Community Forums

RVAJeff · 01-16-2022, 03:19 PM

I've got a new-to-me Seabreeze 2000 and am thinking about replacing the 2 6v house batteries in there with 1 or 2 Lithium 12v batteries. What I thought was a fairly simple matter: replace the charge controller with something that supports charging lithium batteries, buy the batteries, is apparently much more difficult because of the fact that the alternator ALSO charges the house batteries.

In reading other posts, seems like that will literally suck the life out of the alternator and basically destroy it trying to keep up with the voltage the Lithium batteries require.

There's a couple threads on here that make this seem like a project way too complicated for me to embark on...talking about dc-to-dc chargers, ac-to-dc chargers, relays, etc. I'm not an electrician and while I'm perfectly capable of installing a new charge controller and some batteries, I'm not about to get into a complete re-work of everything in the 12v system.

Complicating matters is that the battery box that comes in my RV looks to be specifically designed to only use 6v batteries. There are slotted spots for the two house batteries and I have yet to find an AGM 12v battery that will fit into one of those slots. They're just too short. I've got 12 inches in width max and every AGM I've come across is more than that.

So....I don't know what to do. Any help or guidance would be greatly appreciated. I don't even really care if the alternator charges my house batteries because I'm going to have several hundred watts of solar that will easily keep them topped off.

Iceclimber · 01-16-2022, 05:49 PM

Batteries are probably the most popular topic right after residential vs RV fridge. Here is my advice. Unless there is some super compelling reason to switch, then you will find no more economical batteries than 6v golf carts. If you are stuck with the footprint of two GC's but can go taller, there are other choices like L16's rather huge and powerful 6v's. Plus if you need new inverter/charger etc tends to be a pricey venture. On another topic, as an ex boater lots of yacht guys went great guns for lithium batteries for like a minute, and then for some reason they all went back to either flooded or AGM batteries. As a person that never moved away from 6v's I just went "huh".

TechWriter · 01-16-2022, 07:05 PM

I've leaned on Chad Heiser for advice.

Check out the various RV install schematics on his web site.

jerry8mm · 01-25-2022, 02:44 PM

You need to install an Orion-TR Smart 12 12-30 non-isolated DC to DC charger ($226 from Amazon) between your engine and lithium batteries.

That's what I did, and it works great. The new charger will detect when your engine is running (because the voltage on the engine battery will go up). Then it will start charging your Lithium battery, but only at a maximum rate of 30 amps, so it won't hurt your alternator.

Lithium is the way to go. You can fully discharge the batteries, and they have a 10-year guarantee. They are cheaper in the long run.

DavidEM · 01-25-2022, 02:56 PM

Quote:

Originally Posted by Iceclimber

Batteries are probably the most popular topic right after residential vs RV fridge. Here is my advice. Unless there is some super compelling reason to switch, then you will find no more economical batteries than 6v golf carts. If you are stuck with the footprint of two GC's but can go taller, there are other choices like L16's rather huge and powerful 6v's. Plus if you need new inverter/charger etc tends to be a pricey venture. On another topic, as an ex boater lots of yacht guys went great guns for lithium batteries for like a minute, and then for some reason they all went back to either flooded or AGM batteries. As a person that never moved away from 6v's I just went "huh".

with everything he said. The ubiquitous 6V golf cart batteries give the most bang for the buck when weight or maintenance is not a consideration.

Having said that, two 100 Ah lithium batteries probably won't hurt your alternator. More amp hour capacity than 200 probably will unless you limit the amperage drawn.

David

RVAJeff · 01-26-2022, 04:39 AM

Quote:

Originally Posted by jerry8mm

You need to install an Orion-TR Smart 12 12-30 non-isolated DC to DC charger ($226 from Amazon) between your engine and lithium batteries.

That's what I did, and it works great. The new charger will detect when your engine is running (because the voltage on the engine battery will go up). Then it will start charging your Lithium battery, but only at a maximum rate of 30 amps, so it won't hurt your alternator.

Lithium is the way to go. You can fully discharge the batteries, and they have a 10-year guarantee. They are cheaper in the long run.

So I'm assuming between my engine and my lithium batteries means at my interconnect solenoid? That's the only point I can see from the diagrams where the two are connected. Does that sound right?

RVAJeff · 01-26-2022, 04:40 AM

Quote:

Originally Posted by DavidEM

with everything he said. The ubiquitous 6V golf cart batteries give the most bang for the buck when weight or maintenance is not a consideration.

Having said that, two 100 Ah lithium batteries probably won't hurt your alternator. More amp hour capacity than 200 probably will unless you limit the amperage drawn.

David

Any way to know that for sure? Guess I need to find my alternator and see what it's putting out, lol

jerry8mm · 01-26-2022, 06:18 AM

You could connect the input to the DC to DC charger to the engine battery and the output to your lithium battery. Then you would know that you have it connected correctly.

klspahr · 01-26-2022, 07:41 AM

If you don’t have Solar and plan on adding it Renogy makes a 12V 30A or 50A DC to DC And Solar Input MPPT Battery Charger (for Gel, AGM, and Lithium Batteries). This has an input for your alternator power and an input for your solar power. It will use power from your alternator when available to charge your house battery. When the house battery is full, it will charge your vehicle battery using solar power. One small box does it all. I ditched the isolator relay because this works great. Lithium batteries can pull a ton of amperage from your alternator so overheating the alternator is a real possibility. This will protect you from that.

IdahoBen · 01-26-2022, 09:59 AM

I know this isn't as perfect (or configurable) of a solution as a DC/DC charger but for the most part it has worked well for me. I just replaced my battery isolation manager with this. https://www.precisioncircuitsinc.com...i-BIM-Rev1.pdf

arcaguy · 01-26-2022, 01:04 PM

Quote:

Originally Posted by klspahr

If you don’t have Solar and plan on adding it Renogy makes a 12V 30A or 50A DC to DC And Solar Input MPPT Battery Charger (for Gel, AGM, and Lithium Batteries). This has an input for your alternator power and an input for your solar power. It will use power from your alternator when available to charge your house battery. When the house battery is full, it will charge your vehicle battery using solar power. One small box does it all. I ditched the isolator relay because this works great. Lithium batteries can pull a ton of amperage from your alternator so overheating the alternator is a real possibility. This will protect you from that.

Do you by any chance have a part number or description for this so I can find it on their web site.

I think I found it: https://www.renogy.com/dcc50s-12v-50...ger-with-mppt/