What size converter charger should I get?

Matt_Colie wrote:

They said that you really can't charge a battery too hard if you do not over voltage the charge.

This is true but it's a funny way to state it.
It's kind of like stating that water will not overflow out of a bucket if you don't put too much IN it. ;)

Matt_Colie wrote:



Please do not parallel 12V jars. Even if they were side by side on the assembly line, by the end of the third week, they will not like playing in parallel. If you are lucky, you end up with capacity * 1.7. It will more likely be 1.5.

Please explain ...

Tassel,

I learned most of what I know about batteries from two guys that had run submarines in WWII in the pacific. They came back, so I guess they got it right.

They said that you really can't charge a battery too hard if you do not over voltage the charge. With a modern 12V jar, that is about 16V. None of the good converters go over about 14.5. Because if they do, then you have to replace a lot of light bulbs and other stuff.

The modern 3~4 stage chargers like a 9245, cannot hurt a battery. It will charge it at the best rate that the battery can take and then, after a few hours, it will back down and ask the battery how it is doing. That is what you want. If you later can go to a pair of GC2s, that same 9245 will serve you well.

Please do not parallel 12V jars. Even if they were side by side on the assembly line, by the end of the third week, they will not like playing in parallel. If you are lucky, you end up with capacity * 1.7. It will more likely be 1.5.

Before the depression killed my boat business (no, it is not coming back) I used to have this go-round with owners all the time. They didn't like it that I was right.

Matt

Progressive Dynamics 9245 is an extremely popular converter. That is a 45 amp unit that will work well with one or two batteries.

Consider that a 12VDC battery will demand 17-20AMPS DC CURRENT if you hit them with 14.4VDC Boost Charge voltage whewn charging. This will give you a 90% charge state in a short three hour time frame and then you can reuse the battery again until it runs down to around 12.0VDC...

If you ever plan on going with two batteries on your trailer than you should get a 45AMP Converter/charger unit as both batteries will then demand a total of 34-40AMPS DC current when hit with 14.4VDC boost charge voltage....

You want your battery to make it through at least ONE NIGHT on a battery run and then if you have a 2KW Generator you can hook up your trailer shore power to it and get back in business again for the next day/night run off your battery...

ALot of places will camp at have generator run time restrictions so you want to get your batteries charged back up to their 90% charge state as soon as possible.

Roy Ken

2oldman wrote:
Is this a real consideration? I mean, can a single small battery be harmed by say a, 100a charger?

Yes if it is a cheap single stage one.

Getting one that is an automatic two or three stage is probably more important than the total capacity.

If it automatically steps down as the charge goes up, you can get one with a larger initial capacity for faster charging.

Is this a real consideration? I mean, can a single small battery be harmed by say a, 100a charger?

There are smaller but 35 amp will serve you well.

What brand/model are you looking at? Mostly plugged in or will you be charging on generator power?