Tag Archives: AGM Batteries

batteries, Electrics, learning

Replacing Bus Batteries (Part I)

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So, I’ve always tried to be careful about the bus batteries.  Without them the bus really doesn’t move, which can be frustrating as you sit in your driveway ready to go somewhere, and really frightening if you’re at a site and it’s time to leave. I’ve run into both of these situations, and learned a lot from them.

The two batteries wired in in parallel.

One of the things I had learned was that the two batteries that our bus came with didn’t keep a charge long-term. When we first got it, and I discovered this, I went through the system with as fine a tooth comb as I could for the seeming miles of wiring looking for places where there could be a drain.

I ended up removing a tachograph which had a clock that kept running, and disconnecting a number of system from power, even though they were on a circuit that ran off the ignition switch triggered power relay, just in case.  The one thing that I couldn’t detatch was the ECM, which draws some 700 mA  to maintain the error codes and other brain-related functions.

In order to combat this small drain, I picked up a small solar panel to essentially be a trickle-charger and offset the ECM’s needs over the long periods of not being used. 

As our driveway faced west at the time, and the house and a big elm tree blocked the southern light, I ended up mounting it just on the windshield defroster duct, and running the power over to the line that connected to the batteries/ECM/alternator inside the cab.

While this helped, I continually was having problems if the batteries were left alone, to the point where I’d throw them on the charger before I went anywhere if I hadn’t had a chance to start the bus in the last month.  Overall, it wasn’t so bad.  And after the bus had run for a bit, the batteries would be fine.

Once I installed the DC inverter and ran AC power in, I had thought things would get a little better. The inverter was supposed to not only change the AC power to DC, but also charge up the DC batteries.  I had hooked it to the house batteries, but found after our fateful trip to Evangola State Park (when the alternator died, as did the bus batteries) that it wasn’t doing any charging.

Subsequently, I got a couple of battery-tenders for the battery sets. 

Products from Amazon.com

These will give a full charge, if needed, and the switch to a trickle when the batteries are set, and will work for either AGM, sealed, or lead-acid batteries.  And up until this spring, they worked like a charm on both battery sets.

Unfortunately, due to a number of factors, I didn’t move the bus (or even try to start it) from October to April.  It sat with the maintainer attached, so I wasn’t worried, but when I went to start it to go get it inspected, there wasn’t enough power in the batteries.  A little annoyed, but otherwise un-phased, I got out the car charger, and sit it up to charge overnight.  The next day, I went out to start it, expecting the batteries to be ready, as they usually were after a charging event like that, but they just barely got the engine going.

Usually after some driving time the alternator cranks out plenty of power to charge the batteries, and as I watched the voltmeter on the dash, I could see that the alternator was pushing out 14 volts (which is pretty high compared to the 13 or so I normally see), so I was sure the low batteries were getting what they needed.

So, it was a bit of a surprise to talk with the dealership on the phone (there were some issues with the suspension system in order to pass inspection) and find out that the batteries were dead when they went to bring it into the garage for the inspection.  They asked if I wanted them to deal with the batteries, and I said no.  So long as they could give me a jump to get the bus back home, I’d deal with it.

One of the big reasons for this is that if there’s a short somewhere that’s causing the drain, it could rack up some serious dealership-level mechanic’s hours in fees.  And it’s something that I could trace and deal with on my own.  I was also sure that nothing was an unnecessary parasitic draw (the radio, for example, runs off the house batteries, so even the electricity for the memory for the preset stations doesn’t drain the bus batteries), and I didn’t want to have mechanic time going to check that.

So, I started in on testing …

(Continued in Part II)

batteries, bus trouble, camping, Destination, driving, Electrics, Evangola, horns, Presque Isle, school bus RV, Skoolie, trip

A Trip to Presque Isle State Park, PA

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So, on the 13th of July we set out for Presque Isle State Park in/by Erie, PA.  Our son had a day’s worth of homeschool classes on aquaculture, swamp & beach biomes, the geology of the park, and preservation and maintenance of the park.  While it was only two and a quarter hours away from Buffalo, as the classes started at 9 am, we decided to camp overnight.

