For quite a while now I have been thinking that I want to increase my battery capacity. Two 8D's is a bit more limiting than we have been accustomed to prior to having the Foretrav. Options in a U280 are limited unless I want to spend a whole bunch of money that I don't have.i was thinking of replacing the two 8'Ds with six, six volt wet cells.i would have done it before but what stopped me was the fact that I would have to put three batteries on each rack which makes for uneven wire lengths in the series parallel wiring configuration. I had the six volt battery configuration in our fifth wheel liked it a whole lot better than the two heavy 8d's. My question is how much am i going to lose with the weird wiring set up that I am locked into without spending a whole bunch of money.
Roland
Roland,
The answer depends on how many amps you will be using. At low amp draws, wire length is much less critical. So, running regular household 12 VDC for a long time is OK. High amp loads from an inverter, not so good.
So, if low amp draws, go with the "pair above, pair below and split pair".
If high amp draws think about each pair having one battery above, one below). All pairs would then be in the same configuration. Yes, the interconnect cables would be longer, but balanced.
Roland, would you gain amp-hour capacity with the six 6VDC batteries instead of two 8-Ds? Also, consider whether you might experience more corrosion in the battery compartment from wet cells, as compared to gel or AGM.
I've used all wet cell batteries for 4 years and haven't had any problems. I prefer the wet cell tolerance to occasional over-charging, and the ability to test the electrolyte and verify each cell is good. Occasionally adding water is not a problem for me, as I have good access to the batteries.
JD yes I can get more capacity with six six volt deep cycle batteries. My 8d's are wet cells, so no difference there. The watering system makes maintenance a breeze so no difference there either. It's the wiring imbalance that has me concerned.
Roland
I've started hearing of these batteries recently. They appear to straddle the gap between lead acid and lithium ion batteries with their ability to survive being deeply discharged and not requiring a 100% recharge every time. They aren't cheap but they have no problems with dropping below 50% DOD unlike normal lead acid batteries. They come in both 12v and 4v applications.
Firefly Oasis Battery - Carbon Foam AGM (http://www.bruceschwab.com/advanced-energy-storage-systems/firefly-energys-oasis-group-31/)
Firefly International Energy Co | Innovation takes Wings! (http://fireflyenergy.com)
Firefly Battery Report - Inside Practical Sailor Blog Article (http://www.practical-sailor.com/blog/Can-Carbon-Foam-Batteries-Meet-Hype-11694-1.html)
Robert,
Interesting technology. Actually a spin off of Caterpillar Corp (just down the street in Peoria).
I have been in contact with their director of marketing several times in the last 2 years.
They are still not commercially available.
I measured my battery box and it's not tall enough for golf cart batteries, if that's the type batteries you were considering. You'll want to make a taller cover for your battery box to contain the hydrogen gas and vent it out, away from the charger which is located right above the battery box if it's set up the way my coach is. In addition to the other stuff already mentioned above, consider the likely probability of one cell going bad in a battery. With twelve volt batteries you're okay because you can disconnect the battery with the bad cell and still have twelve volts to run everything. This happened to me and I know it's happened to other people on this forum. Also consider the cost of an 8D battery compared to the cost of a golf cart battery. Go to Parts Plus and buy their standard 8D battery for $155. You'll never find a better deal on batteries. They last just as long as other batteries. It would probably cost you four times as much to buy equivalent performance in a gel cell, agm, or golf cart battery. At this price you can trade your old batteries in every couple of years for new ones and still be far ahead. I did a bunch of research a few years ago and found out that all 8D batteries are "deep cycle" no matter what they're labeled as, so don't let them sell you a deep cycle 8D. I've been running these inexpensive Parts Plus 8D ordinary batteries for several years now and they're very high quality even though they're very low priced... If anyone knows of a better 8D battery deal please post it on here cuz I wanna buy some and do a comparison with the Parts Plus batteries.
They are 85 bucks at Costco. Think of a bunch of drunk golfers running around a course all day and turning in the cart with usually completely depleted batteries. The shop recharges them overnight and the very next day, different drunks do the same thing with their golf cart. Golf cart batteries are rated to completely discharge and recharge over 700 times. I doubt 8d's would compare. I use golf carts batteries.
