13 replies to this topic

[Doff]

Hi

 

We have a 2021 FWC hawk that we bought new.  We made some mistakes our first year and ran our batteries down too low several times.  So, we need to replace them.  I was hoping to get some advice on what we should do.  Currently the camper is set up with two deep cycle AGM  batteries that came with the canoe from FWC.  What would you all suggest to replace with?  Is Lithium the way to go?  Is there a particular battery or brand that you can suggest?  If we were to switch to lithium, are there other modifications we would need to do to the camper to make it compatible with a lithium battery?  Thanks in advance for your tips and advice!

[Wango]

I went through this for about a year and a half. I Bit the bullet, went Lithium and have zero regrets,

Call KP, at Zero Declination. It will sting, but i never worry about power now. 

Vic Harder is another great source of info if you want to try the DIY route.

Good luck,

w

[Cpt Davenport]

I began with the stock FWC 75ah AGM. This provided only 37.5 ah of usable power. This was not nearly enough and would drain down to almost useless in a day. Only form or charging was from the truck alternator and 130 watt solar panel.

 

Upgraded to 100 ah lithium. This now gave me 100 ah of usable power. Also added a 175 watt solar panel in addition to the 130 watt. this would give me around 4 days of solid power with marginal sun (full sun longer). I disconnected the alternator as a charging option as the stock wiring from truck is too small and you need a DC/DC charger for this option. 

 

I now run a 206 ah lithium. Camping in the fog for 4 days with little to no solar charging left me with 78% battery capacity. I added a smart shunt for accurate SOC tracking. I'm sold on this set up! It even seems to charge quicker than the other batteries when the sun hits the panels. I purchased the DC/DC charger and I will upgrade the wire and instal the next time I take the camper off. I'm in no hurry though because with that much battery storage I don't see having any issues unless I go a week in the rain somewhere.

 

Tons of information here on this topic if you search. Bottom line is if you need more power and to save a bunch of weight on your rig go lithium. Sounds like you have a habit of draining batteries. Again go lithium as you can pull them down to 0% with no damage (but you most likely wont). 

 

What do you plan to power?

How are you charging?

What are the average hours of sun you plan to camp in?

How much weight can you handle?

How much money you got?

 

 

Keep at it and you will learn everything you'll need to know from this group of amazingly knowledgable people!

 

Good luck! It's a fun and educational journey.

Edited by Cpt Davenport, 16 October 2022 - 04:01 PM.

[pvstoy]

Hi

 

We have a 2021 FWC hawk that we bought new.  We made some mistakes our first year and ran our batteries down too low several times.  So, we need to replace them.  I was hoping to get some advice on what we should do.  Currently the camper is set up with two deep cycle AGM  batteries that came with the canoe from FWC.  What would you all suggest to replace with?  Is Lithium the way to go?  Is there a particular battery or brand that you can suggest?  If we were to switch to lithium, are there other modifications we would need to do to the camper to make it compatible with a lithium battery?  Thanks in advance for your tips and advice!

 

 

Unless you sorted out the reasons you ran down the existing batteries and now have the proper usage and charging systems in place.  Getting new batteries would still leave you with the possibilities of running the new batteries down the same way.  You did not mention how you moved forward.  Even though you ran down the AGM battery there should be some life left in them unless they were really mistreated and want to divorce you 

[Doff]

I guess I should and I say that, I’m pretty set on going lithium. I am definitely not a DIYer. From what I read I can pretty much swap out the battery without making other modifications. My truck is a 2020 F250. I’ve read about concerns with the alternator. Is that still a concern with newer vehicles? And I’ve read things about installing a DC-DC charger (still don’t get what that is). Do I “need” to install one? And if so, how simple is it to do?

[JaSAn]

I replaced my 8 year old FLA batteries this summer with another set of GC2s for these reasons:

• Cost - $93 x 2 eight years ago, $109/each for 210AH replacements.
• Conditions - I camp a number of times where the temps usually don't get above freezing and can get below 0ºF (longest trip was 18 days).  No problem keeping the batteries charged.
• Setup - my system runs well with FLA, probably have to upgrade other components for LiFePO4.