Our trip was uneventful, except for the fact that I made the mistake of topping up the coolant level in the bus before we left.  Why was this a problem?  Because there was a small leak at the coolant reservoir that dripped down onto the alternator, frying the voltage regulator.  By the time we had hit the Angola Rest Area on the NYS Thruway/I-90, we were running on battery power.  But as on our Evangola trip, I knew that the engine would keep running fine, but unlike that previous trip I had the house batteries fully charged, and chargers for both the house and bus batteries that would work when we got to shore power.  But now I knew the reason WHY the alternator was failing.  Unfortunately, the fluctuations in voltage damaged the board in the fridge, though I got it to work for part of the time we were plugged in.

We stayed at Sara’s Campground, whose lands abut right up to both the Presque Isle State Park and the Tom Ridge Environmental Center.  Their grounds also have sites on both sides of Peninsula Drive/Route 832, the east side has sites for actual beach camping (in tents), and the west side is in the more forested area.

Sara's Campground Site Map
Sara’s Campground Site Map

So, we ended up getting Site 21 in the Forest Section.  It was our first stay in a private campground, and I was frankly surprised at the density of sites! The dashcam recorded our trip into our site, including the trepidation and worries I had of getting the bus in a place I’d have to back out of.

Sara’s Campground, Site 21, with the bus all settled.

But the site was fine.  The electric/water pole had a streetlight on it, so we had to put a blanket up over the windows on that side (thankfully magnets hold to bus steel wonderfully).  But there were no sites to our starboard side (where the firepit was), so it was a nice open site (next to a parking lot). And the concrete pad was very nicely level, so everything was comfortable.

Saras Campground, Site 21, with the bus settled and the fire burning down for Toastites.
Saras Campground, Site 21, with the bus settled and the fire burning down for Toastites.

But right across the street (via a crosswalk with speedbumps and a pushbutton controlled set of flashing lights to cross) was the start of Presque Isle’s beaches, and we walked all the way up past the first couple of breakwaters.  We did a little beachcombing, then returned and we made a fire and some lovely toastites for dinner.  We had some people stop by, interested in the bus, and we gave them the tour, and some skoolie info, as they had expressed interest in working up their own.

The sunset over lake Erie, shining right through the back window of the bus.
The sunset over lake Erie, shining right through the back window of the bus.

A little while later, as the sun was setting, we found that the sun was setting directly behind the bus, through the path to the beach.  It was, however, it was basically 9pm, so we were forced to get to bed before we felt we were ready.

Our next morning was fine, coffee and bowls of cereal for breakfast, and as the engine was running and I was doing our pre-trip, folks came over, interested in the bus. Alas, we didn’t have time for a tour, and weren’t returning, but they thought the concept was cool and were absolutely fine with us being there.

Unfortunately, given the short timing of us getting to the Tom Ridge Center for the aquaponics class, and then us getting from that class to our pontoon boat tour, I forgot to turn the dashcam on for those trips. But after the boat tour, I remembered to turn the cam on, so we have a video tour of Presque Isle, sped up 4x.  You miss out on a whole bunch of the cottonwood tree seeds floating about at that speed, but I recorded us getting from the tour to Barracks Beach, and then down the beach road to the Tom Ridge Center again, and then around the whole park once more.

 

Our trip back was uneventful, except for the one tractor-trailer driver who LOVED the train horn.  He paced us while we were still in PA, blew his horn and motioned for me to blow ours and gave a thumbs-up when I did, and hung out in front of us to break air for us until he got to the Angola, NY exit where he sounded his horn again and waved, and I sounded ours again.

batteries, Electrics, school bus RV, Skoolie, Uncategorized

Cold Weather Care and Feeding of Batteries

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A recent discussion and some questions on the subject of batteries gave me the idea to sum up what I have on the subject in hopes that it will help other folks’ batteries to last longer.  For the RVer who wants to stay quiet, a good, reliable battery bank is the way to keep so many of those systems that make camping life so comfortable going, and most of us can’t afford and don’t want to buy those expensive new batteries often.

There are a number of strategies when choosing batteries for your RV/Camper.  Some people choose one single large battery, like this ‘universal replacement’:  This one has a rating of 200 Amp-hours (It would last for 200 hours under a constant 1 amp draw, or 1 hour at a 200 amp draw) at 12 volts DC, which is the usual power system for your regular vehicle and most RVs.