I have been running 4 - 6V- T 145 wet cells for 4 years now, NO problems.
If something or someone screws up and they are run down and damaged I won't slit my wrists if they are ruined. I can also easily handle them if they need to come out of the compartment.
I look at batteries as a disposable item and can't get myself to invest boat loads of money on something that does the same thing but costs WAY more.
Next battery purchase may be a set of 4- L-16- 6V.
Scott
My setup is somewhat different the yours. I don't have a battery box perse my batteries are in the open behind the rear wheel so no danger of explosive gas accumulation. The racks will support golf cart batteries. I ran six volt batteries in our fifth wheel for many years only time I had a real problem was when I ran them dry but if rather forget about that. It's the wiring configuration with three batteries on each shelf that has me concerned..... Load wise as well as getting a full charge on all batteries.
Roland
Twig
How many batteries you be carrying on your setup?
Roland
The l 16's and such can require regular rotation to equalize the wear like most batteries and should have identical length and size cabling.
Also require perfect water maintenace and regular equalization. Out gassing corrodes the terminals and I would reccomend a six month max cable and terminal maintenace schedule.
The hydrogen is explosive and the batteries would need warming plates if used in cold weather.
Some good reading
http://www.vonwentzel.net/Battery/01.Type/
I believe I have the same battery tray as Roland. I put four golf cart batteries in but made a hold down for six. Using the two pairs made it easy to split the loads as they were already split for two 8d units. The cabling for the third pair will can be equalized on lengths. Had I put six of the golf cart batteries in I would have been unable to use the sewer hose holder in the rear of the left side body panel.
Equal length cables with each pair running to a bus bar would neatly solve the cabling problem. Make each vertical pair a team in series running to positive and negative bus bars where they are paralleled, and make the length the minimum needed for the longest run. Place the bus bars to keep the high current run as short as possible... mine was a little different because I have 4 12 volt 8d's in parallel, but the same principle applies. It uses a bit more cable, but it does optimize the connections...
Don
Wow, I just have a single 8D for the coach and a pair of 8Ds to crank the engine. I have very low electric load so a single 8D works great for me. I think my biggest electric load is when I run my laptop computer with a 12 volt DC power cord. I don't use the inverter. I have a gas refrigerator. I'm obviously not a typical Foretraveler... Well if anyone else out there is using 8D batteries buy them at Parts Plus. I don't own stock in the company or anything. :)
That appears to be the opposite of most setups, I would think that one 8D would be plenty of battery for cranking. We have 2 8D's for the coach and after two nights of dry camping and running one furnace all night the batteries are needing a recharge.
But..... we all have different lifestyles and needs. So........ Whatever works for you...... ;D
Nice meeting you at the "Big Ditch", we had a great trip, hope to see you again "down the road"
Justin
We also have one 8d for start batteries and 4 six volt golf cart batteries for the house , works well ^.^d
GBS LIFEPO4 Battery 12 V100AH for electric bicycle/tool/mower etc with... (http://www.aliexpress.com/item/GBS-LIFEPO4-Battery-12-V100AH-for-electric-bicycle-tool-mower-etc-with-connector/2006940816.html?spm=2114.40010208.4.139.UINUFf)
I was thinking of doing 2 of these for the house.. mine are about wore out so I need to figure out what I need and get them soon. Any ideas?
How do you think a 200ah would last compared to 4 8d's?
Sense of humor? replace 1000 ah with 200 ah. and $1,300 to boot.
A little difficult to compare, as Li-ion batteries can be safely discharged far below the 50% SOC used for "regular batteries".
So, for the Li-ions say 200 amp hrs with ability to discharge to 80%= 160 amp-hrs usable
4 wet cell/AGM 8D's: 220 amp hrs times 4= 880 amp hrs with ability to discharge to 50%= 440 amp-hrs usable.
Was thinking the maintanence would be less, I could draw them down 80% and the voltage doesnt drop until it cuts off. Plus the 2k to 5k cycles is a plus.
