Suggestions on Upgrading stock coach batteries to 400 Watt from stock 160 Watt

[odonnell71]

Hi Airstreamers - Looking into upgrading the normal 160 Watt Coach batteries to 400 or 800 Watt... Ive been Boondocking a lot and a lot of mornings I wake up and the battery is almost drained or drained.... I learned that only 80 Watts of the 160 is usable and you get about 300 charges out of the coach batteries... Does anyone have any suggestions? I gather the 400 Watt Batteries are larger... Im in a 2014 Airstream Interstate Ext... How expensive would it be to do this? I was also looking into a simple bike rack for the front of the Sprinter Van but didn't find anything - Love my AI - Pat OD

[wulfraat]

I believe you mean amp hours, not watts. You'll likely be looking at lithium and that type of energy Managment system will likely run $10k - $20k professionally installed to include solar and a hybrid inverter, etc.

Here is an interstate thread on this topic:

http://www.airforums.com/forums/f240...es-151809.html

Give AM Solar a call and they can help you assess your options.

[FlyFishinRVr]

Lots of threads on this topic. A quick search will give you ideas on everything from a relatively simple and cost effective solution (convert to cheap 6v golf cart batteries and add a bunch under your coach) to complete remodels of your electrical system and switching to lithium batteries (at great cost). Read up and see what might be right for you.

[Camerons]

This is likely the most cost effective way to go. Having done this I find that the batteries last all night running furnace even at -10c. Even cloudy days add enough power back into the Batteries. This is running fridge and freezer as well.

It's not that hard a job to do yourself. Lew can do a great professional job. Add an ags while you're at it.

I like north of toronto where skies are grey a lot. Here is the set up that worked for me.

4x100 w solar. From am solar
Victron charger and Bluetooth (awesome to check charge state from phone)
Magnum me rc50. Great to use ags and bmk
Bmk to know what is going in and out of battery
Ags to start if batteries are low or van gets hot (dog inside)
4x 160 agm batteries hung under rear

Lithium would be great. Just really expensive. Need to determine how much solar you will get based on where you are and how much power you use. Bmk helps a lot with this.

[Scorge-ION]

If you're wanting to increase the lead-acid battery storage, The easiest and most straightforward thing to do would be to put two 6V batteries in series.
Several sizes are available: Groups 27 and 31 are the most common RV house batteries.
Group 31 batteries have more than 100 Ah in 12V or 200 Ah in 6V. I prefer the round figures and the ratings are for new batteries that won't have that capacity for long, so the lower figure is a better estimate.
Two 6V Group 31 in series will give you 200 Ah at 12V.
You can get Group 31 in 2V cells that can give you more than 600 Ah but the prices of 2V Group 31 are prohibitive. You would need six 2V cells and connect them in series. Six of those is a lot of weight and space.
Figure on 65 lb/Grp31. Six would be almost 400 lb.

However, golf car batteries will give you more bang for your buck. If I was building a battery box, I'd use 6V GC2. You can usually purchase them for $150-$200US. They typically hold about 210 Ah at the standard 20-hour rate. CF VRLA-AGM Group 31 deep cycle @ 200 Ah for $150-$350US.
http://www.trojanbattery.com/product/31-agm/
http://www.trojanbattery.com/product/t105-agm/

Recommendation: get for-real VRLA-AGM deep-cycle batteries. Batteries are sometimes labeled Valve-Regulated Lead Acid (VRLA) or Absorbed Glass Mat (AGM) but it's all the same battery. They are much safer than flooded batteries: they must be brutally abused to give off explosive hydrogen and they don't leak even when split open.
Yes, flooded batteries are 1. less expensive, 2. higher capacity, 3. more efficient. Improved safety overrides those.
Get real deep-cycle batteries. You'll find lots of "marine deep-cycle" batteries that are primarily for starting boat motors – avoid them. Avoid any battery that's rated in CCA or CA (cold cranking amps) because they won't have the long-term (deep discharge) capacity that a real deep discharge battery will have.

Happy trails from Dave, the Scourge of the ION

[Lotus54]

It was noted above- but make sure when comparing batteries the company is using the same discharge rate.
I've certainly seen different rates commonly used.

The big storage batteries we used (that easily last 20 years- still have ones almost 30 years old in service) were on an 8 hour rate. The banks we used were 1600 AH at an 8 hour rate (if my memory servers correctly).
Now, these are quite large and heavy lead/calcium and certainly wouldn't work in a MH.

When replacing mine I just went with the largest deep cycle AGM that would fit in the space I had. (100AH at 20 hour rate)

Mark