Some folks like to use golf cart batteries, as they can be obtained used, and even as 6 volt batteries, can be hooked up in series to make a 12 volt output and are often fairly cheap, like these (new): These, hooked up as two sets of series connections by a parallel connection would yield 140 Amp-hours at 12 Volts DC.

Now, the ones above are AGM (Absorbant Glass Mat) batteries. This technology became popular in the early 1980s as a sealed lead acid battery where the acid is absorbed by a very fine fiberglass mat, making the battery spill-proof, and means that it can be mounted in any direction. These batteries have very low internal resistance, are capable of delivering high currents on demand and offer a relatively long service life, even when deep-cycled.

AGM batteries are maintenance free, provide good electrical reliability, and are lighter than the flooded lead acid type (which I’ll mention in a moment). They stand up well to low temperatures and have a low self-discharge, but the major advantages are a charge that is up to five times faster than the flooded version, and the ability to deep cycle without ruining the battery. AGM batteries offers a depth-of-discharge (DoD) of 80 percent, while flooded batteries are specified at 50 percent DoD to attain the same cycle life.  The downsides are that they tend to be heavier/bigger per Amp-hour and higher costs than flooded batteries.

A flooded battery might be a cost- and weight-effective choice, looking something like this one: This battery would give 150 Amp-hours at 12 Volts DC, but with a smaller, lighter battery.  The downside of this battery is that you have to make sure the battery is topped up with distilled water, as it will off-gas explosive hydrogen gas and other corrosive gases (so it has to be placed in a vented compartment). You can get around some of the work of topping your battery(ies) up with an automatic system like this one which makes it a simple job with a a hand pump to fill once you install the hose to each of the cells of the battery(ies).

Another problem with flooded batteries is that a full discharge (50%) causes strain on the battery, and each discharge/charge cycle permanently robs the battery of a small amount of capacity (Unnoticable at first, but each subsequent discharge takes more capacity from the battery). Most of the flooded types will have a life of about 200-300 cycles, while the Lifeline batteries that we got are rated for 1000 cycles.

When it comes to cold weather, AGM batteries have another couple of advantages over flooded batteries in that they are much more likely to survive a freeze intact, and loose less of their charge over the same length of time.  This last is probably the most important of the two, as the trick to keeping a battery healthy over cold weather is keeping it charged.

As the weather gets colder, the effective Amp-hours in a battery drops, while at the same time, its voltage capacity rises.  This means that your charger has to be able to cope with this.  There are a number of ‘Smart Chargers’ out there, like these: 

or as units built into converters like this

The thing about these ‘smart’ chargers is that they will automatically detect the charge that your battery has and adjust their output to give your battery what it needs, from ‘bulk charging’ (up to almost 90% charge) through the ‘absorption charge’ (to charge the last 10-15% of the battery) to ‘float charging’ (which keeps the battery full at a constant lower voltage) and even the maintenance cycle of ‘equalizing’ charging (which highly charges the battery to prolong the battery life by removing sulfur from the plates).  A regular charger like you might have in the garage for your  car generally has settings for either a ‘starting charge’ (lots of amps you use to try and get the car started with a dead battery), a ‘bulk charge’ (To bring the battery to a full or near full charge), and a ‘float charge’ (to keep the battery full), though it doesn’t pay any attention to the battery that it’s connected to and continues to do what the switch is selected to, which can easily over-charge a battery and leave you with sulfur corroded plates.

Some people winterize their system by removing the batteries from their RV/campers, and keeping them warm. This is a perfectly acceptable way to winterize, but for batteries with larger Amp-hour capacities (and especially those that are heavier AGM batteries or built into specialized compartments) this can be a lot of work. You still have to remember to keep the batteries charged, or you might lose a cycle of life through discharge as they sit.  Also, if you have the flooded batteries, taking them out is a great time to top them up, and pay more attention to keeping them charged, as they’ll discharge faster than the AGMs.

Also, if you’ve heard that you can’t store your batteries on concrete over winter, as long as your batteries are in a plastic case, you can disregard it.  This adage comes from the time when batteries were produced in wooden cases, and the wet wood sitting on the porous concrete meant that the concrete would slowly leach away the water from your battery.  The only concern with modern batteries is if you can get your fingers underneath to lift them back into their places so you can get going again in the warmer times of the year.