I think (im no expert) cost would cover itself with time? no? No boondocking as of yet (just overnight). Had a house battery fry last weekend and I think was on the verge of exploding.. that thing got hot and was exhausting fumes like crazy.. what ya think?
The Li-on isnt much more $ to get to that 440 number with longevity. No?( again im no expert)
thanks for the discussion
Sorry, no first hand experience with longevity of Li-ions.
Well treated AGM's, gels and higher end wet cells typically have a 6-8 year life. Poorly treated ones can be killed in a year.
Let me also add I am terrible with batteries :-\ ....and tires for that matter.. they dont like me much!!
I am a busy person and we will use the motorhome 1 time a month approx (thats the plan). just want something that will last and when I get in to drive out I know the batteries will be ok. working 70hrs a week or so is hard to make time for battery care. IF you get my point.. It would be cheaper for me to look into something that will last with less maintenance
Both AGM's and Gels are maintenance-free and if kept on SMART charger (either your inverter/charger properly programmed if on shore power where you store it OR solar with smart controller if stored outdoors) they will live a long life. Only other issue is not discharging below 50%.
These batteries loose a lot of life if deeply discharged or constantly overcharged.
newer mk's have a different plate mounting system according to their engineers phone conversation.
He said he had had many phone calls from Foretravel owners with 10 plus years gels use and he stated the different construction in 2014 could double the life cycles.
Nice guy on the phone. got right through on the switchboard.
I use li-ion on my dirt bike engines. Require warming up to produce the most power.
Really considered a northstar li-ion system like Liberty uses on their busses but two are $12k
One would be enough for my uses.
$2k for three 8g8d's versus $6k? Plus a charger
I'm tweaking my plans to install 4 Trojan L16 (http://www.trojanbattery.com/product/l16h-ac/) 6V deep cycle wet cell batteries. My current plans are to retain the existing pair of 8D house batteries for the standard 12V house loads and add the 4 new batteries wired for 24V.
Going to 24V opens up inverter/charger choices with higher power and charge current capability, and the option to power the entire coach with split phase 240V power instead of just a few dedicated inverter outlets. This will support a future 240V induction cooktop install (for occasional inverter powered usage), and also cuts the DC current in half and reduces the wire size requirements.
Looking at Magnum, Aims and Xantrex 24V inverters, the Magnum and Aims have the capability to provide 240V power without stacking.
Using my existing 12V inverter and a 24V dedicated charger the 12V alternator will charge the 24V battery bank while driving. When on gen or shore power the 24V inverter/charger will charge the 24V battery bank.
Has anyone else ventured into adding a 24V house battery setup?
would not every 12v device need replacing?
Right, that would be a lot of work. I'll leave the existing 12V house system as-is, the 24V batteries and 24V inverter will be a separate system.
Peter,
Do you have 500 pound extra capacity on the wheel position/location in the coach where you want to put them?
Wonder if you would not be more advantageous to add to your current house bank. Remember, the larger the battery bank (all in one bank), the more amp-hrs it can provide (Peukert's law):
Peukert's law - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Peukert%27s_law)
Someone wrote to me to ask how to find the inexpensive Parts Plus 8D batteries I've been using, so here's that information in case others are also trying to find it.
Like most parts stores, Parts Plus has a difficult website to find parts on. The best way is to call the store to see if they have the part in stock. The Parts Plus part number for the 8D batteries I've been using is: 8-DA and I paid $145.82 plus tax the last time I bought one. This includes the core charge for exchanging my old battery. The actual cost of the battery without a core to exchange appears to be $275.97 according to my most recent invoice, which is dated 05 May 2015. I've been using this battery as my coach battery and it does just fine for me. I don't have a heavy electric load. My coach originally came with one cranking battery and two coach batteries. I changed the wiring because I needed more cranking power in cold weather. My two cycle Detroit Diesel uses straight SAE40 motor oil instead of the multi-weight 15W40 motor oil the four cycle engines use. I've never needed more than one coach battery so I'm keeping my wiring modification permanently. My two cranking batteries were purchased at a different Parts Plus store and they're part number PPE8-DA which is probably the exact same battery only with a longer number. Those batteries cost $144.10 each plus tax on the invoice that's dated 19 Nov 2013. The list price was $278.91 which I presume was the price without a core to return. I used these two batteries as coach batteries in parallel for a while, the way the coach was originally designed, then changed the wiring to make them the cranking batteries. All of these Parts Plus batteries have outlasted the original batteries my coach came with that were less than a year old when I bought my coach. I don't even worry about batteries now that I know where to buy them inexpensively. I check the water once a month and pay attention to any particular cell that's using a lot of water. The cell that uses a lot of water is the one that's gonna fail. Honestly, at this price, I'd just go swap out the battery(s) as soon as I noticed a cell using more water than the others. In my experience it's only a short time before the cell fails after it starts using noticeably more water than the other cells.
