Sooner or later, that battery in your Honda CH250 will need 
replacement. What's the best replacement type battery for your scooter? What is ampere hours and why should I care? Is it worth the extra money to install a maintenance free battery? What is AGM type batteries? Here’s a guide.

The original equipment battery that came on your 1985-90 Honda CH250 was a wet type, conventional lead-acid battery. For the 1985-86 CH250, it was rated 12 volts, 12 ampere hours, and for 1987-90, it was rated 12 volt, 10 ampere hour. The battery ampere hour rating was reduced when the digital dash display was replaced with analog.

Motorcycle batteries are normally rated by their amp/hour (A/H) capacity, or cold-cranking amps (C.C.A.). The A/H figure is used in the advertising of car batteries as a months-of-life number, as in a 48-month or 60-month battery. The ampere/hour capacity is based on the total number of amperes the battery can supply in a 20 hour period of even withdrawal. Accordingly, a battery rated at 10 ampere/ hours can supply .5 amperes per hour for 20 hours. If more than .5 ampere per hour is taken from the battery, it will 
not even supply its 10 ampere/ hour rating.

The cold-cranking amp (C.C.A.) rating indicates how many amps a battery can pass in 30 seconds at 0º Fahrenheit and is probably a big bench racing topic among snowmobile pilots. Actually, cold weather works a double hardship on your battery. Not only is your cold bike's engine oil thicker and harder to turn, but the battery loses power as well. A fully charged battery is only 65% as strong at 32º as it was at 80º, and at zero, it drops to only 40% capacity.

The proper trickle-charging rate for a motorcycle battery is one-tenth of the A/H rating for as long as 10 hours, depending on how discharged it is. Charging faster than 2.0-2.5 amps causes overheating which can warp and even melt the battery case if ignored. High-rate charging also speeds up internal corrosion, and its visible sign is sediment buildup under the cells, which if it reaches high enough, will also permanently short out the battery. Too high a charging rate can also result in a battery that does not hold a 
charge because too-rapid transformation of the lead sulfate may actually trap sulfate under a surface coating of rejuvenated lead, producing a battery that can test okay but fails quickly. Thankfully, this last effect can be reversed with a very slow charge of no more than 1/20 (yes, that's one-twentieth) of rated capacity for 25 to 30 hours.

Therefore, because we really don't want a powerful charger, a good battery charger for most purposes is the inexpensive low-output type. Typically selling for around $20, the so-called "trickle chargers" usually produce no more than 1.2 amps. They often incorporate a solid-state feedback circuit that will taper the charge down to even lower levels as the battery voltage comes back up, preventing overcharging. Most convenient are the quick-connect type that provide a pigtail connector that can be permanently 
attached to the battery. The trickle charger will also work on your car battery, but even more slowly, and produces the same battery-friendly results.

Other factors, which reduce the available ampere hours, are battery age, ambient low temperature, and state of charge. Considering some or all of these factors, we rarely have 100% of a battery’s rated capacity available. To compensate, we should consider only 75% of the rated capacity to be available. For most of our CH250s, in general use, a 10 ampere hour battery is sufficient.

Conventional ‘wet” battery vs. Sealed-maintenance-free.

Conventional lead acid batteries come dry from the factory. The dealer or owner adds electrolyte (acid) at the point of installation. The battery is charged for 12 hours until the rated battery capacity is attained and then the battery is installed. The advantages of this type of battery is that it is shipped dry so when energized it is “fresh”. Also, cost is 
relatively low. Most people don't check their conventional battery's water level on a 
regular basis, and as the electrolyte level in the battery goes down, Sulfation begins, which will dramatically shorten a conventional battery's life. If you ‘overcharge” a conventional type battery, excess electrolyte will escape through the fill caps or the overflow tube.

Sealed-maintenance-free batteries offer the scooterist, obvious advantages and long term value over lesser quality conventional batteries. Most sealed batteries today offer Absorbed Glass Mat technology (AGM for short). This design dramatically improves a battery's performance in the following areas:

A) True sealed and maintenance-free design, means you'll never have to check or add electrolyte again, unlike conventional batteries which require periodic fluid checks.

B) Liquid-free AGM design, will not leak or corrode on expensive paint and chrome, and also eliminates corrosion around the battery terminals.

C) AGM batteries have less internal resistance which allows them to produce more discharge current (cold cranking amperage) vs. comparable conventional "wet" batteries, and AGM batteries also recharge faster.

D) Better resistance to both heat and vibration, a major cause of failure in conventional motorcycle batteries.

E) Much slower self-discharge rate, (3% vs. 15% per month) means longer periods between battery recharging over periods of non-use, like winter months or vacations.

(F) AGM batteries eliminate water loss due to heat and evaporation. Also the AGM battery's "Tight pack" lead calcium construction provides better resistance to vibration, there- by
increasing its service life.

(G) AGM motorcycle batteries can use the same low amp battery chargers that conventional motorcycle batteries use. Recommended is a 1-2 amp "Smart" style charger, which will charge only to a certain point then taper down and maintain the battery safely for long periods. The AGM design incorporates special safety valves in the battery case, which are designed to prevent pressure build up inside the battery during periods of excess over charging.

(H) The AGM battery has more reserve cranking power due to its efficient design. There is less internal resistance from one plate to another, allowing for faster current discharge to reach the battery's terminals, i.e. more cold cranking amperage.

Another sealed type of battery is the gel battery. Sealed VRLA (Valve Regulated Lead-Acid) Gel Cell batteries use GRT (Recombinant Gas Technology) and use a thickening agent like fumed silica gel to immobile the electrolyte instead of a liquid electrolyte like the wet batteries. They have a lot of the same advantages of AGM batteries. When comparing Gel Cell to AGM, Gel Cells will typically have:

(A) Greater ability to withstand a deep discharge, but not temperatures over 100°F (37.8° C) because of the possibility of "thermal runaway".

(B) 10 to 15 cycle preconditioning or "break-in" period.

(C) Less Cold Cranking Amps.

(D) 80% of the capacity of a similar sized AGM battery and physically larger.

(E) Slower recharging times and intolerant of higher charging voltages.

(F) Lower capacity in cold temperatures. (G)* Up to 20% more life cycles.

(G) Costs more to manufacture.

(H) Charging losses of 4% and maximum continuous discharge rate 25% of their capacity.

The OEM battery on the Honda CH250 is the YT12-12. It’s dimensions are (5-1/8Hx3-1/4Wx5-3/4L). It was rated at 170 CCA (cold cranking amps). The replacement battery today may be the Yuasa YTX12-BS, CTX12-BS, or GTX12-BS. The Deka AGM ETX-12 is also a highly recommended replacement battery.

Randy Pozzi (Rev. 03/2005)