 40-42v. Thats 20% more voltage. And if your charger periodically de-sulfates by overcharging, you could have as much as 46-48v for a short period of time. This would mean replacing all of the 32v loads with equipment rated for the higher voltage. If you didn't do it right away, you would be doing it incrementally as each piece failed.

I'm not saying that it wouldn't work. But it would be costly. Then I still would not tap 12v off of a 36v bank. You will cause one battery to need more charge than the others and may "cook" the other 2 upon charging. The only way to do this is with a converter or an equalizer. Read Calders chapter on this. He even writes about driving a nail through the case on a 32v system to obtain 12v (which has been done, but he recommends against it just as he does with any other tap of lesser voltage than the whole).

Instead of spending that much money on a complete change, buy some 8v Rolls batteries and a good charger. That should last another 15 years and by then you can reevaluate the situtation.

 

[Spellbound]

Brian -- check your PM's

 

[Trojan]

You could easily convert to the 36 volts with very little trouble. Every thing that ran on 32V could run on the 36V. The only change would be the alternators and chargers. Both charge rates could be set to charge at a lesser rate. Some light bulbs might die a little sooner. But that's a cheap upgrade to 36 when it happens. If you found some long run fans or motor that you though ran on the warm side you could add a small resister. But that's unlikely. No big deal. I would not hesitate to convert if I was in the position where I needed a new expensive charger and batteries. 32 volts was is a stupid design to go to anyway. That was just as bad as 6V cars. I changed all my old 6V boats, cars and farm equipment to 12 volt and never changed a starter and that's a 6v change. I would not change it just because you wanted to. I would need a good reason.


BILL

 

[Brian Degulis]

Then I still would not tap 12v off of a 36v bank. You will cause one battery to need more charge than the others and may "cook" the other 2 upon charging

That wouldn't true when charging with the individual battery chargers as each battery has it's own charger it would be true when charging with alternators.

The actual increase in voltage from 32 to 36 is 15 percent typically you lose 1V thru isolators so you could bring it down even lower if you wanted to. The bulbs I use in my 32V system are actually rated 34V

I'm not certain about the feasability of just thinking about it

Brian

 

[Trojan]

They make a divider that you can charge multi batteries from one source. A fully charged system most likely would never sustain a charge level of 42volts. Plus you do not need to charge to that level. A lower level charge at a longer time is better for the batteries. Heat kills, over charging causes heat. My boat charger runs 24/7 on my 4/8ds. I have never added water in 3 years. I will check them again this spring. If your adding water you had better check your charging system. 32v to 36v is completely feasible. It's just a matter of what you are capable of working with. Change can be hard if your not an electrical minded person. What ever works for you.

BILL

 

[SKYCHENEY]

Okay, before you try it, send a PM to Angela. She had 36v in the boat when she bought it and had to change back to 32v because of all of the problems.

And, after you make the switch, let me know and I'll buy all of your 32v stuff for spares.

 

[Brian Degulis]

And, after you make the switch, let me know and I'll buy all of your 32v stuff for spares.
__________________

Your missing the point I'm not thinking of changing anything except the batteries and charger. I'm thinking of running all the 32V stuff on 36V

Brian

 

[Trojan]

Like I stated. If you don't have an electrical back ground it could be a problem. But then again you don't know back ground of the person that changed the system over. That could be the problem. It could have been a real goober that did the work. I didn't say it was for everybody.


BILL

 

[SKYCHENEY]

So you are going to buy 6 chargers, one for each 12v batt?

Then, lets think about the loads. You're going to run a 32v Windlass, 32v exhaust fans, 32v lights, a 32v alarm panel, a 32v spotlight and 32v starters all at 36v. With the current draw of those starter motors and the windlass motor, are you sure they can handle that? And you still haven't solved the $15 lightbulb issue. If you still use the 34v bulbs and they burn out quicker, that could add up. And how about that Halogen bulb in the old spotlight? I think I paid about $60 for that.

Now, what about an inverter? Do you run that on 24v? If so, will the 2-12v on one bank have enough capacity?

I'm not saying that it can't be done. Just make sure you take all of these things into consideration before taking the plunge. If I were buying a boat like yours, I would feel more comfortable buying one with original systems and wiring diagrams that are still suported by Hatteras when I need to call them, than to buy one that was converted.

Sorry to be so negative on this, but I think you know my opinion now. I just don't want you to get into something that is more than you bargained for. The 32v system is outdated, but you can still make if function and function well without major expense. I'll shut up now and let others comment.

 

[Angela]

In a nutshell, the previous owner's captain tried this on my boat right before I bought her. He put 3 brand new huge 12v batteries on the 32v charger. It does NOT work and Ed and Mario had the pleasure of removing all that.

I don't know enough about it argue the hows and whys, but I do know it doesn't work. I'm back to 4 8-volt batteries in each bank and it works fine.

 

[Brian Degulis]

So you are going to buy 6 chargers, one for each 12v batt?

No it would require 3 chargers the banks can be split to service both sides.