With golf cart batteries you need a pair of them to make 12 volts so for practical purposes when a cell fails the remaining 6 volt battery is also useless and you'll end up replacing both of them together immediately. With 8D batteries you can isolate the bad battery and continue to use the good one for a while because it still makes 12 volts. The bad cell scenario is common and has already happened to me and to others on this forum.
Here's the website for the Parts Plus catalog: Parts Plus Online Parts Catalog (http://www.partsplusecat.com/) and if you put the catalog number 8-DA in the search box you can find the batteries I've been using.
Yes, I have considered the weight. Still planning, but considering placing the new batteries on the opposite side from the existing batteries. I should get wheel weights before making the final plan.
Also, I was originally going to add the new batteries wired for 12V. My motivation for looking at 24V is the better choices for inverters and to have the 240V inverter power capability.
I set up the 1981 with a Trace SW 4024 with the 4 golf cart batteries in series. Bought a military 24v to 12v convertor with enough power to run all the 12v systems. the only thing that ran off of two of the golf cart batteries was the generator starter. The engine still has the original 12v system. The system still works fine. The invertor has 4,000 watt continuous and 11,000 surge. The 240 volt stove only works on generator or hook-ups. One of the big advantages is charging 150 amps at 24volts.
You need the BMS (battery monitoring system) when you install lithium ion batteries. They won't last very long at all without one as the charging demands of LI are very different than lead acid. The BMS devices that are linked on that site are incredibly cheap and don't seem to be up to the demands of an RV (they claim they are designed for scooters) since they can only sustain 30 amps of charge and discharge current and the chargers that came with FT motorhomes tended to be 100 or more amps. You also will need a cell balancer for LI batteries. These extra devices are required.
For this price you are buying the raw components and engineering the system to work on your own. The batteries themselves look like the batteries that Starlight Solar is using but they've designed/supplied all their own equipment to monitor and regulate the batteries which is really the essential thing.
RV Lithium Battery (http://www.starlightsolar.com/RV_Lithium_Battery.html)
That is another place I was looking.. been reading a little trying to see the differences in them.. The bms is a must I understand. I am kinda looking at all angles on this if I am going to spend the money. Fast recharge is another benefit of the Li-on. Probably headed into arizona in the next month. might go to yuma and look around
The advantages of Li-ion batteries are great. The only issue at this point is still the cost of them, as far as I'm concerned.
If you haven't read this article (http://www.aboutrving.com/category/lithium-ion-batteries/), I'd recommend that you do. This person's real world usage indicates that his Lithionics batteries lost about 4-5% capacity per year which seems to line up with what Technomadia (http://www.technomadia.com/lithium/) has been reporting that they lost.
Think I'll wait a while on the Li batteries. Have a nice 40 in LED TV for under $200 a couple of months ago. No idea what it would have cost when they first came out but if I wait on the batteries and full time and live long enough I'll probably get a great deal on them as well. Meantime I'll just keep the AGM's charged.
I'm with you, Larry. Being a "early adopter" carries both risks and rewards. We tend to buy in on the downhill side of the "Innovation Adoption Lifecycle" curve. Extreme example: we just bought our FIRST smart phones last year! However, I DO always try to encourage and applaud the bold pioneers...I'm behind them all the way! ^.^d
I've thought about it more than once, but I've never progressed beyond thinking since I seem to already have way too many projects!