[Doff]

Unless you sorted out the reasons you ran down the existing batteries and now have the proper usage and charging systems in place. Getting new batteries would still leave you with the possibilities of running the new batteries down the same way. You did not mention how you moved forward. Even though you ran down the AGM battery there should be some life left in them unless they were really mistreated and want to divorce you

I think the initial problem stemmed from parking for a week and living out of it. It was hot and humid. The fridge was probably pulling way too much power and we had both ceiling fans running 24/7. The batteries got fully discharged that week. I didn’t realize at the time that wasn’t good. After that we had planned to keep the fridge stocked all the time and turned on, so we could just hop in the camper after work and go for a quick over night. But again…not plugging in when parked in our driveway and having the fridge running all the time kept draining the batteries. When we’d go for a 3-4hr drive, they would charge back up, but quickly discharge again. I recently checked the battery gauge after the truck had been parked for a few days. It literally read “0”.

With the new batteries we are going to turn off the fridge whenever not in actual use. And when camping turn the fridge off at night. I am hoping that will help alot

[Vic Harder]

+1 to what JaSan said. If you take care of your batteries, they will last much longer. Get yourself a Victron battery State of Charge monitor, some new AGM batteries, and start paying more attention to how you use your batteries and the resulting SOC. From there you can plan a much more expensive swap to lithium.

[ckent323]

Doff,

AGM batteries are fine.  They do not have the cold charging issue Lithium Ion batteries have (can't charge if the batteries are below 32 F).  There are pros and cons to both kinds so it is important to understand your need as well as how you will use the batteries.

We have two Lifeline GPL-4CT 6 Volt Deep Cycle AGM batteries that are just over 5 years old and which are healthy and are working well.  They are heavy though. Lithium would provide the same usable power with 1/2 the weight and about twice the cost.

It is imperative to have a shunt type battery monitor e.g. Victron BVM-712 or equivalent to measure what your actual power consumption is as well as to measure the state of charge of your battery bank.  Everything else follows...

We rarely discharge our battery bank below 65% and almost always fully recharge them everyday before discharging again.  We monitor with Victron BVM-702 Battery monitor which has a blue tooth dongle (it is an earlier version before the BVM-72 with built in bluetooth came out)

We had a two panel 200 W solar system with Victron 75/15 Solar Controller and last year the system was upgraded to a 360 W panel and a Victron 100/30 Solar Controller.  Even in Alaska in September and October last year we had plenty of power everyday to recharge the battery bank.  I don't worry much about battery power and recharging anymore.

I strongly recommend putting the largest single solar panel that will fit on the camper.  The additional cost is marginal.  Price per watt is less on bigger panels.  It is also lighter in weight than using multiple panels. If you already have a solar controller capable of handling a 300+ W panel (24 V - 48 V) then getting more solar power by going to a large 360+ W solar panel is cheaper than changing to (or adding more) Lithium Ion batteries.
 

We camp year around and periodically find ourselves in temperatures around 0 deg.  The camper inside gets down around freezing from time to time.  With the AGM battery bank there is no issue or concern with cold charging.

I have lithium on our boat and I know that it will never see temps below zero degrees.  Weight is not an issue on the boat so I moved the two 100 W panels and the 75/15 Solar Controller onto the boat. They keep the Lithium Battery bank topped off.  I installed a Victron BVM-712 on the boat.

 

Beware of mixing AGM and lithium on a common charging circuit unless you use a DC to DC charger like the Victron Orion.  AGM and Lithium batteries have different chemistries and have different charging profiles.  If you simply put them both on the same charge circuit it will result in overcharging the AGM and your starter battery (in your scenario) will be degraded and have a shorter life.

 

If you do not have a smart alternator in your truck you might alternately consider using a Blue Sea ACR near the truck battery and in between the truck and the camper house Lithium battery bank to protect your AGM battery.

Here is a short video reference:

https://www.pysystem...-the-same-time/

 

I hope this is helpful.

Craig
 

Edited by ckent323, 24 October 2022 - 05:18 PM.

[bajaphile]

What is the amp hours of the current AGM batteries? Are they 12V in parallel? (Id assume 200-250 amp-hours total?).

 

Do you have any solar?

 

Having the fridge running all the time without any solar or hookup while you're parked at home is probably unrealistic. If you're parked in the driveway, you can just plug in. If that isn't an option, you can run solar panels, but that is dependent on how much direct sunlight your truck will be seeing each day. 

 

DC-DC charger is an item which was mysterious to myself up until this last year. I had run smart isolators (ACR's from BlueSea) for years and didn't quite understand what the purpose was for a DC-DC charger. It is meant to optimize the charging profile of your auxiliary batteries though as they may be different or at a different state of charge than your starter battery. You will need one for sure if you get a lithium.