I do believe that everthing would work with good life on the aditional 4 volts but the alternators would not have enough voltage to fully charge the batteries and as Angela experienced the batteries won't last.

Another question Could you build a 32V bank from 2 12V and one 8V battery. Would the differance in AH and voltage have any efect?

 

[MikeP]

Perhaps I'm confused. Are you considering this because the 32v system in your boat is "shot" as you described the 70 footer or because you just prefer having a 36v system?

If the latter, then frankly I don't understand why you'd consider it. The 8V batts are not at all hard to find nor are 32v Chargers. True, you won't find the 8 volters sitting in Kmart but, as Sky said, buy a set of Rolls/Surrettes (oem on our '80 53MY) and forget about it for many years. I will also admit that the 32v chargers seem to all be the ferroresonant types but they give good service and are essentially bulletproof. They require checking the batt water periodically but that isn't much of a chore. I found that in our 53's 8V batts water will drop to just above the top of the plates in 4 months. How much of that is "boiling" and how much is evaporation, I don't know. In any case I check and add water every 3 months. Takes maybe a half hour.

I also totally agree with Sky re the advantage of leaving the oem system in place with support/wiring diagrams, etc available. You will be reducing the value of the boat by switching to a different electrical system than was oem. Adding an additional system - like maybe a separate 12V - is one thing but replacing the oem with a different system is quite another when it comes to resale. If I was looking at boats and the listing stated that the electrics had been "upgraded" to a different spec than oem, I wouldn't touch it. Obviously the resale issue may not be of any concern if you don't plan to sell the boat but it's at least worth considering in the overall plan.

 

[Brian Degulis]

The batteries are are old and tiried and the constavolt is just old. 8V large wet cell batteries are going to cost me $238 each so $1900 12V wet cell of the same AH will cost me $95 each (a special deal we buy a lot of them) so $570 total. The $1300 saved goes a long way towards buying a charger. I agree there are a lot of down sides previously posted and it may not work. I don't agree with it harming resale simply because it's not original OEM not if it's a good idea that works and maybe this one isn't.

Brian

 

[captwoodyb]

Hi Brian, I have a 1972 Hatt, certified for carrying passengers and have owned it for some 20 years. About the same time I bought her I had to replace the 8Volt batteries, total of 8 in two banks of 4. Instead of replacing the large surette batteries I opted for two regular size 12 volt and one 8 volt for each bank or 32volts by two 12's and one eight. I have been using that configuration for 20 years now without problems. .....Capt Woody

 

[REBrueckner]

36 volts instead of 32 volts is an increase of 12.5%. For comparison, a 12 volt system when being charged to 14 volts (before float) is running almost 17% higher than "normal". At 13 volts charging, the system is about 8% above "normal" . But many loads applied at this time would draw down the voltage and the heaver the load, like a starter motor, the more the voltage drops back to 12 and likely below that. In addition, many circuits are designed for a 3% voltage drop and this would also offset such a source voltage increase to some extent.

In theory, with a higher voltage source, motors would draw less current, but in practice they'll likely spin faster and draw more current than at 32 volts. So wiring would have to be at least as large as original because loads will operate above nominal design power levels and draw a bit more current.

I would think two 12 volt plus an 8 volt battery in series ( for 32 volts) would work if you don't want all 8 volt batteries. Place the pair of 12 volt batteries closest to ground, the 8 volt near the 32 volt end of the string. Pick your 12 volt supply from the battery directly connected to ground. You can also e-mail or telephone a battery manufacturer for information...but the few times I have done that I have NOT gotten "engineering" knowledgeable people.

My GUESS is that everything will work ok, but there could be problems. 32 volt light bulbs that die prematurely could be replaced with 36 volt bulbs. One thing for sure: in a 32 volt system, active components (like motors, starters) operating at 36 volts cannot last longer than the original design. How much faster they die is anybody's guess. If there are any 32 volt HALOGEN bulbs aboard, they will almost certainly die faster as they are quite sensitive to voltage.

If you separately charge a 12 volt battery in a series string, I'm unsure how effectively a 32 volt charger would handle the others. Again, in theory it should be ok, but the 32 volt charger now sees a parallel load at the 12volt battery charger level. Ferroresonant chargers taper down as battery resistance increases due to batteries becoming charged; three stage smart chargers use more sophistictaed regulation and might be "fooled" by the presence of another charging source. Correspondence with a battery charger manufacturer might provide authoratative feedback.

 

[q240z]

The batteries are are old and tiried and the constavolt is just old. 8V large wet cell batteries are going to cost me $238 each so $1900 12V wet cell of the same AH will cost me $95 each (a special deal we buy a lot of them) so $570 total. The $1300 saved goes a long way towards buying a charger. I agree there are a lot of down sides previously posted and it may not work. I don't agree with it harming resale simply because it's not original OEM not if it's a good idea that works and maybe this one isn't.

Brian

OR, you could buy the $64 Sam's Club 8v batts and save yourself money over the 12v units. lol

What we need to do is bury Xantrex's president with letters and emails, DEMANDING that they build something special just for us. Or is that too Chris Craft for you guys?