I believe the 24-Volt system has advantages when using an inverter to supply 120/240 AC power and I'll be interested to read your reports as you progress.
My reply #33 above is the way I did it. The 240 volt is only necessary for my stove and the generator has to charge the batteries anyway so when cooking, charging..
I am very interested in lithium batteries, but the cost/benefit for us does not make sense. The L-16 batteries add a lot of extra capacity and I have seen Ted H's 4 L-16 batteries this past winter at Quartzite. They worked well for him and really cut down on his generator run time. He has a watering system on them so it is pretty easy to take care of.
I have noticed that you can also get L-16 batteries in AGM. So many things to think about but my 8G8D's were replaced in 2013 and doing well, so I will keep using them as long as they hold up. My original gels lasted from 2001 until I replaced them in 2013.
^.^d
If you are considering lithium, take a look at this site and his experience, Living the Lithium Lifestyle – 3.5 Year Lithium RV Battery Update | Technomadia (http://www.technomadia.com/2015/02/living-the-lithium-lifestyle-3-5-year-lithium-rv-battery-update/)
Please forgive my ignorance. What happens to a 24 volt system when one of the golf cart batteries loses a cell? Do all four batteries have to be replaced immediately or can you run on two of them for a while? If for some reason you can't run your genset is there any other way to charge the batteries, for example, can you start up your coach and drive around a while with the alternator charging the golf cart batteries? I'm curious because I've found myself camped in places where I wasn't allowed to run my genset. I suppose you could run your genset while driving around and then return to your campsite later. Are you using an additional isolator to split up the two pairs of golf cart batteries so the alternator can charge them?... I dunno, these are the questions I think about while reading this thread... and I confess it makes me appreciate gas appliances
On my 24 volt system the generator was the only way to charge them. They made parallel switches years ago in trucks to charge with a 12 volt generator, before alternators. I have never camped where generators were not allowed. The main reason I converted the '81 was economics. I was able to buy the Trace SW 4024 on Ebay from one of the y-2k people that thought the world was coming to an end in 2000 for a few hundred dollars. Because the coach was all electric to begin with my options were few. 24 volt only need half the wire sizes and charging 24 volts at 150 amps cut down on my generator hours.
To answer your question about losing one cell it never happened, but if it did I would have replaced all four.
Trollbridge2400 Information (http://www.yandina.com/troll2400info.htm)
That is what you need to charge a 24v bank off a 12v alternator/charger.
24v battery bank would be ideal if you had solar. Much higher efficiencies in charging/inverting And a 24-12 stepdown would allow you to run your existing 12v house system off a small lightweight 12v battery and keep it charged off the 24v bank.
Ive thought about the ultimate boondocking setup. Replace the house batteries and the huge FT genset with 48v of L16 or lithium (pick your poison). Install a small semitruck APU, as much solar as possible as well as a victron inverter/charger/solar/genset autocontrol. Run the house 12v lights off the engine start bank and charge with a 48-12v stepdown converter. You could easily live without running the genset much, even running AC off such a system for a few hours a day with good solar. Perfect for following the weather around the country and staying mostly in mild climates.
Setting up a 24V inverter/house battery bank is a challenge - solving all the issues is why it is so much fun ^.^d
The Trollbridge 2400 looks interesting, but it appears 24V is not available during alternator charging (12V batteries are in parallel). I would like 24V inverter power to be available in the coach while driving for fridge, microwave, coffee, entertainment system, etc.
With the high efficiency available now in inverters and chargers, I plan to use my existing 12V inverter (powered by the 12V alternator/house batteries) to run a dedicated 24V 50A charger to charge/power the 24V bank while driving. When on gen or shore power, the main 24V inverter will charge the 24V batteries. No plans to go solar right now, but a 24V solar system could easily be added once everything is up and running.
I didn't need to charge the 24 volt batteries from the alternator because when ever we used the coach we needed air conditioning. So generator would be running and a 12.5 kw Yanmar marine generator had no problems charging and running 2 a/c units. Marine 10 gal. electric water heater also. here is the pic of the step down convertor. Steps down anything under 50